罗氏沼虾冻藏过程中质构与理化特性研究

The changes intexture and physicochemical properties of giant freshwater prown(Macrobrachium rosenbergii) during frozen storage

以剪切力、肌原纤维小片化指数、肌原纤维表观直径、TCA-溶解肽、总蛋白酶活和微生物为指标,比较分析了整只罗氏沼虾冻品和去头罗氏沼虾冻品品质的差异,并探讨了其质构劣化的机理。结果表明:随着冻藏时间的延长,虾肉的剪切力均呈下降趋势,整只罗氏沼虾冻品的下降速度明显高于去头罗氏沼虾冻品,冻藏16周后剪切力分别下降了36.81%,25.40%;随着冻藏时间延长整只罗氏沼虾冻品的肌原纤维小片化指数增加,肌原纤维表观直径明显下降,TCA-溶解肽含量增加,说明罗氏沼虾冻藏期间肌原纤维内部结构被破坏,骨架蛋白出现了降解,整只罗氏沼虾冻品在贮藏过程中蛋白发生了降解;虾肉中蛋白酶活性呈上升趋势而虾头中蛋白酶活性则略微下降,说明虾头内的蛋白酶可能向虾肉发生了迁移。菌落总数则随着冻藏时间的延长而下降。相关性分析表明:罗氏沼虾在冻藏期间蛋白变化的各项指标与蛋白酶活性变化和质构劣化之间存在显著相关性(P<0.01)。

The texture and physicochemical properties of giant freshwater prawn during frozen storage were investigated in this study.The quality differences of frozen whole prawn and headless prawn were compared and analyzed by shear stress,myofibrillar fragmentation index,myofibrillar apparent diameter,TCA soluble peptide and total protease activity.The results showed that the shear force of prawn decreased with the extension of storage time.The shear force of frozen whole prawn decreased more rapidly than headless prawn.After 16 weeks,the shear force of frozen whole prawns and headless shrimp decreased by 36.81% and 25.40%.The myofibril fragmentation index and TCA soluble peptide increased with the extension of storage time.However,the myofibril apparent diameter decreased during the frozen storage.This finding suggested that the internal structure of myofibril was destroyed,and the skeletal proteins was degraded.Protein degradation occurred in frozen whole prawns during storage of frozen.The protease activity in muscle increased while that in head is slightly decreased.This finding also indicated that the protease in head transferred to muscle to some extent.The aerobic bacterial of frozen whole prawns decreased with the extension of storage time.Therefore,the correlation analyses showed that there was a significant correlation(P<0.01)between the changes of proteins and the changes of protease activity and texture during the frozen storage.