Giuseppe Arfelli

Analysis of wine phenolics by high-performance liquid chromatography using a monolithic type column

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.

Level of single bioactive phenolics in red wine as a function of the oxygen supplied during storage.

Abstract The influence of three levels of oxygen supply on the phenolic composition of Sangiovese wine was evaluated during 6 months of storage. Oxygenation reduced the total phenolics content and increased the concentration of red polymeric compounds. Saturation with oxygen every 30 days significantly improved the wine colour density as compared to the control. The individual behaviour of phenolic compounds such as (+) catechin, (−) epicatechin, quercetin, caffeic acid, and anthocyanins showed a significant depleting effect of oxygen on wine phenolic composition when wines were oxygenated every month. The supply of oxygen every 60 days limited the oxidation of low molecular weight phenolic compounds and slightly influenced the wine colour. This confirmed that oxygenation could improve the evolution of red wines during ageing, but its control is necessary to reduce detrimental effects upon single bioactive phenolic compounds.

Effects of high pressure processing on polyphenoloxidase enzyme activity of grape musts

Abstract The effects of high pressure processing (300, 600, 900 MPa for 2, 6 and 10min) on the activity of polyphenoloxidase (PPO) enzymes were evaluated in a synthetic must to which an enzymatic extract obtained from grapes had been added, and in a white grapes must. Despite the fact that the results vary as a function of the medium studied, it could be seen that the PPO typical of the musts could only be partly inactivated by high pressure treatment (300–600 MPa). On the other hand, at higher pressures (900 MPa), PPO enzymatic residual activity was clearly lower (1 to 16%) in both the synthetic and the white must.

Characterisation of brewpub beer carbohydrates using high performance anion exchange chromatography coupled with pulsed amperometric detection

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.

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.