Mobilization of phenolic antioxidants from defatted soybean powders by Lentinus edodes during solid-state bioprocessing is associated with enhanced production of laccase

The ability of Lentinus edodes to mobilize phenolic antioxidants from powdered soybean during solid-state bioprocessing was investigated. L. edodes was inoculated into sterilized soybean powder and phenolic antioxidant mobilization was determined. The results show that L. edodes bioprocessing was very effective in mobilizing phenolic antioxidants from soybean powder. Postprocessing, phenolic content had increased 90% to 11.3 mg/g dry weight (wt) in water extract and 232% to 5.8 mg/g dry wt in ethanol extract. Furthermore, phenolic antioxidant mobilization was related to the activity of the carbohydrate-cleaving enzymes α-amylase and β-glucosidase, but not α-glucosidase, and was associated with increased activity of laccase, an enzyme involved in lignin biodegradation. The phenolic antioxidant mobilization and enzyme activities were attributed to remobilization of soybean polymeric phenolics via lignin biodegradation-related activities.