Carrot rhamnogalacturonan I structure and composition changed during 2017 in California

Authors: Hotchkiss, Arland; Chau, Hoa - Rose; Strahan, Gary; NUNEZ, ALBERTO - Retired ARS Employee; Harron, Andrew; Simon, Stefanie; White, Andre; Yadav, Madhav; YEOM, HYE WON - Campbell Soup Research

Submitted to: Food Hydrocolloids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2022
Publication Date: 12/15/2022
Citation: Hotchkiss, A.T., Chau, H.K., Strahan, G.D., Nunez, A., Harron, A.F., Simon, S., White, A.K., Yadav, M.P., Yeom, H. 2022. Carrot rhamnogalacturonan I structure and composition changed during 2017 in California. Food Hydrocolloids. https://doi.org/10.1016/j.foodhyd.2022.108411.
DOI: https://doi.org/10.1016/j.foodhyd.2022.108411

Interpretive Summary: Carrots are a healthy food containing several bioactive compounds including pectin, yet more data is needed in order to obtain health claims for this vegetable. Therefore, researchers in Wyndmoor, PA described the carrot dietary fiber structural composition in greater detail at four different times during the growing season. The carrot dietary fiber had seasonal variability in the pectin structure, which has potential as an anti-viral and gut health promoting compound. This information will be useful to develop carrot pectin as a functional food ingredient and provide more value for this specialty crop.

Technical Abstract: Detailed composition, fine structure, and function of carrot pomace fiber fractions harvested at four different times during the 2017 growing season in California, USA were determined. This pomace was processed using commercial enzymes and the changes in carbohydrate composition were determined. The carrot pomace contained pectic oligosaccharides that were branched, unsaturated, partially acetylated and methylated rhamnogalacturonan I (RG-I) with arabinogalacto-oligosaccharide side chains as well as free galacto-oligosaccharides detected by MALDI-TOF MS and NMR analysis. The molecular weight and degree of galacto-oligosaccharide polymerization decreased while water solubility increased following enzymatic treatment. The carrot pomace structure changed between the June and September harvests so that it was more susceptible to enzymatic degradation. The diversity of RG-I oligosaccharide structures following enzymatic treatment was greatest at the September harvest and the RG-I became completely debranched following enzymatic treatment of the pomace harvested in December. The structural properties of these carrot pomace fiber fractions suggest that they can function as a low viscosity beverage food ingredient, and the rhamnogalacturonan I structure indicated potential for anti-viral, immune-modulatory and prebiotic properties as functional food ingredients.