Fruit quality, nutraceutical and antimicrobial properties of 58 muscadine grape varieties (Vitis rotundifolia Michx.) grown in United States.

Fifty-eight muscadine grape varieties were evaluated for their fruit quality, nutraceutical, and antimicrobial properties during two growing seasons (2012 vs. 2013). Fruit quality was significantly different among muscadine grape varieties, with weight ranged from 2.93 to 22.32g, pH from 3.01 to 3.84, titratable acidity from 0.27% to 0.83%, and °Brix from 10.92 to 23.91. Total phenols for different muscadine juices varied from 0.26 to 1.28mgGA/mL, skins from 10.13 to 30.02mgGA/g DM, and seeds from 22.47 to 72.01mgGA/g DM. Accordingly, the antioxidant activity of grape juices varied from 0.97 to 6.78mmolTrolox/mL, skins from 83.59 to 221.20μmolTrolox/g DM, and seeds from 178.22 to 619.73μmolTrolox/g DM. Study demonstratedgrape seed polyphenols (MIC 54.8-60.1μg/ml) showed stronger antimicrobial activity against S. aureus than skin polyphenols (MIC 70.7-80.2μg/ml). This information could be a valuable asset in the research and extension of muscadine grapes.