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Aquafabanın yanıt-yüzey metodolojisi ile optimizasyonu ve bitkisel bazlı mayonez üretiminde kullanımı

(Lisansüstü Eğitim Enstitüsü, 2023-02-21) Büker, Mine ; Karaça Can, Aslı ; 506201518 ; Gıda Mühendisliği

Aquafaba nohut gibi baklagillerin haşlama işlemi sonrasında tanelerin ayrılması ile elde edilen sıvı olarak adlandırılmaktadır. Yapısında bulunan protein ve karbonhidrat bileşenleri sayesinde köpük ve emülsiyon oluşturma özellikleri bulunmaktadır. Bu özellikleri sebebiyle aquafaba günümüzde vegan ürünler geliştirilirken yumurta alternatifi olarak kullanılma potansiyeli olan bir hammaddedir. Aquafabanın yumurtasız mayonez, mousse, mereng, dondurma, emülsifiye soslar, kokteyller ve fırıncılık ürünlerinde kullanılabilme potansiyeli yüksektir. Çorba ve keklerde emülsiyon, ekmek ve dondurmada su tutma kapasitesi ve tatlılarda yağ tutma kapasitesi sağlaması amacıyla bu tip ürünlerde aquafaba kullanılmaktadır. Aquafabanın fonksiyonel ve kimyasal özellikleri üretim koşullarına göre farklılık göstermektedir. Nohut-su oranı, süre, sıcaklık, pH, ilave edilen katkı maddeleri gibi parametreler aquafabanın bileşimini ve özelliklerini doğrudan etkilemektedir. Bu çalışma aquafabanın köpük oluşturma ve emülsifiye etme özelliklerini iyileştirmek için gereken proses koşullarını Yanıt-Yüzey Metodolojisi kullanılarak optimize etmeyi amaçlamaktadır. Bu kapsamda belirlenen koşullarda deney tasarımı oluşturularak aquafabanın fonksiyonel özellikleri incelenmiştir. Aquafaba numuneleri katı-sıvı oranı 0,20, 0,225 ve 0,25, haşlama süresi 60, 70 ve 80 dk olacak şekilde üretilmiştir. Aquafaba numunelerinin deney tasarımında belirlenen pH değerleri aquafabanın sıcaklığı 20°C'ye düştükten sonra sitrik asit ve trisodyum sitrat çözeltileri ilave edilerek 2, 4 ve 6'ya ayarlanmıştır. Deney tasarımına göre hazırlanan aquafaba örneklerinin °Brix, pH, köpük oluşturma kapasitesi, köpük stabilitesi ve emülsiyon aktivite indeksi değerleri ölçülmüştür. Elde edilen örneklerin °Brix değerleri 1,3-2,2 arasında değerler alırken ilk pH değerleri 6,0-6,1 arasında değişmiştir. Köpük oluşturma kapasitesi ve köpük stabilitesi incelendiğinde pH değeri 4 olan örneklerin köpük oluşturma özellikleri diğer örneklere göre daha iyi sonuç vermiştir. En yüksek köpük oluşturma kapasitesi ve köpük stabilitesi pH 4 olarak ayarlanan örneklerde kaydedilmiştir. Köpük oluşturma kapasitesi %58,5 -74,5 arasında değişirken; köpük stabilitesi % 4,5-83,8 arasında değerler almıştır. Emülsiyon aktivite indeksi köpük özelliklerinin aksine daha düşük pH seviyelerinde daha iyi sonuçlar kaydedilmiştir Emülsiyon aktivite indeksi ise % 96,8- 99,1 arasında değişmiştir. Katı-sıvı oranının emülsiyon aktivite indeksini önemli düzeyde etkilediği görülmüştür (p<0,05). Deney tasarımı ile elde edilen örneklere uygulanan analizler sonucunda optimum koşullarda bir örnek üretilmiş olup; validasyonu yapılmıştır. Yapılan optimizasyon sonucuna göre bu deney tasarımında pH 3,58, süre 80 dk ve katı-sıvı oranı 0,25 olduğunda optimum koşulların sağlandığı sonucuna ulaşılmıştır. Optimize koşullar ile üretilen örnek ile bitkisel kaynaklı bir mayonez üretilmiştir. Üretilen bu mayonez ticari olarak satılan standart ve vegan mayonez ile karşılaştırılmıştır. Mayonez örneklerinin pH, °Brix, asitlik, kıvam, raf ömrü ve ısı stabilitesi özellikleri incelenmiştir. Bunlara ek olarak duyusal analiz ile ürünler panelistler tarafından değerlendirilmiştir. Mayonez örneklerinin kimyasal özellikleri incelendiğinde aquafaba ile üretilen üründe °Brix ve kıvam değerleri daha düşük olarak ölçülmüştür. Bunun sebebi kullanılan formülasyonlar arasındaki farklılıklardır. Mayonez örneklerinin ısıl stabilitesi incelendiğinde 30 dk sonunda aquafaba içeren mayonez ve piyasadan temin edilen vegan mayonezde herhangi bir değişim gözlenmemiştir. Fakat piyasadan temin edilen standart mayonez örneğinde yağ fazının ayrılmaya başladığı ve örnek yüzeyinde sıvı birikmeye başladığı dikkat çekmiştir. Piyasadan temin edilen standart mayonezin ısıl stabilitesi bu çalışma kapsamında üretilen ve piyasadan ticari olarak temin edilen mayoneze göre daha düşük olduğu gözlemlenmiştir. Duyusal analiz sırasında panelistlerden hem demografik sorular içeren; hem de parametreleri puanlayabilecekleri bir form doldurmaları istenmiştir. Duyusal analiz sonucu elde edilen veriler incelendiğinde tüketicilerin %85'i "Bu ürünü satın alır mısınız?" sorusuna "Satın alırım" şeklinde yanıt vermiştir. Panelistlerden gelen yorumlara göre yapılan değerlendirmede piyasadan temin edilen vegan mayonezin ağızda yağlı ve yapay bir tat bıraktığı yönünde yorumlar iletilmiştir. Bu çalışma kapsamında üretilen mayonez için ise için 'Zayıf, ağızda çok çabuk kayboluyor' şeklinde geri dönüşler alınmıştır. Aquafabalı mayonezin renk olarak da geliştirilmeye ihtiyacı olduğu panelistler tarafından vurgulanmıştır. Ürünlerin genel kabul edilebilirliği incelendiğinde en düşük puanı vegan olan ticari ürün almıştır. Aquafabalı ürün hakkında gelen yorumlar incelendiğinde beklenildiği gibi yabancı tadın yoğun hissedilmediği ve düşünülene göre çok daha iyi olduğu ile ilgili yorumlar panelistler tarafından ek olarak iletilmiştir. Aqufabalı ürünün stabilitesi hakkında bilgi sahibi olabilmek için raf ömrü testi yapılmıştır. Bu analizde aquafaba ile üretilen mayonez örneği 5 gün boyunca 37°C'de depolanmıştır. Sürenin sonunda ürün incelendiğinde duyusal özelliklerin önemli ölçüde değiştiği, asitliğin yükseldiği gözlemlenmiştir. Yapılan bu teste göre 5 günün sonunda ürün kalitesinde kabul edilemez ölçüde düşüş meydana gelmiştir. Sonuç olarak aquafanın özellikleri pH, süre ve katı-sıvı oranına göre değişkenlik göstermiştir. Aquafabanın üretim koşulları optimize edilerek istenmeyen yabancı tadı baskılamak ve fonksiyonel özelliklerini geliştirmek mümkündür. Yabancı tat azaldığı durumlarda aquafabanın farklı ürünlerde kullanımı daha kolay olurken; aynı zamanda tüketiciler tarafından da daha kabul edilebilir ürünler elde etmek mümkündür. Bu çalışma kapsamında aquafaba bitkisel bazlı mayonez formülasyonunda başarılı şekilde kullanılmıştır. Fakat yapılan raf ömrü testi sonuçları gözlemlendiğinde ürün stabilitesinin düşük olduğu görülmüştür; bu nedenle ürünün raf ömrünün uzatılmasına ihtiyaç vardır.
Bakladan ultrases destekli alkali ekstraksiyon ile protein eldesi: Teknofonksiyonel, in vitro biyoerişebilirlik ve ade inhibisyon özelliklerinin incelenmesi

(Lisansüstü Eğitim Enstitüsü, 2022-05-30) Mertdinç, Zehra ; Özçelik, Beraat ; 506181516 ; Gıda Mühendisliği

Son yıllarda nüfus artışı, gıda kaynaklarının tükenmesi, iklim değişikliği ve hayvan hakları gibi birçok sebepten dolayı hayvansal gıda kaynaklarına alternatifler aranmaya başlamıştır. Bitkisel diyetlerin çevresel ve ekonomik katkılarının yanı sıra, kardiyovasküler hastalıklar, Tip-2 diyabet, obezite ve hipertansiyon gibi hastalıkların önlenmesinde de etkili olduğu bilinmektedir. Bakla, ülkemizde genellikle Ege, Marmara ve Akdeniz bölgelerinde üretimi yapılan, besleyici değeri yüksek ve biyoaktif bileşenler açısından zengin bir bitkisel protein kaynağıdır. Gıdaların besleyici ve fonksiyonel özelliklerinin geliştirilmesi için bakliyatlardan protein konsantresi/izolatı elde edilmektedir. Bu amaçla, özellikle alkali ekstraksiyon ve izoelektrik noktada çöktürme metodu sıklıkla kullanılan yöntemlerden biridir. Aynı zamanda bu yöntemler, ultrases, mikrodalga ve enzim destekli uygulamalar ile daha verimli hale getirilmektedir. Elde edilen proteinlerin, gıda matrisinde uygulamaları, depolanması ve işlenmesi noktasında teknofonksiyonel özelliklerinin (su/yağ tutma, köpürme kapasitesi/stabilitesi, çözünürlük gibi) incelenmesi gerekmektedir. Bu çalışmada da İzmir'de yetiştirilmiş bir bakla türünden alkali ekstraksiyon ve alkali ekstraksiyon öncesi ultrases uygulaması ile elde edilen protein konsantrelerinin teknofonksiyonel özellikleri incelenmiştir. Gıdalardan biyoaktif peptilerin eldesinde pepsin, alkalaz, tripsin gibi enzimler kullanılarak hidrolizasyonu gerçekleştirilebilir. Elde edilen hidrolizatlar, aminoasit dizilimleri, büyüklükleri ve bazı fizikokimyasal özelliklerine bağlı olarak anti-hipertansif, anti-oksidan ve anti-mikrobiyal etki gösterebilirler. Aynı zamanda hidrolize uğrayan peptitlerin insan vücudunda in vitro gastrointestinal sindirimin ardından biyoerişilebilirlikleri de etkilenmektedir. Bu çalışmada da alkali ve ultrases destekli alkali ekstraksiyonla elde edilen protein konsantrelerine pepsin ile enzimatik hidrolizasyon uygulanmış, ardından elde edilen hidrolizatlarda da in vitro protein biyoerişilebilirliği ve anti-hipertansif etkisinin belirlenmesi amacıyla ADE inhibisyon analizi uygulanmıştır. Bu çalışmada elde edilen sonuçlara göre, %27,32 protein miktarına sahip olan bakla unundan, alkali ve ultrases destekli alkali ekstraksiyonla sırasıyla %65,93 ve %75,04 protein içeriğine sahip konsantratlar elde edilmiştir. Ekstraktların teknofonksiyonel içerikleri de incelendiğinde, alkali ve ultrases destekli uygulamalar sonucunda ekstraktlarda protein çözünürlüğü, su ve yağ tutma kapasiteleri, köpürme stabiliteleri gibi özellikleri geliştirilmiş olup, çoğu uygulamada da ultrases uygulamasının alkali konsantrelerden istatistiksel olarak anlamlı bir farklılık gösterdiği tespit edilmiştir. Ayrıca hammadde, ekstraktlar ve enzimatik yöntemlerle elde edilen hidrolizatların, in vitro gastrointestinal sindirim sonrasındaki protein biyoerişilebilirlikleri incelenmiştir. Bu çalışmada da en yüksek protein biyoerişilebilirliği %46,39 ile ultrases destekli hidrolizatlarda tespit edilmiştir. Öte yandan, hidrolizatlarda ADE inhibisyon değerleri hesaplanarak baklanın potansiyel anti-hipertansif etkisi incelenmiştir. Analizler sonunda sırasıyla alkali ve ultrases yöntemlerinden elde edilen hidrolizatların IC50 değerleri 504,42 ve 222,89 μg/ml olarak hesaplanmıştır. Elde edilen sonuçlar göstermiştir ki, ultrases uygulaması ile ADE inhibisyon aktivitesinin arttığı gözlemlenmiştir. Özetle, bu çalışma ile Türkiye'ye özgü bir bakla türünden iki farklı yöntemle ekstrakte edilen proteinlerin teknofonksiyonel özellikleri tanımlanmış olup, enzimatik hidrolizasyonu ile de in vitro biyoerişilebilirlik ve ADE inhibisyon potansiyelleri incelenmiştir. Sonuç olarak, ultrases teknolojisinin, proteinlerin bazı teknofonksiyonel özellikleri, protein biyoerişilebilirliği ve anti-hipertansif etkileri üzerindeki olumlu etkileri incelenmiş ve gıda uygulamalarındaki potansiyeline dair bir bakış açısı geliştirilmesi hedeflenmiştir.
Bioactive components and protein content in black carrot leaves

