Analysis of Advanced Glycation End products in ribose-, glucose- and lactose-crosslinked gelatin to correlate the physical changes induced by Maillard reaction in films

Abstract

The Maillard reaction (MR), a condensation reaction between carbonyl-containing and free amino-containing compounds, has attracted the interest of scientists within the food industry, nutrition & health, and materials science. However, due to the complexity of the reaction much remains to be clarified regarding the nature of the reaction products and their effect on the properties of protein/saccharide-containing products. In this work, gelatin-based films with various saccharides (glucose, lactose & ribose) and thermally crosslinked (105 °C) for different times (0, 2, 6, 24 h), were analysed to deliver deeper insight into the molecular transformations induced by MR and their effect on the physical properties of films, considered as complex systems. Coloured, ultraviolet–visible (UV–Vis) light-absorbing, crosslinked, and fluorescent compounds were analysed by colourimetry, UV–Vis spectrophotometry, solubility, as well as fluorescence spectroscopy. The colour of the films turned pale yellow and dark brown, the solubility decreased, while the UV–Vis light absorption capacity of the films significantly increased as the heating time increased. Rapid and simultaneous separation of Advanced Glycation End products (AGEs) on a silica hydride column, and their detection using high resolution mass spectrometry (MS) showed an increment in high molecular weight (HMW) compounds and gelatin crosslinking, which was related to the formation of AGEs. Of these, pentosidine, vesperlysine, GOLD and MOLD were quantified, while crossline and glucosepane were also detected. More noticeable physical and molecular changes were observed as the saccharide reactivity increased, which was indirectly related to the molecular size of the added saccharides: pentoses > hexoses > disaccharides.