Study On Extracting The Cottonseed Protein From Low Toxicity Cottonseed Meal By Biological Methods

In this paper, we studied the methods of extracting the cottonseed protein from the cottonseed meal and the methods of purificating and drying process of the sugar which is by-product in the extraction processCrushing the cottonseed meal firstly, then extracting the cottonseed sugar by aqueous in order to avoid the sugar affect the result of separation and purification of cottonseed protein. The best conditions for water extraction: add water, 20 times the quality of raw materials, at 40℃under the conditions of extraction time was 2 hours, then the extraction rate of the sugar is 98.7%.The plant cell walls is mainly composed of cellulose and pectin, and the cell wall is too hard, in order to increase the extraction rate of cottonseed protein, we used cellulose enzyme to damage the cell wall of cottonseed firstly and the easy extraction of proteins inside cells. The best enzymatic hydrolysis of cellulose enzyme are : pH 5.0, temperature 50℃, 2.0 hours of hydrolysis time, 0.4% of enzyme amount.And then, used the alkaline protease alcalase 2 to zymolysing cottonseed protein into peptides and amino acids which is water-soluble, so as to improve the extraction rate of cottonseed meal protein, The best enzymatic hydrolysis of alcalase 2 are: pH 8.5, temperature 55℃, 3.0 hours hydrolysis time, 4.0% of enzyme amount. At this point, the extraction rate of cottonseed meal protein is 86.4%.Removing impurity of the sugar solution which is the by-product of the extraction by the membrane N100 cleaning,the allow transmission is up to 98.7% ,raffinose impurity rejection rate was 18.9%; And then, concentrated by nanofiltration membrane of DLC, the commission concentrated retention rate of raffinose is 99.4% raffinose purity is 87.5%. We can obtain the products of raffinose powder by processing finally.