不同加热条件下牛乳美拉德反应程度的研究

Study on the Maillard Reaction in Milk under Different Heating Conditions

摘要:

牛乳热处理过程中乳糖与蛋白质会发生美拉德反应，使牛乳的色泽、风味、营养等发生变化。本研究通过对影响牛乳褐变的主要因素的研究，即温度、时间和加糖量，探索不同热处理强度以及添加蔗糖、葡萄糖对美拉德反应程度的影响,包括色值、酸度、中间产物（羟甲基糠醛）和风味的变化。研究表明：加葡萄糖比不加糖和加蔗糖对牛乳样品美拉德反应程度影响显著（P<0.05）；加热温度越高，加热时间越长，其颜色变化越大，添加葡萄糖的样品在121 ℃加热25 min，其b*值从3.44上升到27.57；pH随温度升高，时间延长呈显著性下降（P<0.05）；中间产物随加热时间的延长表现为先下降后上升的趋势；电子鼻结果表明加热强度对牛乳含硫、含氮化合物，以及烷烃类、醇类和芳香类物质等风味组成会产生影响。

Abstract:

During heat treatment of milk, the Maillard reaction between lactose and proteins occurs, leading to changes in the color, flavor, and nutritional value of milk. In this study, the major factors (i.e., temperature, time, and amount of added sugar) affecting the browning of milk were investigated, in order to explore the influence of heating intensity and amounts of added sucrose and glucose on the Maillard reaction, including the changes in the color values, acidity, as well as intermediate (hydroxymethylfurfural, HMF) and flavor compositions. The results showed that the addition of glucose had a greater effect on the Maillard reaction than the addition of sucrose or with no added sugar (P < 0.05). Higher temperatures and longer heating time produced greater color changes. The b* value for the sample with added glucose increased from 3.44 to 27.57 after the sample was heated at 121 ℃ for 25 min. With increasing temperatures and time, the pH significantly decreased (P < 0.05). The amount of formed intermediate tended to increase after an initial drop with prolonged heating time. The measurements conducted by the electronic nose showed that the heating intensity affected the content of sulfur and nitrogen-containing compounds, as well as that of alkanes, alcohols aromatics, and other flavor components.