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High performance anion exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD) was optimised in order to quantify mannose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose and maltoheptaose content of beer. The method allows the determination of above mentioned oligosaccharides, in a single chromatographic run, without any pre-treatment. Limit of detection and limit of quantification were suitable for beer. Accuracy and repeatability were good for the entire amount considered. Once optimised HPAEC PAD for the specific matrix, the second goal of this research was to verify the possibility to discriminate beers, depending on their style. The carbohydrates content of brewpub commercial beers was very variable, ranging from 19.3 to 1469mg/L (mannose), 34.5 to 2882mg/L (maltose), 141.9 to 20731mg/L (maltotriose), 168.5 to 7650mg/L (maltotetraose), 20.1 to 2537mg/L (maltopentaose), 22.9 to 3295mg/L (maltohexaose), 8.5 to 2492mg/L (maltoeptaose), even in the same style of beer. However, the carbohydrates content was useful, jointed with other compounds amount, to discriminate different styles of beer. As a matter of fact, principal component analysis put in evidence beer differences considering some fermentation conditions and colour.

Wine samples of Red Sangiovese wines were aged for 3 months using three different techniques (chips, lees, and micro-oxygenation) separately or combined. Later, their evolution in bottle was monitored for 5 months. At the end of aging, the main effect on selected volatile compounds was related to chips addition: as a matter of fact, chips increased aromatic compounds derived from oak, such as vanilla and burnt/toasted aromas. Micro-oxygenation induced a lower amount of 4-ethyl guaiacol than in its control. The combined use of micro-oxygenation and yeast lees led to a lower amount of guaiacol and vanillin than in its control. Wine evolution in bottle was significantly affected by the up-cited aging techniques. The use of chips led to a decrease in 4-ethyl guaiacol than in control. Micro-oxygenation reduced guaiacol and whisky lactone decrease and the increase in 4-ethyl guaiacol. The combined use of chips, micro-oxygenation, and yeast lees reduced the decrease in whisky lactone in a not significant way, instead of all the other trials. A descriptive analysis of wines put in evidence that micro-oxygenation combined with the use of chips and yeast lees reduced astringency, increased balance, and enhanced vanilla perception.

Aims: The aim of this work was to verify the influence of mechanical harvesting and postharvest treatments on wine composition.Methods and results: Trials were carried out in triplicate on cv. Montuni grapes. The estimated best setting frequency for the mechanical harvester was 410 shakes/min. Comparing hand-picked and mechanically harvested grapes, the reduced extract and pH results were lower for the hand-picked grapes, showing a more evident berry breakage caused by the mechanical harvester. The wines obtained from mechanically harvested grapes had a lower phenolic compound content than wines produced with hand-picked grapes, indicating that oxidation phenomena occurred; the trend for postharvest treated grapes was different. The significantly lower amount of higher alcohols in the hand-picked grapes trial than in the mechanically harvested ones could be explained by a lower amount of their precursors and oxygen in musts. The sensory differences among the trials were significant for some parameters, but an overall view of the data suggested that the differences were not remarkable and all the wines were good.Conclusion: Postharvest treatments reduce the loss of natural antioxidant compounds found in wines produced from mechanically harvested grapes. Mechanical harvesting does not have a negative influence on wine composition if matched with the proper vineyard characteristics, machine settings and postharvest treatments. The typicality of Montuni wine is maintained in the cases of grapes harvested mechanically with, but also without, any postharvest treatment. The use of these treatments is otherwise useful to obtain wines with a better stability.Significance and impact of the study: With respect to mechanical harvesting, this study highlights the importance of maintaining and/or improving the quality of mechanically harvested grapes containing the harvesting costs.

An explorative study to verify the applicability of reductive winemaking (RW) on two cultivars was carried out. To this purpose, traditional winemaking (TW) and RW were carried out on a semi-aromatic white grape (Sauvignon blanc) and a white neutral one (Trebbiano romagnolo). All phenolic parameters were higher in RW wines, while other substances such as alcohol, reducing sugars, acids, and volatile acidity acids were less affected by the different winemaking technique. A deeper yellow color (OD 420) was a direct consequence of the higher phenolic content of RW wines, while OD 320 was strictly related to caftaric acid integrity. Analyses showed a modification of the RW wines, also in the case of a neutral cultivar. Principal component analysis (PCA) was applied to the data set, and the first two PCs explained almost 85% of the total variability and divided TW and RW wines in two groups to demonstrate that the effect of winemaking overwhelmed maturation differences. Panelists preferred RW wines, which were characterized by a richer and more delicate aroma. The study demonstrated that a careful exclusion of air combined with an effective oxidation prevention yields to more characterized and pleasant wines.

