Search results for " grapes"

Physico-Chemical Characterization of an Exocellular Sugars Tolerant Β-Glucosidase from Grape Metschnikowia pulcherrima Isolates

2023

A broad variety of microorganisms with useful characteristics in the field of biotechnology live on the surface of grapes; one of these microorganisms is Metschnikowia pulcherrima. This yeast secretes a β-glucosidase that can be used in fermentative processes to liberate aromatic compounds. In this work, the synthesis of an exocellular β-glucosidase has been demonstrated and the optimal conditions to maximize the enzyme’s effectiveness were determined. There was a maximum enzymatic activity at 28 °C and pH 4.5. Furthermore, the enzyme presents a great glucose and fructose tolerance, and to a lesser extent, ethanol tolerance. In addition, its activity was stimulated by ca…

Analysis of total antioxidant capacity and total phenolic content during ripeting of Sicilian red grapes

2010

Assessment of Postharvest Dehydration Kinetics and Skin Mechanical Properties of “Muscat of Alexandria” Grapes by Response Surface Methodology

2016

The dipping of berries in a dilute solution of sodium hydroxide during a short time was evaluated as pretreatment undertaken prior to convective dehydration of wine grapes. The impact of the sodium hydroxide content and dipping time on weight loss (WL) at different dehydration times was thoroughly assessed using central composite design (CCD) and response surface methodology (RSM). Furthermore, the effects of these two variables were also investigated on the skin mechanical properties of dehydrated grapes. The effect of these two pretreatment factors on the dehydration kinetics and skin hardness was satisfactorily fitted to regression models. The berry pretreatment with low sodium hydroxide…

Ecology and technological capability of lactic acid bacteria isolated during Grillo grape vinification in the Marsala production area

2011

Grapes of the “Grillo” variety, used to produce Marsala wine, were harvested from five vineyards with different climatic and agronomic parameters, in order to obtain a first mapping of lactic acid bacteria (LAB) inhabiting the production area. Marsala base wine production was followed at a large-scale, and also two experimental vinifications, with different lysozyme and SO2 concentrations and in combination, were carried out at pilot-plant scale. LAB communities and conventional chemical parameters were periodically analysed. LAB were found on grapes at an average concentration of about 102 CFU g−1 which decreased during the transformation process. A total of 146 colonies were collected, bu…

DETERMINATION OF THE OPTIMAL MOMENT OF HARVESTING FOR CABERNET SAUVIGNON AND MERLOT GRAPES IN DRĂGĂŞANI VINEYARD

2011

This paper presents an analysis of the main characteristics of black grapes during ripening and determining the optimum moment to harvest the grapes in the vineyard Drăgăşani. Monitoring process of maturation of the grapes has been done on the varieties of grapes for red wines Cabernet Sauvignon and Merlot from Drăgăşani vineyard.

Real-time PCR based procedures for detection and quantification of Aspergillus carbonarius in wine grapes

2008

9 pages, 4 tables, 1 figure.

Plant Response to Saline-Water Irrigation in a Sicilian Vineyard

2012

This chapter presents results of a 3-year field investigation in a vineyard located in Sicily (Mazara del Vallo, Trapani) within the framework of the Project “Evolution of cropping systems as affected by climate change” (CLIMESCO). Soil-plant responses to two saline irrigation waters were determined by measuring soil hydrological characteristics, soil salinity, crop transpiration and stomatal conductance in field plots of a Sicilian vineyard. The results proved that crop transpiration (T r) and stomatal conductance (G s) were significantly affected by soil salinity conditions, expressed by electrical conductivity of soil saturation extract (ECe). Significant reductions in T r and G s were f…

ULTERIORI APPROFONDIMENTI DEGLI EFFETTI DELLA DIMENSIONE DEGLI ACINI SULLA QUALITA’ DELL’UVA NELLA CV CABERNET SAUVIGNON

2012

In this study we reported the results of a second year of study conducted during 2008 season on irrigated Cabernet Sauvignon\ 1103 P vineyard. We addressed the study of whether differences in berry size (within a population of berries from different bunches) would lead to differences in qualitative parameters and whether flowering process can influence berries variability and qualitative parameters. Berries were classified at pea size into two categories according to their equatorial diameter: ≤ 7 mm as small and ≥ 9 mm as large berries. Development of the two berry categories was evaluated from “pea size” (12th June) to harvest (16th September) in terms of berry mass, equatorial berry diam…

ANALYSIS OF TOTAL ANTIOXIDANT CAPACITY AND TOTAL PHENOLIC CONTENT (TP) DURING RIPENING OF TWO SICILIAN RED GRAPES VARIETIES

2011

ANALYSIS OF TOTAL ANTIOXIDANT CAPACITY AND TOTAL PHENOLIC CONTENT (TP) DURING RIPENING OF TWO SICILIAN RED GRAPES VARIETIES During the last decade the interest for polyphenols has increased considerably because numerous epidemiological studies, supported by several short term controlled randomised clinical trials, have suggested associations between consumption of polyphenol-rich food or beverages and the prevention of certain chronic diseases associated with the oxidative stress condition (1). In a our previous study on several samples of Sicilian red wine we found that the total polyphenol parameter can not to characterize the nutraceutical properties of a wine by only because the correla…

Effect of leaf removal and ripening stage on the content of quercetin glycosides in Sangiovese grapes

2021

Quercetin haze has been observed over the last few years in some aged Sangiovese wines. This problem could be due to an excess of the quercetin in the wine. Leaf removal increases the exposition of clusters to sunlight, which may enhance flavonol synthesis in the grapes. In this study, we evaluated the dynamics related to extractable flavonols in grapes grown in three usually defoliated Vitis vinifera (L.) cv. Sangiovese vineyards, whose wines showed quercetin precipitates. The particular structure of the vineyards in which the leaf removal experiments were carried out allowed the influence of vineyard, biotype and rootstock on grape flavonol contents at mid-maturation and technological mat…