鲢鱼肽美拉德反应产物（MRPs）经5 kDa、1 kDa超滤膜分离、然后再经溶剂分级后，获得了不同组分，分析其抗氧化活性与理化特性。通过对不同组分的DPPH自由基清除活性、金属离子螯合活性和总抗氧化能力的测定可以看出，水溶性组分中的高分子量化合物比低分子量化合物具有较高抗氧化活性，而醇溶性组分中高分子量的抗氧化活性比低分子量的低。MRPs中水溶性组分F-3（>5 kDa）对DPPH自由基清除活性、对金属离子的螯合活性和总抗氧化力最高；水溶性组分中F-3和F-2（1 kDa~5 kDa）的褐变程度较高，F-3的荧光强度最高；FI-IR分析发现，F-2和F-3在860.01 cm-1和948.61 cm-1处有强烈的吸收峰，这表明肽因美拉德反应发生了结构的变化。因此，鲢鱼肽MRPs中起主要抗氧化作用的为水溶性物质，且其中相对高分子量的有色水溶性产物抗氧化活性较强。

Maillard reaction products (MRPs) from silver carp peptide were isolated using a 5-kDa and 1-kDa ultrafiltration system, which was followed by solvent fractionation in order to investigate the antioxidant activity and chemical properties of different fractions. Measurements of the free-radical scavenging activity, metal ion chelating activity, and total antioxidant capacity of different fractions showed that high molecular weight (HMW) compounds displayed higher antioxidant activity than that of low molecular weight (LMW) compounds in the water-soluble fraction. In contrast, the antioxidant activity of HMW compounds was lower than that of LMW compounds in the alcohol-soluble fraction. The DPPH radical scavenging activity, metal ion chelating activity, and ferric reducing/antioxidant power (FRAP) of the water-soluble fraction F-3 (> 5 kDa) in silver carp peptide MRPs were the highest. The browning intensities of F-3 and F-2 (1~5 kDa) were the strongest and the fluorescence intensity of F-3 was the highest. Fourier transform infrared spectroscopy (FT-IR) showed that MRPs had a strong absorption peak at 860.66 cm-1, while F-2 and F-3 had sharp absorption peaks at 860.01 cm-1 and 948.61 cm-1, respectively, indicating that the reducing sugar may be linked to the peptide skeleton, which thus, leads to structural changes. Therefore, the water-soluble substances from MRPs play a major antioxidant role, and the colored water-soluble products with relatively HMW show strong antioxidant activity.

国家自然科学基金资助项目（31270038）