| In this paper, antioxidant peptides were prepared from collagen through the method of microwave-assisted hydrolysis. Hydrolysis conditions were optimized. The effects of the hydrolysate on skinand antioxidant system in mice irradiated by Ultraviolet B (UVB) were studied through animal experiments, and its effect on calcium absorption was studied as well.Firstly, the method composed of microwave-assisted acid hydrolysis and enzymolysis was used for hydrolysis. With degree of hydrolysis and ABTS·+, DPPH·scavenging activity as indexs, hydrolysis conditions were optimized through single-factor experiments and orthogonal test,which were as follow: phosphoric acid concentation of 4mol/L, solid-liquid ratio 1:5, microwave power 510W for 270s; followed was hydrolysis with neutral protease, pre-hydrolysate concentration of 4%, Enzyme-substrate ratio 4760U/g, temperature 55℃and pH7.0. The maximum degree of hydrolysis was achieved as 21.5%. Compared with conventional enzymolysis, hydrolysis time was decreased by more than 1.5 hours, ABTS·+ and DPPH·scavenging activity were increased by 8.7% and 3.1% respectively.Secondly, UVB irradiated mice skin model was constructed. The results showed that the addition of collagen hydrolysate in diet(10 to 25g/kgdiet) could significantly improve total antioxidant capacity (T-AOC) and acivities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and peroxidase (CAT) both in skin and blood, P <0.05; significant reduction in reactive oxygen species (ROS) and malondialdehyde (MDA) content were showed as well, P <0.05. The results were similar as 0.1% LA. The oxidation indicators were significantly correlated with skin thickness, water content and hydroxyproline (Hyp) content. The results also showed that the hydrolysate could result in promotions of apparent calcium absorption rate and retention rate in mice, P <0.05. It could also increase the length and weight of femur in mice significantly, P <0.05. |
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