Muscadine Grape Skin Research Articles

Antiinflammatory Properties of the Muscadine Grape (Vitis rotundifolia)

The muscadine grape possesses one of the highest antioxidant levels among fruits; yet, the effect of this fruit on mammalian metabolic systems has not received significant attention. To examine the antiinflammatory properties of the muscadine, grape skins were dried, pulverized, and extracted (10% w/v) with 50% ethanol. The extract was then tested in two different assays: the release of superoxide in phorbol myristate acetate-activated neutrophils and the release of cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-beta), and interleukin-6 (IL-6)] by lipopolysaccharide-activated peripheral blood mononuclear cells. The release of superoxide and cytokines was inhibited by increasing concentrations of the extract. A 1:100 dilution of the extract inhibited superoxide release by approximately 60% while the release of TNF-alpha and IL-1beta was reduced at a dilution of 1:200 by approximately 15 and 90%, respectively (all P < 0.05). The inhibition pattern on the release of IL-6 was similar to that seen with TNF-alpha. In a related in vivo study, rats were fed a diet containing 5% (wt/wt) dried muscadine grape skins for 14 days and then were injected with carrageenan in the foot pad. After 3 h, paw edema was measured and the rats on the grape skin diet had approximately 50% less paw edema than controls (P < 0.05). These results demonstrate that the muscadine grape skin powder possesses significant in vitro and in vivo antiinflammatory properties.

Formation and occurrence of flavor components in Noble muscadine wine

Flavor development in Noble muscadine wine during fermentation and aging was determined with a combined gas chromatograph-mass spectrometer. The source of 2-phenylethanol, a major aroma component of the wine, is predominantly through biosynthesis during the vinification process, although the alcohol was also found to be present in fresh muscadine grape skin. The involvement of substituted benzene derivatives in the formation of phenyl ethanol during fermentation and aging of wines is proposed. The complexity of the volatile aroma extracts increased with time, especially after fermentable sugars were exhausted. Anaerobic formation of fatty acid esters also commenced after active fermentation had ceased. These compounds constitute major components of the aged muscadine wine. Effluent sniffing indicated that many odorous compounds including phenyl ethanol and methyl succinate contribute significantly to the muscadine wine aroma.