Enzymatic production and molecular characterization of antifungal bioactive peptides originating from Okara

Conversion of byproducts and reduction of food wastage for the full use of natural resources is one of the main challenges the industrialized world must face nowadays. Okara is a byproduct generated in huge quantities during soymilk or tofu production, thus posing a significant disposal problem since, up to now, it has been mainly used as such in animal feeds or as industrial waste. Okara’s high protein content (about 25-40% on a dry weight basis), makes this byproduct interesting and exploitable from a biotechnological point of view [1]. Production of antifungal peptides has been described in plant seeds and Okara as well, showing its potential as a valuable source of such compounds, exploitable for integrated pest management [2]. This work aims to describe a rapid and economic procedure to isolate proteins from Okara, to produce and characterize an enzymatic proteolyzed product, active against fungal plant pathogens. A dose-response inhibitory activity was established against fungi belonging to the Fusarium genus. Enrichment of the active fraction was obtained through the combination of different chromatographic techniques. Mass Spectrometry analyses allowed the identification of potential candidate bioactive peptides. The exploitation of okara to produce antifungal bioactive peptides has the potential to turn this byproduct into a paradigmatic example of circular economy, since field-derived food waste is transformed into a source of valuable compounds, to be used in field protection of economically valuable crops for human and animal nutrition. [1] JiménezEscrig, A et al. (2010) Eur. Food Res. Technol 230, 655–663 [2] De Benedetti S et al. (2021) Molecules 26, 4858.