Glycation from α-dicarbonyl compounds has different effects on the heat-induced aggregation of bovine serum albumin and β-casein

alpha-Dicarbonyl compounds are generated in large amounts during heat treatment in food production. This work compared the influence of glycation by alpha-dicarbonyl on the hydrothermal aggregation of bovine serum albumin (BSA) and of beta-casein (beta-CN). Glycation by alpha-dicarbonyl compounds was found to be more efficient than glycation by glucose in reducing the free amino groups, surface hydrophobicity and isoelectric point of BSA, thus greatly inhibited the hydrothermal aggregation of BSA. In addition, glycation by alpha-dicarbonyl greatly transformed the rigid BSA aggregates into flexible structures, based on analysis by fluorescence spectrum, transmission electron microscope and small-angle X-ray scattering. In contrast, both the aggregation process and aggregates conformation of beta-CN were found to be minimally affected by glycation, possibly due to the intrinsic disorder of beta-CN. This work highlights the substantial influences of alpha-dicarbonyl on dietary proteins during heat treatment depending on the protein structural characteristics.

Automated summary

The study showed that glycation by alpha-dicarbonyl compounds had a significant impact on the hydrothermal aggregation of BSA by reducing free amino groups, surface hydrophobicity, and isoelectric point, as well as transforming rigid aggregates into flexible structures. In contrast, beta-casein was minimally affected by glycation, possibly due to its intrinsic disorder. These findings highlight the importance of protein structural characteristics in determining the influence of alpha-dicarbonyl compounds on dietary proteins during heat treatment.