Dietary fibres and associated compounds in rape seed and biorefined rape seed products compared to DF in pea

Abstract

Dietary fibres (DF) -their chemical composition and structure, physico-chemical properties, and physiological effects -comprise and area of increasing scientific interest. Progress in this research is, however, rendered somewhat difficult by the disagreement concerning demarcation of the DF concept. In the present study, a physiological based method of analysis for determination of total DF (TDF) corresponding to the sum of insoluble DF (IDF) and soluble DF (SDF) have been used as an initial step in studies of DF from different rape seed varieties and biorefined fractions of double low rape seed compared to DF from peas.A comprehensive characterization of DF from rape seed and peas have been performed, with determination of the neutral monosaccharide composition by different techniques as a first step. The yield of sugars, especially glucose, was found highly dependent on the procedure used for hydrolysis of the polysaccharides. The composition of the polysaccharide fractions also differed according to the type of plant material. This diversity was further emphasised by results from sequential extraction and separation of isolated DF leading to fractionation of DF into four groups: pectins, hemicelluloses, celluloses, and lignins. UV-VIS-spectroscopy of extracts from these groups provided useful information concerning the presence of material of non-carbohydrate origin. The hemicellulose fractions from peas and especially rape seed were shown to have the highest content of proteins and phenolics, possibly being present as strongly adsorbed or covalently bound components. The protein part of the DF fractions was further investigated by biochemical methods of analyses including affinity chromatography, electrophoresis as SDS IEF, and the presence of myrosinases was demonstrated in DF from rape seed. Peas also comprised DF associated proteins, although the level was considerable lower than found in rape seed DF. High performance capillary electrophoresis methods for determination of phenolics have been developed in order to provide an efficient tool for

Dietary fibres in pulse seeds and fractions: Characterization, functional attributes, and applications

“…Crude fibre analysis isolates only a part of the insoluble fibre fraction and so greatly underestimates the total dietary fibre content; nutritionally important soluble fibre components are also lost in ADF and NDF analysis (Bjergegaard, Sorensen, & Sorensen, 1997). Table 2 provides some representative values for the dietary fibre (DF) content of raw pulse seeds (including hulls), obtained using enzymatic-gravimetric methods.…”

Ileal digestibility of protein and amino acids from canola meal in weaned piglets and growing pigs

“…losses in pigs (Schulze et al, 1995;Grala et al, 1997Grala et al, , 1998aGrala et al, ,b, 1999a. Furthermore, canola hulls are rich in protein (Bjergegaard et al, 1997), and this protein has a low apparent ileal digestibility (Grala et al, 1999a). The low protein digestibility of canola meal could encourage a higher secretion of digestive enzymes, as reported in piglets by Salgado et al (2002).…”

Dietary fibres - important parts of high quality food and feeds

“…Based on the analytical method of DF determination, this fraction can be divided into insoluble dietary fibres (IDF) and soluble dietary fibres (SDF). Further separation of DF can be obtained by sequential extraction of DF in water, alkaline solution and sulphuric acid resulting in; pectins, hemicelluloses, cellulose and lignin (Bjergegaard et al, 1997). Each of these fractions are composed of heterogenous groups of compounds ( Figure 1; Table 1) with the DF source, which are in agreement with the complexity of plant cell walls.…”

“…These microfibrils are often twisted together in a ropelike fashion to generate macrofibrils. These special structural features of cellulose result in molecules which are nearly insoluble in water, and for analytical purposes concentrated sulphfuric acid is used initially as solvent for cellulose (Bjergegaard et al, 1997). Cellulose in the cell wall is, however, more than a collection of fibrils, as it is associated with several other types of biomolecules as pectins, hemicelluloses, proteins, glycoproteins, lignins and other phenolics (Figure 1), forming the matrix.…”

“…the possibility of binding I¡ in the helix for each about six D-Glc p units resulting in blue coloured complexes. This is a typical property of amylose, but amylopectins will also, although to a much less extent, give such colour reaction which can be utilized in analytical procedures (Bjergegaard et al, 1997). The extended chain resulting from the y5-(l-4) linked D-GIC/J in the cellulose polymers ( Figure 2) gives thus a big difference in the polymer structure of cellulose compared to the structures of amylose ad amylopectins.…”