(Graduate School, 2024-07-08) Çambel, Hatice ; Karıncaoğlu Kahveci, Derya ; 506211517 ; Food Engineering

Black carrot leaves are considered food waste, even though they may be a multifunctional food commodity. Black carrot leaves contain various bioactive compounds such as phenolics, flavonoids, and proteins, making them a valuable resource for multiple applications in the food industry. In this study, black carrot leaves (BCL) were cold pressed, and 357.47± 40.17 g BCL cold-pressed resulted in 159.51± 14.03 g pulp and 176.50± 28.79 g leaf juice. So, the yield was calculated as 49.22± 4.47 % g leaf juice/ g leaves. The obtained leaf juice was analyzed for TPC (total phenolic content), TFC (Total flavonoid content), CUPRAC (Antioxidant capacity), and DPPH (Antioxidant capacity measurement) analyses by using spectrophotometric methods. The measurements were recorded as 1.912± 0.209 mg Gallic Acid/ g BCL, 2.914± 0.592 mg Quercetin/ g, 6.586± 0.882 mg Trolox/ g BCL, and 0.273± 0.166 mg Trolox/ g BCL, respectively. Subsequently, the protein content in the juice was precipitated by two different methods: acid treatment and heat treatment. The protein yield was calculated as 0.0020± 0.0004 g protein per g BCL via acid-treatment. The protein yield was calculated as 0.0011± 0.0003 g protein per g BCL via heat treatment. The protein content in BCL was determined by the Kjeldahl method. Due to sustainability concerns, the heat-treatment method was chosen in the following steps. The proteins extracted via heat treatment were subjected to in vitro digestion, employing a laboratory setup mimicking the human gastrointestinal tract without symbiotic bacteria in the intestine. This simulation demonstrated that human digestive enzymes can break down Black Carrot Leaves (BCL) proteins, and the Bradford assay examined the results. Moreover, techno-functional properties critical for food and selecting the place to use it were examined. These are water-holding capacity, oil-holding capacity, emulsifying activity and stability, solubility, and foam capacity and stability properties. As a result, the water holding capacity is 4.62± 0.31 g water/ g Pdry, and the oil holding capacity is 5.38± 0.225 g corn oil/ g Pdry. On the other hand, Emulsifying Activity Index (EAI) and Emulsifying Stability Index (ESI) values were examined according to different pH values. EAI increases with increasing pH and reaches its highest value at pH 12. ESI gives very different low or high values with very little pH change. When the solubility was examined as a percentage, it was observed that it increased and as it approached neutral (pH = 7). And, the solubility reached the maximum at pH 12. Foam capacity (FC) and foam stability (FS) values were found to be 0.0516± 0.037% and 33.53± 18.27%, respectively. The evaluation of the antioxidant capacity of BCL, the extraction of protein, and the evaluation of techno-functional properties of BCL, which were commonly considered food waste post-harvest, hold significant importance from a sustainability point of view. Understanding the composition of BCL and its potential applications can contribute to minimizing food waste and exploring sustainable alternatives across multiple sectors.
Biological control of Aspergillus flavus growth and its aflatoxin b1 production by antagonistic yeasts

(Graduate School, 2022-06-29) Dikmetaş, Dilara Nur ; Güler Karbancıoğlu, Funda ; Özer, Hayrettin ; 506181504 ; Food Engineering

The presence of mycotoxins in food and feed poses a risk to human health and animal productivity and result large economic losses. In the field and during storage period, Aspergillus flavus infect grains. Aflatoxin B1, is classified as group 1 carcinogen, having hepatotoxic, genotoxic, and teratogenic properties, may be produced by generally A. flavus and Aspergillus parasiticus in addition to grain deterioration and yield loss. Aflatoxins have been found in a variety of foods including oilseeds, nuts, dried figs and spices. Dried figs, pistachios, hazelnuts and groundnuts cultivated in Turkey are risky products in terms of aflatoxins. The application of synthetic fungicides is the most common method for controlling decay in most crops. However, because of the fungal resistance and detrimental impacts on human and animal health, as well as the environmental concerns in general, their use is being tried to diminished. Due to these concerns, researchers have tended to investigate more eco-friendly and healthy methods to manage fungal diseases. As a result, detecting and preventing Aspergillus species contamination, as well as lowering the level of aflatoxins in foodstuffs used in many agricultural products. To reduce usage of synthetic fungicide, biological control is an important strategy as a promising alternative with low environmental impact in reducing fungal infection and mycotoxin production in the field and during postharvest period. In addition, among microorganisms, yeast species have been extensively studied as antagonist due to simple nutritional requirements, able to colonize dry surfaces for long periods of time and able to grow rapidly in bioreactors with inexpensive substrates. Furthermore, yeast is simply adapted to microenvironments. The crucial and most important step is to develop biocontrol agent is isolation and screening of yeast isolates. Antagonistic yeasts have been showed several different mechanism to control of different moulds such as competition for space and nutrients, biofilm formation, parasitism, production of antimicrobial volatile organic compounds and production of lytic enzymes. The antagonist mechanism generally explained with cell wall-degrading enzyme synthesis including chitinases, β-1,3-glucanase, protease, cellulase and pectinase. Yeasts with high cell wall degrading enzyme activity, also showed high biocontrol efficacy. Biocontrol of aflatoxin has been generally documented by non-aflatoxigenic Aspergillus species. However, the studies to control Aspergillus flavus by yeasts limited. In various industrial processes, the Metschnikowia yeast has wide range of biotechnological application and generally isolated from fruits and flowers. Several Metschnikowia based biocontrol products have been industrialized to control postharvest diseases including Botrytis or Monilinia spp. However, only a few biocontrol agents are converted into industrial products. Meyerozyma, Moesziomyces and Metschnikowia sp. yeasts antifungal activity have been studied by several researchers. Among antagonistic microorganism mechanism of action, production of antimicrobial volatile organic compounds is one of the least studied. Primarily, volatile organic compounds produced by antagonistic yeasts have great potential used as biocontrol agents of filamentous fungi. In this study, four yeast isolates have been isolated and identified by different plant parts including hawthorn, hoşkıran, bean and grape leaf collected from Turkey different region. Four previously isolated and identified isolates from grapes, blueberry have been also included in this study. The eight antagonistic yeasts have been belong to Moesziomyces sp., Meyerozyma sp. and Metschnikowia sp. Yeasts secrete fungal lytic enzymes which are typically associated with biocontrol mechanism. Lytic enzyme activities of yeasts were examined with screening method. All of the isolates have β-glucosidase and chitinase activity, which are crucial for antifungal mechanism, however absence of the pectinase activity. Among antagonistic yeasts, only Metschnikowia pulcherrima (26-BMD) found as protease negative. Dual culture assay have been conducted to observe antagonistic effect of yeasts against aflatoxin B1 producer Aspergillus flavus. All of the antagonistic yeasts formed inhibition zones in dual culture assay against to Aspergillus flavus due to secretion of diffusible antifungal compounds. After that, yeasts antifungal and antiaflatoxigenic impact on aflatoxin producer Aspergillus flavus by spot inoculation method with different incubation period by in vitro studies. Different yeasts used to investigate to control Aspergillus flavus growth. In addition to that, origin of the yeast affect their biocontrol efficacy. All of the antagonistic yeasts formed inhibition zones in dual culture assay against to Aspergillus flavus due to secretion of diffusible antifungal compounds. While Aspergillus flavus mycelial growth of inhibition 86-97% after three days. All isolated and identified yeasts were effective to control Aspergillus flavus, as well as aflatoxin. Aflatoxin B1 production was reduced from 1773 ng/g (in control samples) to 1.26-10.15 ng/g with the application of antagonistic yeast. Metschnikowia aff. pulcherrima (32-AMM) was found as the most effective yeasts to inhibit mycelial growth of Aspergillus flavus among other yeasts. In addition, yeasts plant origin and incubation period also affect their inhibition potential (p<0.05). All of the yeasts might be used as biocontrol agent against Aspergillus flavus growth. Additionally, all of the yeast volatile organic compounds (VOCs) reduced sporulation however among antagonistic yeasts only Moesziomyces bullatus (DN-FY), Metschnikowia aff. pulcherrima (DN-MP) and Metschnikowia aff. pulcherrima (32-AMM) were reduced Aspergillus flavus mycelial growth with in vitro studies. But only VOCs produced by Metschnikowia aff. fructicola (1-UDM) was also found effective in reduction of Aflatoxin B1 production in in vitro experiments. This activity was associated to different volatile organic compounds. As a result, more investigation into the role of volatile organic compounds in Aspergillus flavus and aflatoxin B1 control is required. Further field experiments would indicate yeasts biocontrol potential on the products prone to contaminated from Aspergillus flavus. By the way, also isolation of volatile organic compounds from yeasts should be used to protect products from contamination without harmless to humans and environmentally friendly.
DBUVC ve UVCLED ışınlamanın kiraz ve vişne yüzeyinde mikrobiyel inaktivasyona ve meyve kalite özelliklerine etkisi

(Lisansüstü Eğitim Enstitüsü, 2022-04-21) Bilgin, Ayşenur Betül ; Akocak Başaran, Pervin ; 506181502 ; Gıda Mühendisliği

Ultraviyole – C (UVC), fiziksel bir yöntem olan ve genellikle gıdalarda dezenfeksiyon amaçlı kullanılan mor ötesi ışıktır. Son yıllarda, geleneksel düşük basınçlı UVC (DBUVC) lambaların ve son yıllarda yeni UVC kaynağı olarak kullanılan UVC – ışık yayan diyotların (light-emitting diodes, LED) (UVCLED) gıdalarda meyve ve sebze dezenfeksiyon çalışmaları yoğunluk kazanmıştır. Bu projede, UVC kaynağı olarak UVCLED ve DBUVC ışınlanmasıyla kiraz ve vişne yüzeyinin dezenfeksiyonun sağlanması ve meyvelerin raf ömrünün arttırılması hedeflenmiştir. Kiraz ve vişne yüzeyine daldırma ve spreyleme yöntemi ile Pseudomonas syringae, meyveden izole edilen maya inoküle edilmiştir. Meyve yüzeyinde doğal olarak bulunan toplam aerobik mezofilik bakteri (TAMB), toplam küf ve maya (TKF) ve inoküle edilen mikroorganizmalar hedeflenerek meyve yüzeyi 30 saniye, 3 ve 10 dakika UVCLED (200 – 260 nm) ve DBUVC (253,7 nm) ile ışınlanmıştır. Her iki UVC lamba ile ışınlanmış meyveler, 25-28˚C (%40-60 nem)'de ve +4˚C'de depolanarak mikroorganizmalardaki inaktivasyon etkisi periyodik olarak değerlendirilmiş ve ürünlerin raf ömrü incelenmiştir. Işınlama öncesi ve sonrası meyvelerde meydana gelen fizikokimyasal (meyve ağırlığı, pH, toplam çözünebilir katı madde miktarı, su aktivitesi, toplam fenolik madde miktarı, antioksidan aktivite ve renk) değişimler gözlenmiştir. Tüm bu sonuçlar ile UVCLED ve geleneksel DBUVC lambaların inaktivasyon etkinliği ve kalite üzerinde etkisi karşılaştırılmıştır. 3 ve 10 dakika DBUVC ışınlamanın, UVCLED'e göre, 30 saniye UVCLED ışınlamanın ise DBUVC'ye göre daha etkili olduğu tespit edilmiştir. Toplamda tüm sürelerde ve mikroorganizmalarda en düşük ve en yüksek inaktivasyon UVCLED ışınlama ile 0,31 – 0,86 kob/g, DBUVC ile 0,11 – 1,56 kob/g olarak gerçekleşmiştir. Hem kiraz hem de vişnede ışınlama öncesi ve sonrası toplam ağırlık, su aktivitesi, pH, toplam çözünür katı madde miktarı ve renk değerlerinde (L*, a*, b* ve H˚) önemli bir farklılık bulunmamıştır (p > 0,05). Vişnede UVCLED ışınlama ile fark edilebilir düzeyde (∆EUVCLED* = 1,17 – 3,30) renk değişimi tespit edilmiştir. Toplam fenolik madde ve antioksidan madde miktarında çoğunlukla önemli bir artış gözlemlenmiştir (p < 0,05). Işınlanmış meyvelerin +4 ve 25˚C'de depolanmasıyla raf ömrünün ortalama %30 oranında arttığı tespit edilmiştir. Sonuç olarak; DBUVC, UVCLED ışınlamaya göre genel olarak mikroorganizma inaktivasyonunda daha etkili olduğu, antioksidan aktivitesi ve toplam fenolik madde miktarının artması dışında meyvelerin fizikokimyasal özelliklerinde önemli bir etkisinin bulunmadığı tespit edilmiştir.
Development of pea protein agar based biodegradable film with the incorporation of essential oils

