Sürdürülebilir Kalkınma Amaçları
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- MakaleYalnız künye2020Degradation kinetics of bioactive compounds and antioxidant activity in strawberry juice concentrate stored at high and low temperatures
Menevseoglu, Ahmed; Dıblan, Sevgin; Türkyılmaz, Meltem; Özkan, Mehmet
In this study, changes in ascorbic acid (AA), phenolics, anthocyanins (ACNs) and antioxidant activity (AOA) were monitored during storage at − 25, 4, 10 and 20 °C to observe the stability of bioactive compound in strawberry juice concentrates (SJCs). Half-life periods (t1/2) for ACN and AA degradations were 7.9 and 50 days at 20 °C, respectively. On the contrary, much higher t1/2 values were found for the reduction in AOA and phenolics, i.e. 251 and 430 days at 20 °C, respectively. AOA and phenolics were more stable during storage than AA and ACNs. p-Coumaric acid was the major phenolic identified in SJC. p-coumaric acid (33.8%), catechin (23.1%), vanilic acid (18.6%) and epicatechin (16.1%), which constituted 91.6% of phenolics in SJC, followed by chlorogenic acid (4.9%) and caffeic acid (3.2%). Chlorogenic acid was the least stable phenolic in SJC stored at 20 °C. Strong correlations were found between AOA and ACNs (r = 0.99), phenolics (r = 0.94) and AA (r = 0.92) in SJC stored at 20 °C. Significant ACN and AA degradations occurred at storage temperature as low as 4 °C. Therefore, storage at − 25 ℃ was suggested for SJC to maximize the stabilities of especially ACNs and AA in SJC.
- MakaleAçık Erişim2019Application of multi pass high pressure homogenization to improve stability, physical and bioactive properties of rosehip (Rosa canina L.) nectar
Saricaoglu, Furkan T.; Atalar, Ilyas; Yilmaz, Volkan A.; Odabas, Halil I.; Gul, Osman
The effect of high pressure homogenization (HPH) on physical and bioactive properties of rosehip nectar was investigated. Rosehip nectar has a sedimentation problem while waiting on the market shelf during the sale, for solving this problem, nectars were passed 1, 2 and 3 times through 75, 100 and 125 MPa pressures. Mean particle size decreased as pressure and pass number increased (p < 0.05), whereas zeta potential did not change (p > 0.05). Microstructural images revealed that HPH treatment disrupted the cells and caused to release of cell materials to serum. HPH treatment increased the ΔE values (from 2.48 to 6.03). HPH treated samples showed no sedimentation during storage for 15 days. All samples showed shear thinning behavior and were characterized as weak gel network (G′ > G″). Total phenolic content and ascorbic acid results were decreased by HPH treatments due to increasing outlet temperatures of product, however, antioxidant capacity of nectars increased after treatment due to increasing total carotenoid content. This study indicated that HPH treatment could solve the sedimentation problem during shelf life with minimally affecting bioactive and physical properties of rosehip nectar.
- MakaleAçık Erişim2017Pasting properties of buckwheat, rice and maize flours and textural properties of their gels: Effect of ascorbic acid concentration
Yildiz, Ö.; Toker, O.S.; Yüksel, F.; Cavus, M.; Ceylan, M.M.; Yurt, B.
In the present study, the effect of ascorbic acid addition on the pasting properties of several gluten-free flours, namely buckwheat, maize and rice flours, and textural properties of their gels were also investigated. Pasting curves of control flour and 10 mg/kg ascorbic acid-including flour were found to be very similar to each other. However, higher levels of ascorbic acid significantly influenced the magnitude of all pasting parameters such as peak viscosity, trough viscosity, breakdown viscosity, final viscosity, setback viscosity, peak time and pasting temperature. Regarding textural properties specifying machinability of the doughs, ascorbic acid addition also generally influenced textural characteristics such as hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness and resilience parameters of the samples. According to the results, the ascorbic acid level to be used with the gluten-free flour should be adjusted carefully with regard to pasting and textural parameters. Ascorbic acid addition level directly affected the quality of the end products, determining consumer preference.
- MakaleAçık Erişim2017Effect of brewing conditions on antioxidant properties of rosehip tea beverage: study by response surface methodology
İlyasoğlu, Huri; Arpa, Tuba Eda
The aim of this study was to investigate the effects of brewing conditions (infusion time and temperature) on the antioxidant properties of rosehip tea beverage. The ascorbic acid content, total phenolic content (TPC), and ferric reducing antioxidant power (FRAP) of rosehip tea beverage were analysed. A two-factor and three-level central composite design was applied to evaluate the effects of the variables on the responses. The best quadratic models were obtained for all responses. The generated models were validated under the optimal conditions. At the optimal conditions, the rosehip tea beverage had 3.15 mg 100 mL−1 of ascorbic acid, 61.44 mg 100 mL−1 of TPC, and 2591 µmol of FRAP. The best brewing conditions for the rosehip tea beverage were found to be an infusion time of 6–8 min at temperatures of 84–86 °C.