The effect of amino acid and peptide alimentation on the determination of endogenous amino acid flow at the terminal ileum of the rat

Endogenous ileal amino acid (free + bound) flow was determined in four 190-g male rats given a diet whose sole nitrogen source was enzyme hydrolysed casein and compared with that of six rats whose diet contained synthetic amino acids as the only nitrogen source but excluding alanine, glutamic acid and serine, and six rats fed a protein-free diet. The enzyme hydrolysed casein, a mixture of free amino acids and oligopeptides, was assumed to be completely absorbed in the small intestine of the rat. A further seven rats were given an enzyme hydrolysed casein-based diet and their ileal digesta were treated, post-collection, with perchloric acid to precipitate soluble proteins. The latter procedure removed the need to assume complete absorption of the casein nitrogen. The endogenous flow of amino acids for enzyme hydrolysed casein-fed rats was higher than that for the protein-free diet (P < 0.05) which did not differ from the synthetic amino acid diet for the flows of alanine, glutamic acid and serine. The high apparent digestibility of the synthetic amino acids not excluded from the diet indicated that their ileal excretions were mainly of endogenous origin. It would appear, therefore, that the protein deplete state per se does not influence endogenous amino acid flow at the terminal ileum of the growing rat, but there is a direct effect of small peptides on the net loss of endogenous amino acids from the small intestine. The estimates of endogenous amino acid flow obtained following the perchloric acid treatment of digesta were unrealistically low and thus inconclusive, but raised doubt as to the eficiency of perchloric acid in precipitating protein from rat ileal digesta.     

Supplementation of pig diet with algal fibre changes the chemical and physicochemical characteristics of digesta

Seaweed extracts, because of their physicochemical characteristics and potential nutritional value, could provide a new source of dietary fibre. This study investigated changes in seaweed fibres (physicochemical and fermentative properties) in different digestive sites and their effects on digesta (viscosity and hydration properties). Sixteen pigs were adapted to a test diet supplemented with 5% algal fibre (either Palmaria palmata (PP), a poorly viscous soluble xylan; or Eucheuma cottonii (EC), a partly insoluble carrageenan; or Laminaria digitata (LD), a highly viscous soluble alginate) or 5% cellulose (reference fibre). PP did not modify the characteristics of digesta and was fermented in the caecum (pH 6.1 ± 0.4; short‐chain fatty acids measured in digesta, 1409 ± 691 µmol g⁻¹ dry matter). EC and LD were mainly insoluble in the stomach, becoming soluble in the intestine; EC was slightly fermented in the colon, giving a low concentration of short‐chain fatty acids (303 ± 122 µmol g⁻¹ dry matter). Supplementation of the diet with alginate (LD) increased 3.5‐fold the ileal viscosity of digesta and their hydration capacity in the ileum and colon. Thus the physicochemical properties of pig digesta largely depend on the physicochemical properties of the ingested seaweed fibre, the pH and ionic conditions prevailing in the gut, and their fermentability. © 2000 Society of Chemical Industry     

Breakdown of plant carbohydrates in the digestive tract of pigs fed on wheat‐ or oat‐based rolls

