Effect of gel texture and sucrose spatial distribution on sweetness perception

Layered gels differing in mechanical and breakdown properties (soft, medium and hard gels) and in the distribution of sucrose in the matrix (homogeneous and inhomogeneous distributions) were used to investigate the effects of texture and spatial distribution of sucrose on sweetness perception. Rating tests, 2-Alternative forced choice tests and time-intensity analysis were performed to compare the sweetness of soft, medium and hard gels with homogeneous and inhomogeneous distributions of sucrose. Results showed that all gels with an inhomogeneous distribution of sucrose were perceived sweeter than gels in which sucrose was homogeneously distributed. This indicates that the enhancement of sweetness by an inhomogeneous distribution of sucrose does not depend on the texture of the gel matrix. Furthermore, the time-intensity profiling showed that soft gels, which had low values of fracture strain and fracture stress and broke down in a large number of small fragments upon chewing, had the highest sweetness intensity. The time required to reach the maximum sweetness intensity tended to be shorter in soft gels. These findings suggest that the breakdown behavior of the gel matrix during oral processing affects the perception of sweetness of layered gels.     

Sweetness and texture perceptions in structured gelatin gels with embedded sugar rich domains

Layered and homogeneous gelatin gels with controlled rheological properties were compared for their sensory characteristics, specifically sweetness, hardness, breakdown behaviour and frothing. All gels and layers had a gelatin/water concentration of 5%. The total sugar concentration was 9% in the layered samples and 0, 9, 15 or 22.5% in the homogeneous samples. These concentrations corresponded to the concentrations in the single layers.A seven-layered sample with different sugar concentrations in the layers gave a higher early sweetness intensity than a homogeneous gel with the same mean total sugar concentration. All layered gels were similar in hardness, breakdown behaviour and frothing; for the homogenous samples, sensory hardness was decreased in samples with much sugar. These gels also fell into smaller pieces than the sugarless sample. This study shows that it is possible by controlling the sugar distribution within a sample to produce sweeter gels while the sugar content is maintained.     

Modulation of sweetness perception in confectionary applications

The development of sugar-reduced food products is a strategy to reduce the high sugar intake, which is a leading cause of global health concerns. Replacement and/or reduction of sucrose often leads to reduced sweetness perception with the consequence of decreased consumer acceptance. The aim of this work is to implement sensory modulation principles in a model confectionery system with the goal of enhancing sweetness perception. By using 3D-printing, confectionary samples were meso-structured by inhomogenous distribution of sucrose concentrations and assessed with a trained panel regarding sweetness. All samples were made up of a high and low sucrose phase and compared to a homogeneous reference sample. The overall sugar content was kept constant at 22.8% in all samples and sweetness perception was compared. A significant increase of sweetness perception by over 30% was found for samples consisting of a sweet outer shell and an inner less sweet core with a high sucrose gradient between the two phases. Whilst textural effects on sweetness perception could not be fully excluded, results can be seen as a strong indication that sweetness modulation by inhomogenious distribution has a potential to be applied directly in solid food products.     

EFFECT OF VISCOSITY ON PERCEIVED SWEETNESS INTENSITY OF SWEETENED SODIUM CARBOXYMETHYLCELLULOSE SOLUTIONS

To establish a relationship between perceived sweetness intensity (Y), sucrose concentration (A%) and viscosity of mixed solutions (B poise), mixtures of sucrose solutions in various concentration and sodium carboxymethylcellulose with medium viscosity (CMC–M) in various concentrations were used, resulting in the equation: where "Y"= sucrose concentration of reference solutions. This equation was effective within the ranges of 4% to 16% sucrose and viscosities of from 1 to 100 poises. This equation was applicable to low and high as well as medium viscosity forms of CMC.     

