Rootstock for the ‘BRS Magna’ grapevine grown in a tropical region affects the quality of the stored juice

Resumo

The ‘BRS Magna’ grapevine has the advantage of adapting to different regions of Brazil and producing juice of
good quality. However, it is necessary to define the components of the cropping system, such as the rootstock, for each region.
The aim of this study was to characterise the chemical composition and antioxidant capacity of grape juice collected from
‘BRS Magna’ grapevines grown on different rootstock under the tropical conditions of the Sub-middle São Francisco Valley.
The grapes were harvested in the Experimental Area of Bebedouro/Embrapa Semiárido, in Petrolina, Pernambuco, Brazil. The
treatments corresponded to the ‘IAC 766’, ‘IAC 572’, ‘IAC 313’, ‘Freedom’, ‘Paulsen 1103’, ‘Harmony’ and ‘SO4’ rootstock.
The grape juice was prepared from two harvests for evaluation after storage. For each harvest, a randomised block design was
used, with four replications. The quality of the juice varied with the treatment in each storage period. At nine months, the juice
from the first harvest showed a loss of pigment and phenolic compounds, while the juice made with grapes from plants grafted
onto ‘Harmony’ stood out for soluble solids content (SS), colour intensity (CI), anthocyanins, total polyphenol index (TPI) and
antioxidant capacity. Juice from the second harvest was characterised at four months by higher levels of various compounds,
especially the ‘SO4’ treatment for SS, CI, total extractable polyphenols, TPI and antioxidant capacity. Considering storage
potential and the preparation process, the less-vigorous rootstock resulted in better quality juice.