Abstract: In this paper, we determined the amino acid composition of proteins from 29 varieties of walnut collected from 6 major producing provinces such as Xinjiang and Yunnan in China. Fuzzy pattern recognition method was applied to calculate the degree of closeness (DC) between walnut protein and model protein (whole egg protein). The nutritional value of walnut protein was evaluated by score of ratio coefficient of amino acid (SRC). According to DC and SRC values, the 29 varieties of walnut were classified by hierarchical cluster analysis. The results showed that the total amino acid content of walnut protein was 343.22?985.99 mg/g protein, with essential amino acids accounting for 30%?41% of the total amino acids. The ratio coefficient of amino acids was 67.02?87.98. The first limiting amino acid in walnut protein was lysine. Among the investigated varieties, Wen185, Hetian Xiaohetao, Xinzaofeng, Liaohe 1, Xilin 1 and Xilin 3 had the highest nutritional value. The classification results were significant at greater than 0.05 level, being reasonable.

Key words: walnut, amino acid, nutritional evaluation, hierarchical cluster analysis