Germination as a bioprocess for enhancing the quality and nutritional prospects of legume proteins

Background: Proteins are essential macronutrients of the human diet. Currently, major dietary sources in developed countries are of animal origin. However, the association of red meat consumption to the increased risks of some health conditions and its unsustainable pressure on the environment have increased the interest in plant proteins as healthier and sustainable alternatives. Of these, legumes have a great potential, but part of their proteins are indigestible due to interaction with other components such as phytate and polyphenols. As such, the quest to improve protein accessibility has become of interest to many researchers. Germination is proposed to be a bioprocess method to improve protein digestibility and protein biological properties. Scope and approach: This review discusses the importance of plant proteins and the hindrance of protein digestibility. This paper also highlights the role of germination in the deactivation of antinutritional factors, hydrolysis of indigestible proteins, and improvement of properties and content of proteins of different legume seeds. Key findings and conclusions: Protein digestibility is dependent on the nature of antinutritional factors (e.g. trypsin inhibitors and phytate) in the food matrix. Germination represses the activity of trypsin inhibitors and removes the phytate-related inhibition through hydrolysis. Protein content increases in germinated seeds when compared to non-germinated ones, suggesting that proteins were either hydrolysed or dissociated from anti-nutritional factors. Germination seems like an adequate bioprocessing method to improve the content and nutritional quality of legume seed proteins.