Regular Consumption of Biovalorized Okara‐Containing Biscuit Improves Circulating Short‐Chain Fatty Acids and Fecal Bile Acids Concentrations by Modulating the Gut Microbiome: A Randomized Controlled Crossover Trial

Abstract

Scope: Okara is a fiber-rich food by-product whereby biovalorization with Rhizopus oligosporus can improve its nutritional quality, generating fermentable substrates for improved gut health maintenance. This study evaluates the impact of okara-and biovalorized okara-containing biscuits consumption on gut health in Singapore adults. Methods and results: Participants consume control (C), 20% flour-substituted okara (AOK), and 20% flour-substituted biovalorized okara (RO) biscuits for three weeks, with assessment of gut metabolites, microbiome, and dietary intake. Fecal valeric acid is significantly higher with RO compared to AOK (p = 0.005). RO and AOK have significantly higher total serum short-chain fatty acids (p = 0.002 and 0.018 respectively) and acetic acid (p = 0.007 and 0.030 respectively) compared to C. Higher serum propionic acid (p = 0.004) and lower fecal lithocholic acid (p = 0.009) are observed with RO. Although serum zonulin shows no significant difference amongst interventions, AOK reduces Clostridiales while RO increases Bifidobacterium. Conclusion: Okara consumption improves serum SCFA regardless of fermentation while biovalorized okara further enhances gut metabolites by modulating gut microbiome.