葡萄糖-赖氨酸美拉德产物分级组分对香蕉酶促褐变的抑制

酶促褐变是香蕉加工中拟解决的关键问题，非硫安全高效抑制剂的筛选是目前的研究热点。美拉德产物（Maillard reaction products，简称MRPs）展示了其良好的抑制酶促褐变的能力，然而美拉德产物分级组分的相关研究尚未见报道。通过透析处理得到大于和小于3 500 u的分级组分，比较其抑制香蕉酶促褐变的相关能力，并对抑制机理进行研究。结果显示：3种MRPs中，MW>3 500 u的MRPs具有较好的还原力，MW<3 500 u的MRPs具有较好的DPPH·清除率、螯合铜离子能力以及抑制多酚氧化酶酶活的能力。MW<3 500 u的MRPs对游离酶抑制常数（KI）和对酶-底物络合物的抑制常数（KIS）分别为0.198 mmol/L和1.508 mmol/L，抑制类型属于混合型抑制。

Effect of Fractionation of Glucose-lysine Maillard Reaction Products on Banana Enzymatic Browning Inhibitory Ability

Enzymatic browning is the key issue to be solved in banana processing. Currently finding safe and efficient non-toxic and non-sulfur browning inhibitors is the hotspot. Maillard reaction products showed the ability to inhibit enzymatic browning, but the studies focusing on different molecular weight component has not been reported. Two series of components(larger than 3 500 u and smaller than 3 500 u)by dialysis treatment were obtained and related properties on banana enzymatic browning inhibition and their inhibition mechanism were compared. MW>3 500 u fraction exhibited the best reducing ability, while MW<3 500 u exhibited better DPPH· scavenging ability/copper ion chelating ability and banana polyphenol oxidase inhibitory ability. As for MW<3 500 u MRPs, free enzyme inhibition constant(KI)and enzyme-substrate complex inhibition constant(KIS)was 0.198 and 1.508 mmol/L, respectively. The inhibition type versus banana PPO was mixed-competitively.