Nutraceutical Changes in Muscadine Grape and Grape Segments During Storage

Fresh-market muscadine (Vitis rotundifolia Michx.) cultivars, such as 'Supreme', have reportedly improved postharvest storability. Physiochemical attributes and nutraceutical compounds in 'Supreme' muscadine whole grape berries and grape segments (flesh [skin and pulp] and seeds) were measured at harvest in 2012 and 2013 and nutraceutical compounds were measured during postharvest storage for 6 weeks at 2 degrees C in 2012. Total anthocyanins, ellagitannins, and flavonols in whole berries and flesh were higher than seeds, while total phenolics and Oxygen Radical Absorbance Capacity (ORAC) were higher in whole berries than the flesh and seeds. Anthocyanins were present in the whole berries and the flesh, but not in the seeds. Total ellagitannins were distributed with 81% in flesh and 19% in seeds. Total flavonols were found 90% in flesh and 10% in seeds and total phenolics were present 55% in flesh and 45% in seeds. In 2012, 48% of ORAC was accounted for in flesh and 52% in seeds, conversely in 2013, 63% was in flesh and 37% in seeds. Resveratrol was almost completely found in flesh (96%) with the remaining 4% in seeds. Postharvest storage did not dramatically impact nutraceutical components in the whole berries or the segments. Total anthocyanins were negatively correlated with total ellagitannins (r = -0.94) and total flavonols (r = -0.88). Total ellagitannins were positively correlated with total flavonols (r = 0.97). ORAC was positively correlated with total phenolics (r = 0.88). Both the discovery that postharvest storage of muscadine grapes did not dramatically impact nutraceutical components in the whole berries or the segments and the identification and quantification of nutraceutical components in berry tissues provides additional information on nutraceuticals in this underutilized fruit.