Hemicelluloses dietary fiber

Antenucci, R.N., Method of making a hemicellulose coated dietary fiber. United States Patent, US4927649, 1990. 

Dietary Fiber. Dietary fiber is a broad term that encompasses the indigestible carbohydrate and carbohydrate-like components of foods that are found predominantly in plant cell walls (see Carbohydrates). It includes cellulose lignin, hemicelluloses. pentosans, gums, and pectins. 

Dietary fiber has been suggested to play a protective role against chemically-induced toxicity (1) and against colon cancer (2). However, the mechanism(s) by which dietary fiber modulates chemical toxicity or colon cancer has not been well studied. The fiber fraction of the diet is resistant to mammalian digestive enzymes and consequently dietary fiber is not absorbed from the small intestine (3). However, certain types of dietary fiber specifically fermentable fibers, including the pectic substances and hemicelluloses, are readily digested by the intestinal microflora (4,5). Pectic... 

Wheat bran contains several different forms of dietary fiber including hemicellulose. Some but not all purified dietary fiber sources have been found to have an adverse effect on manganese bioavailability (10). 

Cauliflower has a very high waste index (Kulkami et ah, 2001) and is an excellent source of protein (16.1%), cellulose (16%), and hemicellulose (8%) (Wadhwa et ah, 2006). It is considered as a rich source of dietary fiber and it possess both antioxidant and anticarcinogenic properties. Phenolic compounds and vitamin C are the major antioxidants of brassica vegetables, due to their high content and high antioxidant activity (Podsedek, 2007). Lipid-soluble antioxidants (carotenoids and vitamin E) are responsible for up to 20% of the brassica total antioxidant activity. The level of nonstarch polysaccharide (NPS) in the upper cauliflower stem is similar to that of the floret and both are rich in pectic polysaccharides, while the cauliflower lower stem is rich in NPS due mainly to cellulose and xylan deposition (Femenia et ah, 1998). 

The major components of dietary fiber, cellulose and the hemicelluloses, form complexes with iron (2 D Dietary fiber may promote the conversion of iron II to iron III in some circumstances. Such a conversion would tend to decrease iron availability. 

Cellulose is the most abundant organic molecule in nature. It is a polysaccharide assembled from glucose monomer units, and it (together with other materials such as hemicellulose and lignin) is the main constituent of plant cell walls. Along with several undigestible polysaccharides, cellulose constitutes the main part of dietary fiber. Specifically cellulose is one of the components of insoluble fiber. 

In legume seeds such as SB, the main constituents of dietary fiber are cellulose, hemicelluloses, pectins, and glycoproteins or proteoglycans, found in the parenchymal cells of the cotyledons (Selvendran et al., 1987). The main fiber components of... 

Dietary fiber comprises a heterogenous group of carbohydrates, including cellulose, hemicellulose and pectin, and a noncarbohydrate substance, lignin (19). According to Van Soest (20), fibers can be classified into three groups vegetable... 

Purified plant fibers for dietary purposes are combinations of cellulose, lignin, hemicellulose, gums and pectinaceous substances that exert chemical and physical actions in the gastrointestinal tract. Dietary fiber complexes such as wheat bran contain not only the fiber components but also other organic compounds that contribute to nutrition. In comparison to wheat bran, the deproteinized and decolorized fiber complexes of tobacco and alfalfa have favorable chemical composition as dietary fibers. Their low concentrations in starch and lipids... 

Glucomannan is the most commonly used form of the hemicelluloses. The chain structure consists of a linear backbone of (l,4)-linked p-D-mannopyranosyl units to which (l,6)-linked a-D-galactopyranosyl units are snbstituted. The Man Gal ratio in the chemical structure of glucomannan shown in Figure 28.4 is 2 1. Glucomannan is a water-soluble polysaccharide that is considered a dietary fiber. It is commonly nsed as a food additive, as an emulsifier, and a thickener. It is also used in drug delivery applications. Glucomannans have been specifically derived from softwoods. 

Dietary fibers represent a gronp of carbohydrates, isolable from different plant sources, that are resistant to hydrolysis by enzymes of the gastrointestinal tract. They are divided into two groups water soluble fibers, among which the main are the p-glncans and arabinoxylans, and water insoluble fibers, which include lignins, celluloses, and hemicelluloses. 

Hemicelluloses occur in all plants and thus also in common diet. In the human nutrition, the cell wall polysaccharides contribute to the dietary fiber, which is considered to be of salutary importance in the mobility of digesta through the alimentary tract and may have other desirable attributes, for example, in lipid metabolism [25]. 

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