A quantitative strategy of ultrasound-assisted digestion combined UPLC-MS/MS for rapid identifying species-specific peptide markers in the application of food gelatin authentication

Gelatins are important and frequently-used food additives, but the quality control of gelatins is always an intractable problem in routine analysis. In this work, a new strategy for simultaneously rapid identification and quantification of gelatins from various species using ultrasound assisted digestion-UPLC-MS/MS was described. Fourteen peptide markers were used for authenticity of gelatins by the presence or absence of these speciesspecific peptides. In the meantime, adulteration ratios could be calculated based on the peak area of different species peptide markers. With 10 g/L trypsin and ultrasound application, digestion time could be decreased from >12 h (traditional method) to 5 min, and the determination of animal gelatins could be achieved in 20 min with a single analysis run. Twenty-five commercial gelatin samples were screened, among which two deer-hide gelatin samples were adulterated with 900 g/kg and 265 g/kg cattle-hide gelatin (CHG); two donkey-hide gelatin (ACC) samples were adulterated with 66 g/kg and 381 g/kg horse-hide gelatin; and one ACC sample was adulterated with 786 g/kg CHG. This strategy provides an efficient and sensitive authentication and traceability of gelatincontaining products, and could also be applied to processed meat or protein food.