Effect of successive stimuli on sweetness intensity of gels and custards

Variations of tastant concentration during the consumption of food products were shown to enhance taste intensity. The aim of this study was to investigate the relation between the frequency at which tastant concentration is varied during the consumption of products and the occurrence of taste enhancement. For this purpose, the sweetness intensity of sequences of 4 successive sweet stimuli represented by cubes of a semi-solid gel or spoons of a model custard dessert was assessed. The intensity and the order of the stimuli within the sequences were varied to obtain 4 types of sucrose concentration profile (decreasing, increasing, middle peak and boundary peak) at 2 magnitudes of concentration differences (small and large). Sequences of 4 stimuli containing a constant sucrose concentration were used as a reference. The sweetness intensity of the sequences of successive stimuli was assessed using line scale and time-intensity ratings.Line scale ratings showed that the type of sequence had an effect on sweetness intensity. A sweetness enhancement relative to the reference was observed in sequences that ended with high-intensity stimuli, whereas sweetness suppression was observed in sequences that ended with low-intensity stimuli. The observed sweetness enhancement and suppression were attributed to serial position effects (i.e. recency effects).Time-intensity ratings indicated that each stimulus in the sequences was evaluated individually by the assessors. Sequential effects seem to have occurred during the continuous evaluation of successive stimuli, since preceding stimuli in the sequences affected the evaluation of posterior stimuli. Furthermore, the overall sweetness intensity of the different sequences was not enhanced in relation to the reference. The lack of taste enhancement in sequences exhibiting variations of sucrose concentration was attributed mainly to the long period at which sucrose concentration was varied during the evaluation of the sequences. It was confirmed that the frequency of variation of tastant concentration affects the occurrence of taste enhancement.     

EFFECTS OF HYDROCOLLOIDS AND ASPARTAME ON SENSORY VISCOSITY AND SWEETNESS OF LOW CALORIE PEACH NECTARS

Effects were studied of interactions between each of three hydrocolloids-xanthan gum, guar gum and methylcellulose- and aspartame on sweetness intensity and sensory viscosity of low-calorie peach nectars (60% fruit purée with no sucrose added). The flows of the nectars were characterized as near Newtonian without hydrocolloids, as Bingham plastic at lower hydrocolloids concentrations and as pseudoplastic at higher concentrations (Ostwald flow for guar and methylcellulose, and Herschel-Bulkley for xanthan). Hydrocolloids concentrations were selected to cover viscosity range of commercial whole nectars: 0.10 and 0.20% xanthan or guar, and 0.15 and 0.30% methylcellulose. Aspartame concentrations tested were derived from the calculation of equisweet concentration as referred to a control nectar sample with sucrose (14°Brix) and of the upper and lower limen value: 0.216, 0.360 (equisweet), 0.502, and 0.644 g/L. Addition of either guar or methylcellulose did not alter the perceived sweetness in aspartame-sweetened peach nectars. Xanthan addition, even at 0.10%, significantly lowered sweetness of samples sweetened with the highest aspartame concentration (0.644 g/L). Addition of aspartame did not modify the perceived viscosity in samples thickened with either xanthan or guar gums. At all methylcellulose concentrations tested, samples with the lowest aspartame concentration (0.216 g/L) were perceived as less viscous.     

