北太平洋鱿鱼(Todarodes pacificus)内脏自溶液总氨基酸组成质量评价和体外抗氧化性分析

采用自溶法水解鱿鱼内脏,测定鱿鱼内脏自溶液(squid viscera autolysates,SVAs)的蛋白质提取率、可溶性氮含量、游离氨基酸含量和水解度,分析SVAs总氨基酸组成,评价其营养价值,并对SVAs的体外抗氧能力进行分析。结果表明:SVAs的蛋白质提取率为(53.89±1.17)%、可溶性氮质量分数为(78.47±1.16)%、游离氨基酸质量浓度为(0.22±0.03)mg/m L、水解度为(14.73±2.02)%。SVAs中必需氨基酸含量占氨基酸总量的37.03%,呈味氨基酸(天冬氨酸、谷氨酸、丙氨酸和甘氨酸)含量占氨基酸总量的42.40%。氨基酸组成与联合国粮农组织/世界卫生组织推荐氨基酸评分标准模式和全鸡蛋蛋白质氨基酸模式相比较,得出SVAs是一种营养丰富、且氨基酸组成合理的优质蛋白源。研究还表明,SVAs具有良好的体外抗氧化能力,其中清除1,1-二苯基-2-三硝基苯肼自由基和羟自由基的IC50值分别为0.24 mg/m L和0.74 mg/m L,还原能力强于相同质量浓度的L-肌肽。

Assesment of Total Amino Acids and Antioxidant Activity of Squid (Todarodes pacificus) Viscera Autolysates

The squid viscera were hydrolyzed via autolysis to produce squid viscera autolysates (SVAs). The protein yield, soluble nitrogen content, free amino acid content and degree of hydrolysis (DH) of SVAs were assayed. Moreover, the total amino acid composition of SVAs was evaluated to determine their nutritional value. The in vitro antioxidant activity was also determined. Results showed the protein yield, soluble nitrogen content, free amino acid concentration and degree of hydrolysis of SVAs were (53.89 ± 1.17)%, (78.47 ± 1.16)%, (0.22 ± 0.03) mg/mL and (14.73 ± 2.02)%, respectively. The essential amino acid content of SVAs was 37.03%. Furthermore, the content of taste-active amino acids including aspartic acid, glutamic acid, alanine and glycine was 42.40%. According to the amino acid score pattern recommended by the FAO/WHO and the amino acid pattern of whole egg proteins, SVAs can be seen as a good source of rich proteins and reasonable amino acid components. SVAs displayed in vitro strong antioxidant activity with IC50 values for scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and hydroxyl radicals of 0.24 and 0.74 mg/mL, respectively. In addition, SVAs showed stronger reducing power compared with the same concentration of L-carnosine.