LEE- Gıda Mühendisliği-Doktora

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http://hdl.handle.net/11527/19294

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Yazar "Çapanoğlu Güven, Esra" ile LEE- Gıda Mühendisliği-Doktora'a göz atma
  • Öge
    Effects of novel food processing techniques on bioaccessibility and transepithelial transport of cranberrybush polyphenols
    (Graduate School, 2021-08-06) Özkan, Gülay ; Çapanoğlu Güven, Esra ; 506142507 ; Food Engineering
    Phenolic compounds, which are present in a wide variety of foods such as fruits, vegetables, flowers and leaf of plants, exhibit a variety of beneficial effects including antimicrobial, antioxidant, antidiabetic, diuretic, hypoglycemic, cough reliever, antiinflammatory and antiviral activities as well as prevention of cardiovascular, pancreas, liver and kidney diseases. However, most of the polyphenols have poor water solubility, chemical instability in gastrointestinal tract and, thus, a reduced bioavailability. Therefore, a wide variety of attempts have been investigated to improve the solubility, stability, bioaccessibility and bioavailability of phenolic compounds. Considering the above, a research framework to study the effects of novel processing techniques on the antioxidant capacity, bioaccessibility and bioavailability of cranberrybush polyphenols has been developed. The objectives of this Ph.D. thesis were (i) to determine the effects of novel non-thermal food processing on cranberrybush polyphenols and vitamin C; (ii) to investigate the effects of non-thermal food processing and food matrix on bioaccessibility and transepithelial transportation of bioactive compounds, in particular chlorogenic acid, from cranberrybush (Viburnum opulus) using combined in vitro gastrointestinal digestion/Caco-2 cell culture model; (iii) to obtain an effective Supercritical Anti-Solvent (SAS) coprecipitation of quercetin or rutin with polyvinylpyrrolidone (PVP), enhancing the dissolution rate, and, therefore, improving the bioavailability of these natural antioxidant compounds; (iv) to determine the effects of SAS processing and food models on the antioxidant capacity, bioaccessibility and transport dynamics of flavonol-loaded microparticles by using combined in vitro gastrointestinal digestion/Caco-2 cell culture model. To achieve these goals, four different experiments (Chapters 3-6) were conducted. Firstly, effects of high pressure processing (HPP) and pulsed electric field (PEF) treatments on physicochemical properties, bioactive compounds, antioxidant capacities and polyphenol oxidase activities of cranberrybush purée samples were evaluated (Chapter 3). Following that, non-thermal treated cranberrybush purée samples as well as cranberrybush juice/water, bovine or almond milk blends were subjected to combined in vitro gastrointestinal digestion/Caco-2 cell culture (Chapter 4). In line with the outcomes of previous chapter, in order to increase the bioavailability of some phenolic compounds that could not be absorbed across the gut epithelium after transport experiments with cranberrybush samples, the micronization of two flavonoids, quercetin and rutin, and their coprecipitation with PVP were studied by using SAS processing to increase their solubility and enhance their stability during gastrointestinal tract (Chapter 5). Finally, SAS-processed flavonoids in different simulated food models were exposed to combined in vitro gastrointestinal digestion/Caco-2 cell culture in order to investigate their transport dynamics (Chapter 6). In Chapter 1, research framework and objectives of this Ph.D. thesis are introduced. Following that, in Chapter 2, comprehensive reviews on the antioxidant properties, bioaccessibility and bioavailability of polyphenols are presented, with a specific focus on the application of novel processing techniques. Initially, a critical evaluation of the effects of novel non-thermal food processing technologies on the beverage antioxidants have been provided. Then, the studies about microencapsulation methods for food antioxidants regarding principles, advantages, drawbacks and applications have been reviewed. Afterwards, effects of encapsulation on the bioaccessibility and bioavailability of phenolic compounds were discussed. Lastly, in vitro and in vivo approaches on interactions of phenolics with food matrix were described. In Chapter 3, the effects of high pressure processing (HPP; 200-600 MPa for 5 or 15 min) and pulsed electric field treatment (PEF; 3 kV/cm, 5-15 kJ/kg) on physicochemical properties (conductivity, pH and total soluble solids content), bioactive compounds (vitamin C, total phenolic, total flavonoid, total anthocyanin and chlorogenic acid contents), antioxidant capacities (DPPH and CUPRAC assays) and polyphenol oxidase activity of cranberrybush purée samples were evaluated. Results showed that conductivity increased significantly after PEF (15 kJ/kg) treatment. PEF and HPP treatments resulted with a better retention of bioactive compounds (increase in the total phenolic content in the range of ~4 – 11% and ~10 – 14% and total flavonoid content in the range of ~1 – 5% and ~6 – 8% after HPP and PEF, respectively) and antioxidant capacity compared to untreated sample. HPP reduced residual enzyme activity of PPO comparatively better than PEF. Besides, cranberrybush