(Graduate School, 2022) Ozhan, Selin ; Yeşilçubuk Şahin, Neşe ; Saygun, Ayşe ; 725922 ; Food Engineering Programme

In recent years, there is an increased awareness of sustainability in the world. People are looking for more sustainable solutions in packaging the industry since it is seen as one of the most polluting agents in the environment. Edible films and coatings are alternatives to reduce plastic packaging usage in the food industry. While it has an advantage for being sustainable, it also provides a good barrier, sensory, and quality properties in the foods. This study aimed to investigate the characterization of pea protein and agar edible film and then add essential oils to increase the antimicrobial effect of the edible film. For this purpose, 4 different essential oils are used; eucalyptus, thyme, lemon and niaouli in 1%, 2%, 3%, 4% and 5% (v/v) concentrations. Edible films are produced by using the solvent casting method. As the first step of this study, different film-forming materials were investigated and prepared in the laboratory to observe their edible film-forming capability. According to the results, pea protein and agar were chosen as the main edible film materials because they can form flexible and transparent films. Furthermore, essential oils were researched in the literature. The proper essential oil combination with edible films and the concentration were investigated. Thyme, eucalyptus, niaouli, and lemon oil were chosen because of their high antimicrobial activities and being capable to incorporate with edible films. After the decision of main materials, the pea protein and agar films were produced and thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) was checked to understand the characterization of the main film. After the addition of essential oils, swelling analysis, antimicrobial activity, and color analysis were done. TGA indicates the weight decrease of the film due to the water, volatiles, and plasticizer losses during the analysis. In DSC analysis, the Tg value is observed as 73℃. Since the pea protein and agar film seems flexible structure at room temperature, having a higher Tg value than room temperature may show that it is not mechanically strong for processing and it will be in more rubbery and softer structure at the higher temperatures. Lastly, DMA analysis was unsuccessful due to the weak mechanical strength of the film. After essential oils addition to pea protein based film, antimicrobial activities of essential oil incorporated edible films were analyzed. Based on the results, swelling and color analysis were conducted for the films that showed antimicrobial effect and also 5% oil concentration. For antimicrobial analysis, the agar disc diffusion method was used and essential oil incorporated film's antimicrobial activity was investigated against Escherichia coli, Staphylococcus aureus, and Aspergillus niger. According to the results, 1% addition of essential oil to the edible film did not show any antimicrobial effect against any of the microorganisms. In 2% essential oil addition, thyme and niaouli oil started to show antimicrobial effects against gram (+) and Gram (-) bacteria. After 3% addition of thyme oil, antimicrobial effects were observed against both bacteria and fungus. In bacteria, there is no direct correlation between the concentration of essential oil and the antimicrobial zones in the Petri dishes. The largest zone which was 2.7 cm observed against E. coli is 3% thyme oil incorporated edible film, and the largest zone against S. aureus is from all 3%, 4%, and 5% thyme oil that all give 2.3 cm in one of the analysis. On the other hand, there was a direct correlation between the concentration of essential oil and the antimicrobial activity against fungus. In 5% thyme oil incorporated film, there was almost no growth in the Petri dishes however the growth of the fungus increases as the concentration of thyme oil decreases. Additionally, swelling analysis was conducted for 5% essential oil incorporated films and 2% niaouli, 2% thyme, 3% thyme, and 4% thyme incorporated films that show antimicrobial effects against bacteria. It is found that 5 ml thyme oil is the least absorbent one in the both water and saline water environment. In a saline water environment, it started to lose its weight from the first hour. Hence, it can be said that it is not suitable for salted food application or any salty environment. On the other hand, 2 ml niaouli oil incorporated edible film is seen as the most absorbent one in both environments. During the analysis, all edible films show some peaks in different time zones. The reason can depend on the oil concentrations and hydrophobicity rates. In terms of color analysis, the same samples were used for swelling analysis. According to the average of six repetitive measurements, 2 ml niaouli oil incorporated edible film gives the least yellowish color, and the 4 ml thyme oil incorporation of the film gives the most yellowish. The results are evaluated by using the b* parameter which provides the rate of yellow color on the materials. In conclusion, this study shows that pea protein and agar can yield an edible film, and when incorporates with the proper amount of thyme oil, it can show antimicrobial activity against gram-positive and gram-negative bacteria and fungus.
Effect of atmospheric non-thermal plasma against food-borne bacteria on food packaging film surfaces

(Graduate School, 2024-01-18) Doğanöz, Dilan ; Güler Karbancıoğlu, H. Funda ; 506211507 ; Food Engineering

Over the past decade, non-thermal plasma has become established as a potential technology for microbial inactivation. As commonly known, plasma treatment can produce highly specific surface modifications, so it has been extensively used in packaging. Methods such as heating, surface washing with hydrogen peroxide, irradiation, or their combinations, widely used for sterilization in the packaging industry, are known to have negative drawbacks. For instance, using chemicals or preservatives may cause residue problems, or high thermal processes may cause the loss of the desired structure of the food or package. Despite that, sterilization by non thermal plasma has several advantages: A highly energy-efficient system, eco environmental nature, low cost, and versatility. Vegetative and especially spore forming bacteria exhibit strong resistance to external factors such as environmental stress, chemicals, and thermal inactivation due to their intrinsic resistance, outer layers, and low water content. These characteristics make spores more difficult to kill than vegetative forms. In this study, the effect of atmospheric non-thermal plasma application on Gram positive Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 39327 and Clostridium sporogenes ATCC 3584 spores, which are among the important food pathogens, was compared in different packaging materials. Within the scope of the study, microbial inactivation at different exposure times and application types (wet or dry application) was investigated using dielectric barrier discharge (DBD) plasma and corona discharge plasma devices. Low-density polyethylene (LDPE), biaxially oriented polypropylene (bOPP), and polyethylene terephthalate (PET) were used as packaging materials. Each film (3×3 cm2) was initially treated with DBD with an electrode gap set to 3 mm for 0.4 seconds. The plasma power was high, with 100% voltage and minimum frequency set for all treatments. The test microorganisms were inoculated into the center of the 3x3cm2 DBD-treated film surface before corona NTP treatment. The corona NTP power was set at 25-27% voltage, low power, and minimum frequency. The inoculated films were exposed to cold plasma (with the setting of 1.5 cm electrode gap, ~17 kHz wet or dry application) at different application periods depending on microorganism. Exposure periods for S. aureus and P. aeruginosa were 60, 120, and 180s and for C. sporogenes was 0, 360, 540, and 720s. The results showed that non-thermal plasma had an antimicrobial effect for all microorganisms, and wet application, by adding 10 µL of sterile distilled water before exposure to plasma, enhanced the microbial inactivation effect. There was also a direct relationship between exposure time and microbial inhibition. A significant antimicrobial effect was observed only after longer exposures. Considering the results of dry corona plasma application of all microorganisms, the highest D-value belongs to C. sporogenes inoculated on the PET film surface with 94.81±31.56 min. In addition, it was statistically observed that C. sporogenes was the most resistant bacteria to corona treatment for all films (p <0.05). For S. aureus, after dry and wet corona plasma application, all films showed statistical similarity and wet corona application was more effective than dry application (p<0.05). Dry corona application were not performed for P. aeruginosa due to the lack of vitality on the surface after drying. Among vegetative bacteria, the Gram-negative bacterium P. aeruginosa showed higher microbial inactivation than the Gram-positive S. aureus. The most effective result for P. aeruginosa after wet corona plasma application is 1.99±0.03 min and 1.96±0.02 min, with no statistical difference between LDPE and PET films (p>0.05). The results obtained in this study have provided a new perspective on the surface sterilization of packaging materials used in the food industry with cold plasma application of DBD or corona discharge non-thermal plasma systems. In addition, compared to the currently used packaging surface sterilization methods, its disadvantages have been reduced, and an environmentally friendly, affordable system has emerged without the need for complex high/low-pressure systems or gas systems. Thanks to the atmospheric cold plasma devices used in the study, the effective and innovative plasma system design can be easily integrated into the industry without damaging the film surface by using O2 in the atmosphere without needing a pressurized environment or additional gas systems.
Effects of cold plasma treatment on the quality andantioxidant properties of mixed fruit juice

(Graduate School, 2023) Şahinoğlu, Ecre ; Gözükırmızı Kırkın, Celale ; 814088 ; Food Engineering Programme

