Combinatory Effects of Texture and Aroma Modification on Taste Perception of Model Gels Janine Editha Knoop & Guido Sala & Gerrit Smit & Markus Stieger Received: 5 October 2011 / Accepted: 18 February 2013 / Published online: 9 March 2013 # Springer Science+Business Media New York 2013 Abstract In this study, the effects of texture modification and aroma-induced sweetness enhancement were systematically investigated in apple-flavored semi-solid Na-caseinate gels. Gels containing apple juice as a basic flavor were developed differing in stiffness, brittleness and serum release (texture modification), aroma, and sugar concentration (flavor modifi- cation). In a full factorial design (2×2×2), eight samples were evaluated by a sensory panel on ten attributes (five texture, five flavor). Sweetness was enhanced significantly by modi- fication of texture, aroma, and sugar concentration. Texture modification was found to be by far the greatest contributor to overall sweetness. In comparison to texture modifications, aroma modification and changes of sugar concentration resulted only in small sweetness enhancement. When texture and aroma modifications are combined, a small additive effect of aroma modification on sweetness enhancement was found in addition to the sweetness enhancement caused by texture modification. This suggests that the relationship between tex- ture (modification) and flavor (modification) and sweetness is additive in a nonlinear manner. It can be concluded that texture modification is a valid tool to enhance taste intensity. Hence, texture modification can compensate for a loss of sweet taste intensity induced by sugar reduction, while aroma-induced sweetness enhancement can contribute to fur- ther taste enhancement in order to develop healthier products. Keywords Cross-modal interactions . Taste . Aroma . Na-caseinate gel . Texture . Ethyl hexanoate Introduction Consumers can perceive small variations in the sweetness intensity of food products (Drewnowski and Greenwood 1983; Drewnowski et al. 1998; Drewnowski and Schwartz 1990; Monneuse et al. 1991; Salbe et al. 2004). The taste of a product is affected by the reduction of sugar when devel- oping calorie-reduced foods, which can lead to repercus- sions on the choice of the consumer. Several strategies have been proposed to reduce sugar content while maintaining the taste of the reformulated product unvaried. One strategy to enhance sweetness intensity in semi-solid foods involves the modification of the textural properties of the food matrix. Three approaches have been described, each of which involves the modification of a specific tex- tural property, to achieve taste intensity enhancement by either a reduction of the stiffness of the food matrix or an increase of the brittleness of the food matrix or an increase of the serum release from the food matrix. The three ap- proaches are summarized briefly in the following. Reduction of the Stiffness of the Food Matrix Clark (2002) reported an increase in taste intensity with decreasing stiffness for soft solid foods. Flavor intensity was shown to be enhanced upon reduction of stiffness of a variety of food gels prepared from different biopolymers (Clark 2006). An enhancement of sweetness intensity with decreasing polymer concentration was also reported for k- carrageenan and gellan gum gels containing sucrose and aspartame as tastants (Bayarri et al. 2007). The reduction of k-carrageenan and gellan gum concentration led to a decrease in Young’ s modulus and fracture stress (i.e., a J. E. Knoop : G. Sala : M. Stieger Top Institute Food and Nutrition (former WCFS), P.O. Box 557, 6700AN, Wageningen, the Netherlands J. E. Knoop : G. Sala : G. Smit : M. Stieger Wageningen University and Research Centre, Agrotechnology and Food Sciences Group, P.O. Box 8129, 6700EV, Wageningen, theNetherlands J. E. Knoop (*) Wageningen University & Research Centre, Food Technology Centre, P.O. Box 8129, 6700 EV, Wageningen, the Netherlands e-mail: janine.knoop@internetwerft.de Chem. Percept. (2013) 6:60–69 DOI 10.1007/s12078-013-9141-4