鱼皮抗冻多肽的制备及其对冷冻面团热力学性质的影响

摘要

以鱼皮明胶为原料酶解制备鱼皮抗冻多肽.以鱼皮抗冻多肽的热滞活性为指标,确定制备鱼皮抗冻多肽的最适蛋白酶及酶解时间,并对获得的鱼皮抗冻多肽的微生物保护活性和对冷冻面团热力学性质的影响进行研究.结果表明,选用木瓜蛋白酶,当底物浓度为30 g/L,加酶量为3 000 U/g,酶解温度为40℃,酶解pH为6.0,酶解时间为2h时得到的三文鱼鱼皮抗冻多肽(Salmon skin antifreeze peptide,SaA FP)的THA最高,为0.53℃.SaAFP的分子质量主要分布在小于3 000 Da的范围内.对SaAFP溶液的微生物保护活性测定结果表明,添加量为20 mg/mL时大肠杆菌的存活率为75.71％.差示扫描量热法的试验结果表明,SaAFP不仅能降低新鲜面团的冻结温度(Tf),熔融温度(Tm)和可冻结水含量(Fw),且使面团的熔融区间缩小.此外,在冻融循环过程中,SaAFP能显著降低面团中的可冻结水含量,进而提高冷冻面团的品质.%In this study,the thermal hysteresis activity (THA) was used as the main parameter to determine the optimum protease and hydrolysis time for salmon skin gelatin hydrolysis.The effects of peptides on biological antifreeze activity and thermal properties of frozen dough were investigated.The results showed the antifreeze peptide with maximal THA was obtained from papain treated gelatin,and hydrolysis at pH 6.0 for 2 h at 40 ℃.The substrate concentration was 3％ (w/v) and papain proportion was 3 000 U/g.The THA was the highest of 0.53 ℃ under the above conditions.Their molecular weight were mainly distributed below 3 000 Da.When the concentration of SaAFP was 20 mg/mL,the survival rate of Escherichia coli was up to 75.71％.Differential scanning calorimeter measurement showed that SaAFP did not decreased the freezing temperature (Ti),melting temperature (Tm) and the freezable water content (Fw),but narrowed down the melting temperature (Tm,δ) of fresh dough.The SaAFP significantly lowered Fw of frozen dough after freeze-thaw cycles.