In recent years, non-thermal processes have been used for food sterilization instead of thermal treatment methods. Cold plasma is an example of these new technologies. The fourth state of matter is called as plasma. Main plasma types are classified as cold and termal plasma. Cold plasma refers to plasma with a gas temperature below 1000 K. In this type of plasma, molecules, ions, and electrons are not thermodynamically in equilibrium due to its low temperature. The electron temperature ranges from 10^4-10^5K, while the ion temperature is approximately 25 °C. Cold plasma is applied at low pressure and low energy levels. On the other hand, thermal plasma refers to plasma with a gas temperature above 1000 K. It is used for the modification of heat-resistant inorganic materials due to its ability to reach high energy levels. Cold plasma can be applied at low energy levels, hence it is suitable for use in food applications. Food sterilization, packaging sterilization, surface disinfection of food, and enhancing seed germination speed obtained by plasma in different studies. The sterilization mechanism is achieved through reactive species released by plasma. It relies on the interaction between reactive components in the gas phase and microorganisms, leading to the disruption of their structure. Plasma is a mixture containing gases such as oxygen and nitrogen. When these gases are excited by plasma, reactive compounds generated such as free radicals and ions. These compounds can attach to the surfaces of microorganisms or react with their surroundings, causing damage to the cellular structure of microorganisms. Another inhibition mechanism is the destruction of microorganisms' genetic material by UV radiation and atomic erosion at the atomic level. This method can effectively play a role for inhibition of both vegetative cells and bacterial spores at ambient temperature and in a short time. Additionally, reactive compounds created by cold plasma can interact with microorganisms on the surface of food, leading to their inactivation. These interactions can disrupt the cellular membranes of microorganisms, denature their proteins, or render their enzymes inactive, as a result of this reactions product staling time can be longer. Various mechanisms are being used to generate cold plasma. One of the most commonly used mechanisms is Dielectric Barrier Discharge (DBD) which is having a dielectric material placed between two electrodes and applying an alternating electric voltage to these electrodes. The dielectric material interacts with the electric field, leading to the formation of plasma. Another system is microwave plasma, which generates plasma using microwave energy. Microwave energy is delivered to the plasma chamber through a resonator or waveguide. Microwave radiation stimulates gas molecules, resulting in plasma formation. Corona discharge is a mechanism in which an electrical discharge occurs between a high-voltage electrode and the ground, ionizing the electrical gap to create plasma. The electric field on the electrode ionizes the gas molecules, leading to plasma formation. High-frequency plasma involves applying high-frequency electric current between electrodes to trigger plasma formation. Radio frequency plasma is another mechanism that utilizes radio frequency energy to create plasma. A radio frequency electric voltage is applied between electrodes, resulting in plasma formation. In this study, DBD mechanism was used and plasma treatment was carried out using a pulsed DC power source at 40 kV (56 Hz, 10 mA) for 0 min (control) , 10 min, or 20 min. Its effects on mixed fruit juice was compared to pasteurized samples to observe differences in the quality properties of juice. The outputs of study submitted that cold plasma treatment has positive effects on the quality and antioxidant peculiarities of fruit juice. The color change in samples operated with plasma was barely noticeable compared to pasteurized samples. However, there was an impressive difference in color between pasteurized juice and the control sample. The Brix° values remained unchanged as 10.5 in both processes. The total acidity significantly decreased in the pasteurized sample but no significant difference was observed between the plasma-handled samples and the control sample (p>0.05).The total viable count was found to be extremely low (Log <2), indicating effective microbial reduction. Despite the inhibition observed, there was no significant decrease in mold and yeast counts during the plasma application (p>0.05). Nonetheless, a decrease in mold and yeast count was observed in the pasteurized sample compared to the control sample (p<0.05). It was concluded that cold plasma did not have an effect on the microbial count, but this can be improved by optimizing process parameters. The activity of antioxidant was evaluated using three different methods. No difference was observed according to the DPPH assay. The ABTS value decreased after the cold plasma treatment. The highest CUPRAC value was recorded after the 20 min treatment. The DPPH and CUPRAC values declined in the pasteurized samples compared to the cold plasma samples, but no significant difference was observed in the DPPH assay (p>0.05). The total phenolic content showed a slight decrease in the pasteurized sample compared to the cold plasma samples, but this distinction was not statistically important (p>0.05). The color properties of the fruit juice were recorded after both processes. In the pasteurized samples, a significant color change was observed compared to the plasma- samples. The total color difference was recorded as 20.86±1, while the ratio in the plasma-treated sample was 2.86±2.3, indicating that this color difference was too small to be noticeable. In conclusion, cold plasma process preserved the appearance, taste, and antioxidant properties of fruit juice compared to pasteurization. By optimizing process parameters for microbial inhibition, this method can be applied to fruit juice production.
Effects of dielectric barrier discharge cold plasma on the quality of dandelion root infusions

(Graduate School, 2023-06-20) Elçik, Berfin Ada ; Gözükırmızı Kırkın, Celale ; 506201526 ; Food Engineering

Since ancient times, humans have sought solutions to their illnesses from plants. In the past 30 years, consumers' dietary preferences and interest in healthy nutrition have significantly changed, leading to increased research on medicinal plants. The health effect of medicinal plants primarily stems from their rich sources of bioactive compounds and antioxidants. Taraxacum officinale, commonly known as dandelion, stands out due to its bioactive properties due to its bioactive compounds. The root of Taraxacum officinale, which often emerges as waste in the food industry, is an intriguing plant root due to its bioactive compounds. The compounds found in the root may exhibit antioxidant effects and help prevent cellular damage caused by oxidative stress. Before food products are commercialized, they need to undergo processing to minimize health risks, provide convenience and usability, enable long shelf life, reduce food waste, and offer variety. Traditional food processing methods that have been widely used since ancient times and they are temperature-dependent. However, heat-dependent conventional processing techniques can result in nutrient losses or physical demage in food. Cold plasma, charged and reactive gas molecules and these molecules inactivate harmful microorganisms which present in foods and food packaging materials, is a promising green and appropriate technique for heat-sensitive foods. This method can help preserv the bioactive compounds in foods. Currently, cold plasma (CP) technology is used for various purposes, including extraction of volatile oils, promotion of seed germination, modification of surface structures, inactivation of enzymes and microorganisms, and degradation of pesticides. Antioxidants are bioactive compounds that naturally found in foods and they can reduce the risk of various diseases. However, these most of the bioactive compounds are recognised as sensitive to thermal processing. DBD cold plasma processing will enable food processing without the loss of antioxidant capacity in food due to its operation at low temperatures. Understanding the interaction between plasma types and bioactive compounds is crucial to prevent nutrient degradation and other undesirable effects. Cold plasma is a form of plasma consisting of high-energy ions, electrons, free radicals, and other reactive molecules. This plasma can interact with bioactive compounds and alter their properties. While there are many studies in the literature on the antimicrobial effects of DBDCP application, research on improving the process efficiency is limited. This study focus to analyze the effects of subjecting dandelion roots to cold plasma treatment during tea brewing, specifically focusing on the changes of the exposure time on the antioxidant activity, color concentration and total phenolic content. For this study, dried dandelion roots were obtained from a local vendor in Izmir and ground using a coffee grinder, and samples to be used in the study were separated through the sieves of 212 micrometers and 450 micrometers and samples called ground. Subsequently, a dielectric barrier discharge cold plasma (DBDCP) was generated using a pulsed direct current power supply (400W, 40 kV , 56 kHz, and 1 mA). The process was conducted as follows: Both ground and unground samples underwent treatment with 40 kV DBDCP for 10 min and 20 min. Untreated samples were used as the control. All treatments were repeated three times. The electrode gap was set at 1.1 cm. The samples subjected to cold plasma were prepared for the brewing process. The prepared samples were brewed at 95±2 0C for 4 minutes. During the brewing process, 2 grams of sample and 200 milliliters of distilled water were used. For grounded samples, 2 grams of ground dandelion root was added to 200 mL of distilled water at 95±2 0C and allowed to steep for 4 minutes, followed by centrifugation through 4000 rpm, 5 minutes at a controlled temperature of 4°C. For unground samples: 2 grams of dandelion root was immersed in 200 mL of distilled water at 95±2 0C using a metal sieve and allowed to steep for 4 minutes. After the infusion process, the metal sieves were removed from the water and the samples were cooled to room temperature. Subsequently, the necessary analyses were performed. The first analysis conducted was color measurement to evaluate the brewing efficiency. Color intensity during brewing has positive effects on consumers. In the color measurement results, a statistically difference (p<0.05) was observed only for the b* value. The b* value represents the yellowness. The brewed dandelion roots transitioned from transparent to yellow throughout the brewing process. Thus, it is possible to say that DBDCP can increase the color intensity. Total phenolic content (TPC) analysis is a commonly used method to calculate the amount of phenolic compounds present in a products, reflecting their antioxidant capacity. In the analysis of samples ground into powder, a significant increase was observed only in the 20 min-treated samples (p<0.05). In unground samples, a decrease at the 10th minute and a slight increase at the 20th minute were observed. The observed increase in antioxidants after processing in ground samples can be attributed to an increase in surface area and enhanced interaction with reactive compounds. This phenomenon may be linked to the increased ability of antioxidants to neutralize free radicals through their interaction. However, in unground samples, a decrease followed by a slight increase through processing time can be observed. This may be due to the initial decrease in the amount of antioxidants on the outer surfaces of larger particles. With the application of DBDCP for a longer time, bioactive compounds in the cell can be reached by breaking down the cell wall in the samples. Accordingly, the total phenolic content of the all samples were as followed: 0.122 mg GAE/mL for ground samples without cold plasma treatment, 0.128 mg GAE/mL for ground samples which implied cold plasma for 10 min, 0.140 mg GAE/mL for ground samples treated with cold plasma for 20 min, 0.045 mg GAE/mL for unground samples without cold plasma treatment, 0.027 mg GAE/mL for unground samples treated with cold plasma for 10 min, and 0.036 mg GAE/mL for unground 20 min cold plasma treated samples for. 2,2-diphenyl-1-picrylhydrazyl (DPPH) is a free radical compound that undergoes a change in color when interacts with substances exhibiting antioxidant properties. In the analysis of samples ground into powder, a significant DPPH radical scavenging activity increase was observed only in the 20 min-treated samples compared to the control (p<0.05), while no significant difference was observed in unground samples (p>0.05). Accordingly, the DPPH radical scavenging activity of the samples were as follows: 0.668 mg TE/mLfor ground samples without cold plasma treatment, 0.695 mg TE/mL for ground samples applied with cold plasma for 10 min, 0.774 mg TE/mL for ground samples applied with cold plasma for 20 min, 0.290 mg TE/mL for unground samples without cold plasma treatment, 0.218 mg TE/mL for10 min cold plasma applied ungrounded samples, and 0.241 mg TE/mL for unground samples which treated with cold plasma for 20 minutes. 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay is a commonly used method for evaluating the antioxidant activity. Accordingly, the ABTS radical scavenging activity of the samples were as follows: 0.119 mg TE/mL for ground samples without cold plasma treatment, 0.124 mg TE/mL for ground samples that applied cold plasma for 10 min, 0.135 mg TE/mL for ground samples treated with cold plasma for 20 minutes, 0.049 mg TE/mL for unground samples without cold plasma treatment, 0.036 mg TE/mL for unground samples which cold plasma applied for 10 minutes, and 0.044 mg TE/mL for unground samples which cold plasma applied for 20 minutes Ferric reducing antioxidant power (FRAP) assay is a rapid evaluation of antioxidant activity method. Accordingly, the antioxidant activity as assessed by FRAP assay were as follows: 0.358 mg TE/mL for ground samples without cold plasma treatment, 0.374 mg TE/mL for ground samples cold plasma applied for 10 minutes, 0.387 mg TE/mL for ground samples cold plasma applied for 20 minutes, 0.144 mg TE/mL for unground samples without cold plasma treatment, 0.090 mg TE/mL for unground samples cold plasma treated for 10 minutes, and 0.118 mg TE/mL for unground samples cold plasma treated for 20 minutes. The sensory analysis was conducted by a panel of 12 individuals from the Department of Food Engineering at ITU. The samples were placed in screw-capped test tubes, labeled with randomLy assigned three-digit numbers. Subsequently, the samples were presented to the panelists and evaluated using a 7-point hedonic scale. The scale was used to assess odor intensity, color intensity, clarity, and overall impression. All measurements were reported as means and standard deviations. Minitab software was used for statistical analysis, applying analysis of variance (ANOVA) and Tukey's test for comparisons. No significant differences were observed among any of the samples in the sensory analysis (p>0.05). This study investigates the effect of DBDCP treatment on the process efficiency and antioxidant activity during the brewing process of Taraxacum officinale roots as tea. The study shows that cold plasma treatment can enhance the process efficiency by preserving the antioxidant activity of Taraxacum officinale roots. It can be said that dielectric barrier discharge cold plasma treatment can be utilized in the brewing process of Taraxacum Officinale roots as tea, leading to an improvement in the process efficiency with the preservation or even enhancement of antioxidant activity.
Encapsulation of aqueous Hibiscus sabdariffa L. extract in food-grade high internal phase pickering emulsions stabilized by soy protein isolate

(Graduate School, 2023-06-15) Çavdar, Hümeyra ; Güven Çapanoğlu, Esra ; 506211516 ; Food Engineering

