冻藏过程中多糖对肌原纤维蛋白化学作用力的影响

Effects of different polysaccharides on chemical force of myofibrillar proteins during frozen storage

以草鱼肌原纤维蛋白作为研究对象,添加魔芋葡甘聚糖降解产物及葡聚糖T7,测定冻藏后草鱼肌原纤维蛋白含量、Ca^(2+)-ATPase活性和化学作用力,研究冻藏过程中不同多糖对草鱼肌原纤维蛋白化学作用力的影响。研究发现,冻藏后添加了不同多糖的草鱼肌原纤维蛋白均会发生一定程度的冷冻变性,蛋白质含量、Ca^(2+)-ATPase活性和化学作用力都出现了不同程度的下降,其中化学作用力的下降最为显著。研究结果表明:酶解魔芋葡甘聚糖、辐解魔芋葡甘聚糖和葡聚糖T7均可在一定程度上抑制草鱼肌原纤维蛋白的冷冻变性,这3种多糖主要对高浓度草鱼肌原纤维蛋白的离子键起到保护作用,对氢键起到次要的保护作用,对疏水相互作用的保护不明显。3种多糖都具有冷冻保护作用,其中辐解魔芋葡甘聚糖的保护效果最佳,葡聚糖T7次之,且酶解KGM、辐解KGM和葡聚糖T7的最适添加量分别为2%、0.5%和1%。

The study investigated the effect of different polysaccharides of grass carp myofibrillar proteins added respectively with KGM and dextran T7 on chemical interactions during frozen storage. Then changes in myofibrillar protein concentration, Ca2＋-ATPase activity and chemical interactions were measured. It found that there was a certain degree of denaturation happened in different experimental groups of grass carp myofibrillar protein in cold storage. However the concentration, Ca2＋-ATPase activity and chemical interactions（most obvious） dropped to various extents. Results showed that frozen denaturation of grass carp myofibrillar protein was restrained by enzymatically hydrolyzed KGM, irradiation degraded KGM and dextran T7 to some extent. Those three had the cryoprotective effect on high concentration of grass carp myofibrillar protein of ionic bond with hydrogen bond the better and hydrophobic interaction protect not obvious. In conclusion, above three polysaccharides with cryoprotection were in the descending order： irradiation degraded KGM〉dextran T7〉enzymatically hydrolyzed KGM, with optimum content of 0.5%, 1% and 2% respectively.