Cell wall materials from various cellular tissues of cereals may potentially influence the digestion and absorption processes in different ways. The objective of the present investigation was to study the breakdown of plant carbohydrates in the gastrointestinal tract of pigs fed a low‐fibre (LF; 65 g kg⁻¹ dry matter) wheat flour‐based diet and two high‐fibre diets with added insoluble fibre from wheat bran (HFWB; 112 g kg⁻¹ dry matter) or soluble fibre from oat bran (HFOB; 108 g kg⁻¹ dry matter). The diets were formulated to provide ∼0.31 energy from fat, ∼0.18 energy from protein and ∼0.51 energy from carbohydrates and were offered as baked rolls to eight ileum‐cannulated hypercholesterolemic pigs in a crossover design. Carbohydrates were the predominant ileal constituent, with most of the carbohydrates present as non‐starch polysaccharides (NSP). Starch in all diets was almost completely digested at this site of the gastrointestinal tract, with digestibility values above 0.99. The ingested amount of NSP was quantitatively recovered in ileal materials with the wheat‐based diets, while there was a significant loss of 0.27 of NSP primarily as mixed linked (1→3)(1→4)‐‐D ‐glucan with diet HFOB. The concentration and flow of lactic acid were also highest in the ileum after feeding diet HFOB, indicating that ‐glucan stimulated lactic acid formation. Any soluble components that reached the large intestine were almost completely broken down, while the digestibility of insoluble NSP constituents was significantly lower for diets LF and HFWB than for diet HFOB. The high degradation of oat bran resulted in a lower effect on faecal dry and wet bulking than was found with wheat bran. In conclusion, cereal starch was practically completely degraded in the small intestine, while the site and extent of NSP degradation, lactic acid formation and bulking properties were influenced by the fibre source. © 2000 Society of Chemical Industry     

Comparison of methods to determine the endogenous amino acid flow at the terminal ileum of the growing rat

The aim was to compare a recently developed peptide alimentation method and the protein-free and regression methods for determining endogenous ileal nitrogen (N) and amino acid excretion in the rat, and to apply the endogenous loss estimates to determine the true ileal digestibility of a meat and bone meal (MBM). Preliminary investigations determined the effect of the time of sampling of digesta after a meal (slaughter method) for rats given a protein-free or an enzymically hydrolysed casein (EHC) based diet, on ileal digesta and endogenous N excretion. There was a significant (P < 0.05) effect of the time of sampling on the amount of digesta collected and the endogenous N excretion for both the EHC and protein-free fed rats. The amount of digesta collected from the terminal 20 cm of ileum and the endogenous N excretion for both the EHC and protein-free fed rats were greatest and least variable at 3 h post-feeding. In the main study, endogenous ileal amino acid excretions were determined in the growing rat fed an EHC-based diet (n = 6) and with subsequent treatment of the digesta using ultrafiltration or in six rats given a protein-free diet or by extrapolation from data for 30 animals given five diets which contained graded levels of MBM as the sole protein source. For the EHC treatment, the ileal digesta precipitate plus retentate was used to determine the endogenous flows. The ultrafiltration step excludes unabsorbed dietary amino acids from the measure of endogenous loss. Chromic oxide was the reference marker in all diets. The endogenous N flows determined by the protein-free and regression methods were similar but both significantly (P < 0.01) lower than those for rats fed the EHC-based diet. The mean endogenous ileal N flows determined by the peptide alimentation method, the protein-free and regression approaches were 1866, 1103 and 1019 μg g^?1 freeze dry matter intake, respectively. The endogenous amino acid flows at the terminal ileum were lower when determined using the traditional protein-free or regression methods. The true ileal digestibility coefficients for MBM were considerably higher based on the EHC versus protein-free endogenous flows.     

In vitro digestibility and colonic fermentability of aleurone isolated from wheat bran

Two aleurone preparations, isolated from wheat bran, with different levels of tissue purity, were compared to the wheat bran starting material. Chemical composition, in vitro digestibility and in vitro fermentability were investigated and microscopy was used to visualize morphological changes. Arabinoxylans constituted the main part of the dietary fibre fraction. However, the degree of branching was found to be lower in arabinoxylans from aleurone than in that from original bran. Due to the high fibre content, in vitro digestibility was rather low but digestible compounds were largely eliminated. In vitro fermentability using fresh human faecal material turned out to be higher in aleurone than in wheat bran. Moreover, the degree of purity of the aleurone preparations influenced the amount of fermentation products. Proportions of the main short chain fatty acids were very similar in all samples, with ratios of propionate and butyrate slightly above average compared to other dietary fibre sources. Arabinoxylans from aleurone were virtually completely degraded within 8 h, whereas with wheat bran, substantial amounts were still present after 24 h. Moreover, increasing arabinose:xylose ratios during fermentation suggested a better fermentability of arabinoxylans with a lower branching degree. Microscopic investigations confirmed the better fermentability of aleurone compared to wheat bran. In addition, a specific breakdown pattern of aleurone cell walls could be observed.     

