The presence of animal derived collagen proteins in various foodstuffs poses concern for some consumers, whether for ethical (vegetarian or vegan) or religious reasons. Food labelling laws require all ingredients to be listed, however there is no requirement to indicate the species of origin for products containing protein based additives such as gelatin. Gelatin is composed primarily of type I, II and III collagen, and is derived from acid or alkaline hydrolysis of skin, bones and hide, from porcine and bovine sources. Each collagen proteoform represents a unique opportunity to assess the origin of gelatin used in food manufacturing, and confers proteomics a direct advantage in detecting foodstuffs adulterated with gelatin.
We have developed sample preparation procedures to optimise the recovery of collagen from various yoghurt and confectionery products, and have also developed both untargeted and targeted LC-MS procedures for the identification of proteotypic peptides which uniquely differentiate collagen isoforms at the species level. Using targeted peptide assays we report on the detection of species specific collagen proteoforms using multiple reaction monitoring – high resolution (MRM-HR) and parallel reaction monitoring (PRM) mass spectrometry, and evaluate the detection of porcine and bovine derived gelatin used in the preparation of twenty five yoghurt and confectionery products commonly available in Australian supermarkets.
Our findings indicate that targeted LC-MS can be used to differentiate different collagen proteoforms from bovine and porcine sources, and provides species specific information to distinguish the source of gelatin used in the preparation of various foodstuffs.