Gıda Mühendisliği

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  • Öge
    Abstract book of the international symposium on food rheology and texture, 19 October 2018 - İstanbul, Turkey
    (Istanbul Technical University Press, 2018) Kimya - Metalurji ; Lokumcu Altay, Filiz ; Toker, Ömer Said ; Dede, Sercan
  • Öge
    Alternative plant-based gluten-free sourdough pastry snack production by using beetroot and legumes: characterization of physical and sensorial attributes
    (American Chemical Society, 2024) Yolcu, Zeynep ; Demircan, Evren ; Mertdinç, Zehra ; Aydar, Elif Feyza ; Özçelik, Beraat ; 0000-0002-1810-8154 ; Gıda Mühendisliği
    Objective of this study was to design a formula of a sourdough pastry snack by adding starter inoculum into the formulation which was obtained by the fermentation process through beetroot (Beta vulgaris) puree with black-eyed pea (Vigna unguiculata) and fava bean (Vicia faba). With this development process, it was aimed to review the functional impact of legumes as gluten replacement and emphasize the importance regarding physical and sensory attributes in a pastry snack product. First, a starter inoculum was developed based on modification of the shalgam fermentation process with legumes. An experimental design suggested by the response surface methodology was used to optimize its microbial properties and level of antioxidants with the factors of amounts of beetroot puree, fava bean/black-eyed pea ratio, and fermentation time. In the second part, this starter inoculum was mixed with fava bean flour to obtain a sourdough pastry snack (FBS) with improved physical and sensory attributes and compared to the wheat control sourdough (WCS) pastry snack after the baking process. According to the optimization results to produce starter inoculum with the optimum results of lactic acid bacteria 9.55 log cfu/mL, the level of antioxidant activity 91.86 μM TE/mL, and total yeast level 6.96 log cfu/mL; 75 mL of beetroot puree, 100% for fava bean, and fermentation for 24 h were obtained. Compared to WCS, FBS has approximately 16% higher hardness values. Also, a significant difference was observed for stiffness and springiness among samples. The retention of moisture was higher in the first 4 days following the storage for 8 days; the moisture content continuously decreased with the final moisture content of 12.6%. When compared with the results of textural profile analysis in terms of hardness, stiffness, and springiness, sensory results were correlated. Comparing the overall acceptability of the FBS to WCS, FBS was from moderate to higher scores, which indicated that it could be a promising alternative to chemically developed snack products and a preferred product for people suffering from celiac disease and other gluten intolerances.
  • Öge
    Antifungal Activities of Different Essential Oils and Their Electrospun Nanofibers against Aspergillus and Penicillium Species Isolated from Bread
    (American Chemical Society, 2022) Karbancıoğlu Güler, Funda ; Devecioğlu, Tuğba ; Türker, Mustafa ; 0000-0001-6576-0084 ; 0000-0001-6681-0944 ; Food Engineering
    Mold growth, especially Aspergillus spp. and Penicillium spp., deteriorates the quality of bakery products. Essential oils (EOs) have been categorized as good natural antimicrobials. Hereby, this study aimed to evaluate the antifungal activity of six EOs, ginger, cumin, cinnamon, black pepper, origanum, and clove, and their volatile compounds against fungal strains isolated from bread: Penicillium carneum DDS4, Aspergillus flavus DDS6, and Aspergillus niger DDS7 by disc diffusion and disc volatilization methods, respectively. Among EOs, cumin, cinnamon, origanum, and clove were found to be effective against fungal strains, and their minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined. The observed lowest MIC value of EOs was obtained at 1000 μg/mL concentration, and the lowest MFC value was obtained from the results of clove at a concentration of 1000 μg/mL. Based on the MIC and MFC values, clove and cinnamon EOs were found to be more effective at lower concentrations. Electrospun nanofiber films of clove and cinnamon were produced with 6% poly(vinyl alcohol) (PVA), 2% β-cyclodextrin (β-CD), and 2% EO to overcome the unfavorable sensory impact of EOs on food products. The inhibitory activity of cinnamon EO film (2.64–2.51 log(CFU/mg)) was considerably lower than clove EO film (3.18–3.24 log(CFU/mg)) against P. carneum DDS4 and A. niger DDS7. Furthermore, these nanofiber films prevented fungal growth on bread samples visibly and were shown to be an alternative application for active food packaging.
