Study On Extraction Process Of Protein And Chitosan From The Pupae Of Dendrolimus Houi

Two methods were used to extract protein from pupae of Dendrolimus houi and the result were compared on the basis of the weight of protein. The results of alkali extraction in single-factor treatment show that the ratio of the material and the solution was 1:15, NaOH mass fraction was 1.5%, extraction time was 60 minutes, extraction temperature was 60℃; depositional time was 150 minutes, depositional pH was 4.5 and depositional temperature 25℃. The results of salt extraction in single-factor treatment show that the ratio of the material and the solution was 1:15, NaCl mass fraction was 1.5%, extraction time was 90 minutes, extraction temperature was 40℃, the solution pH was 11; depositional pH was 4.5, depositional time was 60 minutes and depositional temperature was 25℃. To the method of alkali extraction, the weight of protein was 6.57g/100g; To the method of salt extraction, the weight of protein was 3.79g/100g. By comparing on the basis of the weight of protein, the method of alkali extraction is better than that of salt extraction to extract protein from the pupae of Dendrolimus houi.The extraction technology of chitin from the pupae of Dendrolimus houi was studied using single-factor test and orthogonal experimental design, and then the correlation analysis, variance analysis and q test were conducted. The nitrogen content and the production ratio of chitin at different conditions were linear fitted. The optimum extraction conditions were as follows: the pupa were treated with 8%NaOH at 90℃for 10h for removal of organic substances; and then treated with 2.5%HCl at 40℃for 22h to demineralize. The obtained chitin was white solid sheet, and its nitrogen content was 6.23%, ash content 0.22%, water content 6.28%, and production ratio 29.53%.Chitosan was prepared from Dendrolimus houi chitin by deacetylation, which was controlled mainly with NaOH mass fraction and temperature & period of reaction. With 45%NaOH treated at 110℃for 4 hours, it achieved a high degree of chitin deacetylation for a better preparation of chitosan. The obtained chitosan was white solid sheet, and its degree of deacetylation was 92.74%, its degree of viscosity was 21.36mPa·s, ash content 0.51%, water content 4.44%, and production ratio was 84.72%. The product quality is up to the criterion of food grade.Coating grapes with the chitosan solution to keep grapes fresh. After grapes were coated with the chitosan solution, the weight,soluble sugar and Vc content of grapes can be significantly inhibited decrease and the respiratory intensity of grapes can be significantly inhibited increase. The 1.2% chitosan concentration was the best concentration for coating grapes to keep fresh.?...