Sensory characteristics and relative sweetness of tagatose and other sweeteners

The present study investigated the sensory characteristics and relative sweetness of tagatose, an emerging natural low-calorie sweetener with various functional properties, compared to other sweeteners (sucrose, sucralose, erythritol, rebaudioside A), over a wide range of sweetness commonly found in foods and beverages (3% to 20% sucrose [w/v]). A total of 34 subjects evaluated aqueous solutions of the 5 sweeteners for the perceived intensities of sweetness, bitterness, astringency, chemical-like sensations, and sweet aftertaste, using the general version of the Labeled Magnitude Scale. The relationship between the physical concentrations of the sweeteners and their perceived sweetness (that is, psychophysical functions) was derived to quantify the relative sweetness and potency of the sweeteners. The results suggest that tagatose elicits a sweet taste without undesirable qualities (bitterness, astringency, chemical-like sensations). Out of the 5 sweeteners tested, rebaudioside A was the only sweetener with notable bitterness and chemical-like sensations, which became progressively intense with increasing concentration (P < 0.001). In terms of perceived sweetness intensity, the bulk sweeteners (tagatose, erythritol, sucrose) had similar sweetness growth rates (slopes > 1), whereas the high-potency sweeteners (sucralose, rebaudioside A) yielded much flatter sweetness functions (slopes < 1). Because the sweetness of tagatose and sucrose grew at near-identical rates (slope = 1.41 and 1.40, respectively), tagatose produced about the same relative sweetness to sucrose across the concentrations tested. However, the relative sweetness of other sweeteners to sucrose was highly concentration dependent. Consequently, sweetness potencies of other sweeteners varied across the concentrations tested, ranging from 0.50 to 0.78 for erythritol, 220 to 1900 for sucralose, and 300 to 440 for rebaudioside A, while tagatose was estimated to be approximately 0.90 times as potent as sucrose irrespective of concentration. Practical Application: The present study investigated the sensory characteristics and relative sweetness of tagatose, an emerging natural low-calorie sweetener, compared to other sweeteners. Study results suggest that tagatose elicits a sweet taste without undesirable qualities over a wide range of concentrations. Tagatose produced about the same relative sweetness to sucrose across the concentrations tested, while the relative sweetness of other sweeteners was highly concentration dependent. The present data provide a general guideline when considering the use of tagatose and other sweeteners in foods and beverages.     

EVALUATION OF THE SEPARATE CONTRIBUTIONS OF VISCOSITY AND SWEETNESS OF SUCROSE TO PERCEIVED VISCOSITY,SWEETNESS AND BITTERNESS OF VERMOUTH3

The separate effects of sweetness and viscosity of sucrose on the sensory properties of vermouth were evaluated in systems: (1) varying in sucrose concentration and viscosity (2) with constant sucrose concentration but varying in viscosity, and (3) constant viscosity, but varying sucrose concentration. Twenty-one trained judges rated oral viscosity, sweetness and bitterness, while the physical viscosity of the Newtonian systems was measured by capillary viscometry. Both perceived sweetness and oral viscosity increased, while bitterness decreased as sucrose was increased, and as the physical viscosity of the vermouths increased. However, samples in which viscosity was increased by the nonsweet Polycose® were rated sweeter and less bitter than vermouth solutions of the same sucrose concentration, but lower physical viscosity. Similarly, when vermouths of identical viscosity were compared, the vermouths with higher sucrose concentration were judged to be more viscous. Viscosity alone contributed 20-30% of the perceived increase in sweetness due to sucrose addition. The effect of viscosity in reducing bitterness was of the same magnitude. The increase in perceived viscosity caused by addition of sucrose arose from approximately equal contributions of physical viscosity and sweetness of sucrose.     

Ideal and relative sweetness of high intensity sweeteners in mango nectar

The aim of this study was to analyse the ideal and relative sweetness of mango nectar with high intensity sweeteners. The ideal sweetness of the samples sweetened with sucrose at 5%, 7.5%, 10%, 12.5% and 15%, was analysed using an acceptance test with a just‐about‐right (JAR) scale and 100 consumers of mango nectar. The magnitude estimation method was then used to determine the relative sweetness of the high intensity sweeteners. Six samples were prepared and one sweetener added to each: sucrose, sucralose, 100:50:1 acesulfame‐K/sucralose/neotame blend, 1:1 thaumatin/sucralose blend and stevia with 97% of rebaudioside. The ideal sweetness analysis revealed that 6.84% was the ideal concentration of sucrose. The relative sweetness analysis showed that neotame presented the highest sweetening power, being 6026 times sweeter than sucrose with respect to the mango nectar containing 7% of sucrose, followed by sucralose (627), thaumatin/sucralose blend 1:1 (549), acesulfame‐K/sucralose/neotame blend 100:50:1 (259) and stevia (134).     