  • Öge
    Cold plasma application to fresh green leafy vegetables: impact on microbiology and product quality
    (Wiley, 2023) Özdemir, Emel ; Başaran, Pervin ; Kartal, Sehban ; Akan, Tamer ; orcid.org/0000-0002-1627-7333 ; orcid.org/0000-0002-9969-6196 ; orcid.org/0000-0002-0491-4219 ; orcid.org/0000-0003-0907-2724 ; Gıda Mühendisliği
    Fresh green leafy vegetables (FGLVs) are consumed either garden-fresh or by going through very few simple processing steps. For this reason, foodborne diseases that come with the consumption of fresh products in many countries have prioritized the development of new and reliable technologies to reduce food-related epidemics. Cold plasma (CP) is considered one of the sustainable and green processing approaches that inactivate target microorganisms without causing a significant temperature increase during processing. This review presents an overview of recent developments regarding the commercialization potential of CP-treated FGLVs, focusing on specific areas such as microbial inactivation and the influence of CP on product quality. The effect of CP differs according to the power of the plasma, frequency, gas flow rate, application time, ionizing gases composition, the distance between the electrodes and pressure, as well as the characteristics of the product. As well as microbial decontamination, CP offers significant potential for increasing the shelf life of perishable and short-shelf-life products. In addition, organizations actively involved in CP research and development and patent applications (2016–2022) have also been analyzed.
  • Öge
    Combined effects of zein nanofiber coating containing laurel (laurus nobilis) and air fryer cooking on quality properties of fish fillets during cold storage
    (American Chemical Society, 2024) Ceylan, Zafer ; Meral, Raciye ; Alav, Aslıhan ; Torusdağ, Gülşen Berat ; Bildik, Fatih ; Altay, Filiz ; 0000-0002-5484-866X ; Gıda Mühendisliği
    In this study, the effects of zein nanofibers (Zn) containing ground laurel leaves (GLL) and air fry cooking on the quality characteristics of Rainbow trout (Oncorhynchus mykiss) were investigated. The zein nanofibers possessing 335.8 ± 43.6 nm average diameters were fabricated containing GLL. The Fourier transform infrared spectroscopy (FTIR) results of the zein, Zn, GLL, and zein nanofibers containing GLL (LZn) confirmed the electrospinning encapsulation of GLL into Zn and their interactions. The effects of the combination of LZn coating and air fryer cooking of fish fillets on the quality characteristics during storage at 4 °C for 10 days were monitored in terms of oxidative and microbiological stability, color, and sensory parameters. As compared to the control, the combination of LZn coating and air fryer cooking provided a microbial limitation of up to 45.21% during the analysis (p < 0.05). The changes in ΔE values between the control and the LZn-coated samples were obtained as ≤7.56 during 6 days, but then a dramatic color difference was observed. Besides overall sensory acceptability, particularly the odor parameter in the cooked fish samples coated with LZn was significantly preferred (p < 0.05). The combination of LZn coating and air fryer cooking delayed the thiobarbituric acid increase in the fish meat samples (3.51 to 2.57 mg malondialdehyde (MDA)/kg) up to the third day of storage. This study showed that LZn coating is a very functional layer on the fish meat and could be applied for not only fresh fish meat but also other fresh meat products.
