Abstract
The Vitis rotundifolia grape species have a very characteristic aroma and flavour and are used in the elaboration of juices, jellies and fermented products, as well as their in natura consumption in the United States. In Brazil, however, they are still little known. Due to the potential of the muscadine grapes for the diversification of viticulture and the scarcity of data concerning the quality of their juice, the objective of this work was to evaluate the physical and chemical profile of juices elaborated with the Vitis rotundifolia grape varieties: Regale, Noble, Summit and Carlos. The study was carried out in Epagri-Videira/SC, Brazil with the 2016, 2017 and 2018 harvests. A double factorial (variety x harvest) experimental design was used in a completely randomized format with three replications. The physicochemical analyses carried out were: total acidity (TA), soluble solids content (SS), SS/TA ratio, pH, reducing sugars, density and colour. In relation to pH, ‘Regale’ and ‘Carlos’ presented values that remained in the range from 2.82 to 2.98, while the values were higher for ‘Noble’ and ‘Summit’, reaching 3.30. The titratable acidity of 'Regale' and 'Noble' juices stood out from the other varieties in both evaluated harvests due to their higher acidity levels. For the 2016 harvest only the juice from the ‘Summit’ variety reached a total soluble solids content of 14.00 ºBrix, the minimum content required for commercialization as a whole fruit juice according to Brazilian legislation. The fruits of this variety obtained the highest SS/TA ratio in the three harvests evaluated, with values close to 30, an inverse behaviour to that of the ‘Regale’ juices, which presented the lowest averages for this variable, with values around 10. The red varieties gave rise to more acidic juices as compared to the white varieties. The ‘Summit’ variety presented the best sugar/acidity ratio, presenting aptitude for juice elaboration in the three harvests surveyed. The ‘Regale’ and ‘Noble’ varieties presented losses in productivity and sanitation in the 2016 harvest, although they were apt for juice production in the 2017 and 2018 harvests. The ‘Carlos’ variety juices did not reach the minimum content of 14 °Brix in any of the three harvests studied, and could not, therefore be classified as whole fruit juices.
Keywords:
Muscadine; Processing; Composition; Quality; Harvest; Elaboration