Hibiscus Sabdariffa L. is a highly versatile plant that finds applications in various industries due to its abundant nutrients, potent bioactive compounds such as phenolics and anthocyanins, and natural colour pigments. In addition to its use as a colouring agent, its positive health effects, such as antibacterial, antioxidant, anticholesterol and prevention of gastrointestinal problems, spread the consumption of the product for health purposes. However, the fact that bioactive ingredients are easily affected and damaged by many factors limits this product's use in many industries. Therefore, integrating Hibiscus Sabdariffa into food products and various formulations becomes more complex and limits the methods used. Encapsulation, a preferred method for much bioactive protection, appears at this point. Encapsulation comes to fields as a technique that allows us to apply in different areas, such as preserving these components and controlled release and integrating them into product formulations. Emulsification by encapsulation method has gained a solid place in industry and literature. High Internal Phase Emulsions are among the leading emulsions with high volume encapsulation and high stability against external factors. Similarly, double emulsion systems can enhance bioactive components' protection with their nested phase structure. The debate over the many adverse effects of preferred emulsifiers and stabilizers for emulsion stability, such as human health and environmental pollution, has accelerated scientific research into discovering alternative products. Plant proteins have gained tremendous interest in recent years as they have the potential to be an alternative to conventional emulsifiers and stabilizers. The various functional properties and amphiphilic characteristics indicate that these proteins are significantly effective in the stability of the emulsion system. Like many other types of plant proteins, soy protein is a preferred product due to its easy availability and processability. In this study, analyses were conducted to identify and evaluate the encapsulation of aqueous Hibiscus extract in the High Internal Phase Pickering Emulsions (HIPPE) and High Internal Phase Double Emulsions (HIPP-DE) systems stabilized by soy lecithin and soy protein isolate. The stability of the emulsions obtained, characteristics and the effects of in vitro gastrointestinal digestion on the phenolics and anthocyanins in the extract with the presence of soy protein and soy lecithin were investigated. The extraction of phenolics and anthocyanins from powdered Hibiscus calyces was realized by ultrasonic method, and water was used as a solvent. Emulsions with an internal volume of 80% have been created using soy protein isolate (SPI) gel and lecithin. A HIPPE resistant to phase separation could not be obtained using soya protein isolation gel alone, while emulsions (L4 and L6) containing 4% and 6% lecithin and phase separation resistance could be achieved. Combinations of different concentrations of lecithin and soy protein isolated gel stabilized other HIPPEs. After 24 hours of storage, HIPPEs stable against phase separation were obtained by homogenizing HIPP-DEs at a volume of 50% with a 6% SPI gel. When emulsions stored for 24 hours were observed, SPI gels and lecithin at varying concentrations acted as a synergistic mechanism that effectively prevented phase segregation and ensured stability in the emulsion system. All HIPP-DEs also showed superior resistance to phase separation. According to the CI results, an increase in the concentration of soy lecithin from 2% to 4% in HIPPE containing 6% SPI gel resulted, indicating increased stability, leading to a decrease in the CI value on day 1; however, no significant difference in CI was observed between HIPP-DEs. EAI and ESI values show a statistically significant increase when the SPI concentration increases from 2% to 4% in HIPPEs and HIPP-DEs with 4% and 6% lecithin concentrations. Still, surprisingly, no significant increase was observed with further increases in SPI. In contrast, the particle size of HIPPEs with 4% and 6% lecithin concentrations showed a significant decrease as the SPI gel concentration increased from 2% to 6%. In HIPPEs, the zeta potential was negative, and the absolute values increased by increasing the SPI gel concentration from 2% to 4%, while in L4S4, it was observed that the HIPPE had the highest absolute zeta potential (-41.21 ± 1.23 mV). However, an increase in SPI gel concentration from 4% to 6% decreased the absolute zeta potential value. The increase in the concentration of soy protein isolate (SPI) from 2% to 6% resulted in a significant decrease in the PDI values of HIPPE containing 4% and 6% lecithin. The lowest PDI values were obtained in L4S6 and L6S6 HIPPE with an SPI concentration of 6%. The same decline has been observed in HIPP-DEs. Different changes have been observed in the stability and characteristics of emulsions, as well as in the study of bioactive components and their properties. Encapsulation Efficiency (EE) determinations stated that HIPP-DEs produced higher EE than HIPPEs due to high SPI gel concentrations. The total anthocyanin content (TAC), total phenolic content (TPC), DPPH and ABTS of the resulting aqueous Hibiscus extract were analyzed. The TAC (mg Cy-3-GC equivalent/100 g), TPC (mg GAE/100 g), DPPH (mg TE/100g) and ABTS (mg TE/100g) values were found as 31.13±1.23, 2619.01±17.31, 335.12±1.21 and 223.21±2.56 respectively. Significant decreases in TPC in Hibiscus extract were observed with in vitro gastrointestinal digestion. In HIPPEs prepared with a concentration of 4 % lecithin (L4, L4S2, L4 S4, L4S6), the SPI gel concentration increased from 0 % to 4 %, while anthocyanins in the stomach environment showed more excellent stability compared to the intestinal environment. When the TPC of the digested phenolics of Hibiscus extract was compared to those of digestive HIPPEs and HIPP-DEs, higher TPC values were observed in all emulsions. Maximum TPC values in the stomach and intestinal digestion reached 709.82 ±2.06 mg/100g and 1160.71 ±21.01 mg/100g, respectively. In the stomach and intestinal phases of in vitro digestion, the rate of phenolic release has been significantly influenced by the pH of the environment. According to HPLC results, aqueous Hibiscus extract has detected anthocyanins of delphinidin-3-glucoside, cyanidin-3-glucoside, and cyanidin-3-rutinoside. Four phenolic acids have also been detected in the extract and all emulsions, including gallic acid, syringic acid, ferulic acid and chlorogenic acid. After gastric digestion, a decrease in the content of chlorogenic acid, ferulic acid and gallic acid was observed, while syringic acid increased, showing a different tendency. The highest concentrations of each anthocyanins and phenolics concentrations were obtained in L6S6-D. As a result, changes in SPI gel and lecithin concentrations have been effective in many conditions, such as the stability of emulsions, their properties, and the effects of in vitro digestion on anthocyanins and phenolics. In addition, according to the results of encapsulation efficiency, it can be stated that HIPPEs and HIPP-DEs are effective emulsion systems in the encapsulation of Hibiscus extract.
Encapsulation of cumin seed oil in chickpea protein- maltodextrin matrix

(Graduate School, 2022-02-14) Atlı, Onur ; Karaça, Aslı Can ; 506181509 ; Food Engineering

This study aimed to investigate developing a plant-based protein matrix for microencapsulation of cumin oil, by determining optimum pH for solubility, emulsion stability of chickpea protein isolate (CPI) and investigating the effect of the matrix composition on encapsulation effiency and aromatic composition of cumin oil. Solubility, net surface charge, and emulsifying properties (emulsion activity/stability indices, and creaming stability) of CPI at ranging pH 3.0-9.0 were investigated. The highest protein solubility (94.4%) and emulsion activity index (61.8 m2/g), and the highest creaming stability (9.8% separation) was obtained at pH 9.0. CPI stabilized emulsions were optimized based on pH due to the higher emulsion stability index, which is 123.8 min at pH 7.0. CPI concentration of 0.5-2.31% (w/w) and oil concentration of 5-23.11% were adjusted in order to investigate the emulsion stabilization capacity of CPI using response surface methodology. It was observed that obtained CPI has the lowest effect on emulsion formation. Optimum conditions for minimum creaming were identified as: 0.19% CPI concentration and 6.83% oil concentration. CPI was found to be thermally stable with high denaturation temperature (161.4°C) and required 142.2 J/g enthalpy for denaturation. Cumin (Cuminum cyminum L.) seed essential oil was microencapsulated employing the complex matrix formation of CPI and maltodextrin DE 12-16 using spray drying. Effects of cumin oil concentration (10-20%), CPI concentration (1-3%) and maltodextrin (MD) concentration (25-35%) on the physicochemical characteristics and aromatic composition of the microcapsuled cumin oil were investigated. It was observed that, CPI-MD complex matrices had positive effects on microencapsule properties such as relatively lower surface oil, and higher encapsulation efficiency and oil retention, when they were formulated properly. Oil retention of 86.6–96.4%, encapsulation efficiency of 90.9–98.4%, and surface oil of 1.4–7.9% were obtained in samples. Correspondingly, it was observed that MD–CPI interaction was an effective parameter for emulsion stability. Optimum conditions for maximized oil retention (92.9%) and encapsulation efficiency (98.60%) were identified as: CPI concentration of 2.1%, cumin oil concentration of 14.8% and MD concentration of 35%. Moreover, GC-MS analysis of obtained microencapsulates was also carried out to determine the changes in essential oil composition during spray drying. It was observed that cymene, α-pinene, β-pinene, sabinene, terpinene, terpineol, phellandrene, and cumin aldehyde were the major volatile components in cumin oil. It was observed that optimized design not only had the highest encapsulation yield, but also provided better protection against the degradation of volatile composition of cumin oil.
Encapsulation of oil-based cheese aroma by using spray-drying and efficience of microcapsules in model foods

(Graduate School, 2022) Ertan Tütüncü, Sena ; Özçelik, Beraat ; Özgüven, Mine ; 737832 ; Food Engineering Programme

Since the world has existed, food consumption has been critical for the continuation of life. Appearance, flavor, and taste play an important role in the preference of foods in nature. In modern times, these parameters have been controlled and improved. Fermentation is invented to increase the shelf-life of the food; in addition, new volatile compounds are formed during the fermentation process. Cheese is the most consuming fermented product, and different types of cheese are made by changing fermentation and process parameters. These parameters also affect the odor and taste, providing the uniqueness of cheese. Each volatile compound has a special odor and taste, therefore, containing various volatile compounds allows different cheese varieties to have their unique odor and taste. Various extraction techniques are distillation, static headspace, dynamic headspace, solid-phase microextraction (SPME), stir bar sorption extraction, and vacuum distillation applies for the extraction of the cheese volatile compounds. Depending on the volatile compounds' qualifications such as the sensitivity of heat, light, and temperature; appropriate extractions should be chosen. The encapsulation process prevents flavors from being affected by adverse environmental conditions. Various techniques are used to encapsulate the active material. Selecting the suitable encapsulation method depends on the core material release features, wall material properties, project cost, and aim. Preparation of emulsion is the first and fundamental step of encapsulation. Wall materials that cover the core material may be consists of carbohydrates, protein, or other materials. Starch, gum, and maltodextrin carbohydrate-based derivatives to use in encapsulation; however, for getting more encapsulation efficiency carbohydrate and protein-based materials are preferred together. Both animal and plant-based derivatives are used as protein wall materials. High pressure, micrtechniquesing technique, and ultrasonication are used to homogenize and provide emulsion to good dispersion. The spray drying technique is one of the most common encapsulation techniques in the food industry. The spray drying process is based on the principle of atomizing the material to be dried under high pressure and then drying it in a very short time with hot dry air. In this experiment, commercial cheese aroma is encapsulated by the spray drying technique. Using maltodextrin and protein are used as wall material at different concentrations. 30 % of the emulsion mixture consists of solid ingredients. This solid content is prepared with 16 % aroma and 84 % mixture of maltodextrin with dextrose equivalent 11-16 and whey protein concentrate, 50 %. Protein content in the solid mixtures is 8 % and 4%. These emulsions are kept in a shaking bath at 40 C° for 20 hours at 80 rpm to improve hydration. 16 % aroma of total emulsion is added to both emulsions. After the hydration and adding aroma, the emulsion is mixed first at 450 rpm, for 1 hour; then homogenized by Ultra-turrax at 17000 rpm for 5 minutes. Laboratory scale Buchi B-290 is used at an 8 mL/min feed rate, 180 ± 2 C° inlets, and 80 ± 2 C° outlet temperature. Encapsulation duration keeps 40 minutes. Encapsulated and commercial aroma is added, a total of 1 % flavor, in cracker dough samples that include 60 % flour, 15 % oil, and other ingredients. Then the crackers are cooked in the oven at 220 C°, for 10 minutes. The aroma added cracker is oiled at % 10 without aroma. Cracker dough without aroma is prepared and cooked; however, the encapsulated aroma and liquid aroma are added in the oil process at 0.2 %. GC & MS analysis results are compared with the results of commercial liquid flavoring as a reference. Encapsulated A and B aroma volatile compounds concentrations show similar results. Butyric acid is lost after the encapsulation process; however, 9,12-Octadecadienoic acid (Z, Z) concentration dramatically increases after the encapsulation in both encapsulated aromas. 2-Decenal and 2-Nonenal concentrations show a slight rise and these compounds are also derivatives of the oxidation. Heptanoic and Undecanal concentrations in the encapsulated aroma are higher than in the liquid flavor. Other compound concentrations are similar between A & B aromas and commercial products. Added the encapsulated aromas and commercial aroma in cracker doughs, volatile compounds concentrations do not show dramatically difference; however, 2- Decenal concentration in three samples slightly increases with comparing the reference liquid aroma. 9,12-Octadecadienoic acid concentration is differentiated between encapsulated aroma and liquid aroma, higher concentration in the encapsulated aroma. Heptanoic acid concentration could not be maintained in doughs when using liquid flavoring and showed a decrease. After the cooking, adding the aroma to the top oil process demonstrates the different volatile compounds concentrations. Heptanoic acid, 2-Nonenal, 2-Decenal, dihydro-5-pentyl-2(3H)-Furanone, and Tetradecanal compounds concentrations are higher than reference liquid aroma and cracker that include aromas in the dough. Other compounds' concentrations are similar to the commercial aroma. The change in the concentrations of the volatile components in the aroma may be caused by oxidation and the combination of the aroma with other components and creating different reactions. The panelists do not realize dramatically difference between using encapsulated B aroma and liquid aroma in dough with cheese odor, cheese flavor, aftertaste of cheese flavor, and general taste. Significant differences are observed between crackers that use oil including aroma and added commercial aroma in the oil process. The samples using the encapsulated B flavor in the oil are more like in terms of cheese odor and flavor, aftertaste cheese flavor, and general taste than the crackers using the reference aroma. In line with these results, industrial cheese flavor managed to preserve most of its volatile components with its wall material consisting of maltodextrin and whey protein concentration. The encapsulated aromas are used in the dough of cracker samples, which are applied at high temperatures during cooking, and in the oil applied to them after cooking. Although some volatile compounds of crackers, such as butyric acid and 2-nonenal, are lost when high temperature is applied; a high amount of volatile components are retained. Added aroma in oil shows greater volatile compound concentrations, also added encapsulated aroma in oil is more preferred than others.
Endüstriyel havuç suyu atıklarından enzim ve ultrason destekli ekstraksiyon ile gıda bileşeni üretilmesi

