Giuseppina Paola Parpinello

Characterisation of peach juices obtained from cultivars Redhaven, Suncrest and Maria Marta grown in Italy

Abstract The compositions of three peach juices obtained from the cultivars Redhaven, Suncrest and Maria Marta, respectively, were studied. The fruits were grown in the Emilia-Romagna region (Italy). The juices were characterised by pH, CIE L *, a *, b * colour values, soluble solids, individual carbohydrates, organic acids, and phenolic compounds. Univariate analysis disclosed some significant differences among the compositions of the varietal peach juices. Principal component revealed clear group structures in the data matrix, the most relevant variables being glucose, fructose, sorbitol, malic acid, L * and b *-values. Suncrest peach juice was clearly distinguished from Redhaven and Maria Marta juices.

Concentration of Grape Must by Nanofiltration Membranes

In this study the selectivity of two nanofiltration (NF) membranes was tested with the aim of increasing the sugar content of grape must used for wine production. The composition of grape must, concentrate, permeate and the rejection values for selected physicochemical parameters is presented. In particular, the NF membranes provided a high rejection for sugars (range 77–97%), whereas the malic acid was retained to a low extent (range 2–14%). A two-stage NF process of grape must remove a permeate volume of 14%, thus allowed concentration of the sugars, i.e. the potential alcohol, to ca. 16%. The wine obtained from a grape must treated by NF membrane was high in total plyphenols and DO (optical density) at 420 nm.

Targeted analysis of bioactive phenolic compounds and antioxidant activity of Macedonian red wines.

Phenolic composition of twenty-two Macedonian red wines, including ten autochthonous monovarietal Vranec wines produced with different yeasts for fermentation, and twelve wines from international varieties (Syrah, Merlot and Cabernet Sauvignon) from different wine regions was studied. All wines presented relatively high value of total phenols and antioxidant activity. A total of 19 phenolic compounds were identified and quantified using HPLC-DAD and among them, malvidin-3-glucoside and its derivatives were the major compounds, followed by the petunidin derivatives, while caftaric acid was the predominant cinnamic acid derivative in all wines. The anthocyanin content was mainly affected by the grape variety and to a less extent by the yeast used in fermentation. In particular, the use of locally isolated yeasts affected higher amount of anthocyanins and phenolic acids compared to the wines fermented with commercial yeasts. Principal Component Analysis showed a satisfactory grouping of red wines according to the grape variety.

Effect of micro-oxygenation on sensory characteristics and consumer preference of Cabernet Sauvignon wine.

BACKGROUND The main objective of this study was to improve the structure of a Cabernet Sauvignon red wine in a short period of time by micro-oxygenation (MOX) at high rates (25 and 50 mL L(-1) month(-1) ), the effects of which were evaluated based on sensory characteristics and consumer preference. Sensory data were analysed by principal component analysis, discriminant analysis and ordinal logistic regression (OLR). RESULTS MOX led to significant differences in the colour, colour stability and phenolic compounds of wine. Sensory characteristics also changed through MOX treatment, and wine experts were able to discriminate between MOX-treated and untreated samples, with olfactory intensity, complexity, astringency and roundness being the main discriminating characteristics. Ordinal logistic regression enabled identification of the sensory characteristics that drove consumer preference. CONCLUSION MOX at high rates improved the sensory characteristics of wine and may therefore be considered a valid technique for obtaining structured wines in a short period of time, i.e. within just a few months after the vintage. The results highlight the need for (i) careful selection of the MOX dosage rate and duration (the 25 mL L(-1) month(-1) dose for 6 days provided the best result) and (ii) continuous monitoring of the MOX treatment.

Phloretin Glycosides: Bioactive Compounds in Apple Fruit, Purées, and Juices

ABSTRACT Phloretin glycosides are bioactive compounds naturally present in apple fruits. The highest amount of phloretin glycosides was significantly found in apple pureées and commercial juices as a consequence of the processing conditions.

Qualitative discrimination between organic and biodynamic Sangiovese red wines for authenticity

In this study the ability of the droplet evaporation method (DEM) to discriminate between organic and biodynamic Sangiovese red wines was studied for the first time. The relationship between the sizing-parameters and shape-descriptors of the crystal structures and the chemical parameters of wines was evaluated, and the most significant correlations were found between the intensity of red color of wines with circularity (r = 0.90) and solidity (r = 0.94). Moreover the shape-descriptors allowed a discrimination between the organic and biodynamic Sangiovese red wines based on two kinds of structures: (i) needle-like and (ii) flower-like forms.