Effect of condensed tannin in cottonseed hulls on endogenous ileal amino acid loss in the growing rat

The effect of condensed tannin (CT) in cottonseed hulls (CSH) on endogenous ileal amino acid flow in the growing rat was evaluated. CSH contain around 900 g kg^?1 fibre and 52 g kg^?1 total CT. Twenty-four rats were allocated to four semi-synthetic diets, which contained enzymically hydrolysed casein (EHC) as the sole source of dietary nitrogen and chromic oxide as an indigestible marker. Two of the diets contained no CSH while the remaining two contained 50 g kg^?1 CSH. At each level of hull inclusion (0 and 50 g kg^?1), polyethylene glycol (PEG: MW 3500) was added (6 g kg^?1) to one of the diets. The effect of CT was assessed by determining endogenous ileal amino acid loss in the presence or absence of PEG, which binds and inactivates CT. The rats were given their respective experimental diets ad libitum for 14 days. Samples of digesta were collected at slaughter from the terminal 15 cm of ileum. The digesta samples were centrifuged and the supernate ultrafiltered. The precipitate plus retentate (MW > 10000) fraction affords an estimate of endogenous loss. Inclusion of CSH in the EHC based diet increased ileal flow of total nitrogen (1387 versus 1623 μgg^?1 dry matter intake; P ≤ 0.05), increased ileal flow of total amino acids (23%; P ≤ 0.01), and significantly increased ileal flow of several individual amino acids. There was no significant effect of PEG and no PEG × diet interaction; showing that the CSH effects could not be explained by action of CT. The presence of hulls in commercial cottonseed meal would appear to contribute to the reported low apparent ileal amino acid digestibility coefficients for cottonseed meal by increasing endogenous ileal amino acid flow, but this effect is not due to the CT component of the hulls.     

Effect of Oral and Parenteral N Nutrition vs N-Free Nutrition on the Endogenous Amino Acid Flow at the Ileum of the Pig*

Two methods were tested for suppressing the depressive effect of N-free diets on the digestive secretions in pigs: the blood perfusion of amino acids (AA) or the peptide alimentation method. In the latter, enzymically hydrolysed casein (EHC), composed of oligopeptides and free AA, was used as the source of nitrogen. The unabsorbed dietary N molecules were discarded from the ileal digesta by ultrafiltration or gel filtration, assuming that the endogenous fraction did not contain significant amounts of small molecules. The AA supply by blood perfusion had no effect on the ileal endogenous AA losses (8·0 g AA kg⁻¹ DM intake) in growing pigs (±50 kg), compared with the N-free diet alone (8·3 g), whereas the EHC supplementation significantly increased them (18·0 g). The increase was due to both endogenous and dietary N. The presence of unabsorbed dietary AA in the ileal digesta was confirmed by the AA profile of the soluble molecules with a very low molecular mass (<3 kDa), which was close to that of EHC. Both ultrafiltration (cut-offs of 3 or 10 kDa) and gel filtration methods, utilised to discard the remaining dietary molecules, also eliminated a significant proportion of endogenous AA.     

Enzymatic degradation studies of pectin and cellulose from red beets

The influence of structural features of the cell wall polysaccharides pectin and cellulose on the enzymatic degradation of red beet was evaluated. Alcohol‐insoluble substances and acetone‐insoluble residues were prepared from red beets and characterized with respect to the content of dietary fibre, pectin fractions, neutral saccharide composition and water absorption. The high‐methylated and high‐acetylated pectin component was partly soluble in water and in EDTA. Pectin was hardly extractable from alcohol‐insoluble substances as well as from red beets. Isolated pectin could not be completely degraded by pectolytic enzymes. After de‐acetylation, the pectic acid from red beets was degradable in a similar rate like citrus pectic acid. From alcohol‐insoluble substances, several cellulose and lignin fractions were prepared and analysed. A cellulose preparation from red beets was intensely degraded by cellulases with high activities as shown by the release of reducing end‐groups, viscosity and scanning electron microscopy. Cell wall preparations from red beets were able to bind high amounts of water. A decrease in water absorption during enzymatic action or changes in viscosity and flow behaviour are sensitive markers for decomposition or depolymerization processes. Furthermore, an inhibitor of microbial enzymes was isolated from red beets and acetone‐insoluble residues. The main reason for the poor enzymatic liquefaction or maceration of red beets by pectolytic and cellulolytic enzymes is the high degree of acetylation of the pectin component.     