  • Öge
    Effect of spray drying on physicochemical stability and antioxidant capacity of rosa pimpinellifolia fruit extract-loaded liposomes conjugated with chitosan or whey protein during in vitro digestion
    (Springer, 2024) Kasapoğlu, Kadriye Nur ; Gültekin-Özgüven, Mine ; Kruger, Johanita ; Frank, Jan ; Bayramoğlu, Pelin ; Barla-Demirkoz, Aslı ; Özçelik, Beraat ; 0000-0001-6070-4948 ; 0000-0002-2073-8075 ; 0000-0002-1810-8154 ; Gıda Mühendisliği
    Spray drying is a well-established, energy efficient, and scalable process widely used in the food industry, however it may lead to thermal degradation of susceptible compounds, such as (poly)phenols, resulting in biological activity loss to some extent. In this study, we aimed to improve the physicochemical stability and bioaccessibility of (poly)phenols from Rosa pimpinellifolia fruit extract (Rosa extract) loaded in liposomes by generating solid particles via spray drying. Liposomes were conjugated with chitosan (Ch) and whey protein (Wp) to optimize the biopolymer concentrations by monitoring mean particle diameter, polydispersity index, and surface charge. The mean diameter of liposomes ranged between 135 and 210 nm upon optimal addition of Ch (0.4%, w/v) and Wp (4.0%, w/v) which also increased the entrapment efficiency of (poly)phenols from 74.2 to 77.8% and 79.1%, respectively. After spray drying, about 65–76% of the antioxidant capacity were retained in biopolymer-conjugated liposomes (Ch or Wp) while the retention rate was 48% in only spray-dried extract (Rosa extract powder). Compared to unencapsulated Rosa extract, spray drying (Rosa extract powder) and conjugation with Ch (Ch-Lip powder) or Wp (Wp-Lip powder) significantly increased the bioaccessibility of (poly)phenols and preserved their antioxidant capacity. Based on the findings of this study, Ch- or Wp-conjugation of liposomes prior to spray drying could improve physicochemical stability and protect (poly)phenols loaded in liposomes against processing stress and passage through the digestive tract. Further in vitro and in vivo investigations on a variety of bioactive compounds may draw more attention to their potential as functional foods.
  • Öge
    Effects of egg on cake batter rheology and sponge cake texture
    (Wiley, 2024) Inanlar, Batuhan ; Altay, Filiz ; orcid.org/0000-0002-5484-866X ; Food Engineering
    The physical, rheological, and textural properties of cake batters and cakes made from three different eggs were studied. The compositions of the egg samples are significantly different (p < 0.05), except for their fat contents. The flow characteristics of the cake batters showed pseudoplastic behavior with time dependency. In the frequency sweep test, the G" values were lower than the G' values at low frequencies and vice versa at high frequencies. The G" values of the samples decreased with the water content of the egg samples. While the sample with the highest amount of water showed less viscous batter properties, it yielded a cake structure with more moisture and less hardness, chewiness, adhesiveness, cohesiveness, and springiness properties. The G' and G" moduli decreased for all cake batters in the temperature sweep tests. Eggs with high protein and low water contents should be preferred for consumer acceptance.
  • Öge
    Efficacy of atmospheric non-thermal plasma corona discharge under dry and wet conditions on decontamination of food packaging film surfaces
    (Wiley, 2024) Acar, Emine Gizem ; Doganoz, Dilan ; Çavdar, Deniz ; Karbancioglu-Guler, Funda ; Burlica, Radu ; Astanei, Dragos ; Olariu, Marius-Andrei ; Gunes, Gurbuz ; orcid.org/0000-0002-2948-3785 ; Gıda Mühendisliği
    Food packaging materials must be sterilized to prevent cross-contamination of the product. Non-thermal plasma (NTP) corona discharge can be an effective alternative sterilization method for packaging films. The inactivation efficiency atmospheric NTP corona discharge under dry and wet conditions against vegetative cells of Escherichia coli, Staphylococcus aureus and Bacillus subtilis, spores of B. subtilis and Clostridium sporogenes and fungal spores of Candida albicans, Penicillium expansum and Aspergillus niger on polymeric packaging films were studied. The maximum inactivation of these microorganisms was 5.58, 0.54, 1.51, 1.06, 2.47, 1.73, 2.80, 3.20 and 3.50 log, respectively. Microbial inactivation by the treatments was greatly enhanced under wet conditions. Gram-negative bacteria were found to be more sensitive to NTP, but spores were more resistant than vegetative bacterial cells. Although fungi were less susceptible than bacteria in dry treatments, they became more sensitive than the Gram-positive bacteria in wet treatments. Overall, plasma treatments under wet conditions achieved higher microbial inactivation and would be favourable over the dry treatment.
