Taste detection threshold of human (Homo sapiens) subjects and taste preference threshold of black-handed spider monkeys (Ateles geoffroyi) for the sugar substitute isomalt

Sofia Pereira,Matthias Laska,Laura Teresa Hernandez Salazar

doi:10.1007/s10329-020-00868-5

Abstract

The artificial sweetener isomalt is widely used due to its low caloric, non-diabetogenic and non-cariogenic properties. Although the sweetening potency of isomalt has been reported to be lower than that of sucrose, no data on the sensitivity of humans for this polyol are available. Using an up-down, two-alternative forced choice staircase procedure we therefore determined taste detection thresholds for isomalt in human subjects (n = 10; five females and five males) and compared them to taste preference thresholds, determined using a two-bottle preference test of short duration, in a highly frugivorous nonhuman primate, the spider monkey (n = 4; one female, three males). We found that both species detected concentrations of isomalt as low as 20 mM. Both humans and spider monkeys are less sensitive to isomalt than to sucrose, which is consistent with the notion of the former being a low-potency sweetener. The spider monkeys clearly preferred all suprathreshold concentrations tested over water, suggesting that, similar to humans, they perceive isomalt as having a purely sweet taste that is indistinguishable from that of sucrose. As isomalt, like most sweet-tasting polyols, may elicit gastric distress when consumed in large quantities, the present findings may contribute to the choice of appropriate amounts and concentrations of this sweetener when it is employed as a sugar substitute or food additive for human consumption. Similarly, the taste preference threshold values of spider monkeys for isomalt reported here may be useful for determining how much of it should be used when it is employed as a low-caloric sweetener for frugivorous primates kept on a vegetable-based diet, or when medication needs to be administered orally.

Highlights

Isomalt is a widely used sugar substitute which provides only 2 kcal/g, i.e., half the energy value of sucrose (Radeloff and Beck 2013)
Taste preference thresholds of the four spider monkeys for isomalt ranged from 10 to 20 mM (Fig. 1), with a median value of 20 mM. (A threshold value of 10 mM isomalt was only reached in the test with the female.) All four animals failed to show a significant preference for the lowest concentrations presented, suggesting that the preference for higher concentrations of isomalt was based on the chemical nature, i.e., the sweetness, of the stimulus
Our finding that the human taste detection threshold of 20 mM for isomalt was higher than the corresponding threshold value of 5.5 mM reported for sucrose (Low et al 2017) is in agreement with other studies that found the sweetening potency of isomalt as perceived by humans to be lower than that of sucrose (DuBois et al 1991)

Summary

Introduction

Isomalt is a widely used sugar substitute which provides only 2 kcal/g, i.e., half the energy value of sucrose (Radeloff and Beck 2013). In contrast to conventional saccharides, isomalt is suitable for diabetics as no significant increase in body glucose, insulin or lactic acid concentration arises after its consumption (Thiébaud et al 1984). It is non-cariogenic, which makes isomalt attractive for use as a tooth-friendly candy (Featherstone 1994). Psychophysical studies have shown that isomalt is a low-potency sweetener perceived by humans as about 45–60% as sweet as

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Conclusion