Monosaccharides honey

Analysis of honey on this continent dates back to 1892, when 500 commercial samples of honey were analyzed.50 The analytical methods used were, with certain modifications, employed over the years by several workers,51-54 until a critical study of the methods of sugar analysis was made by White and coworkers.55 

South Africa.64 The average composition of 490 samples of honey, with respect to sugar constituents and moisture and their range of values, as determined by White and collaborators,45 is given in Table I. The values given in Table I for maltose and sucrose do not 

In recent years, it has become fashionable to determine the composition of honey, and in the current literature are many reports dealing with the compositional aspects of honey from various parts of the world.65-73 It is, however, regrettable that application of paper chromatography, which has played an outstanding role in the development of carbohydrate chemistry, has not yet been fully explored in 

The use of thin-layer chromatography for the determination of sugars in honey has been proposed,77 and the potential value of gas- 

The present challenge is to determine, quantitatively, most, if not all, of the sugars in honeys, and not merely to determine the content of D-glucose and D-fructose by yet another method. 

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D-Fmctose [57-48-7] (levulose, fmit sugar) is a monosaccharide constituting one-half of the sucrose molecule. It was first isolated from hydroly2ed cane sugar (iavert sugar) ia the late nineteenth century (1,2). Fmctose constitutes 4—8 wt % (dry sugar basis (dsb)) of many fmits, where it primarily occurs with glucose (dextrose) and sucrose (see Carbohydrates Sweeteners). It also makes up 50 wt % (dsb) of honey (3,4). 

Dextrose (D-glucose) is by far the most abundant sugar in nature. It occurs either in the monosaccharide form (free state) or in a polymeric form of anhydrodextrose units. As a monosaccharide, dextrose is present in substantial quantities in honey, fmits, and berries. As a polymer, dextrose occurs in starch, cellulose (qv), and glycogen. Sucrose is a disaccharide of dextrose and fmctose. 

Sucrose, the compound we call sugar, is the most common disaccharide. One of the monomer units in sucrose is a-glucose. The other is fructose, a monosaccharide found in honey and natural fruit juices. 

Fructose is found in honey and fruit and as part of the disaccharide sucrose (common table sugar). Sucrose is hydrolyzed by intestinal brush border sucrase, and the resulting monosaccharides, glucose and fructose, are absorbed into the portal blood. The liver phosphorylates frurtose and cleaves it into glyceraldehyde and DHAP. Smaller amounts are metabolized in renal proximal tubules. The pathway is shown in Figure 1-12-7 important enzymes to remember are ... 

As one would expect for molecules having several hydroxyl groups, monosaccharides are quite hydrophilic and have high solubilities in water. Concentrated solutions of simple sugars in water are known as syrups. As noted earlier, honey is basically a thick, flavored syrup of fructose. 

Fructose a monosaccharide (hexose) found in high concentrations in honey a constituent of sucrose, common table sugar. 

Carbohydrates serve as a general and easily available energy source. In the diet, they are present as monosaccharides in honey and fruit, or as disaccharides in milk and in all foods sweetened with sugar (sucrose). Meta-bolically usable polysaccharides are found in vegetable products (starch) and animal products (glycogen). Carbohydrates represent a substantial proportion of the body s energy supply, but they are not essential. 

Fructose, another common monosaccharide found in fruits and honey, is more soluble in water than glucose and is also sweeter than glucose. It is used as a sweetener for diabetic patients, and in infusion for parenteral nutrition. 

About ten percent of the calories contained in the Western diet are supplied by fructose (approximately fifty g/day). The major source of fructose is the disaccharide sucrose, which, when cleaved in the intestine, releases equimolar amounts of fructose and glucose (see p. 86). Fructose is also found as a free monosaccharide in high-fructose corn syrup (55 percent fructose/45 percent glucose, which is used to sweeten most cola drinks), in many fruits, and in honey. Entry of fructose into cells is not insulin-dependent (unlike that of glucose into certain tissues, see p. 95), and, in contrast to glucose, fructose does not promote the secretion of insulin. 

