Background and aim:
Many foods consumed daily are composed of multiple elements which often display a heterogeneous structure, flavour, and appearance. These heterogeneous food products are generally well-liked by consumers, although little information is available about the key factors responsible for their appreciation. This thesis aims to determine how food and consumer characteristics affect sensory perception and liking of heterogeneous foods by engineering structural heterogeneities at different length scales. The effects of structural heterogeneity on expected and perceived sensory properties and liking of foods were investigated considering different consumer groups.
A combination of model and real food products were used to establish the effect of physical and physicochemical properties of heterogeneous food matrices on sensory perception and liking in relation to consumer expectations and physiological characteristics. Instrumental characterization of the products was related to the sensory perception, studied through a variety of methods (e.g. R.A.T.A., Ideal Profile, TDS). Consumer groups differing in age (i.e. healthy young adults vs. healthy elderly) or nationality/ethnicity (i.e. Dutch, Caucasian vs Chinese, Asian) were used to explore the generalisability of the effects.
Results and conclusions:
This thesis showed that variations in mechanical properties (e.g. fracture stress) between the components are the main driver of perceived heterogeneity by the consumer. For particle-filled foods, oral perception of the product can be influenced by varying both the size and the hardness of added particles, independently from the matrix consistency. Visual recognition of particle as a function of type, size, and concentration can stir expected sensory profile and liking of familiar and novel food products, although the palatability of the food depends on the particle properties. It was demonstrated that consumers prefer the presence of soft and easy-to-chew particles and that the mere mechanical contrast between components does not increase liking of foods. Conversely, this work revealed that congruent and familiar particles that match consumers’ expectations are required to boost palatability of heterogeneous products. Overall, such outcomes appear to be valid for a large spectrum of the population as relative small differences in perception of heterogeneous foods were observed between groups of healthy consumers (young vs elderly; Dutch vs Chinese). Moreover, the combination of different textures by addition of particles was proved to be an effective strategy to compensate for undesired textural sensations (e.g. grittiness) and to control oral consumption time with possible positive consequences for food intake.