  • Öge
    Encapsulated phenolic compounds : clinical efficacy of a novel delivery method
    (Springer, 2024) Özkan, Gülay ; Ceyhan, Tuğçe ; Çatalkaya, Gizem ; Rajan, Logesh ; Ullah, Hammad ; Daglia, Maria ; Çapanoğlu, Esra ; 0000-0003-0335-9433 ; Gıda Mühendisliği Bölümü
    Encapsulation is a drug or food ingredient loaded-delivery system that entraps active components, protecting them from decomposition/degradation throughout the processing and storage stages and facilitates their delivery to the target tissue/organ, improving their bioactivities. The application of this technology is expanding gradually from pharmaceuticals to the food industry, since dietary bioactive ingredients, including polyphenols, are susceptible to environmental and/or gastrointestinal conditions. Polyphenols are the largest group of plants' secondary metabolites, with a wide range of biological effects. Literature data have indicated their potential in the prevention of several disorders and pathologies, ranging from simpler allergic conditions to more complex metabolic syndrome and cardiovascular and neurodegenerative diseases. Despite the promising health effects in preclinical studies, the clinical use of dietary polyphenols is still very limited due to their low bioaccessibility and/or bioavailability. Encapsulation can be successfully employed in the development of polyphenol-based functional foods, which may improve their bioaccessibility and/or bioavailability. Moreover, encapsulation can also aid in the targeted delivery of polyphenols and may prevent any possible adverse events. For the encapsulation of bioactive ingredients, several techniques are applied such as emulsion phase separation, emulsification/internal gelation, film formation, spray drying, spray-bed-drying, fluid-bed coating, spray-chilling, spray-cooling, and melt injection. The present review aims to throw light on the existing literature highlighting the possibility and clinical benefits of encapsulated polyphenols in health and disease. However, the clinical data is still very scarce and randomized clinical trials are needed before any conclusion is drawn.
  • Öge
    Encapsulation of black rice bran extract in a stable nanoemulsion : effects of thermal treatment, storage conditions, and in vitro digestion
    (American Chemical Society, 2024) Saleh, Mohamed N. ; Salam, Mohamed Abdelbaset ; Çapanoğlu, Esra ; 0000-0003-0335-9433 ; Gıda Mühendisliği
    This study aimed to improve the dispersibility of phenolic compounds from black rice bran through the encapsulation process within nanoemulsion. The study focused on assessing the stability of the nanoemulsions, which were prepared using a combination of surfactants with distinct hydrophilic–lipophilic balance (HLB) values and sunflower oil under different thermal treatments and storage conditions. The study revealed a significant correlation between the mixed surfactant HLB value and the nanoemulsions properties, including average particle size, polydispersity index (PDI), and ζ-potential. Specifically, an increase in the HLB value was associated with a decrease in the initial average particle size. The encapsulated polyphenols exhibited remarkable stability over a storage period of up to 30 days at different temperatures with no significant changes observed in particle size or PDI. The study also investigated the impact of different ionic strengths (0.2, 0.5, and 1.00 mol L–1 NaCl) on the physical stability and antioxidant black rice bran extract nanoemulsion, and the results revealed that adding NaCl influenced the particle size and surface charge of the nanoemulsions. Total phenolic content and DPPH results demonstrated a significant impact of salt concentration on antioxidant properties, with varying trends observed among the HLB formulations. Furthermore, the behavior of the encapsulated extracts during digestion was examined, and their antioxidant activity was evaluated.