polyphenols were identified along with their detected accurate mass, molecular formula, error in ppm (between the mass found and the accurate mass < 10 ppm) of each phytochemical, as well as the MS/MS fragment ions. UPLC–QTOF–MS/MS analysis of cranberrybush led to the identification of flavan-3-ols (catechin, epicatechin, epi(catechin) hexoside), proanthocyanidins (procyanidin dimer, procyanidin trimer, procyanidin dimer monoglycoside), flavonols (quercetin, quercetin-deoxyhexose, quercetin-3-O-glucoside, quercetin pentoside hexoside, rutin, isorhamnetin-3-O-rutinoside), flavone (diosmetin-rhamnosylglucoside), phenolic acids (caffeic acid, chlorogenic acid, coumaric acid, p-coumaroyl-quinic acid) as well as anthocyanins (cyanidin-3-glucoside, cyanidin-3-rutinoside and cyanidin-3-xylosyl-rutinoside). In conclusion, high retention of bioactive compounds was achieved, with a potential extraction of vitamin C, phenolics, flavonoids and anthocyanins in cranberrybush purées after HPP and PEF treatments at selected processing intensities. In Chapter 4, effects of food matrix and non-thermal food processing on bioaccessibility and transport dynamics of cranberrybush phenolics, in particular chlorogenic acid, in a combined in vitro gastrointestinal digestion/Caco-2 cell culture model were studied. Results showed that PEF treatment at 15 kJ/kg specific energy input resulted in a higher recovery of total flavonoid content (TFC; increase of 3.9% ± 1.1%, p < 0.0001), chlorogenic acid content (increase of 29.9% ± 5.9%, p < 0.001) and antioxidant capacity after gastrointestinal digestion. The present study also demonstrates that untreated and treated samples display comparable transport across the epithelial cell layer. Besides, addition of milk matrix have a positive effect on the stability and transportation of chlorogenic acid. JM increased the transport efficiency of chlorogenic acid by 3.5% ± 0.8% (p < 0.0001), while JA increased the transport of chlorogenic acid by 3.3% ± 0.5% (p < 0.001) in comparison with JW blend. The in vitro gastrointestinal digestion/Caco-2 cell culture method applied in this chapter was used in the succeeding chapter (Chapter 6). In Chapter 5, micronization of two flavonoids, quercetin and rutin, and their coprecipitation with polyvinylpyrrolidone were studied by using the SAS process. In particular, optimum conditions in terms of operating pressure, type of the solvent, total solute concentration and polymer/active ratio for the formation of spherical composite microparticles were determined. Morphology, mean size and size distribution of the particles were analyzed and discussed. The effectiveness of the process was also verified through entrapment efficiency and dissolution tests. Overall, amorphous microparticles were produced with total solute concentrations greater than 20 mg/mL. Furthermore, release studies confirmed the improvement of the flavonoids dissolution rates: 10 and 3.19 times faster dissolution rates were achieved with PVP/quercetin and PVP/rutin microparticles rather than those of unprocessed quercetin and rutin, respectively. Besides, the high entrapment efficiencies, up to 99.8%, were achieved for quercetin and rutin coprecipitates by using DMSO, which was the solvent chosen to coprecipitate the flavonoid compounds with PVP by the SAS process. Consequently, the characteristics of the powders could allow to use of these quercetin and rutin loaded microparticles in pharmaceutical and nutraceutical applications due to their high antioxidant and anticancer benefits for, in which the flavonoid compounds have high stability and bioavailability. In Chapter 6, effects of SAS processing on bioaccessibility and transepithelial transportation of quercetin and rutin were investigated by using a recognized combined gastrointestinal digestion/cell-based assay. Moreover, aqueous hydrophilic and acidic conditions were simulated to analyze food-related factors that could have an impact on the transport of these compounds across the gut epithelium. SAS processing improved the recovery of the quercetin (94 and 13 times in hydrophilic and acidic conditions, respectively) and rutin (7 and 2 times in hydrophilic and acidic conditions, respectively) after in vitro digestion. Besides, transepithelial transportation of PVP/quercetin and PVP/rutin microparticles were found to be much higher rather than unprocessed quercetin and rutin. Finally, in Chapter 7, based on the outcomes of the previous chapters, the general discussions and conclusions on the antioxidant properties, bioaccessibility and bioavailability of polyphenols were presented. The status and main outcomes of this thesis were discussed under the headings of fate of the polyphenols after application of novel non-thermal food processing techniques, effects of encapsulation on the food phenolics and interactions of phenolics and food matrix. During the discussion on the effects of encapsulation on the food phenolics, important factors to be considered during encapsulation, advantages and drawbacks of these techniques, their impacts on the antioxidant properties, bioaccessibility and bioavailability of phenolic substances were discussed. Besides, while referring to the interactions with food matrix, special attention has been paid to comparison of the different in vitro and in vivo digestion models.
