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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.

Author:
Price, Neil P. J., Vermillion, Karl E., Eller, Fred J., Vaughn, Steven F.
Source:
Journal of agricultural and food chemistry 2015 v.63 no.32 pp. 7286-7293
ISSN:
0021-8561
Subject:
Cymbopogon, Vitis riparia, arabinogalactans, beverages, emulsifiers, emulsions, frost, gels, glucuronic acid, grapefruits, grapes, gum arabic, industry, mannose, molecular weight, nuclear magnetic resonance spectroscopy, oils, stems
Abstract:
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 (HSQC, TOCSY, HMBC, DOSY) identified βGalp and three αAraf spin systems, in an Araf-α1,3-Araf-α1,2-Araf-α1,2-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 (HPRP). 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 h. Lower concentrations (0.1% w/v) were less viscous, yet still gave stable grapefruit oil/water emulsions. Hence, FGP is a β1,3-linked arabinogalactan with potential as a gum arabic replacement in the food and beverage industries.
Agid:
4683347