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Frost grape polysaccharide (FGP), an emulsion-forming arabinogalactan gum from the stems of native north american grape species Vitis riparia Michx.
- Price, Neil P. J., Vermillion, Karl E., Eller, Fred J., Vaughn, Steven F.
- Journal of Agricultural and Food Chemistry 2015 v.63 no.32 pp. 7286-7293
- Vitis riparia, arabinogalactans, emulsifiers, emulsions, flavor, gels, glucuronic acid, grapefruits, grapes, gum arabic, molecular weight, nuclear magnetic resonance spectroscopy, oils, proteins, stems
- A new arabinogalactan is described that is produced in large quantity from the cut stems of the North American grape species Vitis riparia (Frost grape). The sugar composition consists of L-arabinofuranose (L-Araf, 55.2 %) and D-galactopyranose (D-Galp 30.1%), with smaller components of D-xylose (11.2 %), D-mannose (3.5%), and glucuronic acid (GlcA, ~2%), the latter linked via a galactosyl residue. Permethylation identified 3-linked Galp residues, some substituted at the 2-position with Galp or Manp, terminal Araf and Xylp, and an internal 3-substituted Araf. NMR identified ßGalp and three aAraf spin systems, in a Araf-a1,3-Araf-a1,2-Araf-a1,2-Galp structural motif. Diffusion-ordered NMR showed that the FGP has a molecular weight of 1 - 10 MDa. Unlike gum arabic, the FGP does not contain a hydroxyproline-rich protein (AGP). FGP forms stable gels at >15 % w/v, and at 1 - 12% solutions are viscous, and are excellent emulsifiers of flavoring oils (grapefruit, clove, and lemongrass), giving stable emulsions for =72 hours. Lower concentrations (0.1% w/v) were less viscous, yet still gave stable grapefruit oil/water emulsions. Hence, FGP is a ß1,3-linked arabinogalactan with potential as a gum arabic replacement in the food and beverage industries.