The Effects Of Nectar Processing On Sour Cherry Antioxidant Compounds: Changes In Metabolite Profile And Bioavailability

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2013Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2013Bu tez kapsamında, vişne nektarı prosesindeki tüm üretim basamaklarının vişne antioksidanlarının, özellikle de antosiyaninlerin, miktarı ve profili üzerindeki etkisi incelenmiştir. Bunun yanı sıra, in vitro mide-bağırsak sistemi simülasyonu modeli ve in vitro Caco-2 hücre modeli kullanılarak vişne antosiyaninlerinin in vitro biyoyararlığı çalışılmıştır. In vitro Caco-2 hücre modeli analizlerinde, nektar ingredientleri olan sukroz ve sitrik asitin ve gıda matriksinin antosiyanin biyoyararlılığı üzerindeki etkisi de incelenmiştir. Nektar işleme basamaklarından iki tanesi antioksidan madde içeriklerinde istatistiksel olarak önemli değişimlere neden olmuştur. İlki, meyvenin pres suyuna işlenmesi ile miktarlarda (kuru-madde bazında) saptanan 2-3 kat artışlardır. Bu artış, düşük antioksidan madde içeriğine sahip olan posanın presleme aşamasından sonra uzaklaştırılması ile açıklanmaktadır. Posada antioksidan madde içeriğinin düşük olması, posanın ekstraksiyonu için tekrarlanan presleme basamaklarının antioksidan bileşenlerin pres suyuna kazanımını arttırması ile ilişkilendirilmektedir. İkinci önemli değişim, konsantre vişne suyunun nektara işlenmesi ile miktarlarda tespit edilen 2-4 kat azalıştır. Kuru-madde bazındaki bu azalış, nektara işleme sırasında ilave edilen sukroz şurubunun nektarın kuru maddesinin % 50’sinden daha fazlasının sukrozdan oluşmasına neden olmasıyla açıklanmaktadır. Sukroz ve sitrik asit başta olmak üzere, toplam 11 metabolitin nektarda daha yüksek oranlarda bulunduğu ve nektar ile meyvenin metabolit profilleri arasındaki farklılığı oluşturduğu belirlenmiştir. Metabolomik analizleri ile vişnede ilk defa askorbik asit-glikozit varlığı tespit edilmiştir. In vitro biyoyararlılık analizleri nektarda antosiyaninlerin in vitro biyoyararlılığının daha yüksek olduğunu göstermiştir. Sitrik asit ve/veya sukroz ilavesinin her ikisinin de antosiyanin biyoyararlılığını arttırmada rolü olduğu söylenebilir. Bütün meyve ve bütün nektar örneklerinin biyoyararlılığı, meyve ve nektardan ekstrakte edilerek hücrelere verilen antosiyaninlerin biyoyararlılığından daha yüksektir.In this thesis, each step of nectar processing was studied to evaluate the changes in quantity and profile of sour cherry antioxidants. Additionally, bioavailability of sour cherry anthocyanins was assessed using in vitro simulated gastrointestinal digestion and in vitro Caco-2 cell model. In Caco-2 cell experiments the effects of sucrose and citric acid, as well as the food matrix on anthocyanin bioavailability were examined. Two of the applied treatments during nectar processing resulted in significant changes in antioxidant contents. First, steps leading from fruit to pressed-juice led to 2-3-fold increases, on dry-weight-basis. This was linked to the press-cake removal, which was mainly relevant to the removal of dry-weight poor in antioxidants. The lower contents of antioxidants in press-cake was linked to the efficient compound recovery into the juice by facilitated extraction with repeated press-cake-extraction steps. Second, processing of concentrated-juice into nectar gave rise to 2-4-fold reduction in values. This reduction was related to the addition of sucrose to concentrated- juice during nectar processing, which led to a more than 50% sucrose containing in dry matter nectar. Metabolites that strongly distinguished nectar from fruit were in total 11 metabolites, dominated by sucrose and citric acid. Metabolomics analysis also revealed the existence of ascorbic acid-glucoside in sour cherry, for the first time. A higher in vitro anthocyanin bioavailability was determined in nectar sample. Citric acid and/or sucrose inclusion resulted in an enhanced transport of anthocyanins. The anthocyanins in whole fruit and whole nectar were found to be more bioavailable than extracts.DoktoraPh

Effects of honey addition on antioxidative properties of different herbal teas

Tea and herbal infusions are among the major contributors of phenolic compounds, specifically flavonoids, in our daily diet. Honey is another antioxidant-rich food that is widely used as a natural sweetener. In this work, the effects of honey addition on antioxidant properties of different herbal teas were investigated. For this purpose, 2 different types of honey (flower and pine honey) were added into 9 different herbal teas (melissa, green tea, rosehip, sage, echinacea, fennel, linden, daisy, and ginger) at 4 different temperatures (55°C, 65°C, 75°C, and 85°C), and the changes in the content of total pheolics, total flavonoids, and total antioxidant capacity were determined. The total phenolic content and the total antioxidant capacity of the honey-added-tea samples were found to be increased (up to 57% for both), especially with pine honey and at higher temperatures of honey addition. The findings of this study supported the use of honey as a natural sweetener in tea in order to be able to benefit from the health-enhancing antioxidative properties of these two promising food products

Fruit Antioxidants during Vinegar Processing: Changes in Content and in Vitro Bio-Accessibility

