‘修水化红’甜橙皮热风干燥动力学及其品质特性分析

Drying Kinetics and Quality Characteristics of’Xiushui Huahong’Sweet Orange Peel Dried by Hot Air

为明确‘修水化红’甜橙皮热风干燥(hot air drying,HAD)特性及确定适宜的干燥温度,实现对‘修水化红’皮在HAD过程中的质量控制,本研究以‘修水化红’皮为对象,探讨其在不同HAD温度(50、60、70、80、90℃)下水分比与干燥时间的关系并建立动力学模型。同时以外观特征、黄酮含量、抗氧化能力及挥发性风味成分含量为评价指标,综合评价不同HAD温度对‘修水化红’品质的影响。结果表明:‘修水化红’皮的HAD过程分为加速、恒速及降速3个阶段,随着干燥温度升高,‘修水化红’皮干燥速率明显增大,数据拟合结果表明Page模型能准确描述不同热风温度下‘修水化红’皮的干燥过程。50℃HAD能够最大程度地保持‘修水化红’皮的色泽和形状,60℃HAD‘修水化红’皮的总黄酮、橙皮苷含量最高,90℃HAD‘修水化红’皮抗氧化能力较好。5种干燥温度的‘修水化红’皮为共鉴定出24种挥发性风味成分,其中50~70℃HAD‘修水化红’皮均为11种,80℃HAD‘修水化红’皮为15种,90℃HAD‘修水化红’皮为19种。D-柠檬烯是5种干燥温度的‘修水化红’皮主要的挥发性风味成分,相对含量最高。不同HAD温度下的‘修水化红’皮的品质均表现出一定的差异,在选择适宜的干燥温度时需考虑实际生产需求,需求黄酮类物质含量高的产品则考虑60℃HAD,生产香料用产品考虑90℃HAD。

This study aimed to clarity the drying characteristics of‘Xiushui Huahong’sweet orange peel and determine a suitable drying temperature for its quality control during hot air drying.A kinetic model to describe the relationship between moisture ratio and drying time at different hot air temperatures(50,60,70,80 and 90℃).Meanwhile,the effect of different drying temperatures on the dried product quality in terms of appearance,antioxidant capacity and the contents of flavonoids and contents of volatile flavor compounds was evaluated.The drying process involved three stages,acceleration,maintenance and deceleration.The drying rate distinctly increased as the drying temperature increased,and the data fitting result showed that the Page model could accurately describe the drying process at different hot air temperatures.Sweet orange peel dried at 50℃maintained the original color and shape to the greatest extent.The contents of total flavonoids and hesperidin were the highest in the sample dried at 60℃,while the product dried at 90℃showed stronger antioxidant capacity.Moreover,24 volatile flavor compounds were detected in the five dried samples,11 of which were found in each of the samples dried at 50,60 and 70℃,15 for 80℃,and 19 for 90℃.D-limonene was the most abundant volatile flavor compound in all five samples.These samples differed in their quality.Hence,drying temperature should be chosen according to actual requirements,and drying at 60 and 90℃are suitable for higher contents of flavonoids and volatile flavor compounds,respectively.