Studies On The Extraction And Isolation Of Proteins From Rapeseed Meal And Application In Baked Food

The major chemical substances in double-low rapeseed meal were analyzed. For extraction of proteins in rapeseed meal, the method of alkali-dissolution and acid-deposition was used and the process parameters were optimized. Then, the functional properties of the rapeseed proteins were investigated. Thereafter, application research of the rapeseed proteins in baked foods was carried out. The research context and corresponding findings were summarized as follows:1. The extraction of rapeseed proteins from double-low rapeseed meal with the method of alkali-dissolution and acid-deposition under vibration condition (150 rpm) was carried out. The six factors, viz. pH value, ratio of material to water, extraction temperature, extraction time, centrifugation velocity and centrifugation time which might affect rapeseed protein yield were screened out using Plackett-Burman design. Regression analysis suggested that pH value, ratio of material to water, extraction temperature significantly influenced rapeseed protein yield. Thereafter, a response surface methodology was used to optimize the three factors which play more important rule in the extraction yield of rapeseed proteins. A three-level three-factor (pH, ratio of material to water and temperature) Box-Behnken design was employed. By solving the quadratic regression model equation, the optimum parameters was obtained, that was: ratio of material 28.8g/mL, pH11.9 and temperature 53.1℃. under these conditions, the maximum predictive value of protein extraction yield was 85.82%. Statistic analysis showed that correlation coefficient was 0.9964 which indicated that the model was significant (p<0.0001).The molecular weights of rapeseed proteins extracted under different pH value were identified with HPLC. In the graph of HPLC, there was a marked protein peak which had a molecular weight of 30000. The functional properties of rapeseed proteins, including dissolvability, emulsification and stability, bubbling and stability of bubble were investigated. The results showed the emulsification and emulsified stability, bubbling and stability of bubble of rapeseed proteins were better than those of soybean proteins and rice proteins. The stability of emulsification, bubble specialty and stability of bubble were 45%...