Compression resistance,sweetener's diffusion and sweetness of hydrocolloids gels

The effects of the type and concentration of two hydrocolloids—κ-carrageenan and gellan gum—and of the type and concentration of two sweeteners—sucrose and aspartame—on the gel resistance to compression, on the sweetener diffusion and on the intensity of the gel sweetness and the relationships between the gel physical properties and their perceived sweetness were studied. The gels true rupture stress increased with hydrocolloid concentration, this increase being higher for gellan gels. Gellan gels showed lower true rupture strain values, which in contrast with carrageenan gels, decreased on increasing hydrocolloid concentration. The addition of sucrose produced a bigger increase in gel strength at the higher hydrocolloid concentration. The main effect detected on the sweeteners’ diffusion constant was the higher value observed in low concentration (3 g L⁻¹) κ-carrageenan gels. Gellan gels were perceived as sweeter than κ-carrageenan gels. The decrease in sweetness due to an increase in hydrocolloid concentration was greater in gellan than in carrageenan gels. Variations in sweetener concentration, true rupture strain, and deformability modulus values explained 93% of the variability in sweetness for gels with sucrose and 94% for gels with aspartame.     

USE OF MASS TRANSFER THEORY TO PREDICT VISCOSITY-SWEETNESS INTERACTIONS OF FRUCTOSE AND SUCROSE SOLUTIONS CONTAINING TOMATO SOLIDS

The perceived sweetness intensity of sucrose and fructose in solutions of varying tomato solids content was studied. Using magnitude estimation it is shown that as the percentage o f tomato solids increased from 0-2.6%, the perceived sweetness intensity decreased substantially for both sucrose and fructose. The sharpest decrease occurred with a 1.66 molar fructose solution where the assessed sweetness intensity of a 2.6% insoluble tomato solids sample is 63% lower than the corresponding Wo tomato solids solution.
The penetration model of mass transfer explains this psychophysical phenomenon with the following relationship:     

The Influence of the Rebaudioside A Content of Stevia (Stevia rebaudiana Bertoni) on the Determination of Sweetness Equivalence in Bittersweet Chocolates,Using the Time‐Intensity Analysis

The consumption of diet products has increased greatly in recent years. The objectives of the study were to develop a bittersweet chocolate added inulin and stevias with different rebaudioside A contents (60%, 80%, and 97%). Five chocolate samples were formulated with different sucrose concentrations to determine the ideal sucrose concentration for bittersweet chocolate. The use of just‐about‐right scale identified an ideal sucrose concentration of 47.5% (w/w). The sweetness equivalence in sugar‐free bittersweet chocolates was determined by the time–intensity method by 14 selected and trained judges. The data collected during each session of sensory evaluation furnished the following parameters in relation to the sweet stimulus: Imax (maximum intensity recorded), Timax (time at which the maximum intensity was recorded), Area (area of time × intensity curve), and Ttot (total duration time of the stimulus). The time–intensity analysis indicated that the percentages of rebaudioside A did not interfere with the sweetness intensity of the sweetener stevia in bittersweet chocolate and there was no significant difference in the concentrations tested (0.16%, 0.22%, 0.27%) of each stevia, in relation to the parameters evaluated. In addition, the reduction in fat content did not alter the perception of the sweetness intensity of the samples. These results showed important information to research and development of chocolate products. Therefore, the use of the lowest stevia concentration tested (0.16%) is the most indicated for use, since this quantity was sufficient to reach the ideal sweetness of the product, so there was no point in adding more.     

Perceived Sweetness and Redness in Colored Sucrose Solutions

Perceived sweetness and redness in five red colored solutions containing 0.25–5.0% FD&C Red 40 were quantified using magnitude estimation. Three panels of 14 subjects each evaluated solutions containing five sucrose concentrations ranging from 2.7–5.3%. Color had a statistically significant effect (p≤0.05) on sweetness perception in 80% of the treatments. Sweetness in darker colored solutions was 2–10% greater than the lighter reference when the actual sucrose concentration was 1% less. Sweetness increased linearly over all sucrose concentrations and over a narrow range of color intensities. Color was measured using the Gardner XL-23 Colorimeter and the G.E. Recording Spectrophotometer. All color measurements were converted to L*, a*, b* and the value arctan (a*/b*) - used to represent color intensity. The perception of increasing color intensity was a linear power law function of arctan (a*/b*).     

