Correlating psychophysical characteristics with physicochemical properties of sweeteners is of relevance to the understanding of the origin of sweetener synergy, an essential parameter for the food ...manufacturer. Psychophysical evaluation was carried out on bulk sweeteners (sucrose and maltitol) and intense sweeteners (aspartame, sodium cyclamate, acesulfam-K, alitame) in mixtures. The concentrations of mixtures were calculated to be equisweet to 10% sucrose and sweetness intensity was evaluated by reference to sucrose solutions using a “sip and spit” method. While a positive synergistic phenomenon is observed for sugar/sodium cyclamate and maltitol/acesulfamK mixtures, a significant suppression effect is obtained when aspartame is added to sugars. Additivity is observed for sucrose/alitame and sucrose/acesulfamK mixtures. The origin of these differences lies in the influence of the two molecules on water structure and in the nature of their hydration. From physicochemical properties (intrinsic viscosity, Huggins coefficient, apparent specific volume, hydration number, surface tension and contact angle), alitame and aspartame seem characterised by hydrophobic hydration; sodium cyclamate, as well as the bulk sweeteners, appear more compatible with water structure and possess hydrophilic hydration. ACK is differentiated from other sweeteners by a negative hydration. Synergy occurs when components with identical types of hydration are mixed. This phenomenon is accompanied by an increase in the mobility of water molecules in the proximity of bulk sweeteners (maltitol and sucrose) and a reduction of volume of the hydrated solute molecule. Inversely, suppression and additivity occur when constituents of the mixture possess different natures of hydration, as in sucrose/aspartame mixtures, and when physicochemical properties show a reduction of the mobility of water around the sweeteners. For suppression effects, an increase in volume of the hydration sphere is also observed. Interpretation of the sweetness of mixtures of sugars and artificial sweeteners, in terms of their compatibility with water structure, is of relevance at an economic level in food formulations.
Quantitative psychophysical information on the perceptual characteristics of sucrose (as reference), sodium cyclamate, aspartame, neohesperidin dihydrochalcone (NHDHC) and maltitol were established ...through the determination and the modelling of their concentration-response (
C-R) functions according to linear, Beidler or Hill equations, the recording of the time-intensity (
T-I) curves with the determination of the
T-I parameters for each sweetener, and the establishment of the sensory profile of the sweetener solutions by the QDA technique. Bulk and intense sweeteners present dissimilar
C-R functions. The
C-R function observed for maltitol is linear while aspartame, cyclamate and NHDHC exhibit a saturation plateau around 10–13% sucrose equivalent. Temporal characteristics of aspartame and cyclamate are comparable to those of sucrose and maltitol, whereas the
T-I characteristics of NHDHC contrast with those of the other sweeteners, essentially because of its long onset and persistence times. Bitter taste and bitter aftertaste are attributes that differentiate maltitol and sucrose from artificial sweeteners. Bitter and metallic are non-sweet aftertastes characteristic of cyclamate, while NHDHC is mainly defined by a liquorice-like and cooling/ menthol flavour. Caramel flavour is associated with nutritive sweeteners, and burnt sugar flavour is related to synthetic sweeteners, except cyclamate, which is characterized by both flavours.
The perceived effect of adding salts on the sweetness of bulk sweeteners (sucrose, glucose, fructose, sorbitol and xylitol) depends on the sweetener type and concentration and on the type of salt. ...Sodium chloride enhances the sweetness of all the sweeteners to some degree. Potassium chloride has little effect on any sweetener other than sorbitol, which shows sweetness enhancement at low sorbitol concentrations and suppression at high sorbitol concentrations. Magnesium chloride additions tend to enhance sweetness, particularly of sucrose and glucose. The effects observed can not be ascribed to any inherent sweetness of the salts themselves, suggesting that the observed effects are a result of interactions between the salts and sweeteners in the aqueous medium.
During the last decade, there has been a growing interest in understanding food's digestive fate in order to strengthen the possible effects of food on human health. Ideally, food digestion should be ...studied in vivo on humans but this is not always ethically and financially possible. Therefore, simple in vitro digestion models mimicking the gastrointestinal tract have been proposed as alternatives to in vivo experiments. Thus, it is no surprise that these models are increasingly used by the scientific community, although their various limitations to fully mirror the complexity of the digestive tract. Therefore, the objective of this article was to call upon the collective experiences of scientists involved in Infogest (an international network on food digestion) to review and reflect on the applications of in vitro digestion models, the parameters assessed in such studies and the physiological relevance of the data generated when compared to in vivo data. The authors provide a comprehensive review in vitro and in vivo digestion studies investigating the digestion of macronutrients (i.e., proteins, lipids, and carbohydrates) as well as studies of the bioaccessibility and bioavailability of micronutrients and phytochemicals. The main conclusion is that evidences show that despite the simplicity of in vitro models they are often very useful in predicting outcomes of the digestion in vivo. However, this has relies on the complexity of in vitro models and their tuning toward answering specific questions related to human digestion physiology, which leaves a vast room for future studies and improvements.
