Study On The Extraction Of Protein From Pupa Of Dendrolimus Punctatus Walker

The protein from pupa of Dendrolimus punctatus Walker was extracted with different methods. The results of single-factor experiments in treatment of alkali extraction show the optimum conditions were as the follows: NaOH concentration was 1.5%, treatment temperature was 60℃, extraction time was 90 min, the ratio of the material and the solution was 1:15; depositional time, pH and temperature was 120 min, 4.5 and 25℃ respectively. The ratio of the extracting protein was 78.1%, and the protein content of the protein product was 85.8%.The optimum conditions of the salt method were NaCl concentration 1.5%, treatment temperature 40 ℃, solution pH 12.0, extraction time 120 min, the ratio of the material and the solution 1:15; depositional time 120 min, pH 4.5 and temperature 25℃. The ratio of the extracting protein was 69.2%, and the protein content of the protein product was 91.3%.The optimum condition of the alkali proteinase method were as the follows: the ratio of the alkali proteinase and material was 1.6%, treatment temperature was 40 ℃, the pH of the solution was 12.0, extract time was 30 min, the ratio of the material and the solution was 1:10; depositional time, pH and temperature was 120 min, 4.5 and 25℃ respectively. The ratio of the extracting protein was 83.8%, and the protein content of the protein product was 88.7%.The optimum conditions of the compound trypsinase method were as the follows: the ratio of the compound trypsinase and material was 1.8%, treatment temperature was 45 ℃, extract time was 30 minutes, he solution pH was 11.0, the ratio of the material and the solution was 1:15; depositional time, pH and temperature was 120 min, 4.5 and 25℃ respectively.The results of the correctitude design show that the optimum condition were as the follows: the ratio of the alkali proteinase and material was 1.6%, treatment temperature was 40 ℃, the pH of the solution was 12.0, extract time was 30 minutes, the ratio of the material and the solution was 1:10; depositional time, pH and temperature was 120 minute ,4.5 and 25℃ respectively, which had a little difference from the results of single-factor experiments. The mostly important factor was solution pH, followed by the ratio of the material and the solution, the ratio of the alkali proteinase and material, the extract time and treatment temperature.The protein contents of the protein products prepared by different methods, were more than 85%, and the ash content of the protein products were less than 1%, which indicated that the protein products had little minerals. All the products contained 17 types of amino acids, including the 9 types of the necessary amino acids which accorded with the model made by WHO/FAO.The results of mice acute toxicity test show that the protein products were safe for Human and animal. We also found that the mice treated with the protein products were more fatty than those without protein products.In conclusion, several methods for extracting the protein from pupa of Dendrolimus punctatus were compared, and alkali proteinase method was the optimum. These results may be useful for further studies on the protein of Dendrolimus punctatus and...