Galactose, sweetness

Sucralose has the structure most similar to su crose Galactose replaces the glucose unit of sucrose and chlorines replace three of the hydroxyl groups Sucralose is the newest artificial sweetener having been approved by the U S Food and Drug Adminis tration in 1998 The three chlorine substituents do not dimmish sweetness but do interfere with the ability of the body to metabolize sucralose It there fore has no food value and IS noncaloric... 

The hypothesis could also account for differences in the relative sweetness of sugars by simple consideration of the way in which configurational differences might affect hydrogen bonding. The sweetness of D-galactose... 

Glucose-galactose syrups are about three times sweeter than lactose (70% as sweet as sucrose) and hence lactose-hydrolysed milk could be used in the production of ice-cream, yoghurt or other sweetened dairy products, permitting the use of less sucrose and reducing caloric content. However, such applications have not been commercially successful. 

The glucose moiety can be isomerized to fructose by the well-established glucose isomerization process to yield a galactose-glucose-fructose syrup with increased sweetness. Another possible variation would involve the isomerization of lactose to lactulose (galactose-fructose) which can be hydrolysed to galactose and fructose by some / -galactosidases. 

A plethora of lactase-treated products are described in the literature (Zadow 1984 Holsinger 1978). The use of hydrolyzed lactose syrups has been proposed as an alternative sweetener to corn syrup solids. Storage of syrups as concentrated liquids can be a problem due to microorganism growth or to extensive precipitation of residual lactose or galactose. Generally, both problems can be controlled by storage at -10 to -20°C if syrup total solids were around 70%. Guy (1979) has reported on the sweetness of hydrolyzed, demineralized syrups. 

The d and L-sugars and amino acids are enantiomorphs and differ in absolute configuration about every asymmetric carbon atom. The pentose L-arabinose is structurally related to the sweet-tasting hexose, D-galactose, and, to recognize this, we predicted (2) that L-arabinose would probably taste sweet. 

L-Arabinose did taste just about as sweet as D-galactose, and L-sorb-ose, the 5-epimer of D-fructose, also tasted sweet although it was only about one-fifth as sweet as D-fructose. 

Tagatose, a monosaccharide similar to fructose, received GRAS status from the FDA in April 2001. This sugar, 92 percent as sweet as sucrose, with 1.5 cal/g, is produced from galactose obtained from whey, using immobilized enzymes.97 It has similar bulking properties to sucrose. 

As noted in the chapter opener, lactose is the principal disaccharide found in milk from both humans and cows. Unlike many mono- and disaccharides, lactose is not appreciably sweet. Lactose consists of one galactose and one glucose unit, joined by a P-1,4 -glycoside bond from the anomeric carbon of galactose to the 4 carbon of glucose. 

Pigman has prepared crystalline u-altrose from neolactose by cleavage of the disaccharide with sweet almond emulsin, followed by removal of the D-galactose by fermentation with yeast. This procedure avoids the transformation of any n-altrose to u-altrosan, the non-reducing anhydride which is formed to the extent of 57% in the hydrolysis of neolactose by acids. 

This isomer of sorbitol and mannitol is less soluble and less sweet than the other two compounds. Also it is less available for the multiplicity of uses which mannitol and sorbitol have enjoyed. Dulcitol was first designated as the mannite of Madagascar manna and was shown by Laurent in 1850 to be an isomer of mannitol. It is a meso form. In 1871 Bouchardat synthesized the compound by reducing D-galactose with sodium amalgam. Until ten years ago, the only biological studies available on dulcitol were of a bacteriological nature. At that time the authors studied the fate of dulcitol and dulcitan in the animal body. 

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