Composition Of Non-starch Polysaccharides Research Articles

Near infrared reflectance spectroscopy as a tool to predict non-starch polysaccharide composition and starch digestibility profiles in common monogastric cereal feed ingredients

Carbohydrates are the main components of cereal grain ingredients and are comprised predominantly of starch which varies in the rate and extent of digestibility, and non-starch polysaccharides (NSP) from plant cell walls. These components are traditionally measured by chemical methods but there is interest in developing more rapid, cost effective predictions by use of near infrared reflectance spectroscopy (NIRS) technology. In this study, around 400 samples of wheat, corn, barley, wheat bran, oats, rye, corn germ, and sorghum were collected over several years to develop global NIR calibrations. Chemical analysis was performed for NSP, including details on solubility and individual constituent sugars, as well as separate determinations of cellulose and lignin. Total starch content and starch digestibility were characterized by the method of Englyst as rapidly (RDS) and slowly (SDS) digestible starch, and resistant starch (RS) determined as total starch content minus RDS and SDS. The same samples were scanned (400 to 2500 nm, every 0.5 nm) by two NIRS machines: a Foss model DS2500 and a Bruker Tango FT-NIR (Fourier transform near-infrared spectroscopy). The NIRS calibrations were developed by using the combined set of different cereal grains. The modified Partial Least Squares Regression method was employed to establish correlations between the reference chemical analysis and the collected NIRS spectra. The correlation between the NIRS and reference data for total and insoluble NSP and the main component sugars (arabinose, xylose, and glucose) were robust (R2 = >0.97) with a 1-VR > 0.96 and RPD values > 5.3. Similarly, the NIRS predicted lignin (R2 = 0.94; 1-VR = 0.93) and to a lesser extent cellulose (R2 = 0.70; 1-VR = 0.98) but still highly correlated with the reference data. The predicted total starch content was excellent (R2 = 0.99; 1-VR = 0.99). The NIRS prediction for RDS and SDS were lower in linearity (R2 = 0.81 and R2 = 0.97, respectively) but more than sufficient to provide an estimate of the starch digestion profile for many of the raw materials evaluated. In addition, the robust NIRS predictions for total starch content, RDS and SDS could then provide information to calculate the RS fraction of the ingredients. In conclusion, compared with the reference chemical data for this large set of cereal grains the global NIR calibrations developed provide a good prediction of NSP, monosaccharide sugars, lignin, cellulose and total starch content in cereal grains, and for the first time an NIR relationship with starch digestibility fractions in the grains has been shown.

A descriptive chemical analysis of seaweeds, Ulva sp., Saccharina latissima and Ascophyllum nodosum harvested from Danish and Icelandic waters

This study aimed to discuss the chemical composition of three seaweed species commonly found in Nordic countries and its potential use in feed rations for pigs and calves. Two brown seaweeds Ascophyllum nodosum, Saccharina lastissima and a green seaweed Ulva sp. harvested from Danish and Icelandic waters were analyzed for proximate, amino acids, minerals, fatty acids and non-starch polysaccharides composition. All studied seaweeds contained low protein concentrations (i.e. 11.4–15.9 g/100 g DM). The ratio of essential amino acids (EAA) to non-essential amino acids (NEAA) was similar in all studied seaweeds (0.81−0.87). Ulva sp. had the highest ash concentration (48.2–54.4 g/100 g DM), followed by S. latissima (39.9 g/100 g DM) and A. nodosum (29.5 g/100 g DM). The most abundant macrominerals in the seaweeds were Ca, K and Na. Iodine was the most abundant micromineral in brown seaweeds (1.4–2.1 g/kg DM). Moreover, Ulva sp. had the highest Fe (5.1–8.0 g/kg DM), Mn (10.5 g/kg DM) and inorganic As (0.008 g/kg DM) concentrations. Ascophyllum nodosum had the highest crude fat concentration (3 g/100 g DM) and the highest concentration of polyunsaturated fatty acids (FAs) (37.9 g/100 g FA). Eicosapentaenoic acid (EPA) concentration was the highest in A. nodosum (7 g/100 g FA) followed by S. latissima (5 g/100 g FA) and Ulva sp. (2 g/100 g FA). Furthermore, concentration of α-linolenic acid, a precursor for EPA, was the highest in Ulva sp. (6.2–14.6 g/100 g FA). Total dietary fiber concentration was higher in the brown seaweeds (27.8–42.6 g/100 g DM) compared to the green seaweeds (17.9–21.5 g/100 g DM), where S. latissima had the highest soluble dietary fiber concentration. The high concentrations of ash and fiber may limit inclusion levels of the analyzed whole seaweeds in feed rations, mainly due to dilution of other nutrients in the feed, reduced digestibility of the feed and possible toxicities (i.e. high inorganic As). On the other hand, high concentrations of essential and valuable microminerals including I, Cu, Fe, Mn, Se were also detected in the studied seaweeds. High soluble dietary fiber concentration in S. latissima can be of interest as a fermentable substrate for probiotic bacteria. The easily digestible nutrients including, crude protein and fat were low in the seaweeds. However, the protein, fat, ash and dietary fiber fractions of the studied seaweeds were characterized by high concentrations of EAA, EFA, essential microminerals and interesting monomers of functional polysaccharides, respectively; which indicate possibilities for future use of seaweed-extracts in feed rations.

