热泵-微波联合干燥罗非鱼片工艺研究

摘要

In order to increase the drying efficiency of heat pump-microwave drying for tilapia fillets and the quality of dried tilapia fillets, the effects of heat pump temperature and airflow rate and microwave drying time and power on the rate of moisture reduction, rehydration rate and sensory quality of tilapia fillets were investigated. Meanwhile, the appropriate moisture content at the transition from heat pump to microwave was explored. The results indicated that during the heat pump drying stage low-temperature (35℃) drying was necessary to prevent severe protein denaturation, nutrient loss, yellowing and texture hardening of tilapia fillets;in addition, an airflow rate of 3.0 m/s was adopted to prevent hard shell effect. During the microwave drying stage, intermittent drying for 1 min at 1-min intervals was used to improve the taste of tilapia fillets, maintain better color and attenuate protein denaturation. The drying rate became slower when the moisture content was reduced to 40%during the heat pump drying process suggesting the moisture content at the transition from heat pump to microwave to be 40%.%为提高罗非鱼片热泵-微波联合干燥效率和产品品质，考察热泵干燥温度、热泵干燥风速、微波干燥时间、微波干燥功率对罗非鱼片含水率下降速率、产品复水率及感官品质的影响，讨论热泵-微波联合干燥的转换点含水率。结果表明：前期热泵干燥阶段，为避免罗非鱼片蛋白质严重变性、营养成分损失、色泽变焦黄、质地变硬等，采用低温干燥方式，取热泵干燥温度35℃；为避免鱼片表面“硬壳”效应，取热泵干燥风速3.0m/s。后期微波干燥阶段，为改善干制罗非鱼片口感、保持较好的色泽和减缓蛋白质变性等，采取间歇干燥方式，取微波干燥功率为252W，微波单次干燥时间为1min，单次间歇时间为1min。罗非鱼片热泵干燥至40%含水率以后，干燥速率逐渐变慢，取40%作为热泵-微波联合干燥转换时的含水率。