Enzymes of the small intestine of the calf: effect of dietary protein source on the activities of some enzymes in the small intestinal mucosa and digesta

The objective of this study was to examine the effect of dietary protein source on the morphology and enzyme activities in the small intestinal mucosa and digesta of preruminant calves. The control diet contained skim milk powder. Plant proteins from soy concentrate (unhydrolysed or partially hydrolysed) and potato concentrate were incorporated into experimental diets. Duodenal, jejunal and ileal mucosal biopsies and digesta were collected from calves fitted with simple cannulae and continuously infused with milk replacers into the abomasum. Biopsies were used for morphology measurements. The activity of dipeptidylpeptidase IV, aminopeptidases, lactase and alkaline phosphatase was estimated in biopsies and digesta. Incorporating plant protein had a limited effect on the intestinal mucosa. A partial villus atrophy and crypt hyperplasia were noted with the soy concentrate only. Decreases in the activity of dipeptidylpeptidase IV with the potato concentrate diet and of aminopeptidase N and lactase with the hydrolysed soy concentrate diet, were also observed in ileal biopsies. Mucosal enzymes were released in the lumen and most of them accumulated in digesta of the distal small intestine. The activity of aminopeptidase N and lactase in ileal digesta was higher in calves fed the soy and potato concentrate diets than in those fed the control diet. © 2002 Society of Chemical Industry     

Effects of wheat pentosans on endogenous amino acid losses in chickens

The effects of wheat pentosans on protein digestibility and endogenous amino acid losses in precision-fed chickens was investigated using the homo-arginine marker technique. Addition of pentosans equivalent to 15 g and 35 g of wheat arabinoxylans per kg diet significantly depressed (P < 005) the overall digestibility of amino acids and increased (P < 0-05) endogenous losses of amino acids, but the inclusion of cellulose or polyethylene polymer (92 g per kg diet) had no measurable effects.     

Effects of two contrasting dietary fibres on starch digestion,short‐chain fatty acid production and transit time in rats

Dietary fibres may cause dietary starch to escape digestion in the small intestine and enter the large intestine. If this results from the dietary fibres reducing the gastrointestinal transit time, those dietary fibres that reduce this the most would be expected to cause the most starch to escape digestion. We tested in rats the relative abilities of two contrasting dietary fibres, apple pectin (a soluble dietary fibre) and wheat straw (an insoluble, lignified dietary fibre), to reduce the whole gut transit time and to cause dietary starch to escape digestion. We provided male Wistar rats with a control, modified AIN‐76™ diet containing 20% fat but no dietary fibre, and with this diet containing 10% dietary fibre; the dietary fibre replaced the equivalent weight of starch in the control diet. Both dietary fibres, but particularly wheat straw, reduced the transit time compared with the fibre‐free control diet. Pectin, but not wheat straw, resulted in substantial amounts of starch in the caecal contents. This effect may result from the pectin increasing the viscosity of the digesta or causing it to gel. Large amounts of short‐chain fatty acids were found only in the caeca of rats provided with pectin. © 2000 Society of Chemical Industry     

Wheat- and barley-based diets with or without additives influence broiler chicken performance, nutrient digestibility and intestinal microflora

