北部湾海区三种常见牡蛎的蛋白质及氨基酸营养分析与评价

为探究北部湾海区常见的熊本牡蛎、香港牡蛎和近江牡蛎三种牡蛎的蛋白质和氨基酸含量、蛋白质营养价值及基于氨基酸含量的综合品质评价差异。采用国家标准测定牡蛎中蛋白质含量，利用高效液相色谱法测定牡蛎中氨基酸组成及含量，分别进行蛋白质营养价值评价，并以牡蛎中的氨基酸组成和含量为指标进行主成分分析（Principal component analysis, PCA）。结果表明，北部湾海区熊本牡蛎、香港牡蛎和近江牡蛎的粗蛋白含量（以干基计）在43.47~49.27 g/100 g之间，各品种间存在显著性差异（P<0.05）。三种牡蛎均检测出17种氨基酸，必需氨基酸占总氨基酸30.95%~37.39%，其中熊本牡蛎的必需氨基酸构成比例符合FAO/WHO推荐的理想模式。利用氨基酸评分（Amino acid score，AAS）和化学评分（Chemical score，CS）评价牡蛎蛋白质营养价值，AAS中熊本牡蛎和香港牡蛎均大于1，近江牡蛎的第一限制性氨基酸为亮氨酸；CS中熊本牡蛎和香港牡蛎的第一限制性氨基酸为蛋氨酸+半胱氨酸，近江牡蛎为亮氨酸。利用氨基酸比值系数评价牡蛎蛋白质营养价值，可知三种牡蛎中熊本牡蛎蛋白质营养价值最高，其次为香港牡蛎和近江牡蛎。PCA分析中，所抽取的2个主成分的累积贡献率为90.463%，可较好的概括17个氨基酸评价指标的综合信息，三种牡蛎综合得分排序为熊本牡蛎>香港牡蛎>近江牡蛎。该研究为北部湾海区三种常见牡蛎的开发和养殖品种筛选提供了一定的科学参考依据。

Analysis and Evaluation of Protein and Amino Acid Nutrition of Three Common Oysters in Beibu Gulf

The purpose of this study was to explore the differences of protein and amino acid content, protein nutritional value and comprehensive quality evaluation based on amino acid content of three common oysters, Crassostrea sikamea, Crassostrea hongkongensis and Crassostrea ariakensis in Beibu Gulf. The content of protein in oyster was determined by national standard, and the composition and content of amino acids in oyster were determined by high performance liquid chromatography. The nutritional value of protein was evaluated, and the composition and content of amino acids in oyster were used as indexes for principal component analysis (PCA). The results showed the crude protein content (in dry basis) of Crassostrea sikamea, Crassostrea hongkongensis and Crassostrea ariakensis in Beibu Gulf was 43.47~49.27 g/100 g, and there were significantly differences among the three species. 17 kinds of amino acids were detected in three kinds of oysters, and the essential amino acids accounted for 30.95%~37.39% of the total amino acids, among which the essential amino acid composition of Crassostrea sikamea conformed to the ideal model recommended by FAO/WHO. The nutritional value of oyster protein was evaluated by amino acid score and chemical score. The results showed that Crassostrea sikamea and Crassostrea hongkongensis were more than 1 in AAS, the first limiting amino acid of Crassostrea ariakensis was leucine, the first limiting amino acid of Crassostrea sikamea and Crassostrea hongkongensis in CS was methionine+cysteine, and Crassostrea ariakensis was leucine. The protein nutritional value of oyster was evaluated by amino acid ratio coefficient, it was found that the protein nutritional value of Crassostrea sikamea was the highest among the three kinds of oysters, followed by Crassostrea hongkongensis and Crassostrea ariakensis. In PCA analysis, the cumulative contribution rate of the two principal components extracted was 90.463%, which could better summarize the comprehensive information of 17 amino acid evaluation indexes. The comprehensive score of the three oysters was Crassostrea sikamea>Crassostrea hongkongensis>Crassostrea ariakensis. This study provides a scientific reference for the development and breeding of three common oysters in the Beibu Gulf.