Background: Vinegars based on fruit juices could conserve part of the health-associated compounds present in the fruits. However, in general very limited knowledge exists on the consequences of vinegar-making on different antioxidant compounds from fruit. In this study vinegars derived from apple and grape are studied. Methods: A number of steps, starting from the fermentation of the fruit juices to the formation of the final vinegars, were studied from an industrial vinegar process. The effect of each of the vinegar processing steps on content of antioxidants, phenolic compounds and flavonoids was studied, by spectroscopic methods and by high-performance liquid chromatography (HPLC). Results: The major observation was that spectrophotometric methods indicate a strong loss of antioxidant phenolic compounds during the transition from fruit wine to fruit vinegar. A targeted HPLC analysis indicates that metabolites such as gallic acid are lost in later stages of the vinegar process. Conclusion: The major conclusion of this work is that major changes occur in phenolic compounds during vinegar making. An untargeted metabolite analysis should be used to reveal these changes in more detail. In addition, the effect of vinegar processing on bio-accessibility of phenolic compounds was investigated by mimicking the digestive tract in an in vitro set up. This study is meant to provide insight into the potential of vinegar as a source of health-related compounds from fruit

Processing black mulberry into jam: Effects on antioxidant potential and in vitro bioaccessibility

Black mulberries (Morus nigra) were processed into jam on an industrialized scale, including the major steps of: selection of frozen black mulberries, adding glucose-fructose syrup and water, cooking, adding citric acid and apple pectin, removing seeds, and pasteurization. Qualitative and quantitative determinations of antioxidants in black mulberry samples were performed using spectrophotometric methods, as well as HPLC- and LC-QTOF-MS-based measurements. These analyses included the determination of total polyphenolic content, percent polymeric color, total and individual anthocyanin contents, antioxidant capacity, and in vitro bioaccessibility in processing samples

Investigating the antioxidant and antimicrobial activities of different vinegars

Capanoglu, Esra/0000-0003-0335-9433; Guler, Funda Karbancioglu/0000-0001-6576-0084; Devecioglu, Dilara/0000-0001-6681-0944WOS: 000414155800002In this study, the antioxidant contents and the antimicrobial activities of 18 vinegar samples were investigated. For this purpose, total flavonoid contents (TFC) and total phenolic contents (TPC) of different vinegar samples were determined. in addition, total antioxidant capacities (TAC) of vinegars were analyzed using four different in vitro tests: ABTS, CUPRAC, DPPH, and FRAP, in parallel. Results obtained from antioxidant analyses showed that balsamic vinegar had the highest TFC (96 +/- 18 mg CE/100 mL) and TPC values (255 +/- 24 mg GAE/100 mL), as well as the highest TAC determined using CUPRAC (709 +/- 108 mg Trolox/100 mL) and FRAP (421 +/- 28 mg Trolox/100 mL) methods. the phenolic profiles of vinegar samples were identified by performing HPLC analysis. Among all vinegar samples studied, the most abundant phenolic compounds were determined to be gallic acid, protocatechuic acid, and p-hydroxybenzoic acid. Furthermore, antimicrobial activities of different vinegars, against Staphylococcus aureus, Salmonella Typhimurium, and Escherichia coli, were evaluated using disc diffusion method; the results of which were related to the acetic acid contents and the pH values of the vinegar samples. Balsamic vinegar was again determined to be the sample that had the highest antimicrobial activity, which showed a strong antibacterial activity against S. Typhimurium. Antibacterial activities of vinegars could partly be related to both their acetic acid contents and the pH values, and also to their phenolic contents.Istanbul Technical University, Scientific Research Projects (BAP) UnitIstanbul Technical UniversityThis study was financially supported by the Istanbul Technical University, Scientific Research Projects (BAP) Unit. We also thank Mehmet Basri Celiker and Kuhne Co. (Kemalpasa, Izmir, Turkey) and also Erkan Tekgunduz and Icmeli Dogal Urunler Co. for supplying the samples

Home-Processed Red Beetroot (Beta vulgaris L.) Products: Changes in Antioxidant Properties and Bioaccessibility

In this study, the effects of home-processing on the antioxidant properties and in vitro bioaccessibility of red beetroot bioactives were investigated. For this purpose, fresh red beetroot and six different home-processed red beetroot products—including boiled, oven-dried, pickled, pureed, juice-processed, and jam-processed—were analyzed and compared for their total phenolic (TP) and total flavonoid (TF) contents, total antioxidant capacities (TAC), and individual anthocyanin contents. In addition, bioaccessibility of red beetroot antioxidants was determined using an in vitro simulated gastrointestinal digestion method. Dried, pureed, and fresh red beetroot samples had the highest TP, TF, and TAC values, which were 347 ± 23 mg gallic acid equivalent (GAE)/100 g, 289 ± 53 mg rutin equivalent (RE)/100 g, 3889 ± 982 mg trolox equivalent antioxidant capacity (TEAC)/100 g, respectively. The in vitro digestion method revealed the highest recovery for TP (16%) and TAC (1.3%) in jam. This study provides comparative data to evaluate the effects of various home-processing techniques on antioxidant potential of red beetroot products

A review on the effect of drying on antioxidant potential of fruits and vegetables

The role of antioxidants in human nutrition has gained increased interest, especially due to their associated health beneficial effects for a number of chronic diseases, including cardiovascular diseases and certain types of cancer. Fruits and vegetables are perishable and difficult to preserve as fresh products. Dried fruits and vegetables can be easily stored, transported at relatively low cost, have reduced packing costs, and their low water content delays microbial spoilage. Air-, freeze-, microwave- and sun-drying are among the most thoroughly studied drying methods. This review provides an overview of recent findings on the effects of different drying techniques on major antioxidants of fruits and vegetables. In particular, changes in ascorbic acid, carotenoids, flavonoids, phenolic acids, total phenolics and antioxidant activity are discussed in detail