  • Öge
    Enhanced production of gamma-aminobutyric acid in fermented carrot juice by utilizing pectin hydrolysate derived from pomegranate waste
    (Wiley, 2024) Devecioğlu, Dilara ; Kara, Didem ; Tapan, Rabia ; Karbancıoğlu-Güler, Funda ; Kahveci, Derya ; orcid.org/0000-0001-6681-0944 ; orcid.org/0000-0001-6576-0084 ; orcid.org/0000-0003-0450-5682 ; Gıda Mühendisliği
    In this study, a functional fermented beverage enriched with gamma-aminobutyric acid (GABA) was produced. To achieve this, the prebiotic abilities of pectin obtained from pomegranate peel and its enzymatic hydrolysates were evaluated. Additionally, a functional fermented beverage enriched with GABA was produced by fermenting carrot juice with pectin hydrolysates. First, pectin was obtained at a yield of 8.91% from pomegranate peels. Pectinase-catalyzed hydrolysis of the obtained pectin was applied using different enzyme concentrations and hydrolysis times, and the effect of these hydrolysates on the growth of Levilactobacillus brevis was determined. Although the Fourier transform infrared (FT-IR) spectra of the resulting hydrolysates were similar, their degree of esterification compared to that of pectin was statistically different (p < .05). Considering the viability analysis and GABA production of L. brevis in the liquid medium supplemented with pectin or its hydrolysate, the hydrolysate obtained by treatment with 400 μL enzyme for 2 h and having a high glucose content (216.80 mg/100 g) was selected for application in fermented carrot juice. During fermentation (24, 48, and 72 h), a remarkable change was observed, especially in the amounts of lactic acid and malic acid, while the amount of GABA in carrot juice varied between 25 and 46 mg/mL and increased with the increase in hydrolysate concentration. It was observed that the total phenolic content and antioxidant activity of carrot juice were highly affected by the hydrolysate concentration. This study demonstrated that pectin hydrolysate obtained from food waste could be a potential prebiotic and could be used in the production of a functional beverage with improved GABA content.
  • Öge
    Proceedings for the 1st International Multidisciplinary Acorn as Food Workshop
    (İTÜ Yayınevi, 2025) Gıda Mühendisliği ; Urhan, Canan
    By bringing together experts from diverse fields—ranging from biology to food science to social studies and food policy—this event sought to foster interdisciplinary dialogue and collaboration around the multifaceted potential of acorns as a food source. The workshop featured contributions from researchers, practitioners, and policymakers with an international scope, reflecting a growing recognition of acorns' role in addressing critical global food challenges, such as food security, biodiversity conservation, and cultural heritage preservation. Topics explored include the historical and cultural significance of acorns, their nutritional and economic potential, and the challenges associated with integrating them into modern food systems. In addition, the workshop highlighted innovative methodologies and strategies for overcoming barriers, such as limited awareness, fragmented supply chains, and the erosion of traditional knowledge. This proceedings book presents a rich collection of research findings, case studies, and theoretical insights presented by our esteemed participants at this workshop.
  • Öge
    Quality and antioxidant activity of dandelion root infusions as affected by cold plasma pretreatment
    (Wiley, 2024) Elcik, Berfin Eda ; Kirkin, Celale ; orcid.org/0000-0002-8114-1328 ; orcid.org/0000-0003-0736-4213 ; Gıda Mühendisliği
    Ground and unground dandelion roots were subjected to dielectric barrier discharge cold plasma (DBDCP) at 40 kV for 0 (control), 10, or 20 min. Then, infusions of the pretreated dandelion roots in water were prepared, and the changes in color, total phenolic content (TPC), antioxidant activity, and sensory properties were investigated. The 20-min pretreatment increased the b* value, TPC, antioxidant activity, and sage odor of the ground dandelion root infusions compared with the control, whereas decreases in the TPC, antioxidant activity, and sage odor were noted in the 10-min pretreated infusions of the unground roots. DBDCP pretreatment did not affect the overall likeliness of infusions of ground and unground roots. In addition, the TPC, antioxidant activity, and overall likeliness of infusions of the ground dandelion roots were higher than those of the unground samples. In conclusion, it can be said that the DBDCP pretreatment can be utilized to improve the TPC and antioxidant activity of ground dandelion roots.
