Effect of lactic fermentation and extrusion of bean and pea seeds on nutritional and functional properties

Abstract

Controlled lactic acid fermentation of „Bomba” bean and „Opal” pea was used to improved their nutritional and functional properties. The modified legumes were used as a source for extrusion process to obtain snack-type foods. Milled legume seeds were fermented by different population of Lactobacillus plantarum with different moisture content in plant material to estimate the influence of this two parameters on the dynamics of lactic fermentation. Quantitative and qualitative changes in carbohydrates and nitrogen compounds of modified seeds were analyzed (e.g . mono- and oligosaccharides, "in vitro" starch and protein digestibility). In the new snack-type products, functional properties: water solubility index (WSI), water absorption index (WAI), expansion index, bulk density and texture explained as a shearing stress were recorded. Results showed a distinct decrease in raffinose, verbascose and stachyose contents even up to 80 - 90% after fermentation and extrusion process. Lactic fermentation and extrusion of bean and pea seeds contributes to a significant (a ≤ 0,05) increase of "in vitro" protein and starch digestibility. Observations of changes in functional properties of extruderates (e. g., expansion, shearing stress, WSI, WAI) allowed to choose the most efficient model of fermentation pretreatment to obtain the best improvement of nutritional and functional features of the product.