Dynamics of Taste Compound Release from Gel Systems

Looking into recent trend on healthy lifestyle, consumers have opted for healthier food product with low sodium and sugar content. However, the reduction of salt and sugar in food products affects the consumer’s acceptance. This research aims in gaining a more in depth understanding on the dynamics of taste compounds release mechanism in the oral cavity. There were many studies conducted previously on volatile compounds without any oral processing actions. Furthermore, little study was done on volatile compounds and on samples under submerge condition. The findings of this research may offer small portion of information on the dynamics of food system under submerged condition. An instrumental model measuring flavour release from gel systems was developed. The instrumental setup enabled modelling of unidirectional solute mass transfer from a cylinder of gel into the surrounding buffer (at pH 7). Gels formed from -carrageenan, alginate and gelatin were compared, due to their wide application in the food industry. Sodium chloride and glucose were chosen as the initial taste compound carrier due to the simplicity and accuracy of recording its release via conductivity measurements and glucometer respectively. In the attempt to mimic certain oral processing conditions, release from gels was studied under a number of controlled conditions: room temperature (ca. 25 ºC) and body temperature (37 ºC), compressed and non-compressed gels. Results showed that release of sodium chloride and glucose were significantly influenced by increasing concentrations of polymer and therefore rigidity of the gels, but the effect of biopolymer types was even more significant. Alginate exhibited the slowest release rate as compared to the other gels, irrespective of gel rigidity. Release rates of sodium chloride or glucose were higher at the higher temperature, but particularly for the gelatin gels, which melted at 37 ºC. Interestingly, compression of the gels did not significantly increase or change on the rate of release of sodium chloride or glucose, so that the differences between the types of gel may be more connected with specific interactions between the gel matrix and the flavour than the ease of diffusion of the flavour through different gel network structures. Comparing the instrumental data collected, curves agrees with the diffusion theoretical curve which suggest the mechanism governs the release is purely diffusion. Gelatin at higher temperature shows poor fit due to its melting properties. Relatively, faster release in instrumental measurement as compared to theory; this suggests the presence of unbound taste compounds in the gel systems which were readily to diffuse away from the gel matrices. Time-intensity sensory evaluation data revealed the correlation between panellists response with the instrumental analysis. Overall findings showed that the instrumental set up gives reproducible results. Investigation reveals polymer types and temperature plays a significant role in the taste compounds release profile. Understanding the fundamental mechanism lies behind the mechanism or taste compounds release and factors affecting it give the food industry more control over its formulations. Food industry may find ways formulating food product with low sodium and sugar content without jeopardizing the consumer’s acceptance.