Abstract:

The contents of nine essential amino acids were analyzed in 28 purple kernel walnut samples from Yunnan
province in comparison with Juglans sigillata cv. ‘Dapao’ as the reference, and the variability, correlation and principal
component analysis of amino acid contents were studied at the same time. The results showed that histidine had the
maximum value of variation coefficient (39%) among the tested essential amino acids, and arginine revealed the minimum
variation coefficient (7%). No significant correlation was observed among various amino acids based on correlation analysis.
The results of principal component analysis (PCA) showed that the cumulative contribution of the top five principal
components reached 85.59%, which included the major information about the nine essential amino acids. The weight of
each amino acid was determined according to the results of PCA, and nutritional characteristics of purple kernel walnuts
were evaluated by fuzzy comprehensive evaluation. The contents of essential amino acids and nutritional value of 25 purple
kernel walnut samples exceeded the reference ‘Dapao’ walnut.

Key words: purple kernel walnut, Juglans sigillata cv. ‘Dapao’, essential amino acids, nutritional evaluation