Monosaccharides Glucose and fructose are the principal mono saccharides found in food. Glucose is abundant in fruits, sweet corn, corn syrup, and honey. Free fructose is found together with free glucose and sucrose in honey and fruits... 

Honey is a mixture of the monosaccharides glucose and fructose. Glucose is a six-membered ring, and fructose is a five-membered ring. For simplicity, the stick structures introduced in Chapter 12 are shown below each molecular model. 

Glucose is by far the most abundant monosaccharide it occurs free in fruits, plants, honey, in the blood of animals, and combined in many glycosides, disaccharides, and polysaccharides. The structure and properties of glucose will be considered in greater detail than those of the other monosaccharides, not only because of its importance, but because much of what can be said about glucose also can be said about the other monosaccharides. 

Fructose Monosaccharide Found in most foods in small amounts higher concentrations in honey and fruit... 

Other common monosaccharides are fructose, the sugar found in fruits and honey that is also used as a preservative in foodstuffs, and galactose, found in milk sugar. Sucrose, or table sugar, is a disaccharide made up of glucose and fructose molecules bonded together. The chemical names of sugars always end in -ose. ... 

Most important carbohydrates, such as starch and cellulose, are polymers composed of monomers called monosaccharides, or simple sugars. The monosaccharides are polyhydroxy ketones and aldehydes. The most important contain five carbon atoms (pentoses) or six carbon atoms (hexoses). One important hexose is fructose, a sugar found in honey and fruit. Its structure is... 

Carbohydrates are of major interest in ferod science. The monosaccharides and Starches present in natural and processed foods have a marked effect on their color, texture, consistency, and pa la lability. l,actose, the major carbohydrate of milk, can limit its acceptability as a food for those with lactose intolerance. Slowly digestible carbohydrates are used in the diets of certain diabetics, who must eliminate or restrict their intake of foods containing rapidly absorbed carbohydrates such as candies, honey syrup, and jam. 

Fructose, a monosaccharide sugar, occurs naturally in honey and a large number of fruits. It may be prepared from inulin, dextrose, or sucrose by a number of methods. Commercially, fructose is mainly manufactured by crystallization from high-fructose syrup derived from hydrolyzed and isomerized cereal starch or cane and beet sugar. 

Fructose is a sugar found in honey and fruits. Monosaccharides can have various numbers of carbon atoms, and we name them according to the number of carbon atoms they contain by adding prefixes to the root -ose. The general names of monosaccharides are shown in Table 21.3. Notice that fructose is a ketone with six carbon atoms and five —OH substituents. Fructose is a member of the hexose family, where the prefix hex- means six. 

Besides, fructose and glucose, the presence of the monosaccharide D-galactose, in very low quantities (traces) also already was related in honey samples (Goldschmidt Burket, 1955). However, it is important to emphasize that this monosaccharide when in its free form is considered a toxic compwund to the honeybees (Siddiqui, 1970). Moreira De Maria (2001) reviewed about carbohydrates in honey, and repwrted several di-, tri-, and ohgosaocharides presented in honey and they came from nectar. 

The first step is searching out a flower to pick up some nectar. Nectar is a mixture of sugar and water. Specifically, the sugar in nectar used to make honey is sucrose, a disaccharide (see Biochemistry ). A honeybee produces enzymes in its body that Ctm break down the sucrose into monosaccharides, fructose, and glucose as well as gluconic acid. These sugars are the primary constituents of honey. Most of the water evaporates, which is what makes honey so viscous and sticky. 

Sucrose is produced in a high state of purity on an enormous scale—more than 80 million tons per year. About 40% of the world s sucrose production comes from sugar beets and 60% comes from sugarcane. A comparison of the sweetness of common sugars and artificial sweeteners relative to sucrose is given in Table 15.1. Honey, which is a mixture of the monosaccharides glucose and fructose, has been used for centuries as a natural sweetener for foods and is sweeter than sucrose, or cane sugar (Table 15.1). To convert cane... 

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