The
allergy-protective capacity of raw cow's milk was demonstrated to be abolished after heat treatment. The heat-sensitive
whey protein fraction of raw milk is often implied to be the source of this
allergy-protective effect, but a direct link between these
proteins and the protection against allergic diseases is missing. This study therefore aimed at investigating the mechanistic relation between heat damage to
whey proteins and
allergy development. Raw cow's milk was heated for 30 min at 50, 60, 65, 70, 75, or 80 °C and the native
whey protein profile of these differentially heated milk samples was determined using LC-MS/MS-based proteomics. Changes in the native
protein profile were subsequently related to the capacity of these milk samples to prevent the development of
ovalbumin-induced
food allergy in a murine animal model. A substantial loss of native
whey proteins, as well as extensive
protein aggregation, was observed from 75 °C. However,
whey proteins with immune-related functionalities already started to denature from 65 °C, which coincided with the temperature at which a loss of
allergy protection was observed in the murine model.
Complement C7, monocyte
differentiation antigen CD14, and
polymeric immunoglobulin receptor concentrations decreased significantly at this temperature, although several other immunologically active
whey proteins also showed a decrease around 65 °C. The current study demonstrates that immunologically active
whey proteins that denature around 65 °C are of importance for the
allergy-protective capacity of raw cow's milk and thereby provides key knowledge for the development of microbiologically safe alternatives to raw cow's milk.