Antonio Coletta

HPLC-DAD-ESI-MS Analysis of Flavonoid Compounds in 5 Seedless Table Grapes Grown in Apulian Region

UNLABELLED Flavonoids present in skin extracts of red seedless table grape varieties Summer Royal, Autumn Royal, and Crimson, and white seedless varieties Carati and Thompson were analyzed by HPLC-DAD-MS, in 3 y of study (2006 to 2008). The anthocyanins, delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, petunidin-3-O-glucoside (with their corresponding p-coumaroyl derivatives), peonidin-3-O-glucoside, and malvidin-3-O-glucoside (with their corresponding acetyl, caffeoyl, and p-coumaroyl derivatives) were found. In addition the flavonols quercetin-3-O-glucuronide, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-glucoside, kaempferol-3-O-galactoside, and the flavan-3-ols procyanidin B1, procyanidin B2, and catechin were also detected. Anthocyanins were the main flavonoids in red grapes ranging from 24 (Crimson) to 500 (Summer Royal) mg/kg fresh weight of grapes; consistent levels of flavonols and flavan-3-ols were also quantified in all varieties. To determine the effective climatic influence on flavonoids content in field conditions, viticultural practices have been developed, that could exclude the effects of direct solar radiation from confounding the assessment of those related to thermal conditions alone. A strong positive correlation was determined between flavonoids and temperature data that seem to be responsible for the difference of these metabolites along the years; furthermore, it has been possible to define a linear relationship (R(2) = 0.6871, P = 0.0057) between thermal amplitude and total flavonoids values in the red grapes. PRACTICAL APPLICATION Grapes are economically the most important fruit species in the world and approximately 30% of its production is used as fresh fruit. Because of the very important role of flavonoids in food quality as well as their health-promoting properties, and considering that our experiments were performed along 3 consecutive years, gathered results in this research are quite promising to give a useful information on the flavonoid contents and their evolution in 5 seedless table grapes that are widespread in Mediterranean regions but also in California and South America, and are grown in a viticultural climate (Apulia, South Italy) very close to some regions of Spain, Turkey, Tunisia, and Israel.

Analysis of carotenoids in grapes to predict norisoprenoid varietal aroma of wines from Apulia.

To determine a correlation between carotenoid precursors in grapes and norisoprenoid varietal aroma of wine, carotenoids were identified and quantified by HPLC-DAD-MS (ESI+) from four representative wine grape varieties of the Apulian region (Chardonnay, Merlot, Negroamaro, Primitivo) in two years of study (2006-2007), and C13-norisoprenoid aroma potential, DeltaC (microg/kg), was calculated from the difference of total carotenoid concentration between veraison and maturity. C13-norisoprenoids were analyzed by GC-MS in the obtained wines from 2006 and 2007 vintages. Higher DeltaC values, found in Chardonnay and Merlot grapes, corresponded to higher norisoprenoid contents in the respective wines, particularly characterized by highly flavorant compounds such as beta-damascenone and 3-oxo-alpha-ionol. A linear regression was determined that was significant at the 0.01% level (F=36.12, p=0.00096) with R=0.9261, between grape DeltaC values and total norisoprenoid contents in wine. These findings support the hypothesis that DeltaC could be a useful technological tool to predict norisoprenoid aroma of wine and, consequently, to identify grapes with higher aroma potential.

Viticultural practice and winemaking effects on metabolic profile of Negroamaro.

