Mauro De Nisco

Berry morphology and composition in irrigated and non-irrigated grapevine (Vitis vinifera L.).

The present study was carried out in a 5-year-old vineyard (Vitis vinifera L., cv. Aglianico) located in Southern Italy. Half of the plants (IRR) were fully irrigated, whereas the other half were not irrigated (NIRR). In both of the treatments, plant water status, gas exchange, photosynthetic efficiency and productive performance were determined. The arid conditions resulted in significant decreases in stem water potential in NIRR (minimum values of -1.34 and -1.52 MPa in IRR and NIRR, respectively). The values of yield per plant, cluster weight and total berry weight were significantly higher in IRR. Grape berries were separated into four weight classes, and morphometric and microscopic analyses were carried out to measure and calculate berry skin characteristics. Irrigation determined a marked shift toward heavier (+23% in the class ≥ 1.25 g) and bigger (336.35 mm³ vs 299.15 mm³) berries, and induced significant changes in other morphometric berry parameters. No differences among berry weight classes and irrigation treatments were observed for berry skin thickness. In all of the berry weight classes, total anthocyanins extracted from berry skins were significantly higher in NIRR than in IRR (12301.53 and 9585.52 mg kg⁻¹ fresh berry skin, respectively), and appeared to be positively related to berry weight, whereas total flavonols were not significantly different between the two treatments. Qualitative changes in the levels of single anthocyanin and flavonol compounds were detected between IRR and NIRR. In addition, iron, copper and zinc, whose high concentration can negatively affect wine quality, were significantly higher in the IRR treatment. The results highlighted that the absence of irrigation did not determine decreases in grape quality. Such data can be of primary importance in environments where water availability is by far the most important limiting factor for plant growth.

d-Glucosamine in a chimeric prolinamide organocatalyst for direct asymmetric aldol addition

O-TBDPS D-glucosamine coupled with l-proline is reported to act as an efficient organocatalyst in the accomplishment of direct aldol reactions. Excellent results, in terms of chemical yields, as well as diastereomeric and enantiomeric ratios, are reported for the catalyzed additions of cyclohexanone and acetone to variously substituted benzaldehydes.

Anthocyanin composition and extractability in berry skin and wine of Vitis vinifera L. cv. Aglianico

BACKGROUND The present article reports the anthocyanin content in the berry skin and wine of the Italian red grape cultivar Aglianico (clone VCR11 grafted onto 1103 Paulsen), one of the most ancient vines and famous for its deep-red colour. Anthocyanins were extracted from frozen berry skin in an acidified methanol solution. The extraction mixtures, monitored for 120 h, were analysed by high-performance liquid chromatography. RESULTS The extraction from berry skin of delphinidin, petunidin and malvidin appeared to be a time-independent process, whereas the concentration of peonidin increased linearly with time. Peonidin-O-acetyl-glucoside was transferred from skin more slowly than petunidin-O-acetyl-glucoside and malvidin-O-acetyl-glucoside. The anthocyanin composition of the resulting wine showed that the total anthocyanin content was about one-tenth of the corresponding berry skin content. The ratio acetyl/coumaroyl anthocyanins in the wine was sharply higher than the value in berry skin (0.85 and 0.10, respectively), indicating an enrichment of acetyl derivatives in the wine. CONCLUSION Levels of single anthocyanins in wine were not always correlated with those detected in grapes, as they were affected by winemaking. The high values of some anthocyanins in Aglianico wine could ameliorate its quality, increasing the chromatic properties, aging stability and product acceptance.

Chemistry of ethanediyl S,S-acetals 6- An example of vicarious nucleophilic substitution of hydrogen in 1,4-benzodithians☆

Abstract 1,4-Benzodithians, when treated with bromine in anhydrous chloroform, undergo very fast monobromination at the aromatic ring. By the use of quantum mechanical semiempirical calculations, the reaction is shown to proceed most likely via a vicarious nucleophilic substitution of hydrogen.

A general route to D- and L-six-membered nucleoside analogues.

A simple synthetic route for novel L-(as well as D-) six-membered nucleosides is described. Particularly, we have provided a general approach to the synthesis of azasugar-based nucleosides, which preparation has been easily achieved starting from the coupling of our three carbon homologating agent 1 with the well known Garner aldehyde 4 . Further suitable and stereocontrolled functionalizations of the intermediate 9 will provide, after the base insertion, a wide class of six membered modified azanucleosides to be tested as NRTIs.