Sweet intensity

The sweet taste of sucrose is its most notable and important physical property and is regarded as the standard against which other sweeteners (qv) are rated. Sweetness is induenced by temperature, pH, sugar concentration, physical properties of the food system, and other factors (18—20). The sweetening powers of sucrose and other sweeteners are compared in Table 3. The sweetness threshold for dissolved sucrose is 0.2-0.5% and its sweetness intensity is highest at 32-38°C (19). 

Enhancers and Inducers. A sweetness enhancer is defined as a compound that imparts no taste per se, but when combined with a sweetener in small quantities, increases sweetness intensity. A tme sweetness enhancer has yet to be found. However, a good sweetness inducer, miraculin [143403-94-5] or [125267-18-7] (124), is known. Miraculin is a glycoprotein found in the fmit (called Miracle Fmit) of a West African shmb, chardella dulcifica. By itself, miraculin imparts no sweetness. When activated in the mouth by acidic substances, however, a sucrose-like sweetness is perceived. Thus, sour lemon, lime, grapefmit, rhubarb, and strawberry taste sweet when combined with miraculin. The taste conversion effect can last an hour or longer. 

S = sweet, tr = trace sweet, 0 = no sweetness. B = bitter, tr = trace bitter, 0 = no bitterness. Values in parentheses are relative sweetness-intensities compared to sucrose (= 100). Some panelists reported trace sweetness. 

Structurally related to saccharin are the oxathiazinone dioxides (104). Clauss and coworkers synthesized a series of these compounds, and demonstrated that they possess intense sweetness. Acesulfame-K, the potassium salt of 3,4-dihydro-6-methyl-l,2,3-oxathiazin-4-one 2,2-dioxide (104) has a sweetness intensity 130 times that of sucrose. 

Much of our present day knowledge of sweetness intensity, both at the threshold level, where taste begins, and above the threshold level, derives from the application of psychophysical techniques. It is now evident that the psychophysical procedure used measure separate aspects of sweetness perception. Hedonic responses cannot be predicted from intensity of discrimination data, and vice versa. The taste-panel evaluation of sweetness is of fundamental importance in the development of worthwhile structure-taste relationships. Therefore, it is vital that the appropriate psychophysical method and experimental procedure be adopted for a particular objective of investigation. Otherwise, false conclusions, or improper inferences, or both, result. This situation results from the failure to recognize that individual tests measure separate parameters of sensory behavior. It is not uncommon that the advocates of a specific method or procedure seldom... 

Thus, the increase in concentration needed to match the effect of a 10-fold increase in sucrose concentration is 0.154/2.44 x 10 = 630-fold. Crosby and coworkers suggested that this is close to the situation that occurs with saccharin, and it is doubtless responsible for the differences in perceived sweetness intensity (200-700 times that of sucrose) for sensory determinations conducted at different concentrations. 

Intense sweeteners are characterised by a high sweetness intensity on a weight basis. Sweetness intensity values differ for general comparisons standard sweetness intensity values are often used with sucrose being the standard with a sweetness intensity of 1. Sweetness intensities depend on a number of factors, e.g. concentration and presence of flavours or taste components. They are therefore not a suitable tool for calculation of use concentrations except for very preliminary approaches. 

Table 1 Relative sweetness intensity of various glucosyl derivatives 26-29 of stevioside [62]...

Most of the food and feed additives are commoditized. This is also the case for the artificial sweeteners. The main products are Saccharin (550), Aspartame (Canderel, 200), Acesulfam K (Sunnett, 200), and Cyclamate (35). The figures in brackets are the sweetness intensity, whereby sucrose = 1. Sucra-lose, discovered in the 1980s by Tate Lyle, now taken over by Johnson Johnson s formidable marketing machine, is enjoying a revival as Spenda. 

Since no bitter compounds are reported, the A value in Eq. 50 is the net sweet intensity relative to sucrose. The nitro and cyano groups seem to play an identical role and the substituent effects are common in these two series of compounds. 

The taste profile of aspartame is similar to sucrose sweetness (Ripper et al., 1985). It is approximately 200 times as sweet as sucrose. It is synergistic with saccharin, cyclamate, stevioside, acesulfame K and many sugars, in particular fructose, but has little sweetness intensity synergy with sucralose. 

The sweetness quality of sucralose is similar to that of sucrose. Sucralose exhibits synergism with acesulfame K, cyclamate, saccharin and stevioside (Tate Lyle Pic, 1985a, 1986). It is not synergistic with sucrose and shows little sweetness intensity synergy with aspartame. However, the sweetness quality of sucralose can be improved in cola by blending with aspartame (Tate Lyle Pic, 1985b). 