BACKGROUND: To our knowledge, there is scant literature on comparative broiler response to cereal diets high in soluble non‐starch polysaccharides without or with enzyme, prebiotic, probiotic or synbiotic supplementation. In the present study, the effects of a wheat‐ and barley‐based diet with or without supplemental xylanase plus β‐glucanase, inulin, Enterococcus faecium or inulin plus Enterococcus faecium, on bird performance, digesta viscosity, nutrient digestibility and intestinal microflora were compared to a maize‐based diet. RESULTS: In comparison to a maize‐based diet, the wheat‐ and barley‐based diet reduced (P < 0.05) body weight gain and feed intake, but did not affect to the feed‐to‐gain ratio. Apparent digestibility of crude fat and various fatty acids were decreased (P < 0.05) as well as apparent metabolisable energy corrected to zero nitrogen retention content. There was an increase (P < 0.05) in the viscosity of jejunal digesta and in the caecal numbers of Escherichia coli and lactobacilli, and a decrease in the ileal numbers of E. coli and lactobacilli. Performance parameters and nutrient digestibility were not affected (P > 0.05) by dietary inclusion of the additives used, with the exception that exogenous enzyme improved (P < 0.05) the apparent digestibility of crude fat and decreased the viscosity of jejunal digesta. Enzyme and Enterococcus faecium supplementation increased intestinal lactic acid bacteria, whereas inulin addition reduced the number of E. coli (P < 0.05). Addition of inulin–Enterococcus faecium decreased E. coli and increased bifidobacteria numbers in the caeca. CONCLUSION: Enzyme supplementation to a wheat‐ and barley‐based diet significantly improved the apparent digestibility of dietary fat. All four additives had a beneficial effect on the intestinal microflora of broilers. Copyright © 2011 Society of Chemical Industry     

Non-starch polysaccharides of canola meal: Quantification,digestibility in poultry and potential benefit of dietary enzyme supplementation

The non-starch polysaccharide (NSP) content as determined by gas chromatography (component neutral sugars) and colorimetry (uronic acids) was shown to be 16–22% in ten different samples of defatted canola (low glucosinolate rapeseed) seed. The non-cellulosic components of NSP accounted for 13–16% of the meal and on average consisted of arabinose (33%), xylose (13%), galactose (13%), glucose (5%), mannose (3%), rhamnose (2%), fucose (2%) and uronic acids (30%). Yellow-seeded and brown-seeded samples of canola contained similar contents of total dietary fibre although the composition of the fibre components tended to differ with the former showing a low content of lignin and associated polyphenols and a high content of NSP as compared with the latter type. NDF values tended to be lower for yellow-seeded than for brown-seeded canola due to the relatively high content of NSP in neutral detergent solubles of yellow-seeded canola. An initial balance study with laying hens showed low (<3%) digestibility of the polysaccharide components, and further studies were conducted with a commercial enzyme preparation (SP249, Novo Laboratories Ltd, Lachine, Quebec) to enhance the in-vivo hydrolysis of the NSP fraction of the meal. Laying hens were fed a semipurified diet containing 40% commercial canola meal with and without enzyme (1%). NSP digestibility was increased to 37% by the enzyme supplementation.     

The effect of digesta sampling time and dietary protein source on ileal nitrogen digestibility for the growing rat

The effect of time that digesta were collected on the quantity and representativeness of ileal digesta and on the determination of apparent and true ileal nitrogen (N) digestibility for growing rats was investigated. Semi‐synthetic diets containing chromic oxide as an indigestible marker were given to 200 g live weight rats for 8 days as a single daily meal. The experimental treatments comprised six diets (lactalbumin, soy protein isolate, wheat gluten, fish, protein‐free (PF), enzymically hydrolysed casein (EHC)) and four ileal digesta sampling times (3, 4, 5 and 6 h after the start of feeding). On the eighth day the rats were fed and slaughtered according to treatment, and digesta were sampled from the terminal ileum. Endogenous ileal nitrogen excretion was determined using both the protein‐free and peptide alimentation methods. There was a significant (P = 0.027) effect of experimental diet averaged across sampling times for chromium recovery (CrRec). The CrRec was higher for the rats fed the PF diet than for the other diets. Responses to sampling time varied significantly (P < 0.05) among diets for ileal digesta weight (IDW), nitrogen/chromium (N/Cr) ratio, ileal digesta weight relative to dry matter intake (IDW/DMI), CrRec, N flow, apparent N digestibility and true N digestibility (determined using the protein‐free method). The optimal digesta sampling times for each of the diets were 3 h for PF, EHC, lactalbumin and fish and 4 h for soy protein isolate and wheat gluten. Consequently, 3 or 4 h after the start of feeding is recommended as the optimum ileal digesta sampling time for most purified protein sources when fed to the growing rat as a single daily meal. © 2002 Society of Chemical Industry     

