A study on the heat stability of food enzyme induced by amino-carbonyl reaction.

1.本文研究了卵清蛋白与几种二糖（麦芽糖、异麦芽糖、纤维二糖、乳糖、蜜二糖）在50 ℃和65%RH条件下保持0-20天后的美拉德反应。异麦芽糖和蜜二糖与蛋白质混合强烈诱导棕色着色，产生荧光化合物，和蛋白质聚合，而其他人这样做很弱。麦芽糖、乳糖和纤维二糖体系中较弱的高级美拉德反应产物如棕色和/或荧光化合物的产生表明在葡萄糖的C-4 OH上键合的末端吡喃糖苷基团阻碍了Amadori重排产物进一步降解为醛组分。通过使用合成底物测量在美拉德反应中产生的胰蛋白酶-葡萄糖复合物的活性。在贮藏8天内，配合物的活性均高于天然配合物。保存4天的复合物的热变性温度为64.5 ℃，而天然复合物的热变性温度为61.5 ℃。配合物和天然配合物的Km值分别为0.428和0.932。这些结果表明胰蛋白酶-葡萄糖复合物对热变性有保护作用，对底物有较强的亲和力.比较了胰蛋白酶-麦芽糖复合物和胰蛋白酶-葡萄糖复合物的活力。由于胰蛋白酶-麦芽糖复合物停留在美拉德反应的早期阶段，因此该复合物在长时间的贮藏中仍保持较高的活性.采用分批法测定胰蛋白酶-葡萄糖复合物对酪蛋白的活性。胰蛋白酶-葡萄糖复合物显示出比天然复合物更高的稳定性，直到4天的储存。

1. The Maillard reaction of ovalbumin and several disaccharides (maltose, isomaltose, cellobiose, lactose, melibiose) was investigated by measuring several properties of the sugar-protein Maillard adducts after each sugar was kept with ovalbumin at 50ﾟC and 65% RH for 0-20 days. Isomaltose and melibiose mixed with the protein strongly induced brown colorization, production of fluorescent compounds, and protein polymerization, whereas the others did so very weakly. The weaker production of advanced Maillard reaction products such as brown color and/or fluorescent compounds in the maltose, lactose and cellobiose systems indicated that the terminal pyranoside groups bonded at the C-4 OH of glucose retarded further degradation to aldehyde components of the Amadori rearrangement products.2. The activity of trypsin-glucose complexes produced in the Maillard reaction was measured by the use of synthetic substrate. The activities of the complexes were higher than that of native one until 8-day storage. The heat denaturation temperature of the complex stored for 4 days was 64.5ﾟC whereas that of native one was 61.5ﾟC. The Km values of the complex and native one were 0.428 and 0.932, respectively. These results indicated that trypsin-glucose complex have protective effect for heat denaturation, and strong affinity of substrate.3. The activity of trypsin-maltose complex was compared with that of trypsin-glucose. The high activity of trypsin-maltose complex was maintained for long storage, because the complex stay in early stage of the Maillard reaction.4. The activity of trypsin-glucose complex against casein was measured by batch system. The trypsin-glucose complex showed higher stability than native one until 4-day storage.