Levels Of Hemicellulose Research Articles

DIETARY HEMICELLULOSE INTERACTIONS INFLUENCING SERUM LIPID PATTERNS AND PROTEIN NUTRITIONAL STATUS OF ADULT MEN

ABSTRACTThe objective of the present project was to determine the effect of graded levels of hemicellulose added to a constant, plant‐based diet on serum lipid patterns and protein nutritional status of adult men. The 50‐day study was divided into a 2‐day depletion period, a 3‐day pre‐adjustment period, three 14‐day experimental periods (randomly arranged) and a 3‐day post‐adjustment period. During all adjustment and experimental periods, ground peanuts provided 6.0g N/subject/day as the near sole source of dietary protein. In addition to the oil supplied by the ground peanuts, six of the twelve subjects received butter oil while the other six received corn oil on a daily basis. During the three experimental periods, supplements of 4.2, 14.2 and 24.2g of hemicellulose were added daily to the diet. All subjects received all experimental treatments. Graded increases in hemicellulose had no demonstrative effect on nitrogen balances of subjects in strong apparent positive nitrogen balance; however, those individuals in marginal or negative nitrogen balance tended to show poorer nitrogen balances as level of dietary hemicellulose was increased. Mean blood serum cholesterol levels of subjects were slightly lowered as level of dietary hemicellulose was increased regardless of source of dietary fat. While mean serum triglyceride levels of subjects receiving the corn oil and peanut oil combination were quite constant with increases in dietary hemicellulose, the triglyceride levels of all subjects receiving the butter oil and peanut oil combination were increased as levels of dietary hemicellulose were increased.

Alkali solubility of hemicelluloses in relation to delignification

The polysaccharide composition of bark from Pinus radiata, Salix fragilis, and Populus euramericana has been determined. All the barks contained lower levels of cellulose and hemicellulose than the corresponding woods; cellulose: hemicellulose ratios were also lower in the barks. Alkali extracted all of the hemicellulose-A but only half of the hemicellulose-B from P. radiata bark without prior delignification. Similar alkaline extraction removed almost all of the hemicellulose (A + B) from ryegrass leaves without delignification. With the other samples tested only a part of the hemicellulose A and B is extracted without delignification. It is suggested that the polysaccharide so extracted represents wall hemicellulose which is not linked to lignin or other wall constituents by alkali-stable links.

Structural carbohydrate levels in kikuyu grass and ryegrass grown under identical conditions

Abstract Kikuyu grass herbage (Pennisetum clandestinum) contained higher levels of cell-wall constituents than perennial ryegrass (Lolium perenne) grown under identical conditions. Much of this difference was due to hemicellulose rather than cellulose. A similar pattern was obtained with leaf blades from glasshouse-grown plants of the two species. Kikuyu grass stolons and leaf sheaths contained higher levels of structural carbohydrates than their corresponding leaf blades. In all of the kikuyu plant parts analysed the hemicellulosa level was 90-100% of the cellulose level. In leaf blades and sheaths of a second Pennisetum (P. typhoides) the level of hemicellulose was much lower than that of cellulose, which is typical of most festucoid and panicoid grasses.

Structural polysaccharides in leaf blades and sheaths in the Arundinoid grass Chionochloa

Summary Levels of cellulose and hemicellulose were measured in standard leaf samples from four species of Chionochloa (C. flavescens, C. macra, C. rigida, C. rubra) after both acid hydrolysis and alkali fractionation. Characteristic ranges of 24–26% hemicellulose and 30–32% cellulose in the leaf samples were obtained. Chionochloa macra cellulose (26%) and C. flavescens hemicellulose (22%) were clearly below these values. Analysis of successive lengths of mature leaf blades from the four species showed little variation in cellulose over the entire length but some gradation in hemicellulose. Basal sheaths of the four species showed low levels of cellulose compared with the leaves and consequently a higher proportion of hemicellulose relative to cellulose compared with the leaves. Leaf and sheath hemicellulose was fractionated into hemicellulose-A and -B under carefully controlled conditions. Sheath hemicellulose contained a higher proportion of hemicellulose-B than leaf hemicellulose.