Maturation and quality of 'BRS Magna' grapes influenced by rootstocks in rainy season

Seasonal variations and production factors can influence the quality of grapes. Considering the Sub-middle region of the São Francisco Valley, Brazil, differentiated by production in rainy and warmer periods of the year, the climatic conditions in each season affect the duration of the phenological phases and quality of the grapes. The objective of this study was to characterize the changes in the quality components during maturation of 'BRS Magna' grapes on different rootstocks, in rainy seasons under tropical conditions, as a support to define the harvest time. The experiment was conducted in Petrolina, Pernambuco, Brazil, from Jan to Apr 2017 (cycle 1) and Dec 2017 to Apr 2018 (cycle 2) evaluating rootstocks and age of the fruits. Bunches were picked from the start of maturation to the harvest: 49, 56, 61, 64 and 68 days after fruit set (DAF) for cycle 1, and 35, 41, 48, 55, 61, and 66 DAF for cycle 2. In cycle 1 'IAC 572' and 'Paulsen 1103' rootstocks provided higher sugar contents in grapes, which was only repeated in cycle 2 for 'Paulsen 1103'. The accumulation of anthocyanins and yellow flavonoids was favored by 'IAC 313' and 'IAC 572' rootstocks in cycle 1, and by 'IAC 313' and 'IAC 766' in cycle 2. A higher content of polyphenols was conferred on 'IAC 572' in cycle 1 and on 'IAC 766' in cycle 2, which also had a greater antioxidant capacity. Although there were differences between rootstocks, harvesting at approximately 64 DAF maximized grape quality for all treatments.(AU)

Analysis of the phenolic composition and yield of 'BRS Vitoria' seedless table grape under different bunch densities using HPLC-DAD-ESI-MS/MS.

Grapes are considered to be a major source of phenolic compounds as compared with other fruits. To improve the quality of table grapes, some techniques like thinning can be used. In addition, grape cultivars with distinct characteristics are directly linked to its phenolic profile. This study aimed to identify and quantify the phenolic compound profile and yield of the hybrid 'BRS Vitoria' seedless table grape under different bunch densities, using a combination of solid-phase extraction (SPE) methodologies and analytical high-performance liquid chromatography-diode array detector with tandem mass spectrometry (HPLC-DAD-ESI-MS/MS). A trial was carried out in 2016, in a commercial vineyard at Marialva, state of Parana (South Brazil). Three weeks after anthesis, the following bunch densities were evaluated: 4.0, 4.5, 5.0, 5.5, and 6 bunches per m2 (corresponding to an estimation of 16, 18, 20, 22, and 24 tons ha-1). The randomized block design was used as a statistical model with each treatment was replicated four times, with one vine per plot. Different characteristics were evaluated at harvest, e.g., soluble solids content (SS), total acidity (TA), maturation index (MI = SS/TA), bunch and berry masses, yield, as well hydroxycinnamic acid derivative (HCAD), anthocyanin, flavonol, and flavan-3-ol contents by HPLC-DAD-ESI-MS/MS analysis. The evaluated bunch densities did not interfere with the physicochemical characteristics of the berries, such as SS and MI. Under the density of 6.0 bunches per m2, the highest yield of 25 tons ha-1 was reached. Under all bunch densities, the phenolic profile presented the same compounds, but at different concentrations. Under a density of 5.0 bunches per m2, the compounds belonging to the anthocyanin and flavonol families were present in high concentrations. In contrast, at the densities of 4.0 and 4.5 bunches per m2, there was a reduction in the flavan-3-ol content. With respect to stilbenes, only the trans-piceid and its cis- isomer were detected. However, their concentrations had no significant influence on the evaluated bunch densities.

Grape juices produced from new hybrid varieties grown on Brazilian rootstocks - Bioactive compounds, organic acids and antioxidant capacity.

The objective of this study was to assess the content of bioactive compounds, organic acids and antioxidant capacity of grape juices from Isabel Precoce, BRS Carmem, BRS Cora and IAC 138-22 Máximo varieties grown on the 'IAC 766' and 'IAC 572' rootstocks under tropical conditions in Brazil. In general, the color attributes of the 'Isabel Precoce' juice were inferior to those of the other juices due to their low anthocyanin content. In contrast, 'IAC 138-22 Máximo' juices showed the highest content of most individual anthocyanins, flavonols, trans-resveratrol and total phenolic compounds, and thus, higher antioxidant capacity. Except for 'BRS Carmem', all the juices presented higher sugar accumulation when 'IAC 766' was used. This rootstock also contributed to the accumulation of t-resveratrol and most of individual anthocyanins in the 'IAC 138-22 Máximo' juices. However, the monomeric anthocyanin content was higher in 'BRS Carmem' juices when 'IAC 572' rootstock was used.

Rapid determination of the aromatic compounds methyl-anthranilate, 2'-aminoacetophenone and furaneol by GC-MS: Method validation and characterization of grape derivatives.

A methodology for the rapid determination of the aromatic compounds methyl anthranilate (MA), 2'-aminoacetophenone (2-AAP) and furaneol by GC-MS was validated and used to characterize grape juice and wine elaborated with the new Brazilian grape varieties cultivated in northeastern Brazil, and Brazilian grape nectars. The method presented linearity (R2 ˃ 0.9952), good accuracy (CV < 12.9%), recovery (76.6% to 106.3%), limit of detection (23 µg L-1 to 94 µg L-1) and limit of quantification (96 µg L-1 to 277 µg L-1) acceptable in only 20 min of running. The methodology was considered satisfactory for the purpose, being a simple and rapid method for the determination of these compounds in grape derivatives drinks. In the characterization of the nectars the compound that stood out was the MA, being its presence attributed to the addition of flavorings in these products. It was evidenced a significant contribution of furaneol in the aroma of grape juice and wines elaborated with the new Brazilian grape varieties.