The flavor of sugar alcohols is similar to that of sucrose. They taste sweet; however, they seldom are equivalent to the relative sweetness of sucrose. They do not promote dental caries and exert a laxative effect when consumed in quantities in excess of 20 to 30 g per day. Sugar alcohols are utilized as replacements for sugar because they do not raise the concentration of sugar in the blood and also do not require insulin to degrade them. Sugar alcohols include e.g., sorbitol, xylitol, mannitol, maltulose, isomaltulose, maltite, isomaltite, lactulose and lactite.
Determination of D-sorbitol by enzymatic means
Suitable for beer, beer-based beverages and NAB
D-Sorbit is present in pomaceous fruit and stone fruit.
D-Sorbitol is oxidized to D-fructose by nicotinamide adenine dinucleotide (NAD) in the presence of the enzyme sorbitol dehydrogenase (SDH), forming reduced nicotinamide adenine dinucleotide (NADH).
D-Sorbitol + NAD+ \(\xrightarrow{SDH}\)D-G-6-P fructose + NADH + H+
The reaction equilibrium heavily favors the reactants NAD+ and D-sorbitol. It shifts toward D-fructose, when the NADH formed in this reaction reacts with iodine nitrotetrazolium chloride (INT) in a subsequent reaction. Formazan is created in the presence of diaphorase, which is an irreversible reaction.
NADH + INT + H+ \(\xrightarrow{diaphorase}\) NAD+ + Formazan
The maximum absorbance of the formazan is measured at 492 nm.