Avaliação do processamento de leite bovino na digestibilidade e alergenicidade das proteínas lácteas

Abstract

Milk is considered a protein food of high nutritional value, since its proteins are of high biological value. Different processes used in milk processing may generate changes in its conformation, impacting the gastrointestinal digestion of the food and can lead to a change in allergenic responses by modifying the exposure of protein epitopes. Thus, this study analyzed commercially available milk, processed by different technologies, comparing the digestibility and allergenicity of pasteurized whole milk, treated by ultra-high temperature (UHT), in powder and raw milk. The samples were subjected to simulation of the in vitro human digestion process, considering the undigested and digested stages after the gastric and intestinal phases by electrophoresis and protein quantification techniques, in addition to specific enzyme immunoassay for caseins and -lactoglobulin (- Lg). Digestibility among differently processed milks was affected only in the gastric phase, in which -Lg resistance to pepsin was observed, in pasteurized, raw and powdered milks, however, all tested processed milks presented a reduction of protein content over 90 %. Additionally, a tendency to reduce allergenicity was demonstrated in UHT-treated milks (~52 %) after simulated digestion in the stomach and great similarity of allergenic potential for all milks when undigested or after intestinal digestion, with a 96% allergenicity reduction in all samples. The data obtained in this study showed that the milk processing, as far as the tested ones, showed a great similarity with regard to digestibility and protein allergenicity.