中试脉冲喷动床微波冻干山楂干燥特性与品质特性研究

Drying and quality characteristics of hawthorn after pilot-scale pulse-spouted bed microwave freeze-drying

该文针对传统冻干(conventional freeze-drying,CFD)存在的干燥周期长、能耗大及生产成本高等问题,探究中试脉冲喷动床微波冻干(pulse-spouted bed microwave freeze-drying,PSBMFD)山楂的干燥特性与品质特性,分析代替传统冻干进行商业化应用的可行性。以CFD山楂作为对比,研究了两者干燥时间、能耗、山楂品质及干燥均匀性等方面的差异。结果显示,和CFD相比,中试PSBMFD能耗降低72.49%,干燥周期减少62.39%,较好地保留山楂原有风味,所得山楂产品具有多孔结构和较高质构(硬度20.83 N);在水分含量、色差、收缩率方面,中试PSBMFD实现了山楂产品较高的均匀性(>90%);在营养保留方面,中试PSBMFD山楂具有较高的总酚含量[37.03 mg/g干基,以没食子酸当量(gallic acid equivalent,GAE)计]与抗氧化能力。该中试实验结果为PSBMFD商业化提供了有效的理论基础和技术支持。

In view of the problems of long drying time,high energy consumption,and high production cost of the conventional freeze-drying(CFD),this paper explored the drying characteristics and quality attributes of hawthorn and the feasibility of replacing CFD with pilot-scale pulse-spouted bed microwave freeze-drying(PSBMFD).The differences in drying time,energy consumption,quality,and drying uniformity of hawthorn dried by CFD and pilot-scale PSBMFD were studied.Results showed that compared with CFD,pilot-scale PSBMFD could reduce energy consumption by 72.49%,reduce drying cycle by 62.39%,and endow dried samples with porous structure and higher texture(hardness 20.83 N)and better original flavor retention.In terms of moisture content,color difference,and shrinkage ratio,pilot-scale PSBMFD-dried hawthorn showed a higher uniformity(>90%).In terms of nutrient retention,pilot-scale PSBMFD-dried samples showed higher total phenol content(37.03 mg GAE/g dw)and antioxidant capacity.The pilot experiment provides the theoretical basis and technical support for the commercialization of PSBMFD.