(Lisansüstü Eğitim Enstitüsü, 2024-06-28) Demir, Yasemin ; Karıncaoğlu Kahveci, Derya ; 506201523 ; Gıda Mühendisliği

Küresel olarak, insan tüketimi için üretilen gıdaların yaklaşık üçte birinin kaybolması veya israf edilmesi en önemli gıda sistemi sorunlarından biridir. Nüfus ve tüketim sürekli artarken, gıda talebinin en azından bir sonraki 40 yıl boyunca artması beklenmektedir, bu da doğal kaynaklar olan toprak, su ve enerji üzerinde baskı oluşturmaktadır. Gıda israfının önlenmesi bir önceliktir, ancak bazen bu ekonomik veya teknolojik olarak mümkün olmamaktadır. Bu nedenle, gıda atıklarının yem ve enerji üretimi gibi çeşitli süreçler için kaynak olarak kullanılması için çaba gösterilmektedir. Tarım ve gıda sektörlerinden gelen atıklar besin maddeleri bakımından zengin olmasına rağmen, bunların bertarafı çevresel ve sağlık sorunlarına yol açabilmektedir. Araştırmacılar, bu sorunları en aza indirmek ve değerli biyoaktif bileşikleri çıkarmak için ultrasonik ve enzimatik destekli ekstraksiyon gibi çevre dostu teknolojileri araştırmaktadır. Çevre dostu metotlar arasında yer alan enzim ve ultrason destekli ekstraksiyon; çözgen kullanımını azaltarak, daha az enerji sarfiyatı sağlayarak ve verimi artırarak fayda sağlamayı amaçlamaktadır. Havuç sebzesi meyve suyu fabrikalarında işlendikten sonra genellikle endüstriyel atık olarak atılır veya hayvan yemi olarak kullanılırken, ortaya çıkan bu yan ürün karotenoidler ve fenolik bileşikler gibi yüksek oranda yararlı bileşikler içermektedir. Dolayısıyla bu yan ürünün farklı endüstrilerde (gıda, sağlık, kozmetik vb.) kullanılmasının hem katma değerli ürün elde edilmesinde hem de çevresel konularda faydalı olabileceği düşünülmektedir. Bu çalışmanın amacı, endüstriyel havuç suyu atıklarına çevre dostu ön işlemler (enzimatik ve ultrasonik destekli ekstraksiyon) uygulanarak gıda endüstrisinde önemli kullanım alanı olan bileşenlerin elde edilmesi için Sürdürülebilir Kalkınma Hedefleri'ne uygun bir yaklaşım geliştirilmesi amaçlanmakla birlikte çalışmada bahsedilen yöntemler üzerinde optimizasyon koşullarının belirlenmesidir. Öncelikle, geleneksel, enzimatik ve ultrasonik yöntemlerin her biri için solvent türü, katı-sıvı oranı, enzim türü, enzim miktarı, enzimatik ve ultrasonik destekli ön işlem süresi parametreleri beta karoten, likopen, toplam fenolik madde konsantrasyonlarına ve DPPH % inhibisyonuna göre optimize edilmiştir. Analizler spektrofotometre ile belirlenen dalga boylarında ölçümlenmiştir. Yapılan çalışmalar sonucunda solvent türü ve katı-sıvı oranı sırası ile etanol ve 1:40 (w/v) olmuştur. Enzimatik ön işlem parametreleri ise enzim türü için Pectinex® XXL, enzim miktarı için 300 μL ve ekstraksiyon süresi için 120 dk optimum koşulları vermiştir. Ultrasonik ön işlemin süresi 20 dk olarak belirlenmiştir. Sonuçlara göre, belirlenen bu optimum koşulların geleneksel, enzimatik ve ultrasonik ön işlem destekli ekstraksiyon yöntemlerine uygulanması ile istatistiksel olarak enzim ve ultrason ile ön işlem uygulamasının bu gıda bileşenlerinin geri kazanımını artırabileceğini göstermiştir (p<0.05). Optimum koşullar belirlendikten sonra havuç posaları geleneksel, enzimatik destekli, ultrasonik destekli, enzimatik-ultrasonik destekli ve ultrasonik-enzimatik destekli 5 farklı ekstraksiyon yöntemi ve kombinasyonu ile ekstrakte edilmiştir. Elde edilen bütün sıvı ekstraktların önce dönel buharlaştırıcı ile içerdiği etanol uçurulmuş daha sonra ise dondurarak kurutulmuştur. Bütün analizler katı madde üzerine uygulanmıştır. Ekstraksiyon yöntemlerine göre elde edilen bileşenlerin konsantrasyon sonuçlarına baktığımızda enzimatik destekli ekstraksiyonun sonuçları diğer yöntemlere göre daha etkili bulunmuştur. Enzim destekli ekstraksiyonun sonuçları şu şekildedir: 26,37 ± 0,26 mg/g beta-karoten konsantrasyonu, 20,93 ± 0,005 mg/g likopen konsantrasyonu, 9,97 ± 1,38 mg GAE/g toplam fenolik madde konsantrasyonu, 209,44 ± 7,98 mg rutin/g toplam flavonoid madde konsantrasyonu ve 25,57 ± 4,15 DPPH % inhibisyonudur. Ayrıca hem E.coli hem de Salmonella Typhimurium için en etkili antimikrobiyal aktivite gösteren yöntemin enzim destekli ekstraksiyon yöntemi olduğu gözlemlenmiştir. Bulgulara bakıldığında enzim uygulamasının hücre duvarını parçalaması özelliğinden dolayı hedef bileşenlerin salınımını büyük ölçüde etkilediği söylenebilmektedir. Ek olarak Enzim - Ultrason Destekli Ekstraksiyon uygulamasının ise ikinci etkili yöntem olduğu tespit edilmiştir. Bu uygulamada ise ek olarak ultrason kullanımının kavitasyon etkisi ile hücre duvarını parçalayarak verimi artırmada etkili rol oynadığı gözlemlenmiştir.
Evaluation on techno-functional, fatty acids and in vitro antioxidant activity of edible house cricket (Acheta domesticus)

(Graduate School, 2022-03-09) Hacıhasanoğlu, Furkan Ediz ; Özçelik, Beraat ; 506191509 ; Food Engineering

Since prehistoric times, insects have been eaten by humans at every stage of their life, including eggs, larvae, pupae and adults. The main reason for this was that people did not have the necessary tools for hunting or farming. The use of insects for human consumption, as mentioned, is called entomophagy. The origin of this word is basically a combination of two Greek words, "ἔντομον (éntomon)" meaning "insects" and "φᾰγεῖν (phagein)" meaning "food". Currently, approximately 2.5 billion people worldwide engage in insect-eating action. In contrast, insect consumption in Europe is very low. It is thought that the rapidly increasing world population will reach 9.8 billion by 2050. Therefore, current food production needs to be doubled to ensure adequate food supply for the estimated population. This means that both land and water resources begin to become insufficient. On a dry basis, the protein part of insects is between 50% and 82%, and essential and semi-essential amino acids have made them an important food source. They also have a significant amount of lipids on a dry basis; Some insects, among all other sources of lipids, contain very high amounts of fat, up to 75% and carbohydrate value of insects between 6-16%, which contain high levels of glycogen and chitin. They usually contain a good amount of minerals, to be more specific, some insects have iron and calcium values that surpass livestock and also contain good amounts of zinc. The energy values of insects vary according to the amount of fat. Insects in the larval or pupal stage have more energy than adult insects due to their high fat content. In general, its energy values are similar to red meat, but not similar to pork, as it contains a large amount of fat. Insects have been applied to wounds, respiratory and stomach problems since ancient times, and there is little research on their functional properties. Insects possess many bioactive materials; They have attracted more attention from researchers due to their contents such as peptides, polysaccharides, fatty acids and phenols. Moreover, peptides obtained from insect proteins have been shown to have health benefits such as antihypertensive, antimicrobial and antioxidant properties. In vitro antioxidant properties of insects have shown that their protein hydrolysates exhibit similar antioxidant properties to fish, wheat and flaxseed protein hydrolysates. On the other hand, insects bring with them some risk factors when used for human consumption, as they may have some pathogenic microorganisms that carry disease. Moreover, from an industrial point of view, proteins are needed in many areas due to their techno-functional properties. Accordingly, insect proteins can be used to meet such needs. A. domesticus is an insect species that belongs to the Orthoptera order and its common name is "house cricket". Although A. domesticus can be found all over the world, its origin is in Southwest Asia. In the context of the textural, nutritional and taste aspects of this species, it is produced especially in Thailand for use in the diets of individuals. Previously, studies on house crickets were predominantly done for animal feed substitutes, but as times have changed, there is now more room to be studied for human food as well. In the thesis study, the techno-functional properties of A. domesticus were observed as flour, defatted flour, or protein extract obtained from flour. The water and oil binding capacity were performed in both defatted flour and flour. Water binding capacities were found 1.91 gwater/g for defatted insect flour, and 1.41 gwater/g for insect flour. While the oil binding capacity was 1.37 goil/g for defatted insect flour, and 0.93 goil/g for insect flour. The foam capacities of the extracted protein and insect flour were found to be 148.33% and 6.67%, respectively, while the foam stabilities were found to be 91.60% and 97.66%, respectively. The protein extracts of A. domesticus flour were studied at different pH (3-5-7) and different concentrations (0.1%, 0.08%, 0.06%, 0.04%, 0.02%) to find out the emulsifying activity, stability and capacity. In the results examined, the activity varied between 0% and 52.63%. All concentrations at pH 9 showed the highest activity with no significant difference between them. On the other hand, the highest emulsification stability was observed in pH 9 sample containing 85.46% and 0.1% protein. While the emulsifying capacity was observed in the samples at the highest pH value, it was observed that there was an inverse proportion between the protein concentrations and the capacity at this pH. Protein solubility was investigated on insect flour at different pH (3-5-7-9) of different salt concentrations (0% and 3%). Results varied between 2.85% and 52.32%. The highest solubility value was found at pH 9(0%) salt, while the lowest value was found at pH 5(0%). Although the addition of salt at pH 9 significantly reduced the solubility, it remained to show higher solubility than other pH values. A. domesticus flour was analyzed for its fatty acid composition, and cis-linoleic acid (C18:2n6) showed the highest fatty acid value with 35.77% it was followed by palmitic (C16:0) and cis-oleic acid (C18:1n9) with 26.46% and 25.85%, respectively. Linolenic acid (C18:3n3) and cis-linolenic acid (C18:3n6) were found to be 1.04% and 0.27%, respectively. The lowest fatty acid composition was observed as 0.21% for heptadecanoic acid (C17:0). Some saturated fatty acids were also found, such as myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0) and heneicosanoic acid (C21:0). As a result of the DPPH analysis performed after in vitro gastrointestinal digestion, the IC50 (mg/ml) value was found to be too high as 31.96 for the stomach and 78.27 for the intestine. Inhibition percentages were found as 78.3% and 31.96% for the stomach and intestines, and values in terms of Trolox equivalent were observed as 3.62 mgTE/g in the stomach and 1.54 mgTE/g in the intestine. The results of this thesis clearly showed that A. domesticus flour and its derivatives showed potential as techno-functional. In addition, various fatty acid content and moreover, antioxidant properties obtained as a result of in vitro gastrointestinal digestion were similar to the results in the literature on health and showed that it could be used in this direction.
Extraction, characterization and usage of pectin from sugar beet pulp waste

