Solid-state fermentation as a strategy for improvement of bioactive properties of the plant-based food resources

Currently, there is growing interest in gaining healthy eating habits through the consumption of sufficient amounts of natural bioactive compounds such as phenolic compounds and peptides. The major reason behind this interest is that the incorporation of such bioactive compounds into the diet exhibits great potential in the reduction of various types of chronic disease risks. Therefore, several strategies have been developed for the production and isolation of such compounds. Plant-based materials are the main source of natural bioactive compounds. However, the low concentration and the inactive form of these compounds in natural plant-based dietary resources appear as a limiting factor in most cases. Solid-state fermentation is a promising process for the generation and recovery of various high-value bioproducts. It has received more attention due to its exceptional potential to overcome all those limitations. This review provides an overview of various aspects of solid-state fermentation, including historical background, key microbial features, critical process variables, and cultivation systems. Furthermore, the potential of solid-state fermentation on the production of both phenolic compounds and nitrogenous bioactive compounds is described in detail by gathering the previous experiences and knowledge with the additional focus on the biorefinery concept.