Studies On The Separation Of Rapeseed Protein And Rapeseed Oil By The Technology Of Reversed Micelles Extraction

The technology of reverse micelles is a new kind of separation method for biological molecule. The simultaneous extraction of oil and protein from plant by reverse micelles, not only improves the traditional technology of abstracting oil, desolvent and toast the meal, but avoids the disadvantage of protein denaturation during the process. In this paper,it is proved that CTAB/isooctain/octanol is suitable for separating rapeseed protein and oil by comparing the surfactant (CTAB with SDS)and cosolvent (octanol with butanol)on their ability of farming reverse micells and extracting protein. Pre-extraction and backward-extraction process conditions were investigated. Meantime, rapeseed oil and protein were analyzed after separation,and then compared with them extracted by traditional method. It was hoped to provided theoretical foundation for further study and application of reverse micelles extraction.The effects of all factors on pre-extraction protein rate were researched by optimal experiment, including time, temperature, surfactant, w0, pH, ionic concentration, ratio of CTAB and cosolvent. Furthermore, the process of pre-extraction was optimal through orthogonal experiment with the pre-extraction protein rate as the index. The optimal conditions were:rapeseed powder was 60 mesh, rapeseed powder concentration was 0.04g/ml, w0 value was 30, CTAB concentration was 0.06g/ml, ratio of CTAB and octanol was 5:1, pH value was 7.0, KCl concentration was 0.07mol/ml, temperature was 45℃, time was 110min. Analysis of variance result inticated that CTAB concentration fearfully significantly contribute to the protein extraction rate.The response surface analysis for back-extraction process showed that A (pH value), B (ion concentration), C (back-extraction time) all significantly contributed to the protein back-extraction rate. The order of the impact was: pH value﹥back-extraction time﹥ionic concentration. The interaction between the three factors did not significantly contribute to the protein back-extraction rate. The optimal back-extraction process conditions were as follows: pH value was 8.0, ionic concentration was 1.0mol/L, back-extraction time was 80 min.After back-extraction, rapeseed oil was separated from organic phase with ethanol extraction and rotary evaporation according to the physical properties. Fatty acid composition was analyzed by gas chromatography and compared with oil extracted by nhexane, the result indicated that fatty acid composition was almost unchanged.The protein phase was dialyszed after back-extraction and then freeze-dryed to high-purity protein powder. Their amino acid composition was compared with the protein extracted by alkali extraction and acid precipitation. The content of valley histidine, lysine, arginine were more 30% than the latter. While the content of aspartate, threonine, serine, proline, valine, tyrosine, phenyl-C acid were lower 30% than the latter. The remaining amino acids were not very different. There were more than 60% subunit molecular weight were under14kDa by analyzing molecular weight distribution of rapeseed protein extracted by reverse micelles through SDS-PAGE, more than 80% were under 25kDa. Functional characteristics of protein was extracted by different methods was comparied. The protein extarcted by reverse micelles are superior on solubility, frothiness and emulsifying ability, but inferior on water binding capacity and foam stability.