Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 19Citation - Scopus: 20Processing of Hazelnut (corylus Avellana L.) Shell Autohydrolysis Liquor for Production of Low Molecular Weight Xylooligosaccharides by Aureobasidium Pullulans Nrrl Y-2311 Xylanase(Elsevier, 2021) Sürek, Ece; Büyükkileci, Ali Oğuz; Yeğin, SırmaIn this study, a versatile process for the production of xylooligosaccharides (XOS) with a low degree of polymerization (DP 2-6) from hazelnut shells was designed. This process included autohydrolysis integrated with sequential enzymatic hydrolysis by crude xylanase produced with Aureobasidium pullulans NRRL Y-2311-1 from wheat bran. Autohydrolysis of hazelnut shells was carried out at a solid:liquid ratio of 1:6 (w/w) and 190 degrees C nonisothermally. The effects of several parameters on enzymatic hydrolysis of the autohydrolysis liquor were determined. The maximum XOS (DP 2-6) production was 22.5 g/L which was obtained at pH 5.0 and 40 degrees C using enzyme concentration of 240 U/g XOS and substrate concentration of 72 g/L. Under these conditions, 31.29 % of the substrate (total XOS) was converted to low-DP-XOS; xylobiose and xylotriose are being the major oligomers. This is the first study on the application of A. pullulans xylanase in production of xylooligomers from hazelnut shells.Article Kritik Altı Su ile Fındık Atıklarından Antioksidan Bileşiklerin Ekstraksiyonu(Gıda Teknolojisi Derneği, 2018) Sürek, Ece; Büyükkileci, Ali OğuzTürkiye fındık üretim ve ihracatında dünya lideridir. Fındığın tarımı ve işlenmesi sırasında büyük miktarda kabuk, zuruf ve dal gibi atıklar açığa çıkmaktadır. Bu atıkların çevre dostu bir teknoloji ile işlenmesi ve önemli ürünlerin üretilmesi katma değer sağlayabilir. Bu çalışmada, fındık atıklarının farklı sıcaklık (150-200?C) ve sürelerde (0-45 dk) kritik altı su ekstraksiyonu ile elde edilen likörlerinin toplam fenolik madde içeriği (TFİ) ve toplam antioksidan aktiviteleri (TAA) incelenmiştir. Genel olarak, kritik altı su ekstraksiyonu ile aseton ve metanol ekstraksiyonuna göre daha yüksek verim elde edilmiştir. Sıcaklık arttıkça fındık kabuğundan elde edilen TFİ ve TAA artmıştır. Süre artışı 180?C'de istatistiksel olarak önemli bir fark yaratmazken, 190?C'de TFİ süre arttıkça yükselmiştir (P <0.05). Bu iki koşulun fındık kabuğu üzerine etkisi şiddet faktörünün logaritmik değeri (log Ro) hesaplanarak tek bir parametrede de incelenmiştir. log Ro arttıkça TFİ (905.3-2115.7 mg GAE/100 g kabuk) ve TAA (8163.9-12261.5 mg TE/100 g kabuk) değerleri yükselmiştirArticle Citation - WoS: 112Citation - Scopus: 132Production of Xylooligosaccharides by Autohydrolysis of Hazelnut (corylus Avellana L.) Shell(Elsevier Ltd., 2017) Sürek, Ece; Büyükkileci, Ali OğuzHazelnut shell (HS), husk and pruning residues were characterized and evaluated for xylooligosaccharides (XOS) production by autohydrolysis. HS contained the highest amount of xylan and yielded more XOS compared to other hazelnut residues. The temperature and holding time of HS autohydrolysis greatly influenced the composition of the liquor and the remaining solid. The highest XOS yield (62% of the feedstock xylan) was obtained at 190 °C and 5 min of holding time. At this temperature, 30 min of holding time was required to maximize the percentage of XOS with low degree of polymerization. Xylose, acetic acid and furfural concentrations increased with treatment severity. The concentrations of the products in the autohydrolysis liquors followed specific trends with changing severity factor (log Ro) values. Solubilization of xylan in the treatments enhanced the cellulose and lignin contents in the remaining solids.Article Citation - WoS: 16Citation - Scopus: 22Phenolic Contents, Antioxidant Activities and Potential Bioaccessibilities of Industrial Pomegranate Nectar Processing Wastes(John Wiley and Sons Inc., 2016) Sürek, Ece; Nilufer Erdil, DilaraAntioxidant potential and bioaccessibility of co-products from industrial pasteurised pomegranate nectar (PN) processing such as peel (PP), press cake (PC) and precipitate after clarification (PAC) in comparison with raw material (arils) and final products (CON and PN) were determined. Total phenolic (TPC), flavonoid (TFC), anthocyanin (TAC), tannin contents (TTC) and antioxidant activity (TAA) were determined besides identifying major phenolics and investigating in vitro bioaccessibility after gastrointestinal (GI) digestion. PP showed the highest values, except for TAC. Phenolics (12.7-43.0%) were found to be more stable than anthocyanins (0.6-2.1%) after in vitro GI digestion. PAC was found to be a better source for anthocyanins than CON and also showed higher phenolic bioaccessibility (28.8%) than PN (19.6%). PC and PAC possessed as much TPC, TFC, TTC and TAA levels as CON, with some exceptions. Therefore, these results indicated that not only PP but also PC and PAC should be valorised as a good source for phenolics and anthocyanins.Article Citation - WoS: 118Citation - Scopus: 127Investigating the Effects of Food Matrix and Food Components on Bioaccessibility of Pomegranate (punica Granatum) Phenolics and Anthocyanins Using an In-Vitro Gastrointestinal Digestion Model(Elsevier Ltd., 2014) Şengül, Hafizenur; Sürek, Ece; Nilüfer Erdil, DilaraEffects of food matrix and individual food components on potential bioaccessibility of pomegranate were investigated by means of simulating in vitro gastrointestinal (GI) digestion. The foodstuffs (sunflower oil, skim milk, cooked lean meat, bread, skim yogurt, probiotic yogurt, apple, lemon, honey, soy milk, cream, and soybean) and the food components (gluten, casein, isolated meat protein, lactose, fructose, galactose, glucose, salt, ascorbic acid, starch, cooked starch, tocopherol, linoleic acid, cellulose, citric acid and pectin) were codigested with pomegranate in model systems to better understand matrix effects. Total phenolic content (TPC) and total anthocyanin content (TAC) were determined by spectrophotometric methods and major phenolics/anthocyanins were analyzed by RP-HPLC/PDA detection both before and after in vitro GI digestion at post gastric (PG), dialyzable (IN) and non-dialyzable (OUT) fractions. Phenolics of pomegranate were found to be stable during gastric conditions (115%), with 25% loss in pancreatic digestion, available (14%) in IN. Although preserved (89%) in PG, anthocyanins were lost in pancreatic digestion (38%), but still available (12%) in IN. Milk, bread, yogurt, probiotic yogurt, lactose, starch, cellulose, salt, citric acid or tocopherol codigestion with pomegranate decreased TPC for all fractions. Proteins affected losses in PG and OUT fractions. Carbohydrates such as starch, lactose, glucose and pectin appeared to affect the loss of phenolics and exerted 2-fold decreases in serum fraction (IN). For TAC, only meat, soymilk or cream codigestion with pomegranate resulted in IN losses. Proteins did not significantly affect TAC in IN, but were inhibitory in PG. However, carbohydrates and fatty acids significantly increased TAC in IN. Generally cyanidins were found to be more stable in food matrices and pancreatic conditions than other anthocyanins.