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have been a subject of investigation aimed at developing instrumental measurements of human olfactory perceptions.In this paper, a study case on the application of a sensor array aimed at appraising the flavour properties of custarddesserts seasoned with strawberry aroma is presented. These studies were intended to determine the effectsof some key ingredients (milk fat content and sugar type) to the aroma and to the aroma temporal decay undercontrolled storage. Sensor data have been compared and complemented with those provided by gaschromatographyand sensory analysis. The results indicate that custard headspace fingerprinting can obviouslyrecognize the addition of artificial flavours, and, more noteworthy, discriminate among fat milk content andsugar types used to prepare the samples. Furthermore, composition was also found to affect the temporal evolutionof aroma evidencing distinct paths in a principal component analysis (PCA) score plot for samples preparedwith different ingredients.2. Martuscelli M., Savary G., Pittia P., Cayot N. (2008). Vapour partition of aroma compoundsin strawberry flavoured custard cream and effect of fat content. Food Chemistry, 108 (4),1200-1207.Gas–matrix partition coefficients (k) of volatile compounds of a strawberry flavour added to a complex modelsystem (custard dessert, COST action 921 recipe) were determined. The influence of fat content on the volatilityof the strawberry aroma compounds was investigated using full fat milk- (FFM) and skimmed milk- (SM) custards.For the purpose of this study, the phase ratio variation (PRV) method was used because of its easy applicationfor a mixture of volatiles without requiring any calibration. From the 15 aroma compounds present in theflavouring mixture, seven were volatile enough to be detected and concentrated enough to allow the calculationof k values. Gas–matrix partition coefficients were compared to gas–water partition coefficients. For somearoma compounds (ethyl hexanoate, ethyl butanoate, and hexanal) a significantly lower k value was observed inFFM-custard than in water, indicating a retention effect caused by the matrix. As expected, the fat content andthe hydrophobicity of the volatile compounds were of great importance to explain the differences between partitioncoefficients in SM custards and in FFM custards: for SM-custard, a higher release in the vapour phase wasobserved than for FFM-custard; the more hydrophobic the aroma compound, the higher the effect. Moreover,ethyl butanoate and hexanal were less retained in SM-custard than in water. This may be attributed to a saltingouteffect due to sucrose.The results of this study indicate the importance of the interactions between volatiles and non-volatile compoundsas well as of the chemical and physical properties of the aroma compounds in affecting the compositionof the gas phase at equilibrium with a complex matrix. More than that, they provided a basis for the studies developedwithin COST action 921 with the flavoured custard model system.3. Pittia P., Anese M., Manzocco L., Calligaris S., Mastrocola D., Nicoli M.C. (2006). Ethanolvapour pressure in bakery products. Flavour and Fragrance Journal, 21, 3-7.Ethanol is a common ingredient in formulated foods, naturally present or added as liqueur in order to achieve desiredsensorial properties. In many complex food this volatile compound could also exert interesting technologicalfunctionality as well as extend their shelf-life due to its capacity in inhibiting or reducing the rate of microbialgrow. At European level, no restrictions are known regarding the use of ethanol in foods as preservative,whilst in Italy, current regulations allow its addition as anti-moulding agent in pre-packed bread at a maximumconcentration of 2% on dry weight basis. In this research the effect of water activity (a w ) and water content onthe ethanol vapour pressure of sliced white bread previously equilibrated at various a w values and added with 2%of ethanol, was studied. Different aw values were obtained by both rehydration from previously freeze-driedbread, and dehydration from fresh product. Results showed that both a w and moisture affected the vapour pressureof ethanol as a consequence of interactions water-solute and ethanol-solute in the matrix. These interactionsresulted to vary according to the modality of equilibration (desorption or absorption) at a given a w . Results arediscussed in terms of ethanol activity (a e ), computed as ratio between ethanol vapour pressure in bread and vapourpressure of pure ethanol, at the same temperature. This index, analogue to the a w , resulted useful to evaluatethe “freedom” of the ethanol present in a food matrix to be released in the vapour phase.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.it436