The descriptive profiles of three bulk and intense sweetener blends (maltitol-cyclamate, maltitol-acesulfam-K, and sucrose-cyclamate) were established with reference to a 10% sucrose solution. These ...blends were chosen because they had been demonstrated in a previous study (Hutteau
et al., 1998) as having a significant level of synergy. The descriptive profiles were established by a quantitative descriptive analysis-(QDA) type technique and the results were analysed by analysis of variance and by principal component analysis to examine the overall relationships among single solutions and mixtures of sweeteners. A significant reduction of the non-sweet tastes and aftertastes usually associated with acesulfam-K and cyclamate was observed.
We present a compactly integrated, 625 MHz clocked coherent one-way quantum key distribution system which continuously distributes secret keys over an optical fibre link. To support high secret key ...rates, we implemented a fast hardware key distillation engine which allows for key distillation rates up to 4 Mbps in real time. The system employs wavelength multiplexing in order to run over only a single optical fibre. Using fast gated InGaAs single photon detectors, we reliably distribute secret keys with a rate above 21 kbps over 25 km of optical fibre. We optimized the system considering a security analysis that respects finite-key-size effects, authentication costs and system errors for a security parameter of QKD = 4 × 10−9.
The solution properties of binary mixtures of two bulk sweeteners (sucrose and maltitol) and three intense sweeteners (acesulfame K, aspartame and sodium cyclamate) were studied. The parameters ...measured were apparent specific volumes, isentropic compressibilities and compressibility hydration numbers. An attempt has been made to correlate the solution properties of some of the mixtures with their sweetness responses. Both specific volume and isentropic compressibility data have been used to interpret the possibility of synergism or suppression in the mixtures in terms of the affinity of the solutes for the surrounding solvent structure, and hence the effectiveness of transport of the molecules to their appropriate receptor sites. However, an understanding of the nature and stereochemistry of the individual components in the mixtures is necessary for predicting the packing characteristics of molecules in water and their accession to receptor sites. The intense sweeteners seem to play an important role in modifying the structure of water in solution. Although there is no clear proof of how this affects perception, fine differences in solution behaviour can be observed with isentropic apparent specific compressibility measurements. The study supports the idea that receptors lie at different depths in the lingual epithelium, and also that in two-component systems, one species may alter the packing efficiency of the other in solution sufficiently to effect a change in taste quality or intensity.
Intensity/time plots of sweetness produced by D-glucose, D-fructose and sucrose at concentrations ranging from 2.3 to 9.2% (w/v) were recorded for solutions at 15, 22 and 35 degrees C. The intensity ...(I) and persistence (P) power functions were applied to the results obtained with a potentiometer connected to a chart recorder similar to the sensory measurement unit recording flux (SMURF) device. Increasing the concentration of assessed samples leads to an increase of perceived intensity with a tendency to show a compression for D-fructose and sucrose and an expansion for D-glucose. Persistence increases linearly as a function of concentration for the three sugars. Only very slight modification of intensity and persistence are observed when the temperature is varied from 15 to 35 degrees C. Intensity/time plots were also recorded at 22 degrees C for solutions containing 5% sucrose or equisweet concentrations of D-glucose or D-fructose brought to apparent viscosities of 5, 15, 25 and 35 mPas by addition of maltodextrins. It was found that the sweetness intensity decreases as viscosity increases for D-fructose and sucrose solutions whereas it remains constant for D-glucose. The persistence remains almost constant for the three sugars when the viscosity is varied. The effect of temperature on viscosity coefficients and hydration numbers is measured for the three sugars. A decrease in intrinsic viscosity eta, B-coefficients and hydration numbers is observed with increasing temperature whilst the apparent specific volume is increased. From the Raman spectra of water and aqueous solutions of sugars, it may be concluded that increasing the temperature leads to a lowering of the rigidity of the hydrogen bonded clusters and an increase in mobility of H2O molecules. The increase in the size of the sugars derived from apparent specific volume (V2 degree) values reduces their accessibility to the receptor site. This effect is minimised as regards the perceived sweetness by the increased mobility of water. The effects of concentration, temperature and viscosity on the intensity and persistence of the sweet taste of D-glucose, D-fructose and sucrose, together with their physicochemical properties in dilute solution, suggest that the accessibility of the sweet molecule to the receptor is an important step in the taste chemoreception. This step is followed by a biochemical phenomenon involving opening of ion channels which is sensitive to the mobility of water around the site and the sweetener.
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