1,721,009 research outputs found
The use of chitosan to control (+)-catechin oxidation: hypothesis for its use in reduced sulfur dioxide winemaking practices
No full textChitosan is an additive used in the food industry thanks to its proven anti-microbial, chelating and anti-oxidant activities. In 2011, the EU inserted chitosan to the list of additives permitted for use in winemaking practices to stabilize proteins, for microbial control and for the reduction of contaminants and heavy metals. However, even today, there are few studies with regards to the antioxidant capacity of this molecule in matrices similar to wine.
In this study the efficacy of chitosan, in controlling the oxidation of (+)-catechin in a synthetic white wine under notable oxidative conditions, was tested and compared to that of sulfur dioxide, glutathione and ascorbic acid. The formation of intermediate oxidation compounds was determined using chromatographic HPLC-DAD-MS analyses and spectrophotometry. The results showed that chitosan had a notable capacity to delay the oxidative degradation of (+)-catechin and that this phenomena can be the result of mechanisms that involve the chelation of metals, the absorption of intermediate molecules and an anti-radical activity. The presence of chitosan also contributed to limit the oxidation of the thiol components found in the model solutions tested in this study. Based on the results obtained it is possible to propose chitosan as a potential additive capable to complement or substitute sulfur dioxide in winemaking processes aimed at reducing the sulfite content of white wines
Radical Scavenging Activities of peels and pulps cv. Golden Deliciuos as related to their phenolic composition
No full textDiscrimination of some European vinegars with protected denomination of origin as a function of their amino acid and biogenic amine content
No full textBACKGROUND: Twenty-three amino acids and 11 amines were quantified in 37 premium quality European vinegars (traditional balsamic vinegar of Modena, balsamic vinegars of Modena and vinegars of Jerez) by an HPLC-DAD method after derivatisation with diethyl ethoxymethylenmalonate. Data were assessed in the light of the differences in technology and raw materials. RESULTS: The total amount of amino acids ranged from 136 mg kg-1 to 1450 mg kg-1 in traditional balsamic vinegar of Modena and balsamic vinegar of Modena, respectively. Jerez vinegars had a mean content from 351 mg kg-1 to 921 mg kg-1. Proline, glycine and γ-aminobutyric acid were the main amino acids while isoleucine was only found in balsamic vinegar of Modena at a concentration of <1 mg kg-1. Traditional balsamic vinegar of Modena had the lowest amount of biogenic amines. However, for all the vinegars, their concentration did not raise health issues. Based on the entire dataset, samples were successfully segregated and classified by means of principal component and cluster analysis. CONCLUSION: The amino acid and amine content in vinegars is influenced by the production process and raw materials. They may potentially contribute in characterising the European premium quality vinegars also for authentication or anti-fraud purposes
Changes in phenolic composition of red wines aged in cherry wood
Full text linkThe evolution of low molecular weight phenolic compounds in red wines aged in cherry (Prunus avium)
or oak (Quercus petrae) wood has been investigated. In addition, the phenolic composition of hydroalcoholic
extracts of cherry heartwood has been characterized and quantified by means of HPLC-DAD/MS
analysis.
More than 20 phenolic compounds, constitutive of cherry wood, were identified, including flavanols,
flavanones, flavanonols, flavonols and flavones. During ageing, some of these compounds (eryodictiol,
sakuranetin, pinocembrin and chrysin) were transferred to the wines and may represent putative
phenolic markers of the usage of this wood specie.
The phenolic composition of wines was significantly affected by the different woods, the cherry
barriques promoting the fastest evolution of (þ)-catechin, procyanidins and flavonols if compared to oak.
