Browsing by Subject "bioprocessing"

The aim of this thesis was to create an optimized bioprocessing to solubilize the maximal amount of proteins from the wheat bran without losing their nutritional and technological quality. The hypothesis of this thesis was that a maximal degradation of the aleurone cell wall components would lead to a maximal amount of soluble proteins originally located inside the aleurone layer. The literature review further looked into possible extraction methods for wheat bran proteins. Fine wheat bran was chosen to be bioprocessed by using experimental design to find optimal conditions for protein solubilization. Bioprocessing was done either by using starter culture alone or a combination of selected enzymes and starter culture. Independent studied factors were time (8 h, 16 h, 24 h), temperature (20 °C, 27.5 °C, 35 °C) and enzyme dosage (5 nkat/g, 50 nkat/g, 500 nkat/g). Optimization was carried out by applying response surface methodology to analyze the relationship between the response and the independent variables. Optimized bioprocessing of wheat bran led to maximal protein solubilization of >50% for wheat bran both bioprocessed with starter culture and with starter culture and enzymes after fermentation time of 24 h. Thus, the amount of soluble protein increased 23%. This indicated that the use of enzymes did not improve the breaking down of the aleurone cell walls for protein liberation. Furthermore, the use of enzymes affected heavily the protein degradation for fermentations longer than 8 h. Since the amount of solubilized protein was higher for wheat bran bioprocessed for 8 h with starter only (>46%) than for wheat bran bioprocessed for 8 h with starter and enzymes (>40%), the use of enzymes for a larger scale production does not seem feasible.