Diversity of content and composition of cell wall-derived dietary fibre in polished rice

Rice, the staple food of more than half the world's population, is consumed mainly after polishing which removes beneficial components, particularly vitamins, minerals and dietary fibre (DF). Furthermore, the consumption of polished rice and other highly refined foods has been related to high incidences of chronic non-communicable diseases, including type 2 diabetes and cardiovascular disease. We have therefore used monosaccharide analysis to compare cell wall polysaccharides in polished grain of a diversity panel of 370 rice lines, showing that DF varies in amount (by over three-fold) and in composition. The water unextractable (WU) non-starch polysaccharides (NSP) comprise up to 99.6% of total NSP with galacturonic acid and galactose being the most abundant monosaccharides. Correlation analysis of individual monosaccharides predicted pectin, arabinogalactan and glucurono(arabino)xylan as the dominant polysaccharides. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) were used to classify the lines into 10 groups which differed in both total amount and composition of NSP. This identified a small group of lines with high contents of WU NSP which may be exploited to develop new rice cultivars with high contents of DF in polished grain, reducing the risk of chronic diet-related diseases.

Differences between easy- and difficult-to-mill chickpea (Cicer arietinumL.) genotypes. Part III: free sugar and non-starch polysaccharide composition

Parts I and II of this series of papers identified several associations between the ease of milling and the chemical compositions of different chickpea seed fractions. Non-starch polysaccharides were implicated; hence, this study examines the free sugars and sugar residues. Difficult milling is associated with: (1) lower glucose and xylose residues (less cellulose and xyloglucans) and more arabinose, rhamnose and uronic acid in the seed coat, suggesting a more flexible seed coat that resists cracking and decortication; (2) a higher content of soluble and insoluble non-starch polysaccharide fractions in the cotyledon periphery, supporting a pectic polysaccharide mechanism comprising arabinogalacturonan, homogalacturonan, rhamnogalalcturonan, and glucuronan backbone structures; (3) higher glucose and mannose residues in the cotyledon periphery, supporting a lectin-mediated mechanism of adhesion; and (4) higher arabinose and glucose residues in the cotyledon periphery, supporting a mechanism involving arabinogalactan-proteins. This series has shown that the chemical composition of chickpea does vary in ways that are consistent with physical explanations of how seed structure and properties relate to milling behaviour. Seed coat strength and flexibility, pectic polysaccharide binding, lectins and arabinogalactan-proteins have been implicated. Increased understanding in these mechanisms will allow breeding programmes to optimise milling performance in new cultivars.

Review: Supplementation of phytase and carbohydrases to diets for poultry

Woyengo, T. A. and Nyachoti, C. M. 2011. Review: Supplementation of phytase and carbohydrases to diets for poultry. Can. J. Anim. Sci. 91: 177–192. Feedstuffs of plant origin contain anti-nutritional factors such as phytic acid (PA) and non-starch polysaccharides (NSP), which limit nutrient utilization in poultry. Phytic acid contains phosphorus, which is poorly digested by poultry, and has the capacity to bind to and reduce the utilisation of other nutrients, whereas NSP are indigestible and have the capacity to reduce nutrient utilisation by encapsulation. Supplemental phytase and NSP-degrading enzymes (carbohydrases) can, respectively, hydrolyze PA and NSP, alleviating the negative effects of these anti-nutritional factors. In feedstuffs of plant origin, PA is located within the cells, whereas NSP are located in cell walls, and hence it has been hypothesized that phytase and carbohydrases can act synergistically in improving nutrient utilization because the carbohydrases can hydrolyze the NSP in cell walls to increase the accessibility of phytase to PA. However, the response to supplementation of a combination of these enzymes is variable and dependent on several factors, including the type of carbohydrase supplement used, dietary NSP composition, calcium and non-phytate phosphorus contents, and endogenous phytase activity. These factors are discussed, and areas that need further research for optimising the use of a combination of phytase and carbohydrases in poultry diets are suggested.

