Nadia Natali

Gas chromatography-mass spectrometry (GC-MS) characterization of volatile compounds in quality vinegars with protected european geographical indication.

The volatile composition of 26 premium quality vinegars belonging to three different protected geographical indications (traditional balsamic vinegar of Modena, balsamic vinegar of Modena, and sherry vinegar) has been characterized by means of a solid-phase extraction (SPE) gas chromatography-mass spectrometry GC-MS method. Among the about 90 quantified compounds, short-chain fatty acids, furanic compounds, enolic derivatives, and some esters were found to discriminate the samples as a consequence of differences in the extent of Maillard reactions, presence of alcoholic fermentation, or duration of wood aging.

Pre-fermentative replacement of sulphur dioxide by lysozyme and oenological tannins: Effect on the formation and evolution of volatile compounds during the bottle storage of white wines

In this work, the effects on the volatile profile of the pre-fermentative substitution of SO2 with lysozyme and oenological tannins were studied in white wines. At the same time, in order to understand the changes of volatile compounds in SO2-free wines, the evolution of volatiles was evaluated over 1year of storage in bottles. For this purpose, a number of laboratory scale fermentations of SauvignonBlanc musts were carried out and the effects of three variables (SO2, lysozyme and oenological tannins) were investigated by means of GC-MS analysis. Results showed that the replacement of SO2 with lysozyme and oenological tannins influenced the volatile composition of wines at the end of the alcoholic fermentation. Wines fermented with SO2 showed higher total alcohol amounts, while the presence of oenological tannins augmented the level of esters. The presence of SO2 influenced also the alcohols and esters profiles of wines during bottle storage. Moreover, the presence of oenological tannins displayed a positive role in maintaining the amounts of esters over certain levels in wine stored for 1year, likely due to their oxygen scavenging ability. By contrast, acids were less affected by the investigated adjuvants both at the end of the alcoholic fermentation and during the storage time.

Solid‐phase extraction method for determination of volatile compounds in traditional balsamic vinegar

A solid-phase extraction method for the determination of volatile compounds in traditional balsamic vinegar (TBV) has been developed. The optimisation has been carried out using a two-level factorial design expanded further to a central composite design. LiChrolut-EN SPE cartridges were used and the optimised analytical conditions were: 7 g of TBV diluted 1:4, 5 mL of washing water, and elution with 10 mL of dichloromethane. The linear ranges and detection and quantitation limits were adequate for the analysis of the studied compounds in TBV. The accuracy of the method was also studied: recoveries up to 80% and repeatability values lower than 15% were obtained for the majority of the studied compounds. Two TBVs of different age were analysed by the optimised method.

Comparative Changes in Color Features and Pigment Composition of Red Wines Aged in Oak and Cherry Wood Casks

The color features and the evolution of both the monomeric and the derived pigments of red wines aged in oak and cherry 225 L barriques have been investigated during a four months period. For cherry wood, the utilization of 1000 L casks was tested as well. The use of cherry casks resulted in a faster evolution of pigments with a rapid decline of monomeric anthocyanins and a quick augmentation formation of derived and polymeric compounds. At the end of the aging, wines stored in oak and cherry barriques lost, respectively, about 20% and 80% of the initial pigment amount, while in the 1000 L cherry casks, the same compounds diminished by about 60%. Ethyl-bridged adducts and vitisins were the main class of derivatives formed, representing up to 25% of the total pigment amount in the cherry aged samples. Color density augmented in both the oak and cherry wood aged samples, but the latter had the highest values of this parameter. Because of the highly oxidative behavior of the cherry barriques, the use of larger casks (e.g., 1000 L) is proposed in the case of prolonged aging times.

Impact of Wooden Barrel Storage on the Volatile Composition and Sensorial Profile of Red Wine

This study determined the influence of the kind of wood (Allier vs Limousin and Allier vs chestnut), the age (new vs 1 year old Allier oak barriques) and the volume (1000 L vs 225 L ) of Allier oak containers on sensorial profile and volatile composition of a red Sangiovese wine during 360 days of ageing. The greatest sensory differences were found between Allier oak wood and chestnut wood barriques. In chestnut barriques, wines were more fruited and tannic than in Allier where wines were less astringent, more vanilla flavoured and well-balanced. Some differences in chemical composition and sensorial profile were observed in wines aged in used containers with different capacities. The use of containers showed that migration phenomena from wood to wine were more intense in new barriques than in used ones. Therefore, wines aged in new barriques were richer in volatile wood compounds than wines aged in old barriques.

Efficacy of chitosan in inhibiting the oxidation of (+)-catechin in white wine model solutions.

The efficacy of chitosan and sulfites in inhibiting the oxidation of (+)-catechin in aerated model white wines has been compared by monitoring the browning development and the generation of oxidized phenolic compounds. In addition, the protecting effects of these two additives toward the oxidative decay of varietal thiols were investigated. Chitosan effectively contrasted the browning onset in model solutions all along the entire duration of the experimentation. Color development was limited and comparable in both the sulfite and chitosan added samples. Thanks to its polyelectrolyte behavior, chitosan adsorbed up to 80% of the more hydrophilic oxidized phenolic species and chelated 70 and 30% of Fe and Cu added to the solutions, respectively. Thiol oxidation was significantly lowered by chitosan, suggesting that this additive could contribute to maintain the varietal character of wines coming from aromatic grapes and vinified with reduced sulfite amounts.

Evaluation of volatile aldehydes as discriminating parameters in quality vinegars with protected European geographical indication.

BACKGROUND Thirty-six high-quality vinegars with geographical indication belonging to Sherry and Modena areas (vinegars of Jerez, balsamic vinegars of Modena and traditional balsamic vinegars of Modena) with all possible aging periods were analyzed to determine the content of volatile aldehydes. A solid-phase extraction method with in-cartridge derivatization using O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine followed by gas chromatography-mass spectrometry was employed. RESULTS Twenty-two volatile aldehydes were identified and determined in the samples. Analysis of variance provided significant differences among the samples as a function of the type of vinegar, aging time and raw material. Principal component analysis and linear discriminant analysis demonstrated the possibility of discriminating the samples in terms of aging time and raw material. Linear aldehydes and compounds such as furfural, methional, nonenal, hexenal, 2-methylbutanal and i-butyraldehyde were the most significant variables able to discriminate the samples. CONCLUSION Aldehyde content of premium quality vinegars is a function of both ageing time and raw material. Their evaluation could be a useful tool with a view to ascertaining vinegar origin and genuineness.