Abstract

In this study, sour cherry nectar and apple juice were concentrated using thermal concentration (75, 80, and 85 °C), and intermittent microwave concentration (180, 300, and 450 W) under vacuum condition (at 250 mbar). Thirteen different mathematical models were used to describe the concentration kinetics of the samples. The Midilli model exhibited the best fit to all experimental data (R² ≥ 0.9972; χ² ≤ 1.6724; RMSE ≤ 1.2932). The concentration time was reduced with increasing microwave power (from 180 W to 450 W) and thermal vacuum concentration temperature (from 75 °C to 85 °C). In addition, the main quality parameters of the concentrates were comparatively investigated after reconstitution. Generally, major differences were not observed in the physicochemical properties of samples concentrated by thermal and microwave methods. Total phenolic content of the apple juice and sour cherry nectar samples were ranged between 209.87-216.67 mg/L and 571.00-588.57 mg/L, respectively. Fructose was the main sugar in both juices, followed by glucose and sucrose. The particle size of the juice samples increased with concentration processing.

摘要

在本研究中，酸樱桃花蜜和苹果汁在真空条件下（250 毫巴）使用热浓缩（75、80 和 85 °C）和间歇微波浓缩（180、300 和 450 W）进行浓缩。十三种不同的数学模型用于描述样品的浓度动力学。Midilli 模型表现出对所有实验数据的最佳拟合（R ² ≥ 0.9972；χ ²≤ 1.6724；RMSE ≤ 1.2932)。浓缩时间随着微波功率（从 180 W 到 450 W）和热真空浓缩温度（从 75 °C 到 85 °C）的增加而减少。此外，对复溶后浓缩物的主要质量参数进行了比较研究。一般来说，通过热法和微波法浓缩的样品的理化性质没有观察到重大差异。苹果汁和酸樱桃花蜜样品的总酚含量分别介于 209.87-216.67 mg/L 和 571.00-588.57 mg/L 之间。果糖是两种果汁中的主要糖分，其次是葡萄糖和蔗糖。果汁样品的粒度随着浓缩处理而增加。