Studies of matrix effects to increase bioavailability of functional bioactive compounds from okara, the soymilk processing byproduct

The actual interest towards a sustainable food production and consumption is directed to the exploitation of byproducts currently considered a waste. In last decades, the effects of food on health and the effects of processing on food have been deeply investigated often evaluating the quality and quantity of components without considering the supramolecular organization. The “matrix effect” may deeply influence the release of molecules from food during digestion, absorption, and then utilization for physiological functions in the target tissue. Okara is the byproduct obtained during soymilk and tofu production. Although it is considered a waste it still contains a good quantity of nutrients. In this work different extraction methods were tested to overcome the matrix effect to increase the extraction yield, the bioavailability and bioactivity of functional components. To test the effective extraction of the compounds different assays were carried out. MTT assay was performed using human colorectal adenocarcinoma cells (CaCo2). Protein samples were given to the cells to analyse if they have cytotoxic activity at different concentrations and incubation times. The potential protective effects of proteins and peptides on cell inflammation were also studied using CaCo2, whose immune response was triggered by IL1β leading to the induction of NFκB. Since the expression levels of NFκB mirror the expression of chemokine IL8, the expression of IL8 was quantified by qRTPCR to evaluate the antiinflammatory effect of peptides. The results show that the bioactive compounds' extractability and bioavailability still present in the byproducts may be modulated by a detailed study and choice of extraction conditions. This study was carried out within the Agritech National Research Center and received funding from the European Union NextGenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022).