Relationship between structure of hydrocolloid gels and solutions and flavour release

Abstract

To provide further insight into the relationship between the structure of hydrocolloid solutions and gels and perception of taste and flavour, solutions of gelatin and locust bean gum (LBG), and gels prepared from mixtures of (a) high acetyl and low acetyl and gellan (b) carrageenan and LBG were studied. Both the solutions contained sodium chloride and the gels were flavoured with ethyl butyrate. The gels were classified from rheological measurements into three categories: strong/brittle, intermediate and soft/elastic. Volatile release was measured by monitoring nose space volatile concentration during consumption using atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS). In addition headspace measurements were performed with APCI-MS. The headspace concentrations did not exhibit significant differences between the gels system but the release of ethyl butyrate in-nose was affected by the matrix, showing a higher intensity for the more brittle gels containing high levels of low acetyl gellan. The release of Na+ following a two-bite compression was monitored by the use of an ion-specific electrode. The more brittle gels containing high levels of low acetyl gellan and high amount of κ-carrageenan exhibited significantly higher release of Na+. Strain at break correlated inversely with salt release (r2=-0.87) and more weakly inversely with the maximum nose space volatile concentration (r2=-0.55). When LBG solutions containing salt were mixed with distilled water it was found that both salt release and mixing efficiency decreased at polysaccharide concentrations above c*. In contrast gelatin solutions, measured at 50 °C, maintained good salt release and mixing behaviour at high concentrations. It is concluded that the intensity of flavour perception in hydrocolloid solutions and gels is dominated by the release of the tastant. In solutions this is favoured by good mixing behaviour between the hydrocolloid solution and saliva and in gels by a low strain at break. A gelatin replacement should not only show melt in the mouth behaviour but good mixing between the gelatin melt and the saliva. © 2007 Elsevier Ltd. All rights reserved.