Quantitative bottom-up glycomic analysis of polysaccharides in food matrices using liquid chromatography – tandem mass spectrometry

Authors: BACALZO, NIKITA - University Of California, Davis; COUTURE, GARRET - University Of California, Davis; YE, CHEN - University Of California, Davis; CASTILLO, JUAN - University Of California, Davis; PHILLIPS, KATHERINE - Virginia Tech; Fukagawa, Naomi; LEBRILLA, CARLITO - University Of California, Davis

Submitted to: Analytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2022
Publication Date: 12/21/2022
Citation: Bacalzo, N., Couture, G., Ye, C., Castillo, J., Phillips, K., Fukagawa, N.K., Lebrilla, C. 2022. Quantitative bottom-up glycomic analysis of polysaccharides in food matrices using liquid chromatography – tandem mass spectrometry. Analytical Chemistry. 95:1008. https://doi.org/10.1021/acs.analchem.2c03707.
DOI: https://doi.org/10.1021/acs.analchem.2c03707

Interpretive Summary: Carbohydrates are the most abundant biomolecules in nature and specifically, polysaccharides are present in almost all plants and fungi. Due to their compositional diversity, polysaccharide analysis remains challenging. Compared to other biomolecules, rapid analysis for carbohydrates has yet to be developed. Recently, food polysaccharides have been shown to play a vital role in modulating the diversity and function of the human gut microbiome, highlighting the need to obtain polysaccharide structural information. To address this gap in analytical science, we have developed a multiplexed, rapid-throughput, and quantitative approach for polysaccharide analysis in foods. Nine polysaccharides (starch, cellulose, ß-glucan, mannan, galactan, arabinan, xylan, xyloglucan, chitin) were successfully quantitated with sufficient accuracy (5-25% difference) and high reproducibility (2-15% CV). Additionally, the method was used to identify and relatively quantitate polysaccharides present in a sample set comprising of various fruits, vegetables, and herbs. Lastly, absolute quantitation of apple and onions were obtained using an external calibration curve, where varietal differences were seen in some of the samples. The methodology developed in this study will provide complementary polysaccharide-level information to deepen our understanding of the interactions of dietary polysaccharides, gut microbial community, and human health.

Technical Abstract: Carbohydrates are the most abundant biomolecules in nature and specifically, polysaccharides are present in almost all plants and fungi. Due to their compositional diversity, polysaccharide analysis remains challenging. Compared to other biomolecules, high-throughput analysis for carbohydrates has yet to be developed. Recently, food polysaccharides have been shown to play a vital role in modulating the diversity and function of the human gut microbiome, highlighting the need to obtain polysaccharide structural information. To address this gap in analytical science, we have developed a multiplexed, rapid-throughput, and quantitative approach for polysaccharide analysis in foods. Specifically, polysaccharides were depolymerized using a non-enzymatic chemical digestion process followed by oligosaccharide fingerprinting using high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS). Both label-free relative quantitation and absolute quantitation were done based onthe abundances of oligosaccharides produced. Method validation included evaluating recovery for a range of polysaccharide standards and a breakfast cereal standard reference material. Nine polysaccharides (starch, cellulose, ß-glucan, mannan, galactan, arabinan, xylan, xyloglucan, chitin) were successfully quantitated with sufficient accuracy (5-25% difference) and high reproducibility (2-15% CV). Additionally, the method was used to identify and relatively quantitate polysaccharides present in a sample set comprising of various fruits, vegetables, and herbs. Lastly, absolute quantitation of apple and onions were obtained using an external calibration curve, where varietal differences were seen in some of the samples. The methodology developed in this study will provide complementary polysaccharide-level information to deepen our understanding of the interactions of dietary polysaccharides, gut microbial community, and human health. almond milk in significant abundance.