Preliminary Study on Maillard Reaction Products of Chicken Bone Extract Hydrolysate by Membrane Separation

The properties of different fractions separated from Maillard reaction products (MRPs) of enzymatic hydrolysates of chicken bone extract were investigated.The MRPs of enzymatic hydrolysates of chicken bone extract were obtained by Maillard reaction, and then separated by different membrane technologies including microfiltration, ultrafiltration, nanofiltration and reverse osmosis.Afterwards, the separated MRPs were evaluated through the browning degree, flavor composition and antioxidant property.The browning degree of MRPs was analyzed by employing the UV-vis spectroscopy method, and the flavor profiles were characterized by the e-nose and sensory evaluation.Furthermore, the antioxidant activities of MRPs were studied in terms of the reducing power, the ABTS + radical scavenging activity, AEC inhibition rate, oxygen radical absorbance capacity (ORAC) and the capacity of protecting circular plasmid DNA.Results showed that the molecular weights of fractions induced browning were more than 3 kDa while the intermediate products of Maillard reaction ranged from 0.3 to 1 kDa.The flavors were improved after Maillard reaction, and the flavor compounds were from the fractions of microfiltration and nanofiltration.Besides that, the antioxidant activities of the MRPs in comparison with the stock solution of enzymatic hydrolysates of chicken bone extract were all significantly enhanced (p < 0.05).Though the antioxidant properties of different fractions separated from MRPs decreased slightly, but all stronger than the enzymatic hydrolysate of chicken bone extract (p < 0.05).The overall evaluation showed that the score of MRPs stock solution was the highest and the separating MRPs fractions were all higher than stock solutions of chicken bone extract and enzymatic hydrolysate of chicken bone extract.