Technical Study On Hydrolytic Silkworm Pupa Protein By Protease

Silkworm is pupa abundant of protein. The products of Amino-acid and its ramification were widelyapplied in food, medicine, chemical field with development of protein-hydrolyzing technology. Products ofSilkworm pupa protein(edible grade)is in experiment at present. In the paper, With Silkworm pupa as rawmaterial, An optimum hydrolytic technology with silkworm pupa protein by means of hydrolysis withneutral protease, alkaline protein and its mixture were studied through uniform design, The optimumconditions for the limited hydrolysis of silkworm pupa protein were concluded as follows:1. In order to get suitable hydrolyzing conditions, the hydrolyzing time, temperature, content ofsubstrate, adding protease quantity were studied in the orthogonal experiment. The optimum conditions ofsilkworm pupa protein with neutral protease are: the ratio of enzyme to substrate (E/S) is 1.2％(W/W), thesubstrate concentration (S)is 4.0％(W/V), the recreation occurs at 60℃and pH 7.0 for 6 h.2. The optimum conditions of silkworm pupa protein with alkaline protease are: the recreation occursat 60℃and pH 8.0 for 8 h. And the yield of peptide is 92.37％. The other conditions are sameness as neutralprotease.3. Different ratio of neutral protease and alkaline protease to hydrolyzing silkworm pupa protein werestudied, the optimum efficiency are: adding protease in the same time and keeping the ratio 50％(w/w), theratio of enzyme to substrate (E/S) is 1.6％(W/W), the substrate concentration (S) is 4.0％(W/V),therecreation occurs at 60℃and pH 7.5 for 6 h.4. The concentration of flee amino acid were checked in the liquid with neutral protease, alkalineprotease and same-quantity-double-protease, the total quantity of free AA(Exclusion Trp) are:91.636mg/100ml,120.583mg/100ml,134.136mg/100ml. Content of EAA(necessary amino acids) are0.768～13.701mg/100ml,1.380～13.735mg/100ml,2.554～15.775mg/100ml respectively. The ratio of EAAto total AA are: 36.982％,33.967％,31.987％。5. After the silkworm pupa solution is hydrolyzed with different protease, comparing to the totalamino acid content the optimum efficiency is double-protease, the second is alkaline protease. the last isneutral protease. By microbiological hydrolytic enzyme technology, the hydrolytic rate is above 30％.