牛奶加热过程中初始美拉德反应的程度

The extent of the early Maillard reaction in heat treated milk.

牛奶在加热过程中由于发生美拉德反应使有效赖氨酸的数量明显减少．ε－脱氧－果糖－半乳糖－赖氨酸（Ｌａｃｔｕｌｏｓｅｌｙｓｉｎｅ）是美拉德反应初始阶段产生的一种束缚态赖氨酸．传统的酸解处理会造成该化合物分解．本试验研究用蛋白酶水解牛乳蛋白质，再用高效液相色谱法直接测定ε－脱氧－果糖－半乳糖－赖氨酸．根据美拉德反应的动力学原理，建立了在未知初始赖氨酸含量的情况下计算初始美拉德反应程度的数学模型．

Loss of available lysine due to Maillard reaction was serious in heat treated milk. The major form of blocked lysine after early Maillard reaction was lactuloselysine (ε deoxylactulosyllysine) which is broken down on acid hydrolysis. Direct determination of the lactuloselysine with HPLC after complete enzymatic hydrolysis was presented. A mathematical model calculating the extent of the early Maillard reaction without knowledge of the initial lysine value before treatment was established based on the kinetic of the Maillard reaction. The model was proved to be reliable for milk samples heated at 110℃ for shorter than 90 min.