Kinetics of heat-induced denaturation of proteins in model infant milk formulas as a function of whey protein composition

The process of manufacturing infant milk formulas (IMFs) involves heat treatments that can lead to whey protein denaturation. The objective of the study was to determine how protein composition affects the denaturation kinetics of the whey proteins within IMFs. Three model IMFs (1.3% of cow's milk protein) were produced with a caseins: whey proteins ratio of 40:60, differing only by the whey protein composition. The kinetics of heat-induced denaturation of alpha-lactalbumin, beta-lactoglobulin and lactoferrin were investigated between 67.5 degrees C and 80 degrees C by chromatographic quantification of the residual native proteins. Results showed that the heat-denaturation of alpha-lactalbumin was reduced when beta-lactoglobulin was absent. The heat-denaturation of lactoferrin was not affected by the composition of the IMFs but its presence enhanced the heat-denaturation of beta-lactoglobulin. This study revealed that, for higher heat treatments (90 degrees C/15 s, 75 degrees C/15 min), IMF containing alpha-lactalbumin and lactoferrin preserved a higher proportion of native whey proteins than IMFs containing beta-lactoglobulin.