Segmented microwave vacuum drying process and flavor of Hezhou taro

ObjectiveThis paper aims to solve the common problems in the taro industry, such as the high storage and transportation cost of taro and its quick-frozen products, the low drying efficiency of fresh taro, and the flavor loss of taro powder by investigating the conditions of segmented microwave vacuum drying process of taro and the flavor characteristics of taro powder.MethodsBy taking Hezhou taro as the research object, the microwave vacuum drying mode was determined by analyzing the characteristics of the drying curve, and the optimal process was determined by analyzing the whiteness value, drying time, and sensory evaluation results. The flavor characteristics of taro powder were analyzed by using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) technology.ResultsThe optimal process of segmented microwave vacuum drying for Hezhou taro was as follows: vacuum degree of -95 kPa, microwave power of 12.0 kW at acceleration phase with drying temperature range of 60~70 ℃, conversion time of 12 min, microwave power of 6.0 kW at deceleration phase with drying temperature range of 40~60 ℃, moisture content of the sample to drying ≤4%, and total time consumption of 34 min. The taro powder obtained under the optimal process had a strong taro flavor, and a total of 12 volatile flavor components were detected, including nine key volatile flavor components, of which (E)-6,10-dimethyl-5,9-undecadien-2-one might be a unique flavor component of Hezhou taro.ConclusionSegmented microwave vacuum drying is an effective way to improve the drying efficiency of fresh taro and strengthen the taro flavor of taro powder.