Metabolite perturbations in fermented legumes as elucidated using metabolomics: a review

Legumes are vital food sources in global diets, especially in developing nations, offering affordability, nutrition, and sustainability. Legumes are rich bioactive compounds as well as in macro- and micro-nutrients and help combat protein-energy malnutrition. Fermentation is a food processing technique that enhances nutritional content, digestibility and overall composition, rendering fermented legumes like dawadawa, natto, tempeh, and kinema dietary sources worldwide. This simple process leads to significant perturbations in the numerous metabolites contained in legumes and subsequent fermented products. Such metabolites including bioactive constituents, vitamins, minerals, volatile compounds, lipids, amino acids, among others contribute to the flavour, aroma, nutritional value and health beneficial properties of fermented legume products. Modifications in these complex constituents might be somewhat challenging to investigate and understand thus necessitating a robust technique such as metabolomics. Metabolomics as an analytical approach can elucidate how fermentation alters the composition of fermented legumes revealing compositional changes, nutritional enhancements, and impacts of fermentation conditions and microbial metabolism. This review emphasises fermented legumes' dietary importance, the transformative role of fermentation, and the effectiveness of metabolomics in unravelling complex biochemical changes during legume fermentation, providing insights into nutritional, sensory and safety aspects of fermented legumes.