Evaluation of an Okara Beni Koji Based on Antioxidant Properties, and an Application to Cookie Making

摘要

While okara contains various functional components such as isoflavones, it is typically discarded as industrial waste due to its rapid deterioration. In this study, we prepared beni koji by the fermentation of okara using Monascus anka AOK 2026, followed by examination of changes in antioxidant activities and major components during koji fermentation, as well as evaluation of its utility as a food material. Both antioxidant activities and total polyphenol contents were similarly increased during koji fermentation, and a particularly remarkable increase was recognized at 4-days fermentation; a strong positive correlation was evident between them (r=0.99). Tocopherols content did not change appreciably during koji fermentation; however, isoflavone glucosides were converted to their aglycone form, which can be efficiently absorbed into the human body, by beta-glucosidase produced during M. anka fermentation. As an example of the effective utilization of okara beni koji, cookies containing koji from 0% to 10% and 20% were prepared. The cookie with 10% koji was evaluated as highly palatable by a sensory test. In addition, the added koji was effective in preventing lipid autoxidation. These results suggest that okara beni koji has the potential to be a new, usable, high value-added functional food material.