Sensory Quality of Selected Sweeteners: Aqueous and Lipid Model Systems

The sweetness characteristics of sucrose, fructose, aspartame, acesulfame K, sodium saccharin and calcium cyclamate were studied in aqueous and lipid model food systems with and without lemon or vanilla flavoring. Anchored linear scales were used to evaluate sweetened model systems for initial, maximum and residual sweetness intensity and nonsweet aftertaste. Data were analyzed by analyses of variance. Flavor did not influence sweetness, except where residual sweetness was more intense in lemon and vanilla solutions than in plain solutions. No sweetener was perceived exactly like sucrose. Intensity and sweetness profiles varied between systems and among sweeteners. Character of the food system influenced perceptions of sweetness and aftertaste.     

Taste interaction of ethyl alcohol with sweet, salty, sour and bitter compounds

The influence of ethyl alcohol in concentrations ranging from 4 to 24%, on the perceived taste intensities of sucrose, citric acid, quinine, and sodium chloride was determined by 24 subjects. A paired comparison method was used in which subjects selected the sample with the greater taste intensity (sweetness, sourness, bitterness or saltiness) as well as rating the intensity on a 13-point scale. The alcohol generally enhanced the sweetness of sucrose, with results varying slightly according to the subjects' task. The sourness of citric acid, and the saltiness of sodium chloride at all but the lowest concentration, were depressed by increasing additions of alcohol. Alcohol significantly enhanced the bitterness of quinine at all four concentrations. Although these results disagree with previously reported electrophysiological measurements on alcohol-quinine mixtures, they were internally consistent, and meaningful in terms of alcoholic beverage consumption behaviour.     

Perception of taste intensity in solutions of random-coil polysaccharides above and below c

Sensory paired comparison tests were used to study differences in taste intensity in solutions of hydroxypropylmethyl cellulose (HPMC) at concentrations above (1.0% w/w) and below (0.2% w/w) c^*, the coil-overlap concentration (the point at which viscosity changes abruptly with increasing thickener). The sweetness intensities of aspartame (250 ppm), sucrose (5% w/w), fructose (4.5% w/w) and neohesperidin dihydrochalcone (39 ppm) and the saltiness of sodium chloride (0.35%) were all found to be significantly reduced in the more viscous HPMC solution. There was no significant effect of HPMC concentration on the acidity of citric acid (600 ppm) or the bitterness of quinine hydrochloride (26 ppm). The sweetness intensities of sucrose and aspartame were likewise investigated in two further hydrocolloid solutions, guar gum and λ-carrageenan. Experiments were designed so that the ratios of the thickener concentrations (above and below c^*) to their measured c^* values remained constant. The sweetness of sucrose was found to be significantly reduced in the more viscous guar gum solution (P<0.05) and that of aspartame was reduced in the λ-carrageenan above c^* (P<0.001). A multiple paired comparison design was used to show that the perceived sweetness of 6.5% sucrose in 1.0% HPMC did not differ significantly from that of 5% sucrose in 0.2% HPMC. The magnitude of effect with aspartame was broadly analogous.     

Perception of sugar-acid mixtures in lemon juice drink

Acid was removed from lemon juice by selective adsorption on to a weak-base resin. Four levels each of sucrose and citric acid were combined factorially and dissolved in the low-acid juice, providing sixteen stimulus combinations. Using graphic-rating scales, assessors evaluated the stimuli for intensities of overall flavour, sweetness, and acidity; the relation of each of these intensities to ideal; and general acceptability. The various acceptability responses proved to be internally consistent, and the experiment suggested an optimum sugar-acid blend from the sixteen combinations. Ratings of overall flavour strength followed a compressed pattern in a factorial plot, with increasing concentrations of sugar and acid exerting a diminishingly small effect. In the perception of individual components, sucrose clearly suppressed the perceived intensity of citric acid, but only the highest concentration of acid unequivocally suppressed sweetness. There was a striking similarity between each set of intensity responses and the corresponding ideal-relative responses, suggesting a link between intensity and hedonics.