The effect of storage on the solubilization pattern of bean hull non-starch polysaccharides

The storage of Carioca bean at 30 °C and 75% relative humidity for eight months altered the solubilization pattern of hulls non-starch polysaccharides. The polysaccharide physicochemical pattern changed, resulting in a shift in the composition of water-soluble and water-insoluble polysaccharides caused by the insolubilization of galacturonans and xyloglucan. Hulls make up 10% of whole beans, which showed an increase of about 5% in water-insoluble polysaccharides and a decrease of about 1% in water-soluble polysaccharides with aging. These values suggest that cotyledons and hulls together account for an increase of about 2 g of water-insoluble polysaccharides and a decrease of 1.5 g of water-soluble polysaccharides per 100 g of beans. This change in the polysaccharide composition may produce a considerable difference in the dietary fiber profile. The alterations observed in bean hull non-starch polysaccharide composition were similar to those previously observed in the cotyledon.

Non-starch polysaccharide composition of two cultivars of banana ( Musa acuminata L.: cvs Mysore and Nanicão)

Fruits represent a rich source of soluble and insoluble fibre, and the pectin is the most common and known soluble fraction from the cell wall solubilization occurring during fruit ripening. Banana fruit, for example, is one of the most consumed fruits in the world, but its non-starch polysaccharide composition is almost unknown. Despite few works have been carried out about the enzymes concerning cell wall loosening focusing banana ripening, there is no knowledge about the composition of the banana cell wall. Moreover, there is no information about the influence of the cultivar in that composition. Nanicão and Mysore cultivars were chosen for this work because of their differential accumulation of both starch during development and amounts of total fibre in the ripe fruit. Nanicão and Mysore had their fibres subfractioned and their composition analysed. Results showed that the cultivars are distinct not only in terms of starch and soluble sugars accumulation, but also in non-starch polysaccharides amounts and composition. Non-starch polysaccharides are similar in total amounts in both banana cultivars (∼3.5), but substantially different in the content of CDTA and NaOH-4M soluble fractions and also in the molecular mass distribution of WSP and CDTA. Nanicão has more calcium-linked pectin than Mysore, which in turn is richer in hemicellulose-like polysaccharides. Both cultivars likewise cereals polysaccharides seem to be composed of galacturonans and arabinoxylans.

Effect of liquid to feed ratio, steeping time, and enzyme supplementation on the performance of weaner pigs

Two experiments were conducted to examine the effect of liquid to feed ratio, steeping time, and enzyme supplementation on performance of weaner pigs. In Expt 1, 40 male weaner pigs (weaned at 27 days of age) were randomly allocated to 4 treatments, including a dry control and 3 liquid diets of differing liquid: feed ratios (2 : 1, 3 : 1, and 4 : 1). Pigs were fed individually. Bodyweight was measured weekly and feed intake measured daily. The results confirmed the advantage of liquid feeding but indicated that liquid: feed ratio had very little effect on performance of weaner pigs. Whereas the digestible energy (DE) content of the 2 : 1 and 3 : 1 diets was similar to the control diet, the DE content of the 4 : 1 diet was significantly lower, possibly due to the removal of the insoluble marker (long chain hydrocarbon) by the amount of water in the diet.In Expt 2, the effect of a xylanase and steeping time on pig performance was assessed in a 2 × 2 factorial design (2 steeping times, 1 h v. 15 h; enzyme addition, + v. –). Sixty male weaner pigs (weaned at 27 days of age) were randomly allocated to 4 treatments and fed individually for 3 weeks. Bodyweight was measured weekly and feed intake measured daily. The experiment revealed that both steeping and enzyme addition increased feed intake (P�<�0.01) and growth rate (P < 0.05), suggesting that both techniques influence the non-starch polysaccharide composition of the wheat-based diet. Feed conversion ratio (FCR) tended to be improved more by steeping than by enzyme addition (P = 0.06). The results would suggest that steeping improves FCR by allowing increased hydration of feed and subsequent activation of the endogenous enzymes present naturally in grains.The present study was designed to test the hypothesis that the water: solid feed ratio would affect nutrient availability to weaner pigs fed liquid diets.

