Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 52Citation - Scopus: 55Wheatgrass Juice To Wheat Grass Powder: Encapsulation, Physical and Chemical Characterization(Elsevier Ltd., 2017) Akbaş, Elif; Kilercioğlu, Mete; Önder, Özge Nur; Köker, Alperen; Söyler, Betül; Öztop, Mecit HalilWheatgrass juice (Triticum aestivum L.) is known as a healthy drink due to its high antioxidant activity and phenolic content. In order to avoid the undesirable odor and protect the functional compounds, wheatgrass juice was encapsulated using maltodextrin and whey protein. Antioxidant and phenolic content, mean particle size and distribution, morphology, simulated digestion and thermal stability experiments were conducted on the encapsulated powders. Results showed that antioxidant activity was in between 0.30 and 0.06 mg 2-diphenyl-1-picrylhydrazyl (DPPH)/g powder and phenolic content was 3.52–2.28 mg gallic acid equivalent (GAE)/g powder. Encapsulated powders showed good stability in gastric juice and had 62% higher phenolic content compared to the intestinal fluid within 10 min digestion. Phenolic content of powders was also protected against thermal treatment at 40 °C, 55 °C and 70 °C. Kinetic parameters for degradation of the phenolics were well estimated (R2⩾0.85) using fractional conversion model.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: 115Citation - Scopus: 135Antioxidant Activity and Phenolic Content of Fresh and Dry Nuts With or Without the Seed Coat(Academic Press Inc., 2009) Arcan, İskender; Yemenicioğlu, AhmetTotal antioxidant activities based on ABTS free radical scavenging activity and phenolic content of fresh or dry hazelnuts, walnuts and pistachios assayed with their seed coats changed between 3063 and 11,076 μmol trolox equivalents/100 g d.w. and 256 and 755 mg gallic acid equivalents/100 g d.w., respectively. The walnuts used in this study showed the highest antioxidant activity, followed by pistachios and hazelnuts. The removal of seed coat reduced the total antioxidant activity of hazelnuts, walnuts and pistachios almost 36, 90 and 55%, respectively. The total antioxidant activities of investigated fresh and dry nuts are not considerably different. However, phenolic content and antioxidant activity in hydrophilic and ethanolic fractions obtained by successive extraction of nuts showed some variation. The antioxidant activity in 1-serving portion of fresh or dry walnuts is equivalent to that in almost 2-serving portions of black tea, and 1.2-1.7-serving portions of green and Earl Grey tea. One-serving portions of dry hazelnuts and fresh or dry pistachios contained antioxidant activity equivalent to that in 0.7-1-serving portions of black tea. The antioxidant activity measurements correlated with phenolic content (r2 = 0.70). This study showed the potential of using fresh or dry nuts to develop functional foods with high antioxidant activity.Article Citation - WoS: 10Citation - Scopus: 12Effects of Hot Rehydration in the Presence of Hydrogen Peroxide on Microbial Quality, Texture, Color, and Antioxidant Activity of Cold-Stored Intermediate-Moisture Sun-Dried Figs(John Wiley and Sons Inc., 2005) Demirbüker Kavak, Dilek; Arcan, İskender; Tokatlı, Figen; Yemecioğlu, AhmetPectin methylesterase (PME) causes considerable softening in intermediate-moisture (IM) figs rehydrated at 30°C and cold stored at 28% to 29% moisture content. Rehydration of figs at 80°C for 16 min inactivated PME partially (25-30%), but this did not prevent the softening over 3 mo of cold storage. Also, heating did not reduce the microbial load of figs significantly and increased their browning. In contrast, rehydration of figs 1st in 2.5% H2O2 at 80°C for 8 min and then in water at 80°C for 8 min reduced the microbial load of IM figs significantly, turned their brown color to yellow-light brown, and maintained their desired textural properties. The residual H2O2 in IM figs decomposed in 3 or 1.5 wk by the in situ catalase or by application of the iron (II) sulfate-ascorbic acid residue elimination method, respectively. Hot rehydration did not affect the antioxidant activity of IM figs, but treatment of figs with H2O2 increased their antioxidant activity slightly. These results indicate that the hot rehydration of figs in the presence of H 2O2 and cold storage may be applied to obtain safe and SO2-free light-colored IM fig products.