脉冲真空渗透预处理改善热泵干燥罗非鱼片品质

Pulse vacuum osmosis pretreatment improving quality of heat pump dried tilapia fillets

为了获得脉冲真空浸渍预处理条件对热泵干燥罗非鱼片品质的影响,以白度、脱水效率指数(DEI,dehydration efficiency index,)、Ca2+-ATPase活性、复水率和质构为检测指标,结合综合评分,进行了以循环率(真空维持时间/常压维持时间)、循环次数、真空压力和海藻糖浓度为预处理变化条件下单因素影响的系列试验。结果表明:在其他条件不变的情况下,每个单因素均有一个使干燥品质达到最佳的因素范围和最佳值。循环率在4∶4~5∶1min/min之间变化时,其综合品质较好,且以循环率为4∶2min/min时,综合评分达到最高。循环次数在3~5之间变化时,其综合品质与对照组相比提升幅度较高,且循环次数为4时,综合评分最高。脉冲真空压力在4~16 kPa之间变化时,对热泵干燥罗非鱼片的综合品质的提升效果较好,且真空压力为10 kPa时,综合评分最高。海藻糖质量浓度在90~170 g/L的范围内变化时,综合品质的提升效果较好,且海藻糖质量浓度在130 g/L时综合评分值最高。与常压渗透对照组相比,各品质指标都得到了不同程度的提升,各指标达到的最大升幅分别为:白度17.9%,复水率80%,Ca2+-ATPase活性93.6%,差异显著(P<0.05)。脉冲真空条件下的浸渍预处理可以有效提升热泵干燥罗非片的综合品质,研究结果为改善同类产品干燥的预处理工艺提供参考。

Pulsed vacuum takes advantage of the circulatory operation between normal pressure and vacuum pressure.It has been applied to the drying and thawing process of fruits and vegetable.Previous studies have shown that suitable pulsed vacuum pretreatment can effectively improve the drying quality of fruits and vegetables,and is beneficial to the extraction of bioactive substances.However,it is rarely reported about the application of pulsed vacuum pretreatment in fish drying.In order to effectively take the advantages of osmotic dehydration combined with pulsed vacuum effect,this paper attempted to apply pulse vacuum infiltration pretreatment in heat pump drying of tilapia fillet on the basis of osmotic dehydration research.These would break through the limitations of conventional technology and a new process of pulsed vacuum infiltration pretreatment for heat pump drying process of tilapia fillets was obtained.Therefore,in order to obtain the effect of pulsed vacuum impregnation as a pretreatment on the quality of heat pump dried tilapia fillets,whiteness,DEI(dehydration efficiency index),Ca2+-ATPase activity,rehydration rate and texture,as well as the comprehensive scores were evaluated for the quality assessment of tilapia fillets.The relevant evaluation criteria were screened to develop the evaluation factor set according to the test purpose.The weight coefficient of each criterion was determined using the analytic hierarchy process to construct the hierarchical structure models of target layer,factor layer and project layer.A series of single-factor experiments were conducted,and the factors included circulation rate,cycle times,vacuum pressure and trehalose concentration.The results showed:Compared with the control group,the pulse cycle rate could effectively improve the comprehensive quality of the heat pump dried fish fillets,and when the circulation rate was4:2within the range of4:4-5:1,not only the comprehensive score reached the maximum,but also Ca2+-ATPase activity was increased by42.48%;the cycle number could effectively improve the comprehensive quality of the heat pump dried fish fillets;when the cycle number was4within the range of3-5,the whiteness of fillets got the peak value of41.08and increased by16.98%compared to the control group;the vacuum pressure could effectively improve the comprehensive quality of the heat pump dried fish fillets,and when the vacuum pressure was10kPa within the range of4-16kPa,the results were better and rehydration rate obtained the balance gradually;when the trehalose concentration was at130g/L within the range of90-170g/L,the research got the maximum comprehensive score.Moreover,compared with the atmosphere pressure control group,the whiteness,rehydration rate,and Ca2+-ATPase activity of dried tilapia fillets were increased pronouncedly by17.9%,80%,and93.6%respectively.By changing the vacuum pressure,vacuum circulation rate,cycle times and the concentration of trehalose,the quality of the heat pump dried tilapia fillets could be promoted with different degrees.Impregnation under pulsed vacuum condition can improve the comprehensive quality of heat pump dried tilapia fillets effectively,which provides a reference for improving the pretreatment process of similar dried products,and also provides technical guidance for similar product technological update.