Identification of Five Gelatins Based on Marker Peptides from Type I Collagen by Mass Spectrum in Multiple Reaction Monitoring Mode

Direct infusion-multiple reaction monitoring cubed (DI-MRM3) enables widely targeted bi-omics of Colla Corii Asini (Chinese name: Ejiao)

Food authenticity is extremely important and widely targeted bi-omics is a promising pipeline attributing to incorporating metabolomics and peptidomics. Colla Corii Asini (CCA, Ejiao) is one of the most popular tonic edible materials, with counterfeit and adulterated products being widespread. An attempt was devoted to develop a high-throughput and reliable DI-MRM3 program facilitating widely targeted bi-omics of CCA. Firstly, predictive MRM program captured metabolites and peptides in trypsin-digestive gelatins. After data alignment and structure annotation, primary parameters such as Q1 → Q3 → QLIT, CE, and EE were optimized for all 17 metabolites and 34 peptides by online ER-MS. Though a single run merely consumed 6.5 min, great selectivity was reached for each analyte. Statistical results showed that nine peptides contributed to distinguish CCA from other gelatins. After cross-validation with LC-MRM, DI-MRM3 was justified to be reproducible and high-throughput for widely targeted bi-omics of CCA, suggesting a meaningful tool for food authenticity.

Methods for detection and quantification of gelatin from different sources

Gelatin is a water-soluble protein obtained from the collagen of various animal origins (porcine, bovine, fish, donkey, horse, and deer hide) and has diverse applications in the food, pharmaceutical, and cosmetics industries. Porcine and bovine gelatins are extensively used in food and non-food products; however, their acceptance is limited due to religious prohibitions, whereas fish gelatin is accepted in all religions. In Southeast Asia, especially in China, gelatin obtained from donkey and deer skins is used in medicines. However, both sources suffer from adulteration (mixing different sources of gelatin) due to their limited availability and high cost. Unclear labeling and limited information about actual gelatin sources in gelatin-containing products cause serious concern among societies for halal and fraud authentication of gelatin sources. Therefore, authenticating gelatin sources in gelatin-based products is challenging due to close similarities between the composition differences and degradation of DNA and protein biomarkers in processed gelatin. Thus, different methods have been proposed to identify and quantify different gelatin sources in pharmaceutical and food products. To the best of our knowledge, this systematic and comprehensive review highlights different authentication techniques and their limitations in gelatin detection and quantification in various commercial products. This review also describes halal authentication and adulteration prevention strategies of various gelatin sources, mainly focussing on research gaps, challenges, and future directions in this research area.

Exploring peptides from toad venom for source identification by LC-MS/MS using MRM method

Toad venom is a traditional Chinese medicine (TCM) with various sources and wide-ranging preparations. Previous quality assessment studies primarily concentrated on small molecular compounds like toad dienolactones and indole alkaloids, studies on macromolecular peptides and proteins as quality assessment standards remained at the qualitative stage, lacking the development of practical and convenient quantitative methods. In this study, to explore the peptides from toad venom as a new method for identifying and evaluating its source, a complete scan of the water extract of peptides from toad venom was conducted using HPLC-Quadrupole Time-of-Flight Mass Spectrometer (Q-TOF) 5600, leading to the identification of peptides based on mass spectrometry data. Subsequently, HPLC- Quadrupole-Linear Ion Trap Mass Spectrometer (Q-Trap) 5500 employing Multiple Reaction Monitoring (MRM) mode was utilized to quantitatively analyze peptides in various sources of toad venom, followed by Partial Least Squares Discriminant Analysis (PLS-DA) to further analyze the data and evaluate the effectiveness. This study highlights the importance of exploring macromolecular substance in natural products research and provides a foundation for further studies on toad venom.

Quality evaluation of Pterocephali Herba through simultaneously quantifying 18 bioactive components by UPLC-TQ-MS/MS analysis

Pterocephali Herba (PH), the dried whole plant of Pterocephalus hookeri, is a Tibetan medicine commonly used to treat rheumatoid arthritis (RA). Iridoids, triterpenoids, flavonoids and phenylpropanoids are the major groups of bioactive constituents from PH. However, only ursolic acid and oleanolic acid, two unspecific triterpenoid components, are used as markers for the quality control of PH in Chinese Pharmacopoeia. Herein, an UPLC-TQ-MS/MS integrating SIR and MRM mode method for simultaneously quantifying 18 components, i.e., 9 iridoids, 3 triterpenoids, 3 phenylpropanoids, 2 flavonoids and quinic acid, in PH was developed and validated, and was used to evaluate 10 batches of PH samples from different origins. Hierarchical cluster analysis (HCA) was used to show the clustering of PH samples, while spearman correlation analysis was adopted to evaluate the correlation between ursolic acid/oleanolic acid and other quantified components. It was found that the established method was sensitive, precise, and accurate enough for the simultaneous quantification of 18 analytes in PH samples. Significant differences were found among the contents of 18 components in PH samples, no apparent clustering of the quality of PH samples was found to be related to its origins, and the contents of ursolic acid/oleanolic acid were only significantly correlated to the content of sylvestroside I, dipsanoside B, dipsanoside A in PH. Our results suggested that the newly established multi-components quantitative method is an improved approach for quality evaluation of PH samples. Furthermore, the holistic quality was inconsistent among PH samples, and ursolic acid/oleanolic acid alone could not indicate the holistic quality variation trend of PH.