Monitoring of early-stage water uptake by hyperspectral imaging and evaluation of nutritional and technological functionality of germinated faba bean (Vicia faba L.) var. minor and var. major as food ingredients

Faba bean (Vicia faba L.) is a potential, sustainable protein alternative. Germination behavior of Vicia faba L. var. minor and Vicia faba L. var. major needs further studies in order to enable larger scale bioprocessing. In this study, early-stage water uptake of two distinct faba bean varieties was assessed by hyperspectral imaging. Nutritional and technological functionality of germinated faba bean ingredients as such and in combination with fermentation were evaluated. Hyperspectral imaging revealed that early-stage water uptake in faba beans occurred evenly from the different sides of the beans. Germination on petri dishes and in pilot-scale showed that smaller faba beans moistened and germinated significantly (p < 0.05) faster and retained water better through germination than larger faba beans. Germinated faba flour of minor-type variety resulted in 72% higher dextran production in Weissella confusa VTT E-143403 fermentation than respective native faba flour. With both types of faba bean varieties, germination as such, and with minor-type variety, germination as combined with fermentation decreased notably the content of raffinose family oligosaccharides. These bioprocessing methods also improved functionality of faba bean ingredients by increasing protein separation efficiency in air classification, protein solubility, foaming capacity, and foam stability. Based on this study, minor- and major-type or small- and large-seeded faba bean varieties set different requirements to the germination process. In addition, germination alone or as combined with fermentation was proved to improve the nutritional and technological quality of faba bean material promoting its use in several food applications including also gluten-free products.