Study On Preparation Of Royal Jelly Protein Hydrolysates And Its Antioxidant Activities

An in-depth study of royal jelly protein enzymolysis was conducted. Extraction methods of royal jelly protein, the enzymes, main parameters of enzymolysis techinics, antioxidant activities of hydrolysates in vivo and vitro and purification of antioxidant peptides were studied with proteins extraction, enzymolysis, antioxidant test, gel chromatography, SDS-PAGE, RP-HPLC. The results laid a theoretical foundation for the development and utilization of royal jelly protein antioxidant peptides. The main findings were as follows:1.4kinds of methods of royal jelly protein extraction were compared, the highest contents of soluble proteins and total nitrogen of royal jelly protein was from the method of dialysis extraction. And5proteinases (pepsin, trypsin, neutral protease, alkaline protease and papain) were used to digest royal jelly protein. DPPH free radical scavenging activity of royal jelly protein by dialysis with pepsin was highest (38.65%) through the index of the degree of hydrolysis and DPPH free radical scavenging activity. The response surface design was carried to optimize the experiment. The optimum conditions were as follows:[E]/[S]2.24%, substrate concentration1.61%, enzymolysis time3.7h, DPPH free radical scavenging activity of royal jelly protein by dialysis was47.84%under this condition.2. Through the methods of DPPH free radical scavenging activity, hydroxyl radical scavenging ability, reducing power and lipid peroxidation inhibition ability. It was concluded that:When DH was4.18%, the highest DPPH free radical scavenging ability was52.43%; When DH was4.50%, the highest hydroxyl free radical scavenging ability was39.19%; When DH was4.18%, the highest reducing power was0.263; When DH was4.50%, the highest lipid peroxidation inhibition ability was13.19%.3. Antioxidant activities of hydrolysates of royal jelly protein were measured in vivo. The results showed that hydrolysates of royal jelly protein in some certain contents were better than royal jelly protein and Vitamin C in improving the activities of SOD and GSH-Px of blood serum and liver of mice with D-galactose senile model, and decreasing the contents of MDA. It indicated that hydrolysates of royal jelly protein had antioxidant and anti-aging oxidation activities of mice. And its mechanism should be further studied.4. F1and F2were fractionated by gel filtration from royal jelly protein hydrolysates on Sephadex G-25. F2was better than F1on DPPH free radical scavenging activity. Royal jelly protein and the related components were examined by SDS-PAGE, more and more royal jelly proteins with great molecular weights degraded the small peptides with higher HD. The Mr of F1and the F2was smaller than14.4kDa. It was further confirmed that the main protein of royal jelly was MRJP1. RP-HPLC analysis showed that Fl had7components, and F2had3components. The animo acid analysis showed that the peptides with high contents of Asp and Glu may be the reason of acidic property of royal jelly.