Drying kinetics modeling of apple and zucchini slices vacuum impregnated with anthocyanins

ABSTRACT: The aim of this research was to study the drying kinetics of apple and zucchini slices enriched with anthocyanins and to evaluate the influence of drying temperature on the anthocyanin content of apple and zucchini snacks. Apple (Granny Smith) and zucchini (Cucurbita pepo) slices were enriched with anthocyanins by vacuum impregnation with blueberry juice. Then, slices were dehydrated at 40, 50 and 60 ºC with 1.0 m/s air flow. Dehydrated samples were referred to as anthocyanin enriched snacks. Diffusion coefficient values improved by increasing the drying temperature, within the 2.81×10-10 to 5.78×10-10 m2/s range for apple slices and 2.02×10-10 to 3.99×10-10 m2/s for zucchini slices. The activation energy was 31.19 kJ/mol and 80.33 kJ/mol for apple and zucchini slices respectively. Page, Weibull, Logarithmic, Henderson-Pabis and Lewis models best fitted the experimental data. Snacks obtained at 60 °C retained a higher concentration of anthocyanins, reaching values of 592.81±52.55 and 464.62±48.44 mg of cyaniding-3-glucoside equivalent/kg dry matter in apple and zucchini snacks respectively. Combination of vacuum impregnation and hot air drying was a technological alternative for producing snacks with functional properties.

摘要：本研究旨在探究添加花青素(anthocyanins)的苹果与西葫芦薄片的干燥动力学，并评估干燥温度对苹果、西葫芦零食中花青素含量的影响。研究人员采用蓝莓汁真空浸渍法，对苹果（澳洲青苹(Granny Smith)）和西葫芦(Cucurbita pepo)薄片进行花青素富集处理，随后以1.0 m/s的气流速度分别在40 ℃、50 ℃和60 ℃条件下进行脱水，所得脱水样品即为花青素富集零食。随着干燥温度升高，扩散系数值有所提升：苹果薄片的扩散系数范围为2.81×10^-10 至5.78×10^-10 m²/s，西葫芦薄片的扩散系数范围为2.02×10^-10 至3.99×10^-10 m²/s。苹果与西葫芦薄片的活化能分别为31.19 kJ/mol与80.33 kJ/mol。Page模型、威布尔模型(Weibull)、对数模型(Logarithmic)、Henderson-Pabis模型以及Lewis模型可较好拟合实验数据。在60 ℃条件下制备的零食保留了更高浓度的花青素，其中苹果零食与西葫芦零食的花青素含量分别可达592.81±52.55 mg 氰定-3-葡萄糖苷(cyaniding-3-glucoside)当量/千克干物质，以及464.62±48.44 mg氰定-3-葡萄糖苷当量/千克干物质。真空浸渍与热风干燥联用的工艺，可作为制备具备功能特性零食的技术备选方案。