猪皮明胶肽对肌肉的抗冻保护作用

Antifreeze Protection Effect of Pigskin Gelatin Peptide on Muscle

以猪皮明胶为原料,用碱性蛋白酶水解,以冷台冰晶尺寸为抗冻活性依据,超滤得到的1 kDa~3 kDa组分抗冻活性最强。将1 kDa~3 kDa组分以4%添加到猪肉中,以商业抗冻剂(4%蔗糖+4%山梨糖醇)作比较,基于十二烷基硫酸钠聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate polyacrylamide gel electrophoresis,SDS-PAGE)、拉曼光谱和内源荧光光谱分析冷冻后肌肉的解冻损失、肌原纤维蛋白的降解程度和蛋白质的二级、三级结构的变化情况。结果表明,抗冻肽组(添加量为4 mL/100 g)中肌肉解冻损失明显减少,SDS-PAGE结果表明肌原纤维蛋白降解程度降低,肌球蛋白和肌动蛋白得到较好的保护,肌原纤维蛋白中α-螺旋含量、内源性荧光强度升高。与商业抗冻剂比较,猪皮明胶抗冻多肽能够较好地维持肌原纤维蛋白状态以发挥对肌肉的保护作用。

Pigskin gelatin was hydrolyzed with alkaline protease.Based on the ice crystal size of the cold plate,the strongest antifreeze activity was displayed by the 1 kDa-3 kDa fractions obtained by ultrafiltration.These fractions were added to pork at 4%and were compared with commercial antifreeze(4%sucrose+4%sorbitol)by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE),Raman spectroscopy,and endogenous fluorescence spectroscopy analyses of the thawing loss of muscle after freezing,degree of myofibrillar protein degradation,and changes in the protein secondary and tertiary structure.The thawing loss of muscle was significantly reduced in the 4%antifreeze peptide group(4 mL/100 g).SDS-PAGE revealed a reduced degree of myofibrillar protein degradation and significantly increased myosin and actin contents compared with commercial antifreeze(4%sucrose+4%sorbitol).Good protection,increasedα-helix content,and endogenous fluorescence intensity were evident in myofibrillar proteins.Compared with commercial antifreeze,porcine skin gelatin antifreeze polypeptide better maintains the state of myofibrillar protein to protect muscle.