TITLE:
Effect of Rice (Oryza sativa L.) Added to Meju (Korean Soybean Koji) Dough on Variation of Nutritional Ingredients and Bacterial Community Diversity in Doenjang (Korean Soybean Paste)
AUTHORS:
Bo Young Jeon, Doo Hyun Park
KEYWORDS:
Soybean Koji; Soybean Paste; Rice; Antioxidant Activity; Bacterial Community
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.3 No.8,
August
8,
2012
ABSTRACT: In this study, effect of rice added to meju dough was evaluated based on the variation of nutritional ingredients and bacterial community diversity in finished doenjang. The ratio of rice added to meju dough (cooked and crushed soybean before fermentation) was 0, 0.2, and 0.4 based on dry weight. Free amino acids, minerals, polyphenol, and total phenolic compounds relatively decreased by addition of rice. However, 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging and ferric ion reduction activity was not influenced. Organic acids, which are fermentation metabolites, significantly increased in proportion to percentage balance of rice. Seven and four volatile compounds (VCs) were detected in doenjang prepared without and with rice, respectively, and contents of VCs were significantly lower in the rice-supplemented doenjang. Bacterial community diversity was significantly increased by addition of rice to meju dough. Rice alters chemical composition, fermentation products, and bacterial diversity, but does not downgrade the nature of doenjang.