Metabolic profiles of 32 Negroamaro red wines were analysed using (1)H NMR spectroscopy and multivariate statistical analyses (Principal Component Analysis, PCA, and Orthogonal Partial Least Square Discriminant Analysis, OPLS-DA). Among winemaking technologies three were compared: ultrasounds (U; 12 samples), cryomaceration using dry ice (C; 12 samples) and traditional (T; 8 samples). Moreover, each vinification technology was used for grapes grown by two different soil management practices, soil tillage (ST; 16 samples) and cover crop (CC; 16 samples), and by two different training systems, monolateral (M; 16 samples) and bilateral Guyot (B; 16 samples). All statistical models applied on NMR data revealed a good separation between ST (soil tillage) and CC (cover crop), showing a higher influence of the soil management practices compared to the winemaking technologies (ultrasound, cryomaceration and traditional). The differentiation among samples, due to soil management practices, was mainly caused by metabolites such as glycerol, 2,3-butanediol, malic acid, α/β-glucose and phenolic compounds, such as tyrosine and caffeic acid.

Free and bound aroma compounds characterization by GC-MS of Negroamaro wine as affected by soil management†

Negroamaro is an autochthonous wine grape variety of Southern Italy, which is becoming very important for the Italian wine market. The wine aroma is primary affected by the chemical composition of grapes, which can be influenced also by agronomic practices such as soil management. In this study, the free and bound aroma characterization was performed by gas chromatography-mass spectrometry analyses, and the influence of two soil managements (cover cropping and soil tillage) was evaluated. A total of 40 volatile compounds were observed in the wine samples. Alcohols (55.7 mg/L), fatty acids (7.0 mg/L) and esters (6.6 mg/L) were found as the main classes in Negroamaro wine. The results showed that the aroma composition of Negroamaro wine was positively affected by soil tillage probably because of the higher water stress (ψ(s)) recorded in the vines from this treatment. Indeed, among the free volatile compounds, higher contents of esters, carboxylic acids, alcohols, phenolics and acetamides together with lower contents of sulfurs compounds were found in soil tillage wine. Conversely, no difference was observed in glycoside volatile compounds.

Effect of viticulture practices on concentration of polyphenolic compounds and total antioxidant capacity of Southern Italy red wines

This study aims to assess the effect of three wine grape varieties, three training systems and two bud loads on the Total Antioxidant Capacity (TAC) and polyphenolic composition of Southern Italy red wines produced, during two vintages. Overall, Primitivo, Malvasia nera of Brindisi-Lecce and Montepulciano as grape varieties, single Guyot (SG), single spur pruned low cordon (SLC) and single spur pruned high wire cordon (HSLC) as training systems, 8 and 12 buds/plant as bud loads were compared. Significant differences in the polyphenolic families were shown by the grape varieties and by modifying the vine growing practices. Moreover, the results demonstrated that varieties influenced the TAC (indicating the Malvasia as the more effective one), that SLC led to the lowest level of TAC and that 8 buds/plant increased it. The relationship between antioxidant indexes and the concentration of single polyphenolic families was evaluated and the highest correlation was found between the total polyphenols and the proanthocyanidins family.

Effects of Irrigation Volume and Nitrogen Fertilization on Redglobe and Michele Palieri Table-Grape Cultivars

The effects of water management and nitrogen fertilization, on yield, quality, and sensory profile of the red table-grape cultivars Redglobe and Michele Palieri were studied. Two irrigation volumes (1000 and 2000 m3/ha) and two nitrogen levels (120 and 180 kg/ha) were imposed. The effects of these parameters were cultivar-dependent. For Redglobe, irrigation resulted in significant increases in soluble solids and titratable acidity and significant decreases in resistance to compression and resistance to penetration. Increased nitrogen fertilization level exerted a significant effect only on titratable acidity (increased) and resistance to compression (decreased). Significant interactions between the two practices were demonstrated for soluble solids, pH, and resistance to compression. For Michele Palieri, increased irrigation resulted in significant decreases in soluble solids and resistance to penetration and significant increases in resistance to compression. Higher nitrogen caused decreases in berry weight but increases in soluble solid content and resistance to mechanical stress. Significant interactive effects were highlighted on yield, cluster weight, titratable acidity, and resistance to penetration. The lack of a significant correlation between physical/chemical and sensory results indicated that the changes induced by the agricultural practices on composition and mechanical behavior of berries were not perceptible by a trained panel.