Modeling of the evolution of phenolic compounds in berries of “Italia” table grape cultivar using response surface methodology

Phenolic Composition of Brazilian BRS Carmem (Muscat Belly A × BRS Rúbea) Grapes: Evaluation of Their Potential Use as Bioingredients

The BRS Carmem grape was developed as an alternative for processing juices and wines. This study aimed to determine the phenolic compounds (PC) in the edible parts of this grape from two harvests-one harvested at ideal maturation time and another when the grapes were still immature-using HPLC-DAD-ESI-MS/MS. Student's t-test was used (α = 0.05) to evaluate differences in the PC content between the edible parts and between the harvests. Both skins showed a predominance of flavonols, anthocyanins, hydroxycinnamic acids derivatives (HCAD) and stilbenes, with higher concentrations for harvest 1 than harvest 2. For both harvests (harvest 1 and harvest 2), the HCAD (mg of caftaric acid•kg fruit^-1) was higher in whole grapes (383.98 and 67.09) than in their skins (173.95 and 21.74), with a predominance of trans-caffeic acid for all samples; the flavan-3-ols and proanthocyanidins (mg of (+)-catechin•kg fruit^-1) presented higher concentrations in the seeds (flavan-3-ols: 203.20 and 182.71, proanthocyanidins: 453.57 and 299.86) than in the skins (flavan-3-ols: 1.90 and 4.56, proanthocyanidins: 37.58 and 98.92); the stilbenes concentration (µg 3-glc-resveratrol•kg fruit^-1) was higher for the seeds from harvest 2 (896.25) than those from harvest 1 (48.67). BRS Carmem grapes contain a phenolic composition complex, and still have a relevant concentration of flavonols, anthocyanins and stilbenes, even when immature.

Influence of Berry Ripening Stages over Phenolics and Volatile Compounds in Aged Aglianico Wine

The harvest time of grapes is a major determinant of berry composition and of the wine quality, and it is usually established through empirical testing of main biochemical parameters of the berry. In this work, we studied how the ripening stage of Aglianico grapes modulates key secondary metabolites of wines, phenolics and volatile compounds. Specifically, we analyzed and compared four berry ripening stages corresponding to total soluble solids of 18, 20, 22, and 25 °Brix and related aged wines. Wine color intensity, anthocyanins level and total trans-resveratrol (free + glycosidic form) increased with grape maturity degree. Wines obtained from late-harvested grapes significantly differed from the others for a higher content of aliphatic alcohols, esters, acetates, α-terpineol and benzyl alcohol. The content of glycosidic terpene compounds, such as nerol, geraniol and α-terpineol, was higher in wines obtained with grapes harvested at 25 °Brix compared to the earlier harvests. Our work indicated that the maturity of the grape is a determining factor in phenolic and volatile compounds of red Aglianico wines. Moreover, extending grape ripening to a sugar concentration higher than 22 °Brix improves the biochemical profile of aged wine in terms of aroma compounds and of phytochemicals with known health-related benefits.

Vineyard protection with rain-shelter: relationships between radiometric properties of plastic covers and table grape quality

The rise of unpredictable, heavy rainfalls increases incidence of diseases, berry rot, berry cracking, and enhance the need for rain shelters. The influence of the type of rain shelter on microclimate and grape quality is still little explored. The aim of this trial was to investigate the radiometric properties of a new type of cover, its effect on vineyard microclimate and on table grape quality, as compared with a reference cover, during a vintage with unusually abundant precipitation for Southern Italy. The new cover was characterized by lower transmissivity to IRshort radiation, and by a very higher transmissivity to UV radiation. It showed a tendency to decrease air temperature by 1 °C, increase RH by 2–3%, reduce VPD, and improve vine water status with respect to the reference. At harvest, grapes covered with the new sheet had higher TSS concentration, TSS / TA ratio, total skin polyphenol and flavonoids content, and berry skin resistance to rupture. Those berries, moreover, increased the level of volatile compounds such as linalool, typical of ‘Italia’ muscat aroma, and terpineol.