Abstract:

Proteins extraction from the larva of Dendrolimus punctatus with a buffer solution method was studied. The results revealed that granularity of materials, extraction temperature, extraction time and precipitation pH showed significant effects on the extraction rate of the proteins(P<0.05), while relative amount of materials and extraction solvent, precipitation temperature, and precipitation time had no significant effects. The optimal conditions were as follows. The buffer solution was Na₂HPO₄ NaOH（pH　9.5）, materials need to be fine powder (40 mesh), the ratio of materials to extraction solvent was 1∶15 (m/v), extraction time was 5 h, extraction temperature was 40 ℃, precipitation pH was 5.0, precipitation temperature was 5 ℃, precipitation time was 1 h. The protein content of the product obtained at the optimal condition was (7112±0.16)%, and the extraction rate was (60.36±1.25)% total mitrogen. The total amino acids content was 69.58% in the extract, of which the essential amino acids content was 45.16%. LD 50 of the protein product is was more than 12 050 mg·kg^-1, suggesting the product was actually no poisonous.

Key words: insect resources, insect pest, Dendrolimus punctatus, larva, protein, buffer solution