Preparation and analysis of dietary fibre constituents in whole grain from hulled and hull-less barley

Sixteen different barley samples (7 of which were hull-less; H-L) were milled and subjected to pre-extraction with ethanol and hexane. Water soluble materials (WSM-TP-AI), containing mostly β-glucans, were purified from the hot water extracts by the use of heat-stable amylase. Crude arabinoxylans were extracted by an alkali solution (WUM-B-S) and purified by the use of β-glucanase and amyloglucosidase, giving AX. Finally insoluble fibre residues were obtained (WUM-B-R). GC and NMR analyses revealed no marked quantitative and qualitative differences of β-glucans or the water-soluble arabinoxylans in WSM-TP-AI between the H-L and the hulled (H) varieties. Significant differences among the two barley types were found in the Ara/Xyl ratio of the starting materials as well as the alkali soluble material (WUM-B-S) and the alkali insoluble residue (WUM-B-R). For alkali soluble AX the H samples had the lowest arabinose content. A single-tube preparative isolation procedure for starch-free barley fibre was used. Combined with NMR and GC this is a tool to produce defined fibre fractions for biological testing.     

Effects of enzymatic treatment conditions on dietary fibre content of wheat bran and use of cellulase-treated bran in cookie

A commercial cellulase preparation (Viscozyme Cassava C) was employed to process wheat bran to improve the ratio of insoluble to soluble dietary fibre. The effects of initial moisture content, enzyme dosage, and incubation time on the content of soluble and insoluble fibre during the enzymatic treatment were investigated. The appropriate conditions for the cellulase treatment were initial moisture content of 0.75 g water g⁻¹ dry matter, enzyme dosage of 9 U g⁻¹ dry matter and incubation time of 120 min under which the ratio of insoluble to soluble fibre of wheat bran was lowered by 42%. Untreated and cellulase-treated wheat bran was incorporated into cookies at levels of 0%, 20%, 30%, 40% and 50%. Cookie with 50% cellulase-treated bran showed 21% lower ratio of insoluble to soluble fibre as well as 14% lower hardness and 13% higher overall acceptability than sample with the same amount of untreated bran.     

Diurnal Variation in the Composition of Ileal Digesta and the Ileal Digestibilities of Nutrients in Growing Pigs

Diurnal variation in the chemical composition of digesta and its effect on nutrient digestibilities of diets varying in dietary fibre content was examined in pigs fitted with a PVTC-cannula at the terminal ileum. The pigs were fed three times a day (08:00, 16:00 and 24:00 h). A barley control diet and four barley-based diets containing two levels (100 or 200 g kg^-1 diet) of alfalfa meal or white clover meal and Cr₂O₃ as an indigestible marker were fed according to a 5×5 Latin square design. In each experimental period, digesta were collected for 1 h every third hour on each of two separate sampling days, covering in total a 24 h period. The concentration of dry matter (DM), crude protein (CP), ash and chromium (Cr) in the ileal digesta varied in relation to time of feeding. However, the patterns were similar after all three meals (08:00, 16:00 and 24:00 h) and independent of diet. The maximum DM, CP and ash contents were reached 4–5 h post-feeding. The highest (P < 0·05) DM concentration was found in the ileal digesta of pigs fed the barley control diet. The DM concentration decreased (P < 0·05) as the inclusion level of alfalfa meal and white clover meal was increased. The lowest DM concentration was found for the highest inclusion level of alfalfa meal. The ileal digestibilities of both organic matter and CP were lower 1–2 h post-feeding compared with those recorded 3–5 h later, indicating that the less digestible components of a diet have shorter transit times. The pooled ileal digestibilities of organic matter and CP from the three 8 h periods (08:00–16:00 h, 16:00–24:00 h, 24:00–08:00 h) did not differ (P < 0·05) from each other. Therefore, the estimate of digestibility can be based on digesta samples collected from any interval between two consecutive meals. However, care must be taken to obtain representative samples of digesta between meals. © 1997 SCI.     

