凡纳滨对虾虾头自溶过程中游离氨基酸的释放规律及产物的分子质量分布

Free Amino Acids Releasing Principle of Shrimp Head(Litopenaeus vannamei) During Autolysis and Its Molecular Weight Distribution

在优化条件下进行虾头自溶,测定虾头自溶过程中产物的游离氨基酸组成和分子量分布,分析探讨虾头氨基酸的释放规律。结果表明:自溶过程中,0-5 h,游离氨基酸的含量逐渐增加,大部分脂肪族氨基酸溶出较多,特别是天门冬氨酸和谷氨酸,5 h后溶出的含量为未自溶时含量的4倍以上,而芳香族氨基酸中的色氨酸,杂环氨基酸及含硫氨基酸在整个自溶过程中溶出较少;分子质量分布图显示,未自溶前虾头上清液中相对分子质量>10 000 u的大分子物质占大多数,自溶1-3 h,相对分子质量<3 000 u的自溶产物所占的比例显著增加,3 h后增加趋势变缓,自溶5 h后,85%以上相对分子质量>10 000 u的大分子物质被降解为小分子肽和游离氨基酸。

Shrimp head of Litopenaeus vannamei were autolyzed under the optimized condition, the hydrolysate products were determined by HPLC for the characterization of molecular weight distribution and the composition of free amino acids . The results showed that during the autolysis （0 - 5 h）, the release quantity of free amino acids in- creased gradually while fatty amino acid increased more sharply. Aspartic acid and glutamine contents increased more than four times, while the contents of tryptophan, heterocyclic amino acids and sulfamino acid kept unchanged. The distribution profiles of molecular weight （Mw ） exhibited that a majority was the substance with Mw over 10000u before autolysis; the substance with Mw under 3000u remarkably increased during 1 -3h and the increasing trend slowed down after 3h; and 85% of the substances with MW over 10000u were degraded into small peptides and free aminoacids after 5h.