Lactic acid bacteria fermentation as a method to improve off-flavor and enhance the quality of pulse protein.

The plant-based protein market is growing rapidly but faces challenges due to the unpleasant taste, poor functionality, and anti-nutritional factors present in protein. Pulse proteins naturally have strong beany, grassy, and green odours. Moreover, protein extraction and food processing generate undesirable volatile compounds. Traditional protein extraction methods for pea protein do not reduce off-note-generating compounds, and acid precipitation diminishes the nutritional and functional quality of protein through racemization. Major volatile compounds responsible for off-notes mainly include aldehydes, ketones, alcohols, and pyrazines, with key compounds such as hexanal, nonanal, hexanol, 2-pentylfuran, 3-octen-2-one, benzaldehyde, 1-octen-3-ol, 2,4-nonadienal, octanal, and pentanal. In addition, pulse proteins have lower digestibility than soy and milk proteins and contain anti-nutrients like tannins, trypsin inhibitors, saponins, lectins, phytic acid, and flatulence-inducing stachyose and raffinose. This study will review fermentation as a method to improve off-flavor and pulse protein quality.

Fermentation is a proven method to reduce anti-nutritional compounds and enhance nutritional quality. Lactic acid bacteria (LAB), widely used in fermented food production, are recognized for their efficacy, safety, and ability to enhance food aroma and improve desirable sensory qualities. Two fermentation methods address off-flavors in pulse proteins: one reduces beany flavor components to sub-threshold levels, while the other generates new aromatic compounds to mask off-flavors and improve functional quality. Enzymes like aldehyde oxidase, aldehyde dehydrogenase, and hydroperoxide lyase are key in breaking down volatile off-flavor compounds.

Fermentation not only mitigates undesirable flavors but also enhances digestibility and functionality by reducing antinutritional factors. This approach offers an innovative solution to enhance pulse proteins sensory and nutritional properties and meet the growing demand for high-quality plant-based protein foods.