Extraction, Hydrolysis And Purification Of Tenebrio Molitor L. Protein And Studies On Antioxidative Activity

Larvae of Tenebrio molitor is relatively rich in protein,especially suitable for the preparation of insects bioactive peptides. In this paper, four protein were extracted and seperated from larvae of Tenebrio molitor. Water-soluble protein and alkali-soluble protein were bienzymatic hydrolyzed for antioxidant peptides. The bienzymatic hydrolysis conditions were optimized, respectively. Antioxidant activity of the antioxidant peptides was studied. This study provides a basis for full use of protein of Tenebrio molitor and is useful to improve economic value of Tenebrio molitor. The main results were listed as the followings:(1) Results showed that the contents of water-soluble protein, alkali-soluble protein, acid-soluble protein and alcohol-soluble accounted for 42.60%, 16.33%, 1.65% and 1.33%, respectively.(2) Results showed that the optimal hydrolytic conditions of water-soluble protein were, ratio of solid to liquid 1∶20 (m∶V), reaction time 2 hours, dosage of protease 17.36 mg/g (ratio of protease energy 1∶1), pH 8.0 and temperature 46.5℃.(3) Results showed that the optimal hydrolytic conditions were, ratio of solid to liquid 1∶20 (m∶V), reaction time 1.9 hours, dosage of protease 10 mg/g (ratio of protease energy 1∶1), pH 7.2 and temperature 47.8℃.(4) Hydrolysate of water-soluble protein was separated by Sephadex G-25 gel chromatography column and fractionated into three portions. Fraction S2 showed the strongest scavenging activity to·OH of 64.26%. And then the fraction S2 was separated into four ingredients by DEAE Sepharose F.F. The scavenging activity to·OH of S2-1, S2-2 having stronger activity, was 78.44%, 45.39%, respectively. Hydrolysate of alkali-soluble protein was separated by Sephadex G-25 gel chromatography column and fractionated into four portions. Fraction J3 showed the strongest scavenging activity to·OH of 40.55%.And then the fraction S2 was separated into four ingredients by DEAE Sepharose F.F.. The scavenging activity to·OH of J3-2 as the strongest one, was 47.02%.(5) The amino acid composition analysis indicated S2-1 prepared from water-soluble protein was rich in Ala, Pro, Leu, Glu, Val, Gly, Ile, Ser, S2-2 rich in Glu, Asp, Pro, and J3-2 prepared from alkali-soluble protein rich in Glu, Asp, Pro, Gly.