N-carboxymethyllysine in nutritional milk formulas for infants.

Production of infant formulas involves high temperature processing for microbiological safety. However, heat processes generate Advanced Glycation End-products (AGEs), including N-carboxymethyllysine (CML) formed between lysine and lactose. Formulas manufactured from cow or goat milk, with or without whey adjustment, or hydrolysates of cow whey proteins, were tested for CML levels using a commercially available ELISA kit. CML concentrations ranged from 2 to 210 µg/g protein in formulas containing intact proteins. Median CML concentrations were up to 3-fold greater in formulas containing 60% whey protein compared with 20% whey protein, for both cow and goat formulas. Goat milk formulas contained 7 to 12-fold less CML than cow milk formulas. Formulas made from intact proteins contained lower CML compared to formulas using whey hydrolysates. Western immunoblotting techniques detected higher CML levels in whey proteins compared with casein. This study showed whey addition to infant formula significantly contributes to CML levels.