Effect of germination time on protein subunits of Lupinus angustifolius L. and its influence on functional properties and protein digestibility

Abstract

The aim of this research was to evaluate the influence of germination in Lupinus angustifolius L. seeds on protein profile, functional properties (FP), protein digestibility, phytic acid concentration and trypsin inhibitory activity, the latter due to its influence on protein digestibility. The germination was development at 26 ºC for 2-7 days. The ungerminated sample showed a protein content of 24.06% that was increased at 3 days of germination. Electrophoretic profile showed that the germination time generates a reduction in the intensity of the bands with molecular weight of 40, 50, 97 and 116 kDa, corresponding to the β and γ-conglutin subunits. At day 7 of germination, the water and oil absorption capacities increased by 146 and 95.23% respectively. The emulsion and foam capacities also increased by 94.04 and 36.24%, respectively. The swelling capacity was reduced by 51.44%. The protein digestibility remained unchanged after germination due to the presence compounds as phytic acid and trypsin inhibitors activity. Three days of germination in Lupinus angustifolius are necessary to observe changes in the FP. Germinated Lupinus angustifolius flours can have multiple applications in the development of food. Germination time will depend specifically on the application, since the FP change with the germination time.