Identification and quantification of gelatin by a high-resolution mass spectrometry-based label-free method

High-performance liquid chromatography (HPLC) and linear-ion trap/Orbitrap high-resolution mass spectrometry with selected ion monitoring (SIM) mode were used to create a label-free quantitative method for bovine gelatin as a representative mammalian gelatin. Various indexes including linear correlation coefficient, specificity, and reproducibility were used to evaluate this quantitative method via pure bovine gelatin as well as prepared edible films. After accurate mass and tandem mass spectrometry, seventeen marker peptides were detected and identified in pure bovine gelatin. Of these, seven marker peptides were confirmed to quantify pure bovine gelatin with good linearity (R-2 >= 0.99 for calibration equations), specificity, and reproducibility. Moreover, with excellent quantitative results, two peptides with m/z of 824.9177(2+) and 1076.0178(2+) were shown to be useful as characteristic peptides for quantifying bovine gelatin in the edible film systems constituted by mixed gelatins with various ratios and food additives. Due to the simple operation process, low experiment costs, and excellent measurement capability, this label-free method with high-resolution mass spectrometry could be a promising method to quantify gelatin in the food industry.