  • Öge
    Valorization of black chokeberry waste as a potential source of bioactive compounds: Their identification, microencapsulation and impact on the human gut microbiota
    (Graduate School, 2022-12-07) Çatalkaya, Gizem ; Çapanoğlu Güven, Esra ; 506152502 ; Food Engineering
    Epidemiological studies have suggested that adopting a diet rich in fruits and vegetables has been associated with a reduced risk of noncommunicable diseases, such as cardiovascular diseases, neurodegenerative diseases, type II diabetes and cancer. The presence of bioactive substances such as polyphenols has been linked to these potentially health promoting benefits. Polyphenols are secondary metabolites that determine the sensory and nutritional qualities of fruits and vegetables. However, polyphenols are processed as xenobiotics by the human body after consumption, hence the bioavailability of native substances is rather low. Only 5-10% of total dietary polyphenols, mostly those with monomeric and dimeric structures, are estimated to be directly absorbed in the small intestine. The remaining polyphenols pass to the colon, where they are further metabolized by the enzymatic activity of colonic bacteria to molecules with varied physiological significance. These phenolic compounds generated by the microbial catabolism are more absorbable than the original molecules present in foods and may have higher health benefits. In addition to this, dietary polyphenols reaching to the colon can act as prebiotics and they may modulate the gut microbiota by promoting the growth of beneficial bacteria and/or hindering the proliferation of harmful bacteria. Black chokeberry (Aronia melanocarpa) is one of the richest sources of phenolic compounds, especially anthocyanins, among the other berry types. In addition to the anthocyanins, they are a rich source of proanthocyanidins with a high degree of polymerisation. However, despite their health beneficial properties, they are seldomly ingested as fresh due to their distinct astringent flavor, which is perceived as undesirable by the consumers. For this reason, they are processed into juices, jams, etc. Juice processing generates by-products, such as pulp, that might be used in the production of natural colorant and the isolation of the natural nutraceuticals. Although anthocyanins possess potential health-promoting properties and are regarded as promising natural food colorants, unfortunately their unstable nature acts as an obstacle in their practical applications due to their poor bioavailability and susceptibility against environmental factors such as temperature, light, oxygen, pH change, etc. Therefore, encapsulation of these substances might be a suitable method to increase concentrations of bioactive anthocyanins in the gastrointestinal tract and thus boost their beneficial effects. In this useful system, anthocyanins are protected from degradation and prevented from premature color development. Taking all the above-mentioned information into account, this thesis was organized to (i) characterize the polyphenol content of the black chokeberry pulp, (ii) determine the most effective conditions and materials for the encapsulation of the anthocyanin-rich extract obtained from black chokeberry pulp, (iii) determine the effect of black chokeberry polyphenols in different matrices on the human gut microbiota under in vitro conditions. For this purpose, firstly the state of the art on the polyphenol bioaccessibility, bioavailability, interaction with the gut microbiota and analysis through omics approach was comprehensively reviewed and discussed in Chapter 2. In Chapter 3 the extract obtained from the black chokeberry pulp was characterised by both spectrophotometric methods and chromatographic methods. Total polyphenol and total anthocyanin contents of the extract were determined by Folin-Ciocalteu and pH differential methods, respectively. Also, the individual polyphenol composition of the extract was identified by using UPLC-ESI-QqQ-MS/MS method. Dry matter content of pulp was 35.6±0.2%, brix value of the extract was 20% and total anthocyanin content and total phenolic content of extract were determined as 4.91±0.297 mg cyanidin-3-glucoside/mL, 11.5±0.14 mg gallic acid equivalent/mL, respectively. According to LC-MS/MS analysis, ~72% of the total quantified polyphenols consisted of anthocyanins. It is widely known that black chokeberries contain four major anthocyanins, namely cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, cyanidin-3-O-arabinoside, and cyanidin-3-O-xyloside. In this study, cyanidin-3-O-glucoside was identified and quantified. However, apart from the major anthocyanins some other anthocyanins were also detected (cyanidin-3,5-diglucoside, cyanidin-3-O-rutinoside, and pelargonidin-3-O-glucoside). In fact, to the best of our knowledge pelargonidin-3-O-glucoside was identified in black chokeberries for the first time. After characterizing the extract, the second goal of this study was to encapsulate the black chokeberry extract with different coating materials by using spray drying technique