Changes in Angiotensin I-Converting Enzyme Inhibitory Activities During the Ripening of Douchi (a Chinese Traditional Soybean Product) Fermented by Various Starter Cultures

Abstract

Angiotensin I-converting enzyme (ACE) inhibitory activities of commercial douchi were determined, and salt-fermented samples were found exhibiting higher activities than dandouchi. Douchi was prepared in laboratory scale by pure culture fermentation. Results showed that ACE inhibitory activity in bacteria-type douchi decreased during maturation, while it increased in fungi-type douchi, with the highest activity observed in Aspergillus oryzae fermented douchi after ripening for 30 days. These suggested that the type of starters affected significantly the generation of ACE inhibitors during douchi ripening. Sensory evaluation showed that A. oryzae produced more organoleptically acceptable douchi than other cultures used in this study.

Keywords:

• Douchi
• Angiotensin I-converting enzyme (ACE) inhibitory activity
• Starter cultures
• Ripening

ACKNOWLEDGMENTS

This work was supported by the National Key-technologies R&D Program (2006BAD27B09 & 2007BAD83B03) of the 11^th 5-year Plan of the People's Republic of China. This study was also conducted within the framework of the collaborative research project between Japan and China entitled “Development of sustainable production and utilization of major food resources in China” supported by Japan International Research Center for Agricultural Sciences (JIRCAS).