Sustainable valorization of oilseed cake using solid-state fermentation for enhanced nutritional profile

The growing demand for low-waste food production models has intensified the need to upcycle agro-industrial by-products rich in protein, fiber, and other biologically essential compounds. Oilseed cake, husks, and fruit or vegetable peels are some examples of agro-industrial waste that are abundant in beneficial compounds essential for human health. Solid-state fermentation (SSF) has been recognized as a promising technique to enhance the nutritional quality of the oilseed cake. Various microorganisms, including bacteria and fungi, can be used in SSF to upcycle oilseed cake. Enzymes synthesized by different microbes during SSF process lead to biotransformation of oilseed cake, yielding smaller peptides and useful secondary metabolites. The review summarizes the role of SSF in enhancing the bioavailability of nutrients, reducing anti-nutrients (such as tannins, phytic acid, and glucosinolates), and leading to their potential application in food products. Also, SSF facilitates the utilization of microbes to develop industrially valuable enzymes such as amylase, lipase, and protease. However, some of the challenges of SSF include scalability and optimization at the industrial level. Oilseed cake fermented using SSF can contribute to the circular economy and achieve global sustainability objectives. Future prospects of SSF can focus on substrate-specific optimization and co-culture systems for enhanced food and nutraceutical applications of oilseed cakes.