Pure low-methoxyl (LM) pectin and mixtures of LM and high-methoxyl (HM) pectin in different ratios were used to produce gels with control over the theological parameter storage modulus (G'). The gels either had similar pectin concentrations and different G' values, or different pectin concentrations and similar G' values. All gels were prepared with 30 g/100 g sugar, in the presence of 0.1 g/100 g CaCl(2), at pH 3.5; these are conditions that favour gel formation of both LM and HM pectin. The gels were compared for their sensory characteristics; specifically sweetness, sourness, thickness, and glueyness. Sweetness was found to increase with increasing storage modulus (G') in pectin gets of similar pectin concentration, but different G' values. Gels with higher proportions of LM pectin were perceived as sweeter than those with low LM pectin ratios. These gels also had increasing loss modulus (G ''), and increasing differences between G' and G '', which indicates that diffusion has a bearing on the perception of sweetness in pectin gels. Thickness and glueyness were mostly determined by total pectin concentration. Thickness also increased with increasing LM pectin concentration while glueyness increased with increasing HM pectin concentration.
The influence of fat content (700 and 820 g/kg) and homogenization on the texture and flavour of mayonnaise with added citral (semi-polar) or pyroligneous acid (polar) was investigated. The quality of mayonnaise was described by sensory descriptive profiling. Mayonnaise containing 820 g fat/kg had the highest intensity of sour smell, sour taste, thickness and fattiness. Increased fat content, from 700 to 820 g/kg, did not significantly affect the perception of smoke flavour due to pyroligneous acid, or lemon flavour due to citral. Homogenization increased sweetness and whiteness, and depressed thickness and fattiness in mayonnaises with added pyroligneous acid.
The effects of contents of fat, thickener and emulsifier in salad dressing were investigated. Twelve types of dressings were produced according to a full factorial design, whereby the fat content was set at three levels, the thickener and the emulsifier contents at vivo levels. The dressings were analysed by a sensory panel, using both quantitative descriptive profiling and time-intensity (TI) evaluation, and by instrumental/rheological measurements. The two sensory methods were related to each other and the instrumental results were related to tire sensory results. All design parameters had a significant influence on the properties of salad dressing, mainly on texture and mouthfeel. Fat content was the most influencing parameter. Inter-action effects were found and it can he concluded that the content of the emulsifier was less critical when the fat and thickener contents increased Dynamic and descriptive sensory analyses,ere mainly related to each other in the fattiness attribute. There were strong relations between instrumental and sensory analysis according to rheological and texture attributes, /r/ greater than or equal to 0.7 (Pearson correlation coefficient)for most texture attributes.