煮制时间对鹅肉蛋白结构的影响

为了探究煮制对鹅肉蛋白的影响，本文通过测定不同煮制时间（0、30、60、90、120 min）下鹅肉的蒸煮损失率、剪切力、蛋白电泳、肌原纤维小片化指数（myofibril fragmentation index，MFI）、游离氨基酸（free amino acid，FAA）构成及微观结构研究了煮制时间对鹅肉蛋白结构特性的影响。结果表明:蒸煮损失率随着煮制时间的延长而升高，由0 min处的27.5%升高到120 min处的39.0%；剪切力值则是随着煮制时间的延长而呈现先上升再下降的趋势，且在90 min时出现最低值；十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gel electrophoresis，SDS-PAGE）图谱显示，随着煮制时间的延长35~55 kDa处的条带逐渐变浅变细，10~15 kDa处条带随煮制时间延长颜色变深；MFI值随着煮制时间的延长显著增加（P<0.05），煮制120 min时的MFI值约为处理0 min时的2倍；共检出三种呈味氨基酸，从总量看，苦味氨基酸的含量最多，甜味氨基酸含量次之，鲜味氨基酸含量最少。煮制过程中，这三类氨基酸总含量总体表现为随煮制时间的延长而增加的趋势（甜味氨基酸的总含量约增加了2.5倍，苦味氨基酸的总含量约增加了3.1倍，鲜味氨基酸的总含量约增加了3.4倍），而甲硫氨酸和半胱氨酸这两者的含量随煮制时间的延长而减少；扫描电镜（scanning electron microscope，SEM）图中发现肌纤维之间的空隙表现出先变大后减小到粘成一块。同时，肌纤维和肌束膜结构的完整程度随着煮制时间的延长逐步破坏，最终导致部分肌纤维束发生崩塌使它们相互黏成一块。因此，鹅肉在蒸煮过程中，其蛋白组成和含量、MFI值、游离氨基酸组成及微观结构会因时间变化而发生改变，从而影响了鹅肉蛋白结构的变化。研究表明，90 min为鹅肉的最佳煮制时间。

Effect of Cooking Time on the Protein Structure of Goose Meat

In order to explore the impact of cooking on goose meat protein,this paper investigated the impact of cooking time on the structural characteristics of goose meat by measuring the cooking loss rate,shear force,protein electrophoresis,myofibril fragmentation index(MFI),free amino acid(FAA)composition and microstructure of goose meat at different cooking times.The results showed that the cooking loss rate increased with the extension of cooking time,from 27.5%at 0 min to 39.0%at 120 min.With the extension of cooking time,the shear force first increased and then decreased,and the lowest value appeared at 90 min.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)showed that the strips at 35~55 kDa gradually changed to shallow and thin with the extension of cooking time,and the strips at 10~15 kDa became darker with the extension of cooking time.MFI value increased significantly with the extension of cooking time(P<0.05),the MFI value at 120 min of cooking was about 2 times that at 0 min of treatment.Three kinds of flavorful amino acids were detected,and the contents of bitter amino acids were the most,sweet amino acids the second,and umami amino acids the least.Cooking process,the overall performance of three kinds of total amino acids content increased with of cooking time(sweet about increased 2.5 times,bitter about increased 3.1 times,umami about increased 3.4 times),and methionine and cysteine contents of both decreased with longer duration of cooked.In scanning electron microscope(SEM),it was found that the gap between muscle fibers first became larger and then reduced to a lump.At the same time,the integrity of muscle fiber and fasciculus membrane structure was gradually destroyed with the extension of cooking time,which finally led to the collapse of some muscle fiber bundles and made them stick to each other.Therefore,in the process of cooking,the protein composition and content,MFI value,free amino acid composition and microstructure of goose meat will change with time,thus affecting the change of the protein structure of goose meat.This research showed,90 min was the best cooking time for goose meat.