Effects of late defoliations on chemical and sensory characteristics of cv. uva longanesi wines

In this study we investigated the effects of late leaf removal on the berry and wine composition and on wine sensory characteristics of Uva Longanesi, a late maturing red Italian grape variety, which wines are characterized by high levels of alcohol and excessive astringency, the latter apparently intensified by late defoliation practices. During 2008 season, spur-pruned trained vines were submitted to manual defoliation (4 basal leaves) at the onset (DEF I, 210 DOY) or at the end (DEF II, 231 DOY) of veraison and compared with non-defoliated plants (CON). On every DEF II vine, since defoliation until harvest, a cluster was shaded (DEF II + shading). A decrease of the berry soluble solids and skin anthocyanins was found in DEF I vines. Defoliation modified composition and sensory characteristics of wine with DEF II having higher alcohol strength and astringency compared to DEF I, whereas CON wines displayed intermediate values. The practice and timing of partial late defoliation greatly affected the chemical and sensory attributes of wine.

Characterization of Uva Longanesi Red Wine by Selected Parameters Related to Astringency

This research represents a first attempt to chemically characterize wines produced from the autochthonous grape variety, Uva Longanesi, based upon the phenolic compounds responsible for its high astringency as confirmed by preliminary sensory analysis. In addition, a wine produced from Sangiovese, the most popular grape variety in the Emilia-Romagna region, was analyzed for comparative purposes. Results showed that Uva Longanesi wine had a higher pH, alcohol concentration, and total dry extract than the Sangiovese wine. With regards to phenolic constituents, the Uva Longanesi wine had higher color parameters and greater concentrations of total phenolics, including monomeric anthocyanins, small polymeric pigments, and tannins. The phenolic composition of Uva Longanesi wine was found to be responsible for the high reactivity of the wine during fining trials.

Grape Maturity, Yield, Quality, Sensory Properties, and Consumer Acceptance of Fiesta and Selma Pete Dry-on-Vine Raisins

Timely cane severance is the critical first step in the dry-on-vine (DOV) raisin-making process. If canes are severed too early, the berries will have insufficient soluble solids, limiting yield and grade, but if the canes are severed too late, then the grapes will not dry sufficiently. Further, grape maturity at drying may affect the sensory attributes of the raisins, and therefore consumer acceptance. Thus, production studies were conducted over three seasons to determine the relationship between grape maturity and the yield and quality of DOV raisins made from two important DOV raisin grape (Vitis vinifera L.) cultivars, Fiesta and Selma Pete. Additionally, sensory attributes, and consumer acceptance, of “B and better” raisins made from low or high maturity raisins of each cultivar were conducted in one year. There was a positive curvilinear relationship between berry soluble solids level and raisin grades, comparable to relationships established for tray-dried raisins. However, DOV raisins appeared to achieve higher quality grades than would be expected of tray-dried raisins, especially at soluble solids <18, or >20 Brix. Raisin yield, moisture content, and quality grades varied according to year and cane severance date but, in general, an acceptable balance of these variables was achieved by severing the canes at 19 Brix for Fiesta and 21 Brix for Selma Pete. However, consumer acceptance data suggested that most people prefer Selma Pete raisins and raisins from the most mature Fiesta grapes, all of which were made from grapes with >20 Brix at drying. It may be difficult to consistently achieve 20 Brix and adequate drying of Fiesta, suggesting Selma Pete is the superior variety for DOV raisin production.

Mass Spectral Characterization of Uva Longanesi Seed and Skin Extracts

Polyphenolics in grape seed and skin extracts of Uva Longanesi were analyzed at harvest with selected chromatography techniques. Seed extract of Uva Longanesi was characterized by high content of proanthocyanidins (average 49 g/100 g extract), of which 42% was polymeric and ~28% was oligomeric. Epicatechin comprised the primary extension subunit (~75%), whereas catechin predominated as the terminal unit (~67%); epicatechin-gallate was present in both extension (~11%) and terminal subunits (~9%). As skins matured, terminal unit galloylation decreased and extension unit galloylation increased. The mean degree of polymerization of seed proanthocyanidins was relatively constant (average 2.7 subunits) across the sampling dates.