Effect of particle size of pea (Pisum sativumL) flours on the digestion of their proteins in the digestive tract of broilers

Pea (Pisum sativum L) protein digestion in relation to particle size was studied in broilers. Birds were fed coarse pea (CP) or fine pea (FP) or nitrogen-free (NF) diets. Protein digestion was studied in gastro-intestinal contents of chicks by gel filtration and electrophoresis. Apparent ileal protein digestibility was lower for CP (70·2%) than FP (89·5%) diets. A decrease of protein digestibility appeared between ileum and excreta for FP diets. Endogenous proteins in ileal digesta represented important amounts. Estimation of excreta composition was about 24% of microflora in FP and CP. The molecular weight (MW) dis-tribution of nitrogen compounds of diets were characterised by high proportions of components with MW>15000. The relative amounts of very low MW (<500) components were in all cases lower for CP than for FP digesta. In intestine, proportions of high MW (>15000) components were higher for CP than for FP fed birds. Intestinal digesta of NF diet were characterised by higher MW than FP digesta. Similar electrophoresis patterns appeared for CP digesta and pea diet, whereas fine particles of CP and FP showed disappearance of protein bands. It is concluded that the CP diet leads to lower digestion of proteins than FP, but FP diets can lead to low MW proportion in intestine, which could be a limiting factor in pea protein digestion. © 1997 SCI.     

Effect of the insoluble dietary fibre from oil palm fat-free flour on digestibility in rats

This work shows the results of comparing the effects of the insoluble dietary fibre from oil palm fat-free flour and cellulose on the growth, weight, humidity and composition of faeces in adult rats (Sprague–Dawley). Five groups of rats were fed for 4 weeks. The control group was fed with a diet free of fibre, and the remaining four groups with diets containing 50 or 100 g of either oil palm fat-free flour or cellulose, respectively. The adaptation period was 4 days. The evolution of growth and food intake did not vary significantly p<0.05 regardless of the type of diet. On the other hand, faeces excretion increased by 3.3–4.7 g/day in the groups of rats fed with oil palm fat-free flour, while it increased by only 3.1–4 g/day in diets based on cellulose. A higher content of water was observed in the faeces of rats fed with insoluble dietetic fibre from oil palm fat-free flour. The apparent digestibility of the insoluble dietary fibre of oil palm fat-free flour was low (35%), showing resistance to fermentation. The digestibility of the protein tended to decrease more with the insoluble dietary fibre of oil palm than with the cellulose, which may be related. ©     

From apple to applesauce: Processing effects on dietary fibres and cell wall polysaccharides

Modifications in dietary fibre content of apples during industrial processing into applesauce were investigated. Samplings with different post-harvest storage times were performed at five different processing steps (apple sorting, cooking, refining, sugaring and pasteurisation) and the samples examined for their insoluble, soluble and total fibre contents, following the AOAC method. Total fibres were also estimated through preparation of alcohol-insoluble solids and polysaccharide compositions of the various fibre residues were determined. Total fibre content decreased from apple to applesauce from 2.4 to 1.7 g for 100 g of fresh weight and the soluble fraction increased. Fibre loss and soluble/insoluble redistribution occurred during processing. Refining triggered a loss of insoluble polysaccharides whilst cooking and, surprisingly, sugaring led to pectin solubilisation and further degradation due to prolonged heating. These pectic changes, moreover, seemed to be dependent on the post-maturity stage of the apples.