  • Öge
    Recent Insights into the Use of Antagonistic Yeasts for Sustainable Biomanagement of Postharvest Pathogenic and Mycotoxigenic Fungi in Fruits with Their Prevention Strategies against Mycotoxins
    (American Chemical Society, 2023-06-23) Karbancıoğlu Güler, Funda ; Öztekin, Sebahat ; Dikmetaş, Dilara Nur ; Devecioğlu, Dilara ; Acar, Emine Gizem ; 0000-0001-6576-0084 ; Food Engineering
    Fungi-induced postharvest diseases are the leading causes of food loss and waste. In this context, fruit decay can be directly attributed to phytopathogenic and/or mycotoxin-producing fungi. The U.N. Sustainable Development Goals aim to end hunger by 2030 by improving food security, sustainable agriculture, and food production systems. Antagonistic yeasts are one of the methods presented to achieve these goals. Unlike physical and chemical methods, harnessing antagonistic yeasts as a biological method controls the decay caused by fungi and adsorbs and/or degrades mycotoxins sustainably. Therefore, antagonistic yeasts and their antifungal mechanisms have gained importance. Additionally, mycotoxins’ biodetoxification is carried out due to the occurrence of mycotoxin-producing fungal species in fruits. Combinations with processes and agents have been investigated to increase antagonistic yeasts’ efficiency. Therefore, this review provides a comprehensive summary of studies on preventing phytopathogenic and mycotoxigenic fungi and their mycotoxins in fruits, as well as biocontrolling and biodetoxification mechanisms.
  • Öge
    Recovery, bioactivity, and utilization of bioactive phenolic compounds in Citrus peel
    (Wiley, 2024) Durmuş, Nihal ; Gülsünoğlu-Konuşkan, Zehra ; Kılıç-Akyılmaz, Meral ; orcid.org/0000-0002-2068-0336 ; Gıda Mühendisliği
    Citrus peels are rich in bioactive phenolic compounds with various health effects including antioxidant, antiobesity, antiinflammatory, antihypertensive, antihypercholesterolemic, antimicrobial, antidiabetic, and anticarcinogenic activities. Both extractable and nonextractable phenolics are present in significant amounts in Citrus peel with diverse bioactivities. While extractable phenolics can be recovered from the fruit peels by conventional extraction methods, nonextractable phenolics remaining in the residues must be released from the cell matrix first by hydrolysis with acid, alkali, or enzymes. Novel processing technologies can help in improvement of extraction efficiency. Extreme process or medium conditions degrade phenolics and their bioactivity where encapsulation can be applied to improve their stability, solubility, and bioactivity. Citrus peel powder including ascorbic acid and dietary fiber besides phenolics or extracts therefrom can be used as functional food ingredients to extend shelf life and provide health benefits. In addition, phenolic extracts can be used as antioxidant and antimicrobial agents in active food packaging applications. Phenolic extracts have also a potential to be used as nutraceuticals and pharmaceuticals. In this review, phenolic compounds in different forms in Citrus peels, their recovery, bioactivity and possible applications for upcycling in the industry are presented.
  • Öge
    Recruiting grape-isolated antagonistic yeasts for the sustainable bio-management of Botrytis cinerea on grapes
    (Wiley, 2024) Öztekin, Sebahat ; Karbancıoğlu-Güler, Funda ; orcid.org/0000-0003-0859-1776 ; orcid.org/0000-0001-6576-0084 ; Gıda Mühendisliği
    Botrytis cinerea is the causative agent of grey mould disease in grapes, which was linked to significant postharvest losses. This study examined three grape-isolated yeasts (Metschnikowia aff. fructicola, Metschnikowia pulcherrima, and Hansenispora uvarum) through in vitro and in vivo tests on detached grape berries against grey mould, as well as the elucidation of their possible mechanisms of action. The antifungal mechanism of action of yeasts was determined by the lytic enzyme activity, inhibition of spore germination, biofilm activity, iron depletion, diffusible metabolites, wound-site colonisation, mycocin, and volatile organic compounds (VOCs) production. The highest in vitro efficacy (83.13%) was observed on M. aff. fructicola, followed by M. pulcherrima (82.10%) and H. uvarum (71.66%). Metschnikowia yeasts exhibited comparable enzyme activities, including protease, β-1,3 glucanase, gelatinase chitinase, and cellulase, while H. uvarum had a poor enzymatic activity with chitinase and gelatinase. M. aff. fructicola showed relatively higher iron depletion activity than M. pulcherrima, while M. pulcherrima outperformed via diffusible metabolites. All yeast cultures significantly reduced spore germination by at least 86%. Overall, M. aff. fructicola exhibited the highest biocontrol activity with its iron depletion, inhibition of conidial germination, biofilm formation, VOCs, and well colonisation on grape berries. M. aff. fructicola 1-UDM outperformed all other yeasts by significantly reducing disease incidence and lesion diameter values (93.4% and 94.3%, respectively). Remarkably, H. uvarum VOCs demonstrated potential as a biofumigant for suppressing grey mould. All yeasts are well adapted to their ecological niche to bio-protect grapes from grey mould disease.
