Spectroscopic analysis of the effect of glycation on casein structure and aggregation and its dependence on lactose...

In order to study the effect of glycation on the molecular structure of casein (CN), three groups of simulated milk powders with different lactose (Lac) contents, CN:Lac = 1:1.5, 1:2, and 1:2.5 (m:m), were constructed. The glycation level and the structural changes of CN were analyzed by multiple spectra. The results showed that the interaction between Lac and CN molecules was based on the dynamic quenching of collision. A higher quenching constant, K_SV, means that the 1:1.5 group showed more distinct glycation levels. In addition, CN glycation reduced the aggregation of casein micelles caused by heating treatment and repaired the structural damage of CN induced during the heating process. There was no positive correlation found between Lac content and protein glycation; thus, decreasing the Lac content of milk powder is not likely to be an effective method to prolong storage stability.