Sugar Alcohols (Polyols) - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 46

an abridgement of “polyalcohol” or “polyhydric alcohol.” Preferred names are “polyol” or “hydro-
genated carbohydrate”; the latter makes explicit that these substances are carbohydrate (Livesey
2003).
Production of sugar alcohols started in the 1920s with a health concern related to consumption
of too much sugar with foods. After their irst production, they have started to become one of the
most consumed food and pharmaceutical ingredients; hence, their digestion does not require insulin
synthesis, they are noncariogenic, they stimulate salivation when consumed, and they can be used
in the production of foods for diabetics (Livesey 2003; Marie and Piggott 1991).

3.2 IMpOrtaNCe OF SUGar aLCOhOLS FOr
FOOD INDUStrY aND hUMaN heaLth

Sugar alcohols can be obtained from monosaccharides, disaccharides, and mixture of monosac-
charides, disaccharides, and oligosaccharides (Tables 3.1 and 3.2). Depending on the saccharide
type, they can have different physical, chemical, and sensory properties (Table 3.3). With regard to
the sweetness of sugar alcohols, the relative sweetness level varies from 1 for xylitol to about 0.4
for lactitol and mannitol. Generally, compared to other carbohydrate sweeteners, the relative sweet-
ness level of polyols is more concentration dependent. Due to the fact that the enthalpy of the polyol
solutions is different from that of sugar, the sweetness levels of the polyols are different (Table 3.4;
Counsel 1987; O'Brien and Gelardi 1991). Cooling sensation (refreshment) in the oral cavity is
caused by the polyols with a higher positive enthalpy of solution (Schiweck et al. 2011).
The hygroscopic abilities of individual polyols differ greatly. For example, sorbitol (crystalline
and aqueous solutions) and maltitol syrups are very hygroscopic, but mannitol and isomalt are prac-
tically nonhygroscopic with water activities lower than those of sugar (Schiffman and Gatlin 1993;
Schiweck et al. 2011). The melting (sintering) points are changed among the polyols. They range
from 92°C for xylitol and sorbitol to 165°C for mannitol. Polyols with a lower melting point (mp)
give products with a smooth surface when used in tablets (Schiweck et al. 2011; Table 3.5).
The solubility of polyols in water changes depending on the temperature (Figure 3.1); the solu-
bility of the polyols sorbitol, xylitol, and maltitol at 20°C is of the same order of magnitude as that
of sucrose. However, the solubility of isomalt and mannitol is signiicantly lower. The temperature
dependence of solubility of all polyols is greater than that of sucrose. The most important physical
and chemical parameters such as boiling point, elevation, density, and viscosities of aqueous solu-
tions and melts are changed among polyols (O'Brien and Gelardi 1991; Schiweck et al. 2011).
Sugar alcohols affect the water activity ( a w ) of solutions differently. Compared to sucrose, sor-
bitol and erythritol have bigger impact on lowering the water activity of the solutions (Figure 3.2).
The ability of sugar alcohols to lower water activity is dependent on the concentration.
Because sugar alcohols lack a carbonyl group, their sweetness differs considerably from that of
carbohydrates (Table 3.3). Therefore, Maillard reactions and the Strecker degradation are inhibited.
Moreover, monosaccharide and disaccharide alcohols are much more resistant to enzyme systems,

table 3.1 Common Sugar alcohols

2 Carbon
polyols

3 Carbon
polyols

4 Carbon
polyols

5 Carbon
polyols

6 Carbon
polyols

12 Carbon
polyols

Others

Glycol Glycerol Erythritol Arabitol Mannitol Isomalt Polyglycitol

Threitol Xylitol Sorbitol Maltitol

Ribitol Dulcitol Lactitol

Iditol