  • Öge
    Releasing angiotensin I-converting enzyme inhibitory (ACE-I) peptides by Yamadazyma spp. in non-fat milk
    (Wiley, 2024) Devecioglu, Dilara ; Sarıakcalı, Busra ; Orhan, Betul ; Daskaya-Dikmen, Ceren ; Ozcelik, Beraat ; orcid.org/0000-0001-6681-0944 ; orcid.org/0000-0002-7756-108X ; orcid.org/0000-0002-1810-8154 ; orcid.org/0000-0001-6576-0084 ; Gıda Mühendisliği
    The objectives of this study were to analyse the impact of both temperature and different isolates on microbial protease production ability and to examine the hypertensive effect of bioactive peptides (BAPs) that inhibit the angiotensin I-converting enzyme released by fermentation of non-fat milk. First, the ability of several Yamadazyma spp. isolates, which were previously isolated and identified from several sources, was screened in terms of the production of proteolytic enzymes at 15 and 25 °C. The effect of temperature on proteolysis activity of selected isolates was considerable, and incubation at 25 °C was favourable for protease production. Besides, combinations of three different isolates showed remarkable proteolytic activity during the incubation periods of 24, 48 and 72 h. The highest angiotensin I-converting enzyme inhibitory (ACE-I) activity was detected for the combination Yamadazyma spp. BO10 and B514-1, with an inhibition of 92.5%. The partial purification of peptides by ultrafiltration (cut-off 10 kDa) has no crucial impact on ACE-I activity, and further purification might improve their effectiveness. The implications of fermentation with co-culture may have symbiotic potential to increase the antihypertensive effect of the product. Therefore, these results suggest that Yamadazyma spp. may be used to produce functional products or bioactive peptides presenting health-promoting attributes.
  • Öge
    Sequential extraction and characterization of essential oil, flavonoids, and pectin from industrial orange waste
    (American Chemical Society, 2024) Dikmetaş, Dilara Nur ; Devecioğlu, Dilara ; Karbancıoğlu-Güler, Funda ; Kahveci, Derya ; 0000-0002-1514-7166 ; 0000-0001-6681-0944 ; 0000-0001-6576-0084 ; 0000-0003-0450-5682 ; Gıda Mühendisliği
    Orange is one of the primary fruits processed into juice and other products worldwide, leading to a vast amount of waste accumulation. Such waste has been considered as an attractive candidate for upcycling to obtain bioactive components remaining. The present study investigated the extraction of essential oil (EO), flavonoids, and pectin from industrial orange waste with a holistic approach. To maximize EO yield and d-limonene concentration, hydrodistillation (HD) conditions were selected to be 5.5 mL water/g solid for 180 min. Remaining solids were further used for flavonoid extraction where conventional solvent, sequential ultrasound + solvent, and ultrasound-assisted extraction (UE) were applied. UE applied for 50 min with 120 mL solvent/g solid yielded the highest total phenolic (TPCs) and total flavonoid contents (TFCs), antioxidant capacity, and hesperidin and neohesperidin concentrations. In terms of TPC, TFC, antioxidant capacity, and antibacterial activity, both EO and flavonoid fractions demonstrated moderate to high bioactivity. At the final step, ethanol precipitation was applied to obtain the pectin that was solubilized in hot water during HD and it was characterized by Fourier transform infrared, degree of esterification, and galacturonic acid content. Practical application: to ensure utilization in the food, pharmaceutical, and cosmetic industries, this study presents a combined method to obtain several value-added compounds from industrial orange waste. Bioactive EO and flavonoids obtained could have applications in functional food, supplements, or cosmetic formulations, whereas extracted pectin can be used in many formulated foods and drugs.
