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Öğe Functional properties of chickpea protein isolates dried by refractance window drying(Elsevier B.V., 2018) Tontul İ.; Kasimoglu Z.; Asik S.; Atbakan T.; Topuz A.In the present study, the effect of Refractance Window (RW) drying on the functional properties of chickpea protein isolates was investigated and compared to freeze drying at different pH levels. The functional properties investigated were protein solubility, water and oil holding capacity, emulsifying properties, foaming properties, flocculation and coalescence indices and textural properties. The solubility, oil holding capacity and foam stability of the freeze dried protein isolates were determined to be higher than the RW dried samples. On the other hand, the RW dried samples had better water holding capacity and emulsion stability compared to the freeze dried protein isolates. The emulsion activity index, flocculation and coalescence indices of the chickpea protein isolates prepared by different drying techniques showed different tendencies depending on the pH level. Freeze dried protein isolates exhibited higher gelation ability than RW dried samples according to the texture profile analysis. This study clearly showed that the drying technique used in the preparation of protein isolates can affect their functional properties. © 2017 Elsevier B.V.Öğe Influence of microwave, the combined microwave/hot air and only hot air roasting on the formation of heat-induced contaminants of carob powders(Taylor and Francis Ltd., 2018) Gunel Z.; Tontul İ.; Dincer C.; Topuz A.; Sahin-Nadeem H.This study aims to investigate the effects of microwave, combined microwave/hot air treatment and hot air-only roasting on the formation of heat-induced contaminants of carob powders. Moisture content, water activity and pH values of the product decreased with the increasing roasting time and microwave power, while browning index (BI) and ultraviolet absorbance (UV-A) values were increased. While L and b values of carob powders decreased with increasing the roasting time and microwave power, a and ?E values were increased. Varying roasting conditions also significantly affected the content of Maillard reaction products (MRPs): 5-hydroxymethylfurfural (HMF) (0.69–28.32 mg/kg dry matter), furfural (Öğe Optimization of aqueous extraction and spray drying conditions for efficient processing of hibiscus blended rosehip tea powder(Blackwell Publishing Ltd, 2018) Eroğlu E.; Tontul İ.; Topuz A.The present study aimed to optimize extraction and spray-drying conditions used to produce rosehip tea powder from a blend of rosehip fruit and hibiscus. The optimum conditions of the extraction and spray drying processes were investigated using response surface methodology. The responses of the optimization were the ascorbic acid (AA) and total monomeric anthocyanin (TMA) content of the products. Optimal parameters for the extraction process were determined to be 5.3% loading ratio for 5.4 min at 64 °C. For the spray-drying process, an inlet air temperature of 130 °C, outlet air temperature of 85 °C, and 18.4% maltodextrin ratio was found to be optimal. The powders produced at these conditions were stored at 4 °C and ambient temperature for 90 days to test the stability of AA and TMA. The degradation rates at 4 °C and at ambient temperature were found to be 41.4 and 48.2% for AA and 23.3 and 37% for TMA, respectively. Practical applications: Nowadays there is a significant increase in the use of foods that are easy to prepare for consumption or ready for direct consumption. When consumers choose these products, they consider both ease of use and product quality. Tea bag and similar products are one of the most widespread product groups in this area. However, there are some disadvantages such as the waste problem and inadequate brewing conditions in use of these products. The solution of these problems requires alternative methods to prepare the product. The transformation of rosehip tea into instant rosehip tea form at optimum conditions determined in the current study can be used as an alternative method to solve these problems. © 2018 Wiley Periodicals, Inc.Öğe Physical and microbiological properties of yoghurt powder produced by refractance window drying(Elsevier Ltd, 2018) Tontul İ.; Ergin F.; Eroğlu E.; Küçükçetin A.; Topuz A.The present study aimed to determine the effect of refractance window (RW) drying comparatively with freeze drying on some physical properties and microbiological properties of yoghurt powder. Physical properties of yoghurt powders obtained by RW drying were generally better than those of yoghurt powders obtained by freeze drying except for colour properties. RW drying caused reduction in the counts of yoghurt bacteria during drying, and this reduction increased as the drying temperature increased. Spreading thickness did not play a critical role on the viability of yoghurt bacteria in dried samples. The viability of yoghurt bacteria in yoghurt powders was observed during 90 days of storage at 4 °C. At the end of storage period, the survival of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the yoghurt powders produced by RW drying at 50 °C was higher than those produced by RW drying at 60 °C and 70 °C. © 2018 Elsevier Ltd
