红枣热风微波耦合干燥工艺优化及干燥特性和微观结构研究

Optimization of hot air-microwave coupling drying process and study on drying characteristics and microstructure of Ziziphus jujuba Mill.

中文关键词:  红枣  热风微波耦合干燥  预处理  特性  品质

英文关键词:Ziziphus jujuba Mill.  hot air-microwave coupling drying  pretreatment  drying characteristics  microstructure

中文摘要:

      目的 优化红枣热风微波耦合干燥工艺, 并考查其干燥特性和微观结构, 解决传统热风干燥效率低、维生素C损失严重等问题。方法 以新疆地区灰枣为原料, 利用热风微波耦合干燥技术进行干制红枣加工, 研究了热风微波耦合干燥对红枣干燥特性的影响, 同时以热风温度、微波功率、载重量为影响因素, 以维生素C保留率、色泽和复水比作为评价指标, 采用三元二次通用旋转组合设计优化红枣热风微波耦合干燥工艺参数, 并与热风干燥、微波干燥产品的干燥时间、品质及微观结构进行对比分析。结果 红枣热风微波耦合干燥分为增速阶段和降速阶段; 各因素对红枣色泽、维生素C含量、复水比的影响顺序均为热风温度>微波功率>载重量; 红枣热风微波耦合干燥的较佳工艺参数为: 热风温度48℃、微波功率94 W、载重量190 g; 热风微波耦合干燥产品品质优于热风干燥及微波干燥, 维生素C保留率比热风干燥提高了36.43 mg/100 g; 扫描电镜观测表明热风微波耦合干燥产品微观结构平整紧凑。结论 本研究优化后的热风微波耦合干燥工艺缩短了干燥时间, 保证了产品品质, 可为红枣干制加工提供一种新的干燥技术和理论依据。

英文摘要:

      Objective To optimize the hot air-microwave coupling drying process of jujube and investigate its drying characteristics and microstructure, so as to solve the problems of low drying efficiency and serious loss of vitamin C. Methods Fresh Ziziphus jujuba Mill. from Xinjiang area were dried with a new type of drying technology, namely hot air-microwave coupling drying. The effect of hot air-microwave coupling drying on the drying characteristics of Ziziphus jujuba Mill. were studied. The hot air temperature, microwave power and carrying capacity were selected as influencing factors, retention rate of vitamin C, color, and rehydration ratio were used as evaluation indicators, the process parameters of hot air-microwave coupling drying of Ziziphus jujuba Mill. were optimized by ternary and secondary general rotary combination design, and the drying time, quality and microstructure of hot air and microwave drying products were compared. Results The drying process of hot air-microwave coupling drying was divided into growth rate and deceleration period; The influence of each factors on the color, retention rate of vitamin C and rehydration ratio of Ziziphus jujuba Mill. was hot air temperature>microwave power>carrying capacity. The optimal process parameters: Hot air temperature of 48℃, microwave power of 94 W and rehydration ratio of 190 g; The product quality of hot air-microwave coupled drying was better than that of hot air drying and microwave drying, and the retention rate of vitamin C was 36.43 mg/100 g higher than that of hot air drying. Microstructure detection indicated that hot air-microwave coupling drying technologies could make a smooth and compact structure and thus change the properties of Ziziphus jujuba Mill.. Conclusion Hot air-microwave coupling drying shortens the drying time and ensures the drying quality, which can provide a new drying technology and theoretical basis for Ziziphus jujuba Mill. drying processing.