A novel emulsion-forming arabinogalactan gum from the stems of Frost grape (Vitis riparia Michx.)

Authors: Price, Neil; Vermillion, Karl; Eller, Fred; Vaughn, Steven

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/5/2015
Publication Date: 8/12/2015
Citation: Price, N.P., Vermillion, K., Eller, F.J., Vaughn, S.F. 2015. A novel emulsion-forming arabinogalactan gum from the stems of Frost grape (Vitis riparia Michx.) [abstract]. Phytochemical Society of North America.

Interpretive Summary:

Technical Abstract: A novel arabinogalactan polysaccharide (FGP) is described that is produced in large quantities from the cut stems of Frost grape (Vitis riparia Michx.). 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 and Manp, terminal Araf and Xylp, and internal 3-substituted Arap. NMR identified betaGalp and three alphaAraf spin systems, in a Araf-alpha1,3-Araf-alpha1,2-Araf-alpha1,2-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. FGP forms stable gels at >15 % w/v, and solutions at lower concentrations (1 - 12% w/v) are viscous, and are excellent emulsifiiers of flavoring oils (grapefruit, clove, and lemongrass), giving stable emulsions for more than or equal to 72 hours. Lower concentrations (0.1% w/v) were less viscous, yet still gave stable grapefruit oil/water emulsions. These properties indicate that FGP is a beta-1,3-linked arabinogalactan with potential as a gum arabic replacement in the food and beverage industries.