Original article Aromatic profiles of spray-dried encapsulated orange flavours: influence of matrix composition on the aroma retention evaluated by sensory analysis and electronic nose techniques M. V. Galmarini, 1,2 * M. C. Zamora, 1,2 R. Baby, 1,3 J. Chirife 2 & V. Mesina 4 1 Consejo Nacional de Investigaciones Cientı´ficas y Te´cnicas (CONICET), Av. Rivadavia 1917 – (C1033AAJ), Buenos Aires, Argentina 2 Facultad de Ciencias Agrarias, Universidad Cato´lica Argentina (UCA), Cap. Gral. Ramo´n Freire 183 – (C1426AVC), Buenos Aires, Argentina 3 Centro de Investigaciones en So´lidos (CINSO), Juan B. de Lasalle 4397 – (B1603ALO), Villa Martelli, Argentina 4 Instituto de Investigaciones Cientı´ficas y Te´cnicas de las Fuerzas Armadas (CITEFA), Juan B. de Lasalle 4397 – (B1603ALO), Villa Martelli, Argentina (Received 28 September 2006; Accepted in revised form 22 March 2007) Abstract Spray-dried orange flavour encapsulated in different amorphous matrices composed of maltodextrin (MD) and different combinations with; sucrose, trehalose, lactose, modified starch and gum arabic (ga); were evaluated by sensory analysis and electronic nose (e-nose). With both techniques the flavours encapsulated in MD-sucrose and MD-lactose–sucrose were perceived as similar. However, the e-nose did not detect any differences among the other matrices (MD-trehalose, MD, MD-sucrose at a different concentration and MD-ga). On the contrary, sensory analysis was able to group MD-trehalose and MD describing them by: woody, marmalade, syrup, citrus terpenes, and Vitamin C; MD-sucrose at 40% and 10% concentration and MD-lactose–sucrose were grouped and represented by powder juice, tangerine and pungency, while MD-ga was differentiated from the rest by the attributes peely, plastic, solvent and green. In this way, it was shown that matrix composition determines the aromatic profile of spray-dried encapsulated orange flavours. Keywords Electronic nose, orange encapsulated flavours, sensory profile, spray-dried, sucrose, trehalose. Introduction Spray-drying is the most common technique to produce flavour powders from food flavour emulsion; recipes for spray-dried flavours contain, in addition to the liquid flavour, carrier materials, such as maltodextrin (MD), gum arabic and modified starch. Ingredients are mixed, emulsified ⁄ homogenized and spray-dried; water content is reduced to below 5% and the flavour is encapsulated in an amorphous glassy carbohydrate matrix. The requirements for an ideal spray-drying carrier include a high degree of solubility, limited viscosity at the 35–45% solution solids range, emulsifying charac- teristics, good drying properties, non hygroscopic char- acter, bland taste, non reactivity, and low cost. For these reasons MDs are commonly used for this type of spray- drying applications. Also, the high glass transition temperature (T g ) of low DE MDs provides good product stability to the dried powder (Beristain et al., 2002; Bhandari & Hartel, 2005). It is well known that, among other factors, the type of carrier governs flavour retention during the spray- drying process (Menting et al. 1970; Thijssen, 1971); and for this reason disaccharides, such as sucrose or lactose are sometimes included with MD in commercial formulations to improve retention characteristics. However, the low T g of sucrose (Roos, 1995) may adversely affect stability. Food powders containing amorphous carbohydrates can undergo several physical changes which lead to the deterioration of quality (Roos & Karel, 1991). Recent work carried out on strawberry and orange spray-dried powder flavours showed that the presence of sucrose in the carrier formulation (MD and sucrose) affected storage stability in a negative way (Busso Casati et al., 2007), because it reduces the glass transition temperature dramatically when 40% of sucrose is incorporated in the dry carbohydrate matrix. Trehalose is a naturally occurring non-reducing disac- charide which consists of two glucose molecules linked in a 1,1-position by a a-glycosidic bond. In the last years the use of trehalose as a functional food additive has been approved in many countries. The glass transition tem- perature for trehalose is much higher than that of sucrose *Correspondent: Tel ⁄ Fax (54–11) 4552-2711; e-mail: mgalmarini@gmail.com International Journal of Food Science and Technology 2008, 43, 1569–1576 1569 doi:10.1111/j.1365-2621.2007.01592.x Ó 2007 Institute of Food Science and Technology