美拉德糖基化对玉米蛋白粉双酶水解产物抗氧化活性的影响

利用复合蛋白酶和碱性蛋白酶协同作用于玉米蛋白粉,将得到的双酶水解产物与壳寡糖进行美拉德糖基化反应,研究不同蛋白浓度下的酶解物和糖基化产物的抗氧化活性。结果表明,酶解物和糖基化产物都具有良好抗氧化活性,美拉德糖基化反应可以提高酶解物的抗氧化活性。当糖基化产物蛋白浓度为5.00 mg/mL时,其·OH清除率和DPPH·清除率分别达到了90.91%和61.75%,蛋白浓度为1.00mg/mL时,Fe^(2+)螯合能力为83.42%,比酶解物·OH清除率和DPPH·清除率分别提高了48.78%和32.26%,Fe^(2+)螯合能力提高了22.63%。

玉米谷蛋白的美拉德糖基化改性

玉米谷蛋白在中性及偏酸性条件下溶解性差的特点限制了其在食品工业的应用。为了改善其溶解性,在D-氨基半乳糖盐酸盐存在条件下,对玉米谷蛋白进行美拉德糖基化改性。结果表明,在玉米谷蛋白质量浓度30 g/L、蛋白与糖质量比为1:2、反应温度90℃、反应体系pH10和反应时间2 h条件下,玉米谷蛋白的糖基导入量为(439.863±10.700)mg/g玉米谷蛋白。与未糖基化改性的蛋白相比,改性玉米谷蛋白的溶解性非常显著改善,起泡性提高了1.692倍,起泡稳定性降低了42.467%,乳化性提高了86.152%,乳化稳定性基本不变,持水性提高了1.13倍,持油性降低了13.684%。

Antiglycation and antioxidation properties of juglans regia and calendula officinalis:possible role in reducing diabetic complications and slowing down ageing

OBJECTIVE:Accumulation of advanced glycation end products(AGEs) in the body due to the non-enzymatic glycation of proteins and oxidation is associated with aging and diabetes mellitus.In this study we wanted to investigate the antiglycation and antioxidation potential of two medicinal plants:Juglans regia and Calendula officinalis.METHODS:In-vitro investigation was carried out to discover the antiglycation and antioxidation potential of J.regia and C.officinalis.Using an Ultraviolet Double-beam Spectrophotometer,we evaluated the antiglycation property of the crude methanolic extracts of J.regia and C.officinalis by assessing their ability to inhibit the Maillard reaction.Employing the same instrument we also measured the antioxidation potential of these plant extracts using the nitric oxide(NO) free radical-scavenging assay.RESULTS:J.regia had greater antiglycation ability,with a minimum inhibitory concentration(MIC 50) of 28 μg/mL as compared with that of C.officinalis(270 μg/mL).C.officinalis had greater antioxidation potential(26.10,22.07 and 16.06% at 0.5 mg,0.25 mg and 0.125 mg,respectively,as compared with 18.15,16.50 and 16.06% of J.regia,respectively).CONCLUSION:J.regia and C.officinalis inhibited the Maillard reaction and prevented oxidation in-vitro.Hence,the extracts of these plants could have therapeutic uses in curbing chronic diabetic complications and slowing down aging.