  • Öge
    Simultaneous Detection of Ochratoxin A and Aflatoxins in Industrial and Traditional Red and isot Pepper Flakes along with Dietary Exposure Risk Assessment
    (American Chemical Society, 2022) Karbancıoğlu Güler, Funda ; Öztekin, Sebahat ; 0000-0001-6576-0084 ; 0000-0003-0859-1776 ; Food Engineering
    This study focused on the co-occurrence of aflatoxins (AFs) and ochratoxin A (OTA) in traditionally and industrially dried red pepper flakes (DRPFs) and isot pepper flakes (IPFs). Following the multitoxin immunoaffinity column (IAC) clean-up, high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) was used to quantify AFs and OTA. The limit of detection (LOD) and limit of quantification (LOQ) values were 0.11 and 0.18 μg kg–1 (AFB1), 0.04 and 0.08 μg kg–1 (AFB2), 0.13 and 0.18 μg kg–1 (AFG1), 0.04 and 0.11 μg kg–1 (AFG2), and 0.10 and 0.21 μg kg–1 (OTA), respectively. AFB1, AFB2, AFG1, and OTA were found to be positive in 93, 74, 17, and 94% of all samples, respectively. The contamination levels in positive samples ranged from 0.23 to 38.69, 0.04 to 2.14, 0.13 to 0.88, and 0.18 to 52.19 μg kg–1 for AFB1, AFB2, AFG1, and OTA, respectively, while no AFG2 was found above the detection limit (0.04 μg kg–1). None of the industrial isot peppers exceeded the European Union limits, while the levels of AFB1 (5 μg kg–1), total AFs (10 μg kg–1), and OTA (20 μg kg–1) of the traditional peppers were above the limit by 30% (16/54), 26% (14/54), and 4% (2/54), respectively. Co-occurrence of AFB1-AFB2-OTA was the most frequent, accounting for 54% (29/54) of all samples. At the upper bound (UB), estimated average exposure to AFB1, total AFs, and OTA was determined to be 0.175, 0.189, and 0.124 ng kg–1 bw day–1 in all samples, respectively. The margin of exposure (MoE) value of AFB1 and total AFs was found to be 977 and 909, indicating high health concerns compared to OTA (MoE >10,000). AFB1 and total AFs may result in 0.0058 and 0.0062 liver cancer cases/100,000 person/year at UB, respectively, and weekly OTA exposure was 0.868 ng kg–1 bw, well below the provisional tolerable weekly intake, hence not of health concern. AFs exposure could endanger health, whereas OTA posed no toxicological concerns through dried red pepper consumption
  • Öge
    The role of fermentation with lactic acid bacteria in quality and health effects of plant-based dairy analogues
    (Wiley, 2024) Erem, Erenay ; Kılıç-Akyılmaz, Meral ; orcid.org/0000-0002-2068-0336 ; Gıda Mühendisliği
    The modern food industry is undergoing a rapid change with the trend of production of plant-based food products that are more sustainable and have less impact on nature. Plant-based dairy analogues have been increasingly popular due to their suitability for individuals with milk protein allergy or lactose intolerance and those preferring a plant-based diet. Nevertheless, plant-based products still have insufficient nutritional quality, undesirable structure, and earthy, green, and bean-like flavor compared to dairy products. In addition, most plant-based foods contain lesser amounts of essential nutrients, antinutrients limiting the bioavailability of some nutrients, and allergenic proteins. Novel processing technologies can be applied to have a homogeneous and stable structure. On the other hand, fermentation of plant-based matrix with lactic acid bacteria can provide a solution to most of these problems. Additional nutrients can be produced and antinutrients can be degraded by bacterial metabolism, thereby increasing nutritional value. Allergenic proteins can be hydrolyzed reducing their immunoreactivity. In addition, fermentation has been found to reduce undesired flavors and to enhance various bioactivities of plant foods. However, the main challenge in the production of fermented plant-based dairy analogues is to mimic familiar dairy-like flavors by producing the major flavor compounds other than organic acids, yielding a flavor profile similar to those of fermented dairy products. Further studies are required for the improvement of the flavor of fermented plant-based dairy analogues through the selection of special microbial cultures and formulations.