Analyses of Free Amino Acids in Different Parts of Bean Sprouts by Different Cooking Methods and from Different Merchants

Abstract

This study was performed to quantitatively analyze free amino acids in the bean sprouts of three different merchants by the parts and the cooking methods in order to evaluate the nutritional and sensory values of bean sprouts. Three merchant bean sprouts were analyzed from total, cotyledon and hypocotyls. Aspartic acid was the most common acid isolated from bean sprouts from all three merchants and was found more in the hypocotyls than the cotyledon. On the other hand, arginine, the second most common amino acid, was found more in the cotyledon than the hypocotyls while valine, the third or fourth most common amino acid in total bean sprout, occurred in a greater amount in hypocotyls than in cotyledons. After cooking, was the most concentrated amino acid in the liquid portion of both boiled bean sprouts and bean sprout soup was glutamic acid. Total bean sprouts from merchant C showed significantly higher contents of the most abundant amino acids, such as aspartic acid, arginine, alanine, serine, glutamic acid, isoleucine, leucine and tyrosine (p＜0.05). After cooking, bean sprouts from merchant B showed less of a decrease in amino acid content in the solid parts than the products from merchants A and C. In conclusion, aspartic acid was the major amino acid in bean sprouts, regardless of the source, but after cooking, glutamic acid became the most abundant amino acid in the liquid part. Additionally, the pattern of release of the amino acids from the solid beans to the liquid portion during cooking was different with each merchant.