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have demonstrated that the intake of tagatose produces a signiicant increase in lactic acid bacteria,
important inhabitants of the intestinal tract of man and animals where they provide functional ben-
eits (Livesey 2003).
Tagatose is noncariogenic and also exhibits a probiotic effect, being a not-digestible food ingre-
dient able to beneit humans by selectively stimulating the growth and/or activity of a limited num-
ber of bacteria, thus improving host health (Bertelsen et al. 1999; Johnson 1995). Tagatose induces
butyrate production by a limited number of microorganisms, especially enterococci, lactobacilli,
and a few other butyrate-producing bacteria, with a signiicant decrease in coliforms in the colon.
Many studies highlight the importance of butyrate in the colon, where it is the major and preferred
fuel for the epithelium (Bertelsen et al. 1999; Roediger 1980), and where it plays an important role in
controlling the proliferation and differentiation of the epithelial cells (Johnson 1995). Based on the
documented selection of bacteria and butyrate effects in the colon, tagatose represents a promising
food bulk sweetener with a prebiotic action (Manzoni et al. 2001).
Originally developed as a reduced-calorie sugar substitute, d-tagatose is poorly absorbed in
the small intestine, thus preventing the stimulation of insulin secretion and lowering blood glucose
levels. d-Tagatose passes directly to the lower intestine, where it is fermented by bacteria to produce
short-chain fatty acids and carbon dioxide. It is considered a prebiotic, promoting more favorable
microbial lora in the colon (O'Brien and Gelardi 1991).
Tagatose gained GRAS status, with the subsequent possibility of commercializing it as a bulk
sweetener (GAIO, Arla Foods) in April 2001. Although tagatose is obtainable from natural sources,
its availability appears limited and its recovery expensive, a major impediment to its use in the food
industry (Levin et al. 1995).
3.4 DISaCCharIDe pOLYOLS
3.4.1 Maltitol
Maltitol, 4-O-α-d-glucopyranosyl-d-glucitol, is a disaccharide consisting of a glucose unit linked
to a sorbitol one via an a-1,4 bond (Figure 3.12). It has an mp of 146°C-147°C. Maltitol forms ortho-
rhombic crystals. It is weakly hygroscopic in the solid state. The viscosity of aqueous maltitol solu-
tions corresponds to that of sucrose solutions. In the pH range 5-7, maltitol and maltitol solutions are
stable up to about 150°C. Lower pH values, temperature >50°C, and longer contact times result in
cleavage of the disaccharide bond. Maltitol is also cleaved by enzyme systems (e.g., of the mucosa).
The relative sweetness level of maltitol is generally given as 0.65, although values up to 0.9 are
encountered in chocolates (Dziedzic and Kearsley 1984; Rugg-Gunn 1989; Schiweck et al. 2011).
Because of the nonreducing character of its molecular structure, maltitol has a high stability on
both the thermal and chemical levels (Schouten et al. 1999). Although several of its properties are
OH
HO
OH
O
O
OH
OH
HO
OH
OH
OH
Figure 3.12
Maltitol structure.
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