Quality of ‘Royal Gala’ cut apple during osmotic dehydration

Abstract The present work aimed to evaluate quality parameters of ‘Royal Gala’ apple cubes during osmotic dehydration (OD). We investigated the following OD conditions: osmotic agent, pressure, and temperature. The osmotic agent, being lower after OD with sorbitol than sucrose solutions, mainly influenced the water activity of the product. The color changes increased with increased temperature and were higher in vacuum experiments than at atmospheric pressure. In general, we recommend OD at 25 °C and atmospheric pressure for the preservation of the total phenolic content (TPC) and antioxidant activity (AA) of apple cubes during the process. Peleg’s model was found to provide the best fit of TPC and AA data.

摘要 本研究旨在评估渗透脱水（osmotic dehydration, OD）过程中“皇家嘎啦”苹果块的品质参数。本研究考察了三类渗透脱水条件：渗透剂、压力与温度。相较于蔗糖溶液，采用山梨醇进行渗透脱水后所得产品的水分活度更低，渗透剂是影响产品水分活度的主要因素。颜色变化随温度升高而加剧，且真空实验中的颜色变化幅度高于常压条件。总体而言，为在加工过程中保留苹果块的总酚含量（total phenolic content, TPC）与抗氧化活性（antioxidant activity, AA），推荐采用25℃、常压条件下的渗透脱水工艺。研究发现，Peleg模型可最优拟合总酚含量与抗氧化活性的相关数据。