Influence of Sweeteners on Bitterness. In model system studies, natural fruit juice sugars were observed to raise the limonin threshold (24). An expanded study of natural and artificial sweeteners (26) demonstrated that sucrose, neohesperidin dihydro-chalcone (NHD), hesperetin dihydrochalcone glucoside (HDG) and aspartylphenylalanine methyl ester (AP) all raise the limonin threshold. At low sweetness levels HDG was the most effective followed by AP and NHD. Sucrose was without effect up to the 2% level. At sweetness levels equivalent to 1% sucrose, HDG, AP and NHD raised the limonin threshold in water from 1.0 ppm to 3.2, 2.5 and 1.3 ppm, respectively. Because of its high sweetness intensity, the concentration of NHD (16 ppm) was considerably lower than HDG (80 ppm) and AP (90 ppm). At 3-10% sucrose sweetness equivalency, the effectiveness of NHD increased substantially, sucrose moderately and HDG slightly, while that of AP decreased. Therefore, the sweeteners HDG, AP and NHD can effectively suppress limonin bitterness at low concentrations. 

L-Asp-D-Abu-Gly-OMe (40) was selected as a next candidate in order to determine its sweetness intensity relative to L-Asp-D-Ala-Gly-OMe (39). The sweetness intensity of this peptide was predicted to be lower than that of L-Asp-D-Ala-Gly-OMe after examining their formulas. As expected, the synthesized L-Asp-D-Abu-Gly-OMe was sweet, and its sweetness intensity was lower than that of L-Asp-D-Ala-Gly-OMe. 

The chemical structure of the most important nonnutritive sweeteners is shown in Figure 11-4. Saccharin is available as the sodium or calcium salt of orthobenzosulfimide. The cyclamates are the sodium or calcium salts of cyclohexane sulfamic acid or the acid itself. Cyclamate is 30 to 40 times sweeter than sucrose, and about 300 times sweeter than saccharin. Organoleptic comparison of sweetness indicates that the medium in which the sweetener is tasted may affect the results. There is also a concentration effect. At higher concentrations, the sweetness intensity of the synthetic sweeteners increases at a lower rate than that which occurs with sugars. This has been ascribed to the bitter-... 

The increasing market demand for sweeteners resulted in the development of a number of chemicals. The major artificial sweeteners in the present market include acesulfame-K, alitame, aspartame, cyclamate, saccharin, and sucralose. Sweetness-intensity factors of several sweeteners compared with sucrose are given below ... 

Commonly cited relative sweetness-intensity values are listed however, the concentration and the food or beverage matrix may greatly influence actual values. 

Moskowitz and Arabic (1970) found that the taste intensity (sweetness, sourness, saltiness, and bitterness) was related to the apparent viscosity of carboxymethylcel-lulose solutions by a power function with a negative slope. Pangbom et al. (1973) observed that the influence of different hydrocolloids on the perception of some basic taste intensities (saltiness, bitterness, sourness) appeared to be more dependent on the nature of the hydrocolloid and the taste of the substance than on the viscosity level. In contrast, sweetness imparted by sucrose was found to be highly dependent on viscosity, that is, the hydrocolloid concentration above a certain viscosity threshold, it was shown that the sweetness intensity of sucrose was significantly depressed. Saltiness was the taste attribute less affected, sourness, imparted by citric acid, was significantly reduced by all hydrocolloids tested, and for the other taste substances, the presence of a hydrocolloid generally enhanced the taste intensity of saccharin and depressed that of sucrose and caffeine (bitterness). 

Launay and Pasquet (1982) studied the relationship between sweemess and solution viscosity using sucrose solutions thickened with guar gum prepared to two constant viscosity levels. The results showed that the sweetness intensity decreased in the presence of the gum, but this reduction was not dependent on the viscosity level, a result that seems to be in conflict with the results previously reported by Moskowitz and Arabie (1970). 

An interesting engineering approach was proposed by Kokini and coworkers to model viscosity-taste interactions. Kokini et al. (1982) have studied the perception of sweetness of sucrose and fructose in solutions with various tomato solids contents, and with basis on the observed decreasing of sweetness intensity as the percentage of tomato solids increased, they have proposed a more complex but rather comprehensive physical model relating viscosity and taste intensity, based on the physics and chemistry in the mouth. This model was further successfully applied (Cussler et al., 1979) to explain the effect of the presence of hydrocolloids at different levels on the subjective... 

Launay, B. and Pasquet, E. 1982. Sucrose solutions with and without guar gum rheological properties and relative sweetness intensity. Prog. Food Nutri. Scl 6 247-258. 

---