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.

A red Sangiovese wine was aged using separate or combined different technological treatments and techniques (chips, chips and micro-oxygenation, chips and lees and micro-oxygenation), to evaluate their influence on phenolic compounds. The use of chips induced slight modifications on wine phenolic composition, while micro-oxygenation, jointly with chips, increased wine colour even if a lower level of monomeric pigments was determined. Aging with lees (jointly with chips and micro-oxygenation treatments) slightly affected phenolic composition but increased colour and red polymeric pigments more than other treatments. The application of different technologies during bottle storage affected wine composition and micro-oxygenated wines were more stable.

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.

To evaluate the viability of the A280 value for monitoring the development of cava sparkling wine during its ageing in contact with lees and its commercial shelf life, an accelerated test was applied to four types of sparkling wines obtained at industrial scale. All cava types were stored under oxygen and carbon dioxide conditions at 37 °C for 13 weeks. During the accelerated test, a positive relationship between absorbance at 280 nm (A280) and time was observed, while the main phenolic compounds decreased even under nonoxidative conditions. The increase in the phenol index value corresponded (p < 0.01) to an increase in a colourless compound. Both increases occurred mainly under nonoxidative conditions. This compound is a tentatively identified polyhydroxylate structure with a λmax 284 nm and an accurate mass of 178.0398, which corresponds to the molecular formula, C6H10O6. The present study found that sugars are the origin of this compound and play an important role in A280 increase under reductive conditions. The value of A280 could be a simple marker for monitoring the quality of the evolution of sparkling wine during its ageing in contact with lees and its commercial shelf life. © 2008 Elsevier Ltd. All rights reserved., We are grateful to Freixenet S.A. wineries for providing samples. This study was made possible thanks to financial assistance from the Comisión Interministerial de Ciencia y Tecnología (CICYT) (Spain) AGL2005-03451, from Project 2005SGR-00156 of the Generalitat de Catalunya (Spain), and through a grant from the Generalitat de Catalunya to the PhD student J. Bosch-Fusté.

The total antioxidant capacity (TAC) of five different wines (four red and one white) was determined in five different steps of winemaking carried out in a commercial wine cellar by a chemiluminescence (CL) assay. The CL method is suitable to determine the antioxidant capacity of beverages, and preliminary trials showed that the TAC immediately after the bottle was opened was greater than the day after (about 25% decrease). Immediate analysis or a correct sample storage is therefore necessary. The wines were characterized by different levels of total phenolics and TAC: these differences were related to grape composition and winemaking technologies. The TAC values were the highest immediately after devatting. The TAC suffered the highest decrease (30–50%) after the clarification procedure, which may be due to the fining agents used and to oxygen contact, then remained more or less constant in the subsequent steps. Copyright © 2006 John Wiley & Sons, Ltd.

A HPLC method involving direct injection was developed to determine phenolic compounds in wine. The separation was carried out on an RP C18 monolithic column using a binary gradient elution and diode array detection. In this way 17 monomeric compounds of different phenolic groups (hydroxybenzoic acids, hydroxycinnamic acids, hydroxycinnamyltartaric acids, flavanol, flavonol and stilbenes) could be separated and quantified in a single run and in a very short time.

A high-performance liquid chromatographic method is proposed for the simultaneous separation of main carboxylic acids, carbohydrates, ethanol, glycerol, and 5-HMF in beer by direct injection. A column packed with a sulfonated divinyl benzene-styrene copolymer and an isocratic elution with 0.0045N sulfuric acid and acetonitrile (6%, v/v) are employed. UV and refractive index detectors connected in series are also used to reduce the matrix interference of phenolic compounds. In conditions described, nine compounds are quantitated in a single chromatographic run without any pretreatment except for sample dilution and filtration before injection. Precision, accuracy, linearity of response, limit of detection, and limit of quantitation are also evaluated for each compound. Satisfactory results are obtained to justify the application of this method to all phases of beer production for process and quality control.