Biscuits Prepared with Enzymatically-Processed Soybean Meal Are Rich in Isoflavone Aglycones, Sensorially Well-Accepted and Stable during Storage for Six Months.

Soybean meal (SBM) is a co-product of the soybean oil industry that is rich in bioactive compounds, such as isoflavones. We aimed to study the effects of processing SBM by fermentation (Saccharomyces cerevisiae) (FSBM) and enzymatic hydrolysis (CelluMax C, a commercial cellulase) (ESBM) on its chemical composition, with emphasis on isoflavones. Fermentation increased protein content by 9%, ash content by 7%, dietary fiber by 11% and minerals by up to 38%, except for iron, which decreased by 26%. Fermentation completely removed oligosaccharides from SBM, while enzymatic processing decreased oligosaccharides by 45% in SBM. Both processes converted glycosylated isoflavones into the corresponding aglycones, the content of which increased by up to 7.7-fold. Biscuits containing SBM, FSBM and ESBM could be labeled as dietary sources of dietary fibers, potassium, phosphorous, calcium and zinc, as well as high in proteins, copper, iron, manganese and magnesium. While FSBM biscuits had lower sensory scores compared to SBM biscuits, ESBM biscuits had equivalent scores. During storage for 180 days at room temperature, the isoflavone profile of all biscuits remained stable. Moreover, storage did not impair microbiological and sensory qualities of any biscuits. Altogether, ESBM biscuits show great marketing potential.

Fermentation of soybean meal improves isoflavone metabolism after soy biscuit consumption by adults.

BACKGROUND: Urinary excretion of isoflavones and their metabolites after the consumption of soybean meal (SBM) and fermented soybean meal (FSBM) biscuits was investigated in humans in a randomized double-blinded crossover clinical trial. RESULTS: Aglycones were the most abundant metabolites in urine in both treatments. After FSBM consumption, total urinary excretion of aglycones and metabolites was 54% higher when compared to SBM biscuits. All metabolites were more rapidly excreted after FSBM biscuit consumption when compared to SBM biscuits. Urinary recovery of isoflavones was higher after FSBM biscuit consumption, reaching 67%. Women excreted higher amounts of colonic metabolites and lower amounts of aglycones than men. The prevalence of O-demethylangolensin-producer, equol-producer and nonproducer metabotypes was 56%, 11% and 36% after SBM consumption and 72%, 11% and 17% after FSBM consumption, respectively. CONCLUSIONS: Together, our findings indicate that fermentation improves isoflavone bioavailability and possibly reduces the impact of gut microbiota on the metabolism of isoflavones. © 2020 Society of Chemical Industry.