Our findings confirmed that cherry wood is highly oxidative towards wine phenolics but, at the same
time, suggested that a portion of those phenols are involved in condensation phenomena able to stabilize
both the tannins and the pigments of the aged red wines
Volatile and fixed composition of sulphite-free white wines obtained after fermentation in the presence of chitosan
Full text linkConsumers are increasingly interested in healthier wines containing reduced levels or totally absent of sulphites. In the present investigation distinct fermentations of white musts either in the presence of chitosan or sulphur dioxide were carried out in order to compare the volatile and fixed composition of the wines produced, and evaluate the impact of chitosan as an alternative to sulphur dioxide. Chitosan promoted a 24 h extended lag-phase and diminished the titratable acidity of wines by about 1 g L−1 as a consequence of the absorption of tartaric and malic acids onto the polymer surface. The volatile composition of wines was analysed at the end of the alcoholic fermentation and then after 12 months of storage in glass bottle. Hexanoic, octanoic and decanoic acids were significantly higher in chitosan added wines, which further contained an increased amount of ethyl and acetate esters. Results demonstrated that, when added before the alcoholic fermentation, chitosan may affect both the acidic and volatile composition of wines, likely due to its polycationic behaviour and interaction with yeast wall constituents. This also suggests that attention to wine acidic balance should be paid before its use in other vinification steps such as must clarification or wine fining
Sensory and Volatile characterization of Australian White wines from cv. Verdelho produced in the Queensland Granite Belt region
No full textVerdelho is a white-grape-vine, traditionally used in Madeira wine production, which grows well in the Granite Belt region of the Australian state of Queensland, where it usually originate dry white wines. In this work, a complete volatile characterisation of Verdelho wines from the 2012 vintage produced in the Granite Belt region was carried out. Volatile compounds were isolated by Solid Phase Extraction (SPE), and identified and quantified using Gas Chromatography-Mass Spectrometry analysis (GC-MS). At the same time, a corresponding sensory characterisation of this distinctive Australian wine style has been investigated, by subjecting the most characteristic wines to a sensory descriptive analysis. The chemical compounds that mostly contributed to the flavour of these Verdelho wines were related to fruity sweet notes (ethyl esters and acetates), grass notes (3-hexenol), floral aromas (2-phenylethanol and β-linalool) and cheesy aromas (fatty acids). The results from sensory analysis confirmed that all the Verdelho wines analysed were characterised by fruity aroma attributes, especially of “tree-fruit” and “rockmelon”, together with “herbaceous”, while some significant differences in the other sensory attributes were found between samples
Influence of canopy-applied chitosan on the composition of organic cv. Sangiovese and Cabernet Sauvignon berries and wines
No full textThe effects of canopy-applied chitosan on grapes and derived wine were evaluated in an organically managed mature vineyard. The experiment was performed on Sangiovese and Cabernet Sauvignon red grape cultivars, the application of a chitosan solution was compared to water spraying. Each treatment was applied 3 times (beginning and end of veraison, and pre-harvest) in a randomized block experimental design. Significant differences in (+)-catechin, (-)-epicatechin and procyanidin B2 amounts in berries and wines were detected in Cabernet Sauvignon but not in Sangiovese. Chitosan did not influence the berry skin anthocyanin and flavonol amount or t-resveratrol concentration in both skins and wines. A considerable increase in γ-aminobutyric acid (GABA), together with some other amino acids, ammonium and amines was observed in the berry flesh of cv. Cabernet Sauvignon. The increase in phenolic acids and nitrogenous compounds, especially GABA, in the pulp of Cabernet Sauvignon grapes suggests changes in stress response
Characterisation of Australian Verdelho wines from the Queensland Granite Belt region
No full textVerdelho is a white-grape-vine, growing well in the Granite Belt region of Queensland. Despite its traditional use in Madeira wine production, there is scant literature on the flavour characteristics of this variety as a dry wine. In this work, for the first time, volatile compounds of Verdelho wines from the Granite Belt have been isolated by solid phase extraction (SPE), and analysed using gas chromatography-mass spectrometry (GC-MS). A corresponding sensory characterisation of this distinctive wine style has also been investigated, using sensory descriptive analysis. Chemical compounds that mostly contribute to the flavour of these wines were related to fruity sweet notes (ethyl esters and acetates), grassy notes (3-hexenol), floral aromas (2-phenylethanol and β-linalool) and cheesy aromas (fatty acids). Sensory analysis confirmed that the Verdelho wines were characterised by fruity aroma attributes, especially “tree-fruit” and “rockmelon”, together with “herbaceous”, while significant differences in the other attributes were found
- …