(Graduate School, 2024-07-05) Kartal, Elif ; Akyılmaz Kılıç, Meral ; 506211528 ; Food Engineering

The worldwide accumulation of substantial agro-industrial waste causes serious economic and ecological problems. Agro-industrial wastes are the byproducts produced during the processing of crops in the food industry. Converting by-products from the processing of plant foods into valuable functional products helps mitigate the waste problem in the food industry. Sugar beet pulp is the residual by-product after sugar is extracted from sugar beets. It is an underutilized waste currently used for animal feed or as feedstock in biorefinery facilities. Sugar beet pectin is a promising variant of pectin derived from sugar beet pulp. In 2021, Turkey imported approximately 676,000 kilograms of pectin. Given its extensive applications in the Turkish food industry, this import volume is expected to increase in the coming years. Turkey is the world's fifth-largest sugar beet producer, but despite the great potential, currently there is no facility producing pectin. Pectin is a heteropolysaccharide made up of α-D-galacturonic acid units connected at the 1,4 position, with additional side chains of neutral sugars including 1,5-linked αL-arabinose and 1,4-linked β-D-galactose. Pectin is found in the middle lamella of plant cell walls providing structural support and protection with cellulose and hemicellulose. Pectin is classified into two types based on its degree of methylation (DM): Low methoxy pectin (LMP) with a DE of less than 50%, and high methoxy pectin (HMP) with a DE greater than 50%. Pectin is widely utilized in the food industry, mainly serving as a gelling and thickening agent in jams, marmalades, and sugar confectionery, and a stabilizer in milk and fruit products. In this study, pectin was extracted from sugar beet pulp waste using conventional extraction (CE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) methods. The objective was to determine the effect of extraction methods on its physicochemical properties and performance in fermented milk beverage. An aqueous solution of homogenized sugar beet pulp waste acidified with citric acid was prepared for extraction. CE involved heating the solution to 85°C in a water bath. For UAE, an ultrasonic processor with maximum power of 400 W and a frequency of 24 kHz was used. A sonication amplitude of 50% was applied to the solution for 15 minutes to heat to the same temperature as in CE. MAE was performed using a microwave unit with a maximum power of 1400 W and a frequency of 2450 MHz was used. The sample solution was subjected to a power of 420 W for 15 min to reach the same temperature as others. Heated solutions were mixed for 60 min and homogenized. After cooling and removing sedimented particles, pectin was separated from the remaining solution by using ethanol. Obtained precipitate was then purified by dialysis to remove small molecules and then dried. The extraction yield, degree of esterification (DE) and galacturonic acid content (GalA) of pectin extracts were determined. Pectin extracts were also analyzed using FTIR spectroscopy for structural elucidation in the wavenumber range of 650-4000 cm-1 . Dried pectin was used in a fermented milk beverage and rheological properties and serum separation level of the beverages were measured. Pectins were also used in an emulsion model for determining their effect on emulsion stability. The properties of the extracted pectin samples were compared with those of commercial citrus pectin. Pectin yields ranged from 5.3% to 10.3%, with the highest yield of 10.3% achieved by UAE. The CE took 35 minutes to reach a comparable yield, while MAE and UAE required only 15 minutes. Notably, the protein content in the pectin sample from UAE was 8.6%, significantly higher than those from CE at 6.6% and MAE at 6.2%. It is important to emphasis that lower protein content is indicative of higher sample purity. Pectin samples extracted via UAE, MAE, and CE showed similar degrees of esterification, 75.8%, 72.7%, and 72.3%, respectively. All extraction methods produced DE values above 50%, qualifying that the pectin was high methoxyl pectin (HMP). GalA content in pectin samples ranged from 56.8% to 61.3% with no significant difference among the value in terms of extraction method. FTIR spectra of sugar beet pectin samples showed peaks at similar wave numbers. All pectin samples exhibited absorbance peaks at 1643.57 cm⁻¹, 1732.69 cm⁻¹, and 1729.18 cm⁻¹, which are attributed to the C=O stretching of methyl-esterified carboxyl groups and carboxylate ions, respectively. FTIR analysis revealed that the different extraction methods had minimal impact on the chemical structure of pectin. In fermented milk beverages prepared with pectin from UAE, MAE, and CE, as well as commercial pectin, significant increases in apparent viscosity, flow behavior index and consistency coefficient values were observed compared to those of the control sample without any additive. All fermented milk beverages showed pseudoplastic behavior. The serum separation levels in the pectin containing beverage samples were lower than that of the control sample (13.6%) after 7 days of storage. The sample with commercial citrus pectin had a lower serum separation level than those of the other samples. In addition, pectins obtained with UAE and MAE provided a higher stability in emulsion compared to pectin from CE and commercial citrus pectin. These results showed that the sugar beet pectin had a potential for use as a food ingredient. In this study, UAE, MAE, and CE generally yielded sugar beet pectin with similar properties and performance in fermented milk beverage and emulsion. However, UAE and MAE can be preferred to reduce extraction time significantly compared to CE. UAE can also be beneficial to increase protein content in the pectin in some cases. Pectin extraction from sugar beet pulp can be a way to upcycle this valuable waste in a sustainable food production system.
Farklı bitkisel protein kaynaklarının glutensiz bisküvinin kalite özelliklerine etkisi

(Lisansüstü Eğitim Enstitüsü, 2024-01-30) Engi, İpek ; Karaça Can, Aslı ; 506191525 ; Gıda Mühendisliği

Glutensiz atıştırmalık ürünlerine olan talep gün geçtikçe artmaktadır. Gluten, bitkisel kaynaklı bir protein olup, buğday, çavdar ve arpa gibi tahılların yapısında bulunmakta ve çölyak hastalığı gibi çeşitli sağlık sorunları nedeniyle bazı tüketiciler tarafından tüketilememektedir. Çölyak hasatlığı, gluten tüketimi olması durumunda ince bağırsağa zarar vererek bir dizi ciddi semptoma neden olur. Bu hastalığa karşı en önemli çözüm ise günlük diyetten glutenin tamamen çıkarılmasıdır. Ancak gıda ürünlerinden glutenin çıkarılması ürünlerin besin değerinin azalmasına ve çeşitli kalite özelliklerinin olumsuz etkilenmesine sebep olabilir. Glutensiz tahıl ürünleri ile baklagillerin birlikte kullanılması, glutensiz ürünlerde daha dengeli bir esansiyel amino asit profili sağlarken, ürünlerin besin değerini de iyileştirmektedir. Baklagiller ve yağlı tohumlar, proteince zengin yüksek besin içeriği ve gluten içermemeleri sebebiyle glutensiz ürünlerde tercih edilmektedir. Bisküvi, kolay erişilebilir, doyurucu ve uzun raf ömrüne sahip özellikleri ile sıklıkla tüketilen fırıncılık ürünlerinden biridir. Bisküvi üretiminde gluten, ekmek ürünlerindeki gibi temel bir role sahip olmadığından, bitkisel proteinler ile içeriği zenginleştirilmiş glutensiz bisküvi üretimi büyük ilgi görmektedir. Ayrıca, literatürdeki glutensiz ürün çalışmaları incelendiğinde, bisküvi kategorisinde bitkisel protein kaynaklarının un formunda kullanıldığı gözlemlenmiş, "izolat veya konsantre" formda bitkisel protein ilaveli bir çalışmaya rastlanılmamıştır. Tüm bunlardan yola çıkarak, bu çalışmanın amacı, farklı bitkisel protein kaynakları ile glutensiz bisküvi reçetesi geliştirmektir.
Farklı diyet lifi türlerinin şeker ilavesiz yumuşak şekerlerin fizikokimyasal, tekstürel ve besinsel özellikleri üzerine etkilerinin incelenmesi

(Lisansüstü Eğitim Enstitüsü, 2024-02-13) Gezici, Dilara ; Fıratlıgil, Fatma Ebru ; 506211508 ; Gıda Mühendisliği

Günümüz sosyoekonomik koşullarının etkisi ile tüketicilerin sağlıklı beslenme ihtiyaçlarında yaşanan artış gıda ürünlerinden de beklentilerini değiştirmiştir. Son yıllarda tüketiciler ürünlerden yalnızca beslenme ihtiyacını karşılamasını değil buna ek olarak sağlıkları için pozitif bir etki yaratmasını beklemektedir. Bu kapsamda beğenilen orgonoleptik özellikleri ve ve düşük fiyatı ile özellikle çocuk tüketicilerin en çok tükettiği ürünlerden biri olan yüksek şeker oranına sahip yumuşak şekerler bu tez çalışmasının ana ürünü olarak seçilmiştir. Bu ürünlerden ilave şeker çıkarılarak yerine prebiyotik lif olan fruktooligosakkaritler (FOS) eklenmiş ve %30 vişne suyu konsantresi ile üretimleri sağlanmıştır. Bu ürünlere %2, %4 ve %6 oranlarında selüloz, bambu ve buğday lifi eklenerek bu liflerin fizikokimyasal özellikler, antioksidan miktarı ve biyoerişebilirlik üzerine etkileri araştırılmıştır. Fizikokimyasal analizlerde nem analizi için Karl Fischer yöntemi, renk analizi için ise Konica Minolta cihazı kullanılmıştır. Tekstür analizi için tekstür profil analizi (TPA) yöntemi kullanılmıştır. %2, %4 ve %6 oranlarda selüloz, bambu ve buğday içeren numunelere %80 metanol ile ekstraksiyon yapılarak toplam fenolik madde miktarı, toplam flavonoid madde miktarı, bakır (II) indirgen antioksidan kapasitesi (CUPRAC) ve 2,2-difenil-1-pikrilhidrazil (DPPH) antioksidan aktiviteleri spektrofotometrik yöntemler ile ölçülmüştür. Buna ek olarak tüm ürünlere in vitro gastrointestinal sindirim similasyonu yapılarak mide ve bağırsak fazlarından alınan numunelerin toplam fenolik madde miktarı, toplam flavonoid madde miktarı, bakır (II) indirgen antioksidan kapasitesi (CUPRAC) ve 2,2-difenil-1-pikrilhidrazil (DPPH) antioksidan aktiviteleri spektrofotometrik yöntemler ile ölçülmüştür. Yapılan fizikokimyasal analiz sonuçlarına göre nem değeri kontrol için %27,4 ± 0,5 olarak bulunurken, lif ilavesinin nem değerinde azalmaya sebebiyet verdiği sonucuna varılmış ve %2, %4 ve %6 oranlarında selüloz, bambu ve buğday lifi ilave edilmiş yumuşak şekerlerin nem değerleri %23,8 ± 0,2 ile %26,6 ± 0,9 aralığında tespit edilmiştir. Lif seviyesi sabit tutularak nem değerleri karşılaştırıldığunda ise bambu lifi ilaveli ürünlerin nem değerlerinin selüloz ve buğday lifi ilaveli ürünlerden daha yüksek olduğu görülmüştür. Renk analizi için a*, b*, L* ve ΔE* değerleri değerlendirilmiştir. Kontrol numunesi için a* değeri -0,11 ± 0,08 bulunurken, %2, %4 ve %6 oranlarında selüloz, bambu ve buğday lifi ilave edilmiş yumuşak şekerlerin a* değeri 0,41 ± 0,08 ile 5,42 ± 0,88 değerleri arasında bulunmuş ve lif ilavesinin a* değerinde artışa sebebiyet verdiği tespit edilmiştir. Kontrol numunesi için b* değeri 1,51 ± 0,13 bulunurken, %2, %4 ve %6 oranlarında selüloz, bambu ve buğday lifi ilave edilmiş yumuşak şekerlerin b* değeri 0,61± 0,04 ile 2,56 ± 0,25 değerleri arasında bulunmuş ve lif ilavesinin b* değerinde artışa sebebiyet verdiği tespit edilmiştir. Kontrol numunesi için L* değeri 22,8 ± 0,7 bulunurken, %2, %4 ve %6 oranlarında selüloz, bambu ve buğday lifi ilave edilmiş yumuşak şekerlerin L* değeri 21,5± 0,2 ile 22,6 ± 0,4 değerleri arasında bulunmuş ve lif ilavesinin L* değerinde azalmaya sebebiyet verdiği tespit edilmiştir. Kontrol numunesi için ΔE * değeri 15,8 ± 0,8 bulunurken, %2, %4 ve %6 oranlarında selüloz, bambu ve buğday lifi ilave edilmiş yumuşak şekerlerin ΔE * değeri 16,2± 0,4 ile 13,2 ± 0,3 değerleri arasında bulunmuştur. Selüloz, buğday ve bambu lifinde lif oranı artırıldıkça ΔE değerlerinde azalma tespit edilmiştir.
Farklı gaz geçirgenliklerine sahip ambalaj malzemelerinin toz formda ezogelin ve şehriyeli tavuk çorbalarının kalitesi ve raf ömrü üzerine etkileri

