Influence of Wine-Grape Skin Hardness on the Kinetics of Anthocyanin Extraction

Abstract

The main aim of this work was to study in a model hydroalcoholic solution, containing 12% of ethanol and at pH 3.20, the kinetics of anthocyanin extraction from Vitis vinifera L. cv Nebbiolo berries of different skin hardness. This mechanical property was evaluated as the breaking skin force measured by Texture Analysis, a rapid and low-cost analytical technique. By TAxT2i Texture Analyzer, a puncture test was carried out on two groups of berries separated according to their density by flotation in order to obtain more homogenous samples and minimize the effect of different stages of ripening of the berries. Among the berries containing 242±8 g/L of reducing sugars in the pulp juice, two groups of berries with different skin hardness were selected: soft (0.26±0.04 N) and hard (0.47±0.05 N). In our experimental conditions, at the end of maceration, the extracts from the higher skin hardness group showed the higher contents of total anthocyanin: +25 mg/L (+9.4%). The anthocyanin profile of extracts, obtained at different extraction times, showed no significant differences among the distribution of different anthocyanins. Only in the early phases of dissolution, did the extracts reveal a dissimilar anthocyanin profiles and in the extracts of hard skins higher percentages of cyanidin and peonidin derivatives were present. Additionally, the evolution of skin mechanical properties from veraison to overripe and the influences of biotype on these parameters at harvest are reported in this work.

Modifications in Chemical, Physical and Mechanical Properties of Nebbiolo (Vitis vinifera L.) Grape Berries Induced by Mixed Virus Infection

“…Briefly, the higher the EA% values, the slower and less the dissolution of anthocyanins in the must during maceration (Cagnasso et al, 2008). In contrast, the extraction of anthocyanins from the harder skins of the Nebbiolo grapes is more complete but slower (Rolle et al, 2012).…”

Instrumental Texture Analysis Parameters as Markers of Table-Grape and Winegrape Quality: A Review

“…In fact, from veraison to ripeness, an increase was observed for the berry skin hardness and thickness in Nebbiolo grapes, particularly in the first ripening phases, with a steady value or a slight decrease close to the technological maturity (Rolle et al 2012b). A renewed increase was then observed in overripe berries (Rolle et al 2009a).…”

“…Moreover, in Nebbiolo grapes, variations in the same cultivar can be imputed to clonal differences (Rolle et al 2012b).…”

Varietal Comparison of The Chemical, Physical, and Mechanical Properties of Five Colored Table Grapes

“…[21] The contents of citric, tartaric and malic acid (g kg -1 pulp) were analyzed using an HPLC system (P100-AS3000, grape, as TP) in berry skin and pulp, and total hydroxycinnamic acids (mg caffeic acid kg -1 grape, as HCA) in the pulp. [23][24][25][26] The relative standard deviations (RSD) based on repeated analysis (n=20) of the same sample were 1.14, 1.58 and 1.82 % for TAI, TP and HCA, respectively. [25] The analysis of individual anthocyanins was performed using the same HPLC described above with the Spectra The solvent flow rate was 1 mL min -1 and the column temperature was 20 °C.…”

“…The solvent gradient used was previously reported in the literature. [13,23,24] The identification of the free forms of anthocyanins in berry skin extracts was performed by comparison with external standards. The acylated forms of anthocyanins were identified by matching DAD spectrum and retention time of each chromatographic peak, and by comparing these with available data in the literature.…”