Foam mat drying kinetics of jambolan and acerola mixed pulp

ABSTRACT Acerola and jambolan are fruits with several bioactive compounds of phenolic origin and a product made with these two raw materials appears to be a food with high antioxidant and nutraceutical potential. Therefore, this study aimed to evaluate the foam mat drying of the mixed pulp of jambolan and acerola. Mixed pulp formulations, containing 1.0% albumin with 0.5% xanthan gum (F1), 0.5% carboxymethylcellulose (F2) and 0.5% guar gum (F3), were dehydrated at 50, 60, 70 and 80 °C, with foam mat thickness of 0.5 cm. The elevation of the drying temperature decreased the water content and dehydration time of the samples. Formulation F3 obtained the shortest drying times; all drying models resulted in good adjustments, especially Midilli. Formulation F3 obtained greater effective diffusivity; the activation energy was higher in the F1 combination. The samples with albumin-guar (F3) showed greater enthalpy and entropy and samples with albumin-xanthan gum (F1) showed the highest Gibbs free energy. Foam mat drying is an efficient way of preserving the jambolan and acerola mixed pulp.

摘要：金虎尾果（Acerola）与乌墨果（Jambolan）均含有多种酚类来源的生物活性成分，以这两种原料制备的产品具备较高的抗氧化活性与营养保健潜力。本研究旨在评估乌墨果与金虎尾果混合果浆的泡沫干燥法（Foam mat drying）工艺。研究设置了三种混合果浆配方：添加1.0%白蛋白与0.5%黄原胶（Xanthan gum）的F1组、添加1.0%白蛋白与0.5%羧甲基纤维素（Carboxymethylcellulose）的F2组，以及添加1.0%白蛋白与0.5%瓜尔胶（Guar gum）的F3组，分别在50、60、70与80 ℃条件下进行脱水处理，泡沫层厚度设定为0.5 cm。实验结果显示：干燥温度升高会降低样品的含水量与脱水时长；F3组的脱水时长最短；所有干燥模型均取得了良好的拟合效果，其中米德利模型（Midilli）的表现尤为突出；F3组的有效扩散系数更高，而F1组的活化能更高。此外，白蛋白-瓜尔胶复配的F3组样品展现出更高的焓与熵值，白蛋白-黄原胶复配的F1组样品则拥有最高的吉布斯自由能。综上，泡沫干燥法是保留乌墨果与金虎尾果混合果浆品质的高效手段。