Impact of Germination on the Protein Solubility and Antinutritive Compounds of Lupinus angustifolius and Vicia faba in the Production of Protein-Rich Legume-Based Beverages

Abstract

Lupines and faba beans are protein-rich legumes, which can be utilized as a plant-based substitute for animal proteins in human nutrition in general and in the beverage industry in particular. However, their application is hampered by low protein solubility in the acidic pH range and by antinutrients such as flatulence-causing "raffinose family oligosaccharides" (RFOs). Germination is known in the brewing industry for increasing enzymatic activities and mobilizing storage compounds. Therefore, germinations of lupines and faba beans were performed at different temperatures, and their impact on protein solubility, the concentration of free amino acids, and degradation of RFOs, alkaloids, and phytic acid was evaluated. In general, changes were comparable for both legumes but less pronounced in faba beans. Germination depleted the RFOs entirely in both legumes. The protein size distribution was found to be shifted toward smaller fractions, the concentrations of free amino acids multiplied, and protein solubility increased. No substantial reductions in the binding capacity of phytic acid toward iron ions were observed, but a release of free phosphate in lupines was detected. The results prove that germination is an applicable process for refining lupines and faba beans for use not only in refreshing beverages or milk alternatives but also in other food applications.

Sensory and Physical Properties of Fibrous Meat Analogs Made from Faba Bean, Pea, and Oat Using High-Moisture Extrusion

“…Germination is another treatment of raw materials that could improve the sensory qualities of plant-based protein ingredients [19,20]. Furthermore, germination can reduce the content of raffinose family oligosaccharides in legume-based ingredients, resulting in less gastrointestinal discomfort to consumers [21].…”