Protein-polysaccharide glycates are food ingredients that use the Maillard reaction to form a Schiff base linkage between the carbonyl of a polysaccharide and the free amino moiety of a protein. Glycates are excellent emulsification, foaming, and gelling agents in foods and improve protein solubility and heat stability. The present work examined if glycates dissociate by hydrolysis, returning to free un-glycated protein and dextran due to the reversibility of the Schiff base linkage. Hydrolysis of glycates made from whey protein isolate and dextran was measured versus time and temperature, allowing determination of the rate constants and equilibrium constants for glycate hydrolysis. Glycates underwent hydrolysis when placed into aqueous solutions at common food processing temperatures. For example, during hot food storage (60 °C), equilibrium fractional hydrolysis was 44%, whereas at ambient temperature (22 °C), it was 8%. The present work aims to increase the successful use of glycates in new foods by knowing what foods and conditions avoid glycate hydrolysis.
Keywords: carbohydrates; conjugation; dairy.