Chemical Composition, Amino Acid Profile and Antioxidant Activities of Germinated Mung Beans (<i>V</i> <i>igna radiata</i>)

Abstract

Mung bean variety Kampangsean 2 was analyzed during 24-h germination period. Total phenolic content and crude protein content of germinated beans significantly increased with increasing germination period. The 24-h germinated mung beans showed the highest crude protein content but not significantly different compared to that of the 18-h germinated bean. The increase in crude protein content was due to an increase in nonprotein nitrogen, not the protein nitrogen. During germination, the amount of proteins with molecular weight of 20, 29 and 36 kDa gradually decreased. Germination caused an increase in certain amino acids especially phenylalanine. Tryptophan was found to be a limiting amino acid. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric-reducing antioxidant power (FRAP) of germinated mung beans increased to 31.23 and 61.27%, respectively, after germination for 24 h. The DPPH radical scavenging activity and FRAP decreased about 10 and 20%, respectively, after steaming for 10 min. Practical Applications A short germination period (0–24 h) should be introduced for germinated mung bean production. This process shows an increase in crude protein content. Moreover, phenylalanine, an essential amino acid, significantly increases. The germinated mung beans also contain high total phenolic content and are rich in antioxidant activity which could prevent damages caused by free radicals. Steaming, a common home cooking treatment, is considered as one of the proper techniques for cooking germinated mung beans as it was found to show a slightly decrease in antioxidative activity. Thus, germinated mung beans should be promoted as a part of daily consumption.