IN-VITRO ACCESSIBILITY OF UNTREATED, TOASTED, AND EXTRUDED SOYBEAN MEALS FOR PROTEASES AND CARBOHYDRASES

The in vitro accessibility of the water unextractable solids (WUS) fro m untreated, toasted, and extruded soybean meals toward different enzy me activities was studied. WUS was incubated with seven commercial enz yme preparations. Two enzyme preparations were selected for further re search. Upon addition of Neutrase, the extruded sample yielded conside rably more solubilized protein compared with the toasted and untreated soybean meals. Energex solubilized high amounts of neutral sugars aft er heat treatments compared with the untreated meal. Cell wall polysac charides solubilized by the enzymes were released as small oligosaccha rides and monosaccharides. SDS-PAGE analysis showed that after enzyme addition to the extruded sample, proteins were more rapidly and comple tely degraded compared with enzyme addition to the toasted and untreat ed soybean meals. Neutrase degraded both beta-conglycinin and glycinin . Energex could only, partly, degrade beta-conglycinin. The basic poly peptide from glycinin showed the highest resistance against proteolyti c activity.