真空低热烹饪对鲟鱼肉物性品质及微观结构的影响

为评价鲟鱼肉真空低热烹饪(LTVH)过程中肉质变化程度并明确其变化原因,本试验以冷冻鲟鱼肉为原料,进行真空包装,于48,52,56℃下分别进行40和60 min的低温热处理,并与常压100℃,15 min的传统烹饪方式(TC)进行对照,对鲟鱼肉的蒸煮损失率、质构、色差等物性指标,以及肌原纤维蛋白构象、SDS-PAGE图谱和微观结构变化进行分析。结果表明,随着温度的升高和时间的延长,鲟鱼肉的蒸煮损失、硬度、咀嚼性呈显著上升(P<0.05),弹性则先显著下降后上升(P<0.05);亮度(L值)和白度(W值)显著下降(P<0.05),而色度角(H值)较为稳定。分析圆二色谱发现,肌原纤维蛋白二级结构呈现向无序性发展的趋势。根据SDS-PAGE图谱可知,肌球蛋白重链、肌原蛋白和肌球蛋白轻链等主要条带颜色变浅,降解较为明显。微观结构观察发现,鲟鱼肉肌纤维间隙、肌内膜和肌纤维形态均发生明显改变。相较于TC方式,LTVH方式处理的鲟鱼肉物性品质更优,肌原纤维蛋白构象破坏及降解更少,肌纤维结合也更为紧致,空间破坏程度小。

Effect of Low Temperature Vacuum Heating on Physical Quality and Microstructure of Sturgeon Meat

In order to evaluate the degree of meat quality change during the low temperature vacuum heating(LTVH)process of sturgeon meat and to determine the cause of the change,the frozen sturgeon meat was used as raw material,and was processed at 48,52 and 56℃for 40 and 60 min respectively.Physical indicators,myofibrillar protein conformation,SDS-PAGE pattern and microstructure of sturgeon meat which was processed under different temperature and time were analyzed.The result showed that the cooking loss,hardness,chewiness increased significantly(P<0.05)as the temperature rised and the time increased,springiness rised first and then fell significantly(P<0.05)as the temperature rised;the L value and W value decreased significantly(P<0.05),and the H value was relatively stable.The CD showed the secondary structure of myofibrillar protein showed a trend toward disorder.The SDS-PAGE showed that the main bands of the myosin heavy chain,troponin and myosin light chain became lighter gradually as the temperature increasing and the time prolonging,indicating that the degradation of these three proteins in the cooking process was more obvious.Microstructure showed that the muscle fiber gap,endomysium and muscle fiber morphology of sturgeon meat changed significantly with the increase of temperature and time.The LTVH treated sturgeon meat had better physical quality,the myofibrillar protein conformation was less damaged with less degradation,muscle fiber combined more tightly,and less space was damaged compared with the TC treated.