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Öğe Comparison of chemical, physical, and ultrasound treatments on the shelf life of fresh-cut quince fruit (Cydonia oblonga Mill.)(Wiley, 2020) Yildiz, Gulcin; İzli, Gökçen; Aadil, Rana MuhammadThe study was conducted to examine the effect of chemical treatment (ascorbic acid and calcium chloride), physical treatment (water bath at 65 degrees C), and ultrasound (US) in ultrasonic bath for the prevention of enzymatic browning of fresh-cut quince slices during 14 days of storage. The treated quince slices were analyzed in terms of color, polyphenol oxidase, and pectin methyl esterase activity, bioactive compounds, sensory, and microbial analysis. The results showed that US treatment inhibited (p < .05) the growth of bacteria, mold, and yeast in fresh-cut quince slices during 4 degrees C storage. The US-treated slices showed a significant (p < .05) improvements in bioactive compounds as well as improved physical properties as compared to all other treatments. Similarly, US-treated samples showed the best color values with the lowest value of enzyme activities showing less enzymatic browning. Moreover, the findings showed that the lowest score for decay and off-odor were obtained for the quinces treated with US. Practical applications A significant improvement in the quality of US-treated fresh-cut quinces with the comparison of other chemical and physical treatments was achieved. This study will contribute a novel method to develop US-treated fresh-cut fruit and vegetables with an enhanced product quality and extended shelf life. In overall, processing of fresh-cut quince fruit with a US treatment might be applied to get a high-quality and browning-free product.Öğe The effect of ultrasound pretreatment on quality attributes of freeze-dried quince slices: Physical properties and bioactive compounds(Wiley, 2019) Yildiz, Gulcin; İzli, GökçenThe study was conducted to examine the effect of ultrasound (US) pretreatment on physical and chemical/nutritional attributes of freeze-dried quince slices. The quince fruits were washed, hand-peeled and cut with a dimension of 1 cm (L) x 0.2 (W) cm x 1 cm (H). The quince samples were treated in an ultrasonic bath in three different times which were 10, 20, and 30 min. Untreated and ultrasonically pretreated quince samples were dried in a freeze dryer. Freeze-dried samples were analyzed in terms of physical properties such as shrinkage, rehydration, color, water activity, and hardness and bioactive compounds including total phenols, ascorbic acid, and antioxidant capacity. A significant difference was observed among untreated and ultrasonically pretreated quince samples. The freeze-dried quince slices treated with a US (especially 20 min-treatment) showed a higher preservation of bioactive compounds in addition to improved physical properties compared to the untreated quince samples. In overall, US pretreatment is a promising process as demonstrated in current research by its capability to better retain freeze-dried quince quality in terms of physical and chemical properties. Practical Applications The freeze drying of quince fruit with the aid of US pretreatment was investigated. A significant development in the quality preservation of freeze-dried of quince slices with an US-pretreatment was accomplished. This research will contribute a useful technique to produce freeze-dried quinces with a significantly enhanced product quality. Drying of quince samples with a freeze drying in addition to US-pretreatment might be applied to get a high-quality fruit with an improved bioactive compounds and physical property.Öğe Influence of microwave and microwave-convective drying on the drying kinetics and quality characteristics of pomelo(Wiley, 2019) Yildiz, Gulcin; İzli, GökçenThe present study investigated the effects of microwave (90 and 160 W) and combined microwave-convective (90 W-55 degrees C, 90 W-65 degrees C, 90 W-75 degrees C, 160 W-55 degrees C, 160 W-65 degrees C and 160 W-75 degrees C) drying techniques on the drying kinetics, color parameters (L*, a*, b*, C, alpha degrees and Delta e), total phenolic content (TPC), and antioxidant capacity (ATC) of pomelo samples. The drying data were fitted to 10 typically used thin-layer drying models to select a suitable model for drying of pomelo. Comparing the statistical parameters of applied models, the Diffusion Approach, Midilli et al., and Page models were found to be the best-fitting models in describing drying kinetics of the pomelo samples. It was observed that the drying temperature and/or microwave power changed significantly the all color parameters, TPC, and ATC. The combined microwave-convective drying resulted in shorter drying times with higher drying rates and high-quality dried pomelo samples. Practical applications A significant improvement in the quality retention of combined microwave-convective drying of pomelo slices was achieved. This piece of work will provide a novel method to produce microwave-convective-dried pomelo fruits with a significantly improved product quality. A practical implication is that drying of pomelo slices with an optimum condition by combined microwave-convective process can be used to get a high-quality product with a higher ATC, TPC, and color.Öğe Quality retention in pumpkin powder dried by combined microwave-convective drying(Springer, 2022) İzli, Gökçen; Yildiz, Gulcin; Berk, Senel EcemThree distinct drying methods, microwave drying (MWD), convective drying (CVD) and microwave-convective drying (MWCVD) with a grinding process were applied to obtain pumpkin powder. The effects of CVD (60, 70 & 80 °C), MWD (100 & 200 W) and MWCVD (100 W-60 °C, 100 W-70 °C, 100 W-80 °C, 200 W-60 °C, 200 W-70 °C, and 200 W-80 °C) applications on the physicochemical properties (water activity, bulk, tapped & particle densities, porosity, flowability, cohesiveness, swelling capacity, water holding capacity and water solubility index), color values (L*, a*, b*, C, αo and Δe), bioactive compounds (5-Hydroxymethyl-2-furfural (HMF), total phenolic content (TPC) and antioxidant capacity (DPPH and ABTS)) of the eleven pumpkin fruit powders were compared. The MWCVD, namely pumpkin powders dried at 200 W–80 °C resulted in shorter drying times with high‐quality dried pumpkin powders. The bulk, tapped and particle densities of pumpkin powders at 200 W-80 °C by MWCVD were 0.56, 0.66 and 1.74 g/cm3, respectively. These values are indicators of the good porosity (61.82%) of pumpkin powders. In addition, the highest TPC (1277.08 mg GA/100 g dw) and ABTS (126.99 ± 3.31 µmol Trolox/g dw) was observed for microwave-convective dried pumpkin powders at 200 W-80 °C. On the other hand, the lowest HMF level (10.12 ± 1.78 mg/kg dw) was found for the pumpkin poowders dried by MWCVD at 200 W-80 °C. In overall, dried pumpkin powders by a MWCVD method can be employed to acquire a high-quality food material along with an enhanced physicochemical properties, color and bioactive components.
