Composition of Dietary Fiber: Neutral and Acidic Sugar Composition of the Alcohol Insoluble Residue from Human Foods

Abstract

The alcohol insoluble residue (AIR) isolated from 12 foods was acid hydrolyzed and analyzed for neutral and acidic sugars. Aliquots taken at 1 hr were reduced, acetylated and analyzed for neutral sugar content with GLC. Glucose from cellulose, starch and noncellulosic polysaccharides was analyzed with calorimetric methods. The predominant sugars present in the dietary fiber were arabinose, xylose, galactose, glucose and uranic acids. Pectin and hemicellulose together comprised the majority of cell wall polysaccharides. Samples high in starch generally contained the greatest amounts of dietary fiber and the least amount of water on a fresh plant basis.

Studies on vegetables: fiber content and chemical composition of ethanol-insoluble and -soluble residues

“…The amount of dietary fiber for the four vegetables (Table IV) ranged between 1.1 and 4.7%, cellulosic content varied in the range 18.5-44.8%, noncellulosic neutral polysaccharide content was between 28.5 and 44.6%, uronic anhydride content was between 12.4 and 25.5%, and the lignin content was between 0.9 and 2.4%. The fiber value for celery of 1.1% compared to 1.0% (lignin excluded) reported by Bittner et al (1982) is in excellent agreement with our value. However, our cellulosic and noncellulosic polysaccharide and uronic anhydride contents and total recovery figure for celery (Table IV) are considerably higher than their values.…”

“…However, our cellulosic and noncellulosic polysaccharide and uronic anhydride contents and total recovery figure for celery (Table IV) are considerably higher than their values. A considerable variation in the values of percent dry matter for celery (5.4) reported by Bittner et al (1982) and our value (1.4) was also noted.…”

“…The results (Table I) indicated the most appropriate conditions were 72% for 1 h at 5 °C and then 1 M sulfuric acid for 2 h at 100 °C. The conditions were milder than 12 M sulfuric acid, 0.5 h, room temperature, and then 1 M sulfuric acid, 1 and 3 h, 100 °C of Bittner et al (1982) and 12 M sulfuric acid, 2 h, room temperature, and then 0.358 M sulfuric acid, 6 h, 100 °C of Theander and Aman (1979). In the context of hydrolysis it is imperative that the optimum conditions of hydrolysis be determined on the basis of the nature of the product to be hydrolyzed.…”

“…A critical review of available methods (Southgate et al, 1978) points to some of the difficulties inherent in the methodologies. The drawbacks associated with these methods have been adequately reported (Theander and Aman, 1979;Bittner et al, 1982;Selvendran and Dupont, 1984). Additional information has appeared in a book by James and Theander (1981) and a review by Asp and Johansson (1984).…”