脂肪添加量和冻藏时间对冷冻水饺肉馅肌原纤维蛋白氧化和凝胶特性的影响

Influence of Fat Addition and Frozen Storage Time on Oxidation and Gelation of Myofibrils from Frozen Dumplings Fillers

研究脂肪添加量和冻藏时间对速冻水饺肉馅肌原纤维蛋白氧化和凝胶特性的影响。通过测定冷冻水饺肉馅中肌原纤维蛋白的氧化性变化和凝胶性质变化来揭示冷冻水饺在冻藏过程中食用品质下降的机理。在水饺肉馅中添加不同比例的背膘,在-18℃贮藏,分别测定水饺肉馅在0、30、60、90、180d时的羰基含量、热诱导凝胶的黏弹性的变化情况,并通过聚丙烯酰胺凝胶电泳(SDS-PAGE)观察肌原纤维蛋白的聚集和降解,通过感官评定指标评价水饺的感官品质的变化。结果表明:随着脂肪添加量的增加和冻藏时间的延长,水饺肉馅中肌原纤维蛋白中羰基含量显著增加(P<0.05);肌原纤维蛋白凝胶的储能模量G′下降,最大峰值对应的温度不断减小;SDS-PAGE图显示肌球蛋白的重链和肌动蛋白的百分含量下降,肌球蛋白的轻链2在贮藏180d时消失;在冻藏90d时,水饺的质地明显变得粗糙,多汁性降低(P<0.05),酸败味值增加,总体接受性下降。冷冻水饺在冻藏过程中,受脂肪添加量的影响,肌原纤维蛋白因氧化而严重变性,影响了其形成凝胶的能力和凝胶的黏弹性,从而影响了冷冻水饺的食用品质。

The objective of present study was to elucidate the effects of fat addition and frozen storage time on the oxidation and gelation of myofibrils from frozen dumpling fillers. The oxidation and gelation of myofibril extracted from fillers in the frozen dumplings were studied in order to evaluate the quality deterioration mechanism of frozen dumpling during frozen storage. The carbonyl content, heat-induced gelatin viscosity and sodium dodecyl sulfate- polyacrylamide gel electrophoresis （SDS-PAGE） of myofibrils of frozen dumplings and sensory evaluation were determined. The results indicated that the carbonyl content in myofibrillar protein increased significantly （P 〈 0.05） with the increases of frozen storage time. The storage modulus （G＇） and the peak temperature of myofibril protein decreased gradually. The SDS-PAGE showed that the percent of myosin heavy chain （MHC） and actin reduced and myosin light chain2 disappeared at 180 days of frozen storage. After 90 days of frozen storage, the texture of dumpling filler became tougher; juiciness reduced sharply （P 〈 0.05）; and rancidity value increased significantly （P 〈 0.05）, overall acceptability also reduced generally. Because fat oxidation could cause protein oxidation, the myofibril protein denatured seriously for more addition of fat in dumpling, which would further affect the gelling ability and viscoelasticity of protein. Therefore the quality of frozen dumplings decreased with increasing fat content and extending storage time.