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5. Sacchetti G., Di Mattia C., Piva A., Mastrocola D., Cichelli A. (2008). Effect of sulphur dioxideon the antioxidant activity of wine. In Proceedings of 31° World Congress of Vine andWine. Organisation Internationale de la Vigne et du Vin: Paris, PIV10.Sulphur dioxide, whose utilization is under regulation due to its possible toxycological effects, is an antioxidantadditive widely used in wine processing. Its in vitro and in vivo antioxidant activity or its influence on the totalantioxidant capacity of wine has not been reported in literature.Aim of this work was the evaluation of the contribution of sulphur dioxide on the antioxidant activity (AOA) ofwine as determined by some of the most used methods in literature. To this purpose, three different samples: awhite wine, a red wine and a wine model solution were used. All samples were added with different amounts ofpotassium metabisulfite in order to reach different sulphur dioxide contents. Three methods were used for theAOA determination: the ABTS radical cation decolorization assay (TEAC), the DPPH free radical method andthe Ferric Reducing Antioxidant Power (FRAP).The AOA of model solutions and white wines evaluated by means of the TEAC method resulted strongly dependenton the sulphur dioxide content that was therefore proven to exert radical scavenging activity. In particular,most of the antioxidant capacity of the tested white wine was due to the sulphite content rather than to thephenolic fraction. The sulphur dioxide content influenced also the TEAC values of red wines samples but in aless extent than that of white wines; this result was ascribed to a matrix effect caused by compounds, naturallypresent in red wines, able to complex sulphur dioxide.Also the radical scavenging activity and the reducing activity, of white wines and model solutions tested by theDPPH method and the FRAP assay respectively, were proven to be positively affected by sulphur dioxide.In order to test the antioxidant activity of wine it is thus of fundamental importance to evaluate the sulphur dioxidecontribution; in fact, while the positive effects of polyphenols on health are largely documented, the antioxidanteffect of sulphur dioxide in vivo has not been the target of systematic studies as yet.6. Di Mattia C., Sarker D.K., Sacchetti G. , Occhino E., Pittia P. (2008). Effect of phenolicantioxidant compounds on the colloidal properties and on the oxidative stability of olive oilO/W emulsions. In: Tenth international congress on food and engineering. Book of abstracts.20-24 April 2008, Vina del Mar, Chile: D06.Oil-in-water (O/W) emulsions are among the main dispersed lipid systems in food. Antioxidants are often usedin order to avoid or to reduce the rate of lipid oxidation reactions that, in this case, can be mainly considered asinterfacial phenomena. Interaction might take place at this level between the emulsifying agents, antioxidant andthe pro-oxidant compounds that affects the colloidal properties of the system and the oxidative stability.The objectives of the work were: i) to study how antioxidant molecules and the interactions between thesecompounds and emulsifying agents at the interfacial level can modify the colloidal properties of a characterisedemulsified system; ii) to study the effect of the content and activity of antioxidants on lipid oxidation inemulsified systems over storage timeEmulsions were prepared using refined olive oil (20% w/w) and PBS (50mM, pH 7). Gallic acid, catechin andquercetin were chosen as antioxidant compounds while Tween 20 and β-lactoglobulin were used as surfaceactive agents. Surface tension measurements, ξ-sizing and ξ-potential were carried out on model solutionscontaining the phenolic compounds both alone and in combination with the emulsifying agents. Particle sizedistribution, bulk rheology, lipid hydroperoxide content, TBAR’s and tryptophan fluorescence determinationswere carried out on the emulsified systems over storage time (33 days at 40°C).All the antioxidants proved to be slightly surface active with catechin being the most efficient among them. Inemulsions, quercetin and catechin concentrations were negatively correlated against droplet size. The antioxidantconcentration used to test the emulsions' oxidative stability was set to10-4 M according to colloidal andrheological measurements in order to have the maximum amount of antioxidant solubilised in the system withoutaltering their overall colloidal properties.Gallic acid, despite its partitioning in the water phase, due to its polarity proved to delay both the primary andsecondary oxidations and to retard the formation of oxidation products.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it429