Impact of Maillard reaction on the proteolysis of lactoferrin under simulated infant gastric-duodenal conditions
Résumé
Recently there is an increasing realization that dietary proteins may affect health beyond their mere nutritional value. In this respect, bovine lactoferrin (LF) has been extensively studied due to diverse biological functions, including antimicrobial, antioxidant and immune-modulatory activities. Moreover, its high concentration in human breast milk makes it a much needed ingredient in infant formulas which undergo various processing operations. To this end, scarce data exists on the influence of Maillard reaction, which may occur even unintentionally during thermal processing, on LF's structure and functionality. This STSM investigation aimed to study the impact of controlled thermal processing on the functionality of LF under simulated infant gastric and duodenal conditions. Specifically, various LF-based Maillard conjugates were produced through controlled dry heating of LF with prebiotic dietary fibers. Maillard-type conjugation was ascertained and characterized in terms of size, absorbance and MW based on DLS, spectrophotometer and SDS-PAGE assays. Samples collected from in vitro gastric and duodenal infant digestion were analyzed by SDS-PAGE, ELISA and LC-MS/MS. These revealed that even slight extents of Maillard conjugation modulated LF susceptibility to proteolysis and the expected profiles of its breakdown peptides. Hopefully, this work will help establish a link between the physicochemical changes in LF induced by thermal processing and its digestive fate.