Metabolomics-Driven Comparison of the Nutritional and Functional Food Characteristics of Postbiotic and Probiotic Okara

Okara, a nutritious processing side-stream of soybean,poses asignificant food waste challenge in regions with high soybean consumptionsuch as Asia. Consequently, its valorization through probiotic fermentationhas received considerable attention, but the use of live probioticsin foods raises concerns due to potential side effects and probioticviability decline over product shelf-life, especially when subjectedto cold chain interruptions. To address this, a dual fermentation-heattreatment method with Lactobacillus sp. and Bifidobacteria sp. was employedto produce postbiotic okara. Nutritional and compositional analysesrevealed increased soluble fiber by 156%, total isoflavones by 151%,and total phenolic content by 21% when compared to the unfermentedcontrol, which was further validated by metabolomic analyzes of okarasamples, demonstrating the retention of or enhanced functionalitypost-heat treatment. Additionally, postbiotic okara extracts exhibitedimproved inhibitory activity against enzymes & alpha;-amylase (IC50 = 13.50 & PLUSMN; 0.56) and & alpha;-glucosidase (IC50 = 19.76 & PLUSMN; 0.96) in vitro, as compared to unfermented okara.Overall, the novel processing method was able to increase nutrientretention and functional properties and improve safety of postbioticokara through the inactivation of live microbes, increasing its versatilityas a functional probiotic alternative ingredient suitable for a widerrange of consumers.