which was also detailed in Chapter 3. Among the encapsulation techniques, the spray drying method has been largely utilized for drying heat-labile nutraceuticals since it is precise, efficient, simple and cost-efficient in the processes. The selection of coating material to entrap the active material by spray drying is crucial to achieve an efficient encapsulation. Therefore, five different coating materials have been tested for the microencapsulation of black chokeberry extract (maltodextrin with dextrose equivalent of 6, maltodextrin with dextrose equivalent of 20, its blends with gum Arabic, xanthan gum or whey protein isolate). Spray drying conditions were chosen as follows: inlet temperature of 150 °C, the outlet temperature of 90 °C, 4.5 mL/min feed flow rate, 0.357 m3/h air flow rate, and an aspirator capacity of 100%. For the determination of the most effective system, physicochemical characteristics of the powders such as moisture content, particle size, capsule morphology, color, spray drying yield, encapsulation efficiency, total anthocyanin content, total and individual phenolic content, and total antioxidant activity were investigated. Within the five different wall materials, maltodextrin:gum Arabic provided the maximum encapsulation efficiency (71.5%) while MD6 resulted in the lowest encapsulation efficiency (38.3%). The spray-dried powders presented low moisture content in an acceptable range from 2.57 to 3.27%. Also, spray drying yield varied between 51.4 to 78.1%. The addition of gums or protein significantly enhanced both total phenolic content and total antioxidant capacity. The highest increase in total phenolic content was observed when gum Arabic was used along with maltodextrin as a coating material. Although significantly different results were obtained for most of the parameters tested for each wall material, all of them resulted in successful microencapsulation of black chokeberry pomace extract. However, within the tested wall materials, the maltodextrin:gum Arabic combination had better results compared to the other wall materials. For this reason, the next step of the study was continued with the spray-dried powders obtained by using maltodextrin: gum Arabic as a wall material. The effect of black chokeberry phenolics on the human gut microbiota in a sophisticated, computer-controlled dynamic colonic fermentation model (TIM-2) was investigated in Chapter 4. For this purpose, black chokeberry pomace as juice processing by-product, anthocyanin rich extract from black chokeberry pomace, and microencapsulated extract in maltodextrin-gum Arabic system were examined in terms of the changes in microbial composition, short-chain fatty acid (SCFA) and branched-chain fatty acid (BCFA) contents. Stool samples were collected from 5 healthy donors to prepare a standardized microbiota cocktail. The experiments in TIM-2 were last for 40h where the first 16h was adaptation period of the human fecal microbiota and the last 24h was the test period. Samples were collected from lumen and dial compartments at time 0h and 24h. Genomic DNA from the luminal samples was extracted and sequencing by polymerase chain reaction (PCR) amplification of the 16S rRNA gene V3-V4 region was carried out by using Illumina MiSeq and BCL2FASTQ pipeline. The QIIME2 (Quantitative Insights Into Microbial Ecology) software package was employed for taking sequencing data from raw sequences to interpretation for the microbiota analyses. The statistical analyses were done in RStudio. The abundances of microbial species in the total microbial community were calculated and shown as relative abundance (RA). According to the results, the fermentation of black chokeberry polyphenols in the in vitro colon model (TIM-2) resulted in shifts in the standardized microbiota and differentiation in the extent of the production of SCFA and BCFAs. Synergy between maltodextrin+gum Arabic+polyphenols resulted in an increase in the relative abundances of some health-promoting taxa (Anaerostipes, Blautia, Christensenellaceae R7 group, Prevotella 9) and decrease in the disease related taxa Alistipes. Encapsulation increased the SCFA production and decreased the BCFA production in the lumen. Nevertheless, none of the metabolites could be correlated with the identified operational taxonomic units. In the final chapter (Chapter 5), overall evaluation of the results obtained throughout this study, conclusions, and recommendations for the future research were presented. The main outcomes of this study revealed that pulp obtained from Turkish black chokeberries has a unique polyphenol profile with bioactive properties. The successful microencapsulation of polyphenols extracted from black chokeberry pulp can be used as a value-added natural colorant in powder form with bioactive properties in food, pharmaceutics or cosmetic product formulations. Also, clack chokeberry polyphenols present in the extract, pulp or encapsulate have the potential to be used for establishing a healthier gut as it caused a shift in the gut microbial composition and SCFA levels in a good way.