干燥工艺对罗非鱼片品质的影响

Effects of drying processes on quality of tilapia fillets

【目的】通过比较不同干燥工艺对罗非鱼片品质的影响,寻求一种可替代真空冷冻干燥的技术,为高品质干制罗非鱼片及其同类水产品的加工及规模化生产提供技术支持。【方法】以复水率、白度值、硬度和Ca^2+-ATPase活性为品质检测指标,通过单因素和正交试验优化超声波辅助聚葡萄糖渗透热泵干燥和超声波辅助聚葡萄糖渗透真空冷冻—热泵联合干燥罗非鱼片的预处理工艺条件,再比较这2种干燥方式和热泵干燥、真空冷冻干燥方式对罗非鱼片干制品品质的影响。【结果】超声波辅助聚葡萄糖渗透热泵干燥罗非鱼片的最佳预处理工艺条件:超声波功率400 W、超声波时间65 min、聚葡萄糖浓度60 g/L,其中超声波时间影响最大;超声波辅助聚葡萄糖渗透真空冷冻—热泵联合干燥罗非鱼片的最佳预处理工艺条件:超声波功率450 W、超声波时间65 min、聚葡萄糖浓度80 g/L,其中超声波功率影响最大。超声波辅助聚葡萄糖渗透真空冷冻—热泵联合干燥的罗非鱼片干制品复水率、白度值和Ca^2+-ATPase活性最高,分别达78%、71.8和2.42μmol Pi/(mg prot·h),显著高于热泵干燥和超声波辅助聚葡萄糖渗透热泵干燥(P<0.05,下同),但与真空冷冻干燥无显著差异(P>0.05);真空冷冻干燥的产品硬度(4.31 N)最低,显著低于其他3种干燥方式的罗非鱼片干制品硬度;而热泵干燥的罗非鱼片干制品复水率、白度值和Ca^2+-ATPase活性最低,硬度最高,分别为51%、34.1、0.46μmol Pi/(mg prot·h)和9.98 N。【结论】超声波辅助聚葡萄糖渗透真空冷冻—热泵联合干燥罗非鱼片的干制品品质接近真空冷冻干燥制品的品质,干燥时间缩短,值得在同类水产品干制加工中推广应用。

【Objective】In order to find a technology that could replace vacuum freeze drying technology by comparing the effects of different drying processes on the quality of tilapia,and provide technical supporting for the high-quality of dried tilapia fillets and the processing and large-scale production of similar aquatic products.【Method】The rehydration rate,whiteness,hardness and Ca^2+-ATPase activity were used as quality indicators,optimum pretreatment conditions of ultrasonic assisted polyglucose permeation heat pump drying and ultrasonic assisted polyglucose permeation vacuum freezeheat pump combined drying were obtained by single factor and orthogonal experiments.Then,the quality of tilapia fillets processed by ultrasonic assisted polyglucose permeation heat pump drying,ultrasonic assisted polyglucose permeation vacuum freeze-heat pump combined drying and heat pump drying and vacuum freeze drying were compared.【Result】The optimum pretreatment conditions of ultrasonic assisted polyglucose permeation heat pump drying were ultrasonic power 400 W,ultrasonic time 65 min,polydextrose concentration 60 g/L,and the effects of ultrasonic time was the largest.The optimum conditions of ultrasound-assisted polyglucose permeation vacuum freeze-heat pump combined drying were ultrasonic power 450 w,ultrasonic time 65 min,polydextrose concentration 80 g/L.In addition,the ultrasonic power had the greatest influence.The rehydration rate,whiteness value and Ca^2+-ATPase activity of the samples processed were the best,reaching 78%,71.8 and 2.42μmol Pi/(mg prot·hour),respectively,when tilapia fillets were dried by optimum pretreatment conditions of ultrasound-assisted polyglucose permeationvacuum freeze-heat pump combined drying.Compared with heat pump drying and ultrasonic assisted polydextrose osmotic heat pump drying,they were significantly higher(P<0.05,the same below).But it was not significantly different when compared with vacuum freeze drying(P>0.05).The product hardness of the vacuum freeze-dried product was the lowest,its hardness was only 4.31 N,which was significantly lower than the hardness of the dried tilapia fillet products of the other three drying methods.However,the rehydration rate,whiteness and Ca^2+-ATPase activity of tilapia fillets by heat pump were the lowest,and the hardness was the highest,being 51%,34.1,0.46μmol Pi/(mg prot·hour)and 9.98 N,respectively.【Conclusion】The quality of dried tilapia fillets in ultrasonic assisted polydextrose osmotic vacuum freezing heat pump is close to that of vacuum freeze-drying products,in addition,its drying time is shorter than that of vacuum freeze drying,therefore,it should be applied in the drying processing of similar aquatic products.