(Lisansüstü Eğitim Enstitüsü, 2023-02-01) Cellat, Ayşe Merve ; Güneş, Gürbüz ; 506191502 ; Gıda Mühendisliği

Son zamanlarda tüketicilerde hazır gıdaya ilgi gün geçtikçe artmaktadır. Hazır toz çorbalar da bu ürünlerden biridir. Kolay taşınabilir ve pişirme açısında zaman kolaylığı sağlaması bu gıda ürünlerinin en önemli avantajlarındandır. Hazır çorba, kurutulmuş bileşenleri içermekte olup, su aktivitesi 0,60 değerinin altında olması sebebiyle dayanıklı gıda sınıfına girmektedir. Bu sebeple genel olarak mikrobiyal bozulma tehlikesi oldukça düşüktür. Bunun yanı sıra bu gıda ürünlerinde kimyasal bozulmalar meydana gelmekte olup bunların içinde en önemli yeri yağ oksidasyonu almaktadır. Hazır çorbalar kurutma prosesinden geçirilen ürünler olup bozulmalara karşı oldukça dayanıklı ürünler olmasına karşın doğru ambalaj materyali seçmek gıdanın raf ömrünü ve maliyetini önemli ölçüde etkilemektedir. Ambalaj materyalinin geçirgenliği gıda ile çevre arasında madde geçişini dolayısıyla gıdanın raf ömrünü önemli şekilde etkilemektedir. Çalışmanın amacı farklı oksijen geçirgenilk özelliğine sahip üç farklı ambalaj materyalinin (1,3-17,1 arasında), hazır çorba ürünlerinin raf ömrüne etkisini araştırmaktır. Bu çalışmada farklı geçirgenlik özelliğne sahip üç farklı ambalaj materyali kullanılmıştır. Bu materyaller Ambalaj-1, Ambalaj-2 ve Ambalaj-3 olarak kodlanmış olup oksijen geçirgenliği sırasıyla 1.31, 17.07, 4.79 cm3/m2.gün'dür. Ambalajların su buharı geçirgenliğ oldukça birbirine yakın olup sırasıyla 2,29, 1,45 ve 1,81 g/m2.gün'dür. Çalışmada test ürünü olarak ezogelin çorbası ve şehriyeli tavuk çorbası ürünleri kullanılmıştır. Bir ticari firmanın kendi tesisinde dolum yapılan ve test ambalaj materyalleri ile normal atmosfer gazı altında ambalajlanan ürünler fakülteye getirilmiş olup farklı depolama koşullarında depolanmıştır. -15℃ depolama sıcaklığı taze kontrol örneklerini oluşturmakta olup, 25℃ depolama sıcaklığı ticari depo sıcaklığı ve 35 ℃'de depolanan örnekler ise hızlandırılmış test koşullarını temsil etmektedir. Ayrı ayrı gruplandırılıp, belirtilen şartlarda depolanan numuneler her 2 ayda bir çeşitli kalite özellikleri açısından analiz edilmiştir. Bunlar tepe boşluğu gaz analizi, renk analizi, nem analizi, oksidasyon için TBARS analizi ve duyusal analizdir. Çalışmada sonuç olarak Ambalaj-1 ve Ambalaj-3 ile ambalajlanan numunelerde tepe boşluğundaki oksijen oranı zaman içinde azalmış olup, karbon dioksit oranı artmıştır. Ambalaj-2 ile depolanan numunelerde ambalaj içi gaz konsantrasyonu önemli şekilde değişmemiştir.Ambalaj-1 ile depolanan ezogelin çorbası numuneleri rengini daha iyi muhafaza etmiştir. Şehriyeli tavuk çorbası numunelerinde zaman içinde renkte koyulaşma görülmüştür. Hem ezogelin hem de şehriyeli tavuk çorbası numunelerinde nem içeriği, TBARS değeri ve duyusal özellikler önemli şekilde etkilenmemiştir. Sonuç olarak yapılan analiz ve gözlemler ile 12 aylık depolama süresi içerisinde ambalaj materyalinin geçirgenliğinin 1,3 ve 17, 1 aralığında, test edilen ezogelin ve şehriyeli tavuk toz çorbası örneklerine etkisi önemli bulunmamıştır.
Improvement of functional properties of chickpea flour and application in bakery products

(Lisansüstü Eğitim Enstitüsü, 2022) Nazari, Parnia ; Karaça, Aslı Can ; 741152 ; Gıda Mühendisliği Bilim Dalı

Nohut unu, besleyici ve fonksiyonel özellikleri ile ön plana çıkan ve yeni ürün formülasyonlarında sıkça kullanılmaya başlanan bir gıda bileşenidir. Bu araştırmanın amacı, kavurma ve ultrason işlemlerinin nohut ununun fonksiyonel özellikleri üzerindeki etkilerini araştırmaktır. Emülsiyon ve köpük oluşturma ve stabilize etme özelliklere özel önem verilmiştir. İlk çalışmada, numuneler önceden 80, 90, 100, 110 ve 120 °C'ye ısıtılmış bir fırında 1 dakika süre ile kavrulmuştur. Daha sonra fizikokimyasal ve fonksiyonel özellikler incelenmiştir. Her numunede kavurma işlemi ile kütle yoğunluğunun önemli ölçüde arttığı bulunmuştur. Kavurma işlemi sonrasında renk parametreleri, emülsiyon aktivitesi ve stabilitesi, köpürme ve termal özellikler arasında anlamlı farklar tespit edilmiştir. İkinci çalışmada 100°C ve 120°C'de 2,5, 5, 7,5 ve 10 dakikalık farklı sürelerde kavurma incelenmiştir. Sonuçlar, suda çözünürlük indeksinin önemli ölçüde arttığını, kırmızılık ve sarılık değerlerinde farklılık olduğunu göstermiştir. Numunelerin emülsiyon, köpürme ve termal özellikleri, kavurma süresi ve sıcaklığına göre değişimi göstermiştir. Sonuç olarak, 100℃'de 2,5 dakika kavrulmuş numunenin özelliklerinin en iyi olduğu gözlenmiştir. Son olarak, farklı süreler için farklı amplitüd değerlerinde ultrason işleminin köpük oluşturma ve emülsiyon özellikleri üzerindeki etkileri araştırılmış ve bu faktörlerin hiçbirinin anlamlı ölçüde etkilenmediği bulunmuştur. Son olarak, en uygun koşullarda kavurma işlemi uygulanmış nohut unu fırıncılık ürünlerinde kullanılarak ürünün duyusal özellikleri üzerindeki etkisi incelenmiştir. Duyusal değerlendirmeleri incelemek için uygulama olarak bir çeşit nohut kurabiyesi hazırlanmıştır. Toplam 20 kişi tarafından değerlendirilen duyusal panellere dayanarak, kontrol numunesinin tadı ve dokusuna göre, genel olarak 90 ve 100°C'de kavrulmuş unun kullanıldığı numuneler daha iyi sonuç verdi. 100°C'de 2,5 dakika kavrulmuş numunede sonradan oluşan tat (fasulye/yeşil tat) önemli ölçüde azaldı. Sonuç olarak, incelenen özellikler ve duyusal değerlendirmeler göz önüne alındığında, fırıncılık kullanımı için en uygun örneğin 100℃'de 2,5 dakika kavrulmuş un örneği olduğu görülmüştür. Kavurma işlemi ile nohut ununun fonksiyonel ve duyusal özelliklerini iyileştirilmesinde kullanılabilir.
Kakao yağının serbest yağ asitliği düzeyini etkileyen proses parametrelerinin incelenmesi

(Lisansüstü Eğitim Enstitüsü, 2023-02-28) Çiçek, Büşra ; Yeşilçubuk Şahin, Neşe ; 506181517 ; Gıda Mühendisliği

Ham kakao yağında yüksek miktarda bulunan serbest yağ asitleri (SYA) yağın deodorize edilmesi ile belli bir seviyeye düşürülür. Daha yüksek SYA içeriğinin, kakao yağının sertliğinde bir azalmaya yol açtığı ve hem üreticiler hem de çikolata üreticileri için ham kakao ticari değerini azaltan bir faktör olduğu düşünülmektedir. Hem yağın kalitesini arttırmak hem de yasal sınırlara uygun hale getirmek için çeşitli proseslerle SYA kontrol altında tutulmalıdır. Bu çalışmada, kakao yağı üretiminde SYA'ya etki edecek debakterizasyon, kavurma ve deodorizasyon proseslerindeki debakterizasyon sıcaklığı ve süresi, kavurma alt-üst sıcaklıkları, deodorizasyon sıcaklığı, süresi, buhar basıncı ve vakum değerleri değişkenlerinin etkisinin istatistiksel yöntemlerle incelenmesi amaçlanmıştır.Yapılan veri analizine göre anlamlı bulunan değişkenler deodorizasyon süresi, deodorizasyon vakum değeri ve çok sayıdaki verinin medyanı alınarak analiz edilen kavurma üst sıcaklığı olmuştur (p ≤ 0,05). Deodorizasyon sıcaklıkları 150-174 °C arasında değişmiş olup, SYA'ya etki etmemiş ve anlamlı değişken olarak gözlemlenmemiştir. Bunun yanı sıra deodorizasyonda kullanılan buhar basıncı/miktarı SYA değişiminde efektif bir değişken olarak gözlemlenmemiştir (p> 0,05). Kakao yağını oluşturmak için birden fazla kakao çekirdeği partileri kavrularak birleştirilir, veri analizindeki farklı partilerin kavurma sıcaklık dağılımları geniş skalada olduğundan ortalama alınarak elde edilen tek veride, istatistiksel analize göre değişken anlamlı bulunmamıştır (p> 0,05). Medyan alınarak elde edilen kavurma verilerinde ise sadece üst sıcaklık anlamlı çıkmıştır (p ≤ 0,05). Kavurmanın üst sıcaklıkları nemin uzaklaştırılması amacı ile kullanılırken, kavurmanın alt sıcaklıklarında ise aroma ve renk oluşturma işlemlerinin yapılmasından dolayı kavurma alt sıcaklıklarında SYA değişimi minimal düzeyde olmuştur ve kavurma alt sıcaklığı SYA'yı etkileme noktasında anlamlı çıkmamıştır. Debakterizasyon proses aşamasında uygulanan sıcaklıklar 250℃ altında ve işlem süresi saniye düzeyinde olduğundan SYA uzaklaştırılması minimal düzeyde olmakta ve etki düzeyi düşük olduğundan SYA'yı etkileme noktasında anlamlı bulunamamıştır (p> 0,05). Çalışmanın sonucuna göre, debakterizasyon süresi arttırılarak prosesin devamında SYA için stabilizasyon durumunun arttırılabileceği ve deodorizasyon sıcaklıkları da 200 °C ve üzerine çıkarılarak uzaklaştırılan SYA arttırılarak proses veriminin arttırılabileceği tespit edilmiştir.

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