ABSTRACT: Three kinds of dough and 4 kinds of frying oil were used to study the doughnut preferences of a consumer panel composed of 100 female university students. A trained panel first performed a difference test, and those doughnut samples the trained panel could discriminate were submitted to the consumer test. The texture of the surface region affected the discrimination. The consumer panel preferred the hardened soybean oil to the liquid soybean oil for the hard cake doughnut because the solid fat content of the hardened soybean oil was high and the surface region was short in texture. There was no significant difference between the soft cake doughnut and the yeast doughnut.
ABSTRACT The perceptibility of grittiness and the threshold value of grittiness were examined in five disperse model systems: aqueous suspensions, low and high viscous suspensions, and soft and hard gels. Fourteen types of microcrystalline cellulose were used having different particle sizes (between 6–79 μm) and physical properties (shape, degree of polymerization, and state at the material stage). In each system, the proportion of people who perceived grittiness increased with increasing particle size and decreased with increasing particle concentration demonstrating that perception of grittiness depended on both particle size and concentration. The proportion of people who perceived grittiness was found by multiple regression analysis to have a high correlation with the logarithm of (particle size × concentration). Each system gave an approximate regression equation representing this relation. The value of particle size × concentration at the grittiness threshold was defined as the point where 50% of people perceived grittiness. These values were calculated to be 6.0 (aqueous suspension). 19.7 (low viscosity), 26.7 (high viscosity suspension), 30.7 (soft), and 42.1 (hard gel). The factor contributing most to grittiness was concentration, followed by dispersion medium and particle size. The proportion of people who perceived grittiness was also expressed by a multiple regression equation which included these three factors. The obtained results suggest the possibility of predicting and controlling grittiness in foods.
ABSTRACT Microcrystalline cellulose was dispersed as a gritty substance in an emulsion, and sensory evaluation was conducted to examine the effect of the presence of oil on grittiness felt in the mouth. Samples were prepared with three types of microcrystalline cellulose of average particle size 14, 38, and 76 μm and with a concentration in water of 0.03–2.7%, with three types of emulsion with an oil‐volume fraction of 0.2–0.7, and with three rates of homogenization of 500–15,000 rpm. The flow behavior and loss modulus of each sample were measured and sensory evaluation was made of the perceived grittiness. A multiple regression analysis of the data shows that the proportion of people who could perceive grittiness was influenced by the following factors and in that order: concentration of microcrystalline cellulose, oil droplet size, loss modulus, and particle size of microcrystalline cellulose. The proportion of people who perceived grittiness also increased with increasing oil droplet size. This was conceivably caused by the uneven distribution of microcrystalline cellulose particles promoted by large oil droplets. An equation was developed relating the proportion of people perceiving grittiness to the physical properties of the sample. The result indicates that factors effecting grittiness perception are identical for emulsions, aqueous suspensions, viscous suspensions and gels, studied previously.
The hardness of Japanese radish was increased by pressurization and standing after the release of pressure. We measured the variations of pectin fractions with time after pressure release. Only the hexametaphosphate-soluble pectin, which is bound to divalent metal ions, increased slightly after standing. Calcium ion content in water-soluble pectin was decreased by pressurization. Water-soluble calcium ions decreased with pressure treatment and standing. However, sodium chloride-soluble calcium ions, which are bound to tissue components, increased. The hardening is considered to be brought about by changes in the interactions among tissue components. It is also suggested that calcium ions play an important role in pressure-induced hardening.
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