Determination of the authenticity of plastron-derived functional foods based on amino acid profiles analysed by MEKC

•An MEKC method for analysis of amino acids in plastron was established.•Amino acid profile of plastron and other collagen-containing foods were comparatively studied in order to identify plastron.•Principal component analysis was adopted for the first time to distinguish plastron from other foods containing collagen.•By comparing the AA profiles and the PCA results, plastron was successfully differentiated from 11 materials.•The proposed method to authenticate turtle shell glue in the market, fake products were commonly found. Plastron is a nutritive and superior functional food. Due to its limited supply yet enormous demands, some functional foods supposed to contain plastron may be forged with other substitutes. This paper reports a novel and simple method for determination of the authenticity of plastron-derived functional foods based on comparison of the amino acid (AA) profiles of plastron and its possible substitutes. By applying micellar electrokinetic chromatography (MEKC), 18 common AAs along with another 2 special AAs — hydroxyproline (Hyp) and hydroxylysine (Hyl) were detected in all plastron samples. Since chicken, egg, fish, milk, pork, nail and hair lacked of Hyp and Hyl, plastron could be easily distinguished. For those containing collagen, a statistical analysis technique — principal component analysis (PCA) was adopted and plastron was successfully distinguished. When applied the proposed method to authenticate turtle shell glue in the market, fake products were commonly found.