Assessment of Amino Acid Nutrition in the Several Peanut (Arachis hypogaea L.) Varieties from Fujian, China

Objective: The aim of this study is to investigate the amino acid nutrition of different peanut (Arachis hypogaea L.) varieties from Fujian, China. Method: Laifang peanut, Yakou xiaoryukyu peanut, Zhukou small seed peanut, Wenheng Hongyi peanut and Yanghou peanut were selected as experimental materials. The composition of amino acids of peanut kernel was analyzed by an amino acid automatic analyzer after hydrolysis. Based on the obtained data , the amino acid nutrition value was evaluated according to egg protein model and the ideal model recommended by WHO/FAO. A series of indexes, including the amino acid score (AAS), chemical score (CS), and score of ratio coefficient of amino acid (SRC), were calculated. Results: At least 18 amino acids were found in these peanuts. The contents of protein in these peanuts varieties ranged from 29.88~33.18 g/100 g. The contents of essential amino acids, non-essential amino acids, sour amino acids, sweet amino acids, bitter amino acids, essential amino acids for child, medical amino acids, flavoring and coloring amino acids, anti-bacteria amino acids, primary amine amino acids, branched chain amino acids, and aromatic amino acids were 7.83~8.95, 19.71~22.53, 8.93~10.29, 6.01~6.86, 10.24~11.58, 4.12~4.68, 19.44~22.23, 14.28~16.01, 3.63~4.11, 17.11~19.76, 3.95~4.44 and 3.14~3.53 g/100 g，respectively. The highest values of these indexes were found in Yakou xiaoryukyu peanut, which were obviously higher than others except Yanghou peanut (P<0.05). The values of AAS, CS and SRC in these peanuts were 24.29~28.29, 37.58~43.67, and 41.61~45.70, respectively. The contents of Lys, Val, Ile, Leu, Thr, and (Met+Cys) in these peanuts were insufficient, while the contents of Trp, Phe and Tyr were relatively surplus. The firstly restrict amino acid was Met+Cys. Conclusion: The protein content of five famous and special peanut from Fujian reached the standard of first-class edible peanut in China, indicating that these five peanuts have great utilization value.