Effects of feed enzymes on nutritive value of soyabean meal fed to broilers

1. The effects of two enzyme products on the nutritive value of soyabean meal (SBM) were investigated with the emphasis on changes in composition of non-starch polysaccharides (NSP) along the digestive tract. Enzyme A was a commercially available product containing mainly hemicellulase, pectinase, β -glucanase and some protease activities and Enzyme B was an experimental product with mainly β -galactanase activity. 2. Enzymes were added at the recommended dosage (normal) and at 5 times the recommended dosage (high) to a semi-purified diet based on maize with SBM as the sole protein source. 3. The enzymes had no effect on digesta viscosity in the jejunum or ileum. 4. Enzyme A at the high dosage significantly (P < 0.05) improved AMEN, reduced excreta moisture content and improved ileal protein digestibility. The addition of the same enzyme at the recommended dosage had no effect on any of the above parameters. 5. Analysis of the monosaccharide composition revealed that Enzyme A tended to reduce the amounts of rhamnose and galactose in the soluble and insoluble NSP fractions in the jejunal and ileal digesta. The reduction was significant (P < 0.05) when the same enzyme was added at the high dosage. 6. Enzyme B significantly (P < 0.05) improved AMEN of the diet but not the growth or the feed conversion ratio (FCR) of the birds. Enzyme B at the high dosage significantly reduced (P < 0.05) ileal protein digestibility. 7. Enzyme B significantly (P < 0.05) increased the amount of free sugars in the jejunum and reduced (P < 0.05) the concentration of soluble NSP in the ileum. 8. Analysis of the monosaccharide composition in the jejunal and ileal digesta showed that this enzyme was highly effective in releasing galactose from both the soluble and insoluble NSP fractions. 9. It is concluded that glycanases with galactanase and pectinase activities supplemented at appropriate dosages can improve the digestibility of the NSP in SBM and increase the metabolisable energy content of the diet containing high levels of SBM. 10. Furthermore, the addition of Enzyme B at the high dosage significantly (P < 0.05) reduced protein digestibility without any measurable reduction in growth performance.

Effect of food enzymes on utilisation of lupin carbohydrates by broilers

1. The effects of 3 commercial enzyme products on the nutritive value of 2 lupin species were investigated with the emphasis on changes in composition of non-starch polysaccharides (NSPs) along the digestive tract. Enzyme A contained primarily cellulase, β -glucanase and xylanase activities, enzyme B primarily hemicellulase, pentosanase and xylanase activities, and enzyme C primarily hemicellulase, pectinase and β -glucanase activities. 2. The enzymes were added to semi-purified diets based on sorghum and casein containing 35% whole seed lupins (Lupinus angustifolius cv Gungurru or Lupinus albus cv Kiev mutant). Control diets contained no lupins. 3. Food conversion ratio (FCR), excreta moisture content and apparent metabolisable energy (AME) were affected by lupin species but not by enzyme supplementation. 4. In diets with L. angustifolius, enzyme C significantly increased digesta viscosity and increased the concentration of soluble NSPs in all sections of the intestine. 5. Digestibility of protein and NSPs in the ileum and microbial fermentation in the ileum and caeca were not affected by adding enzymes to diets containing L. angustifolius. 6. Enzyme addition to diets with L. albus did not affect digesta viscosity nor concentration of soluble NSPs but caused a significantly (P <0.05) reduced concentration of insoluble NSP in the ileum. 7. Enzyme addition to L. albus significantly (P <0.05) increased NSP digestibility in the ileum but had no effects on protein digestibility and fermentation in the ileum and caeca.

Hull-less barley for swine: ileal and faecal digestibility of proximate nutrients, amino acids and non-starch polysaccharides

The nutritive value of three hull-less barley cultivars (Condor, Falcon and CDC Buck) were evaluated. The samples were analysed for proximate composition, amino acids and non-starch polysaccharides (NSP). Wheat and normal barley were used for comparison. Apparent digestibilities were determined with eight cannulated pigs. The diets were formulated to have all energy and protein supplied by the cereals. Compared to normal barley, hull-less barley has higher contents of protein and amino-acids, and lower levels of fibre components. The levels of several essential amino acids in hull-less barley are higher than in wheat. No obvious differences in NSP composition were observed, but the hull-less barley contained considerably higher levels of β-glucan compared to hulled barley and wheat. In digestion trials the piglets did not accept the diet in which conventional barley was formulated as the only energy and protein source, whereas hull-less barleys were well consumed. The results showed that, in the order of Condor, Falcon, CDC Buck and wheat, the overall tract digestibilities of intake energy were 83·1, 80·3, 83·2 and 82·9%, and of protein were 72·6, 69·5, 76·5 and 77·6%, respectively. The averages of apparent ileal amino acid digestibility were 56·5, 58·4, 65·3 and 65·4%, respectively. Hull-less barleys showed 20–37% ileal digestibility of total NSP. This study provides digestibility coefficients of hull-less barleys, and it is concluded that the digestibility of hull-less barley is comparable to wheat and superior to hulled barley in terms of nutrient composition and acceptability. © 1998 SCI.

Chromosomal location of factors affecting content and composition of non-starch polysaccharides in wheat-rye addition lines

Content of dietary fibre (DF) as well as content and composition of non-starch polysaccharides (NSP) were evaluated in disomic wheat-rye addition lines and octoploid triticale compared to their parental species — wheat (Grana) and rye (Dankowskie Zlote). Large variation in the contents of NSP and DF were observed in the wheat-rye addition lines, especially in the soluble fractions. The double addition of rye chromosomes led to important transgression effects on content and composition of DF in wheat grain. Chromosomes 2R and 5R increased SDF content above the rye level, whereas the 3RS arm decreased SDF content below the wheat level. The octoploid triticale demonstrated the highest content of total arabinoxylan (AX), exceeding that of rye, while the double addition of chromosomes 4R, 6R and 6RL had an impact on high expression, comparable to that of rye content of total AX in wheat grain. Chromosomes 2R and 5R notably increased the proportion of soluble non-cellulosic glucose in the NSP fraction, in contrast to the rest of wheat-rye addition lines, octoploid triticale, wheat and rye, where AX was found to be predominant among NSP constituents. The effects of single chromosome pairs on content and composition of NSP proved to be higher than the effect of the whole rye genome in octoploid triticale. The most remarkable effect, especially considering the direction of changes, was of a 3R chromosome short arm addition. The obtained data might be of interest in breeding rye or triticale with lower viscous AX content as well as rich in soluble non-starch glucose polymers, regarded as a corrective factor in modern diseases.

Non-starch polysaccharide composition and in vitro fermentability of tropical forage legumes varying in phenolic content

The fermentation kinetics of leaves of eleven tropical forage legumes varying in phenolic and condensed tannin content were investigated. The leaf samples were from Acacia cyanophylla, Chamaecytisus palmensis, Calliandra sp., Dioclea guianensis, Flemingia macrophylla, Leucaena leucocephala, Sesbania sesban, S. goetzei and three accessions of Tadehagi sp. (accession numbers 13269, 13275 and 23227). The phenolic, condensed tannin (bound condensed tannin and extractable condensed tannin) and non-starch polysaccharide (NSP ≡ to dietary fibre) contents of leaves were determined. Leaves were incubated at 39 °C with rumen micro-organisms in a habitat-simulating medium and the fermentation kinetics investigated using a pressure transducer. The NSP content of leaves both pre-and post-incubation was quantified and proportional losses of the NSP constituents calculated. The NSP content of leaves ranged from 124–252 mg g −1 dry matter, the major components in each case being cellulose-derived glucose and the uronic acids. In all samples, the most degradable NSP constituent was the uronic acids, closely followed by arabinose; cellulose-derived glucose and xylose were the least degradable NSP components. Samples ranked in terms of asymptotic gas-pool in descending order as follows: L. leucocephala = C. palmensis > D. guianensis > S. sesban > A. cyanophylla > S. goetzei > Tadehagi sp., (23227) > Tadehagi sp., (13269) > F. macrophylla > Calliandra sp. > Tadehagi sp., (13275). There were significant relationships between gas accumulation throughout the incubation and the NSP loss (NSP L) values at the end of the incubation. Moreover, the gas pool at the end of the incubation period and NSP L were significantly correlated ( r = 0.90) with a yield constant (ml gas g −1 NSP loss) of 200 ml. Furthermore, there were significant ( P ≤ 0.05) negative relationships between both gas accumulation and NSP L and the phenolic and condensed tannin content of leaves.

Predictive Modelling of the Bread-making Performance and Dough Properties of Wheat

Data describing the basic chemical composition, Farinogram, Extensogram and test baking results from 100 wheat samples were analysed by principal component analysis and partial least-square regression. The stabilities of variables in models for prediction of bread volume were investigated. Variables (e.g. bulk density, flour yield and Falling Number) with large differences in correlations with bread volume in different sample groups (cultivar and year of harvest) had to be excluded in order to create stable models. Variables related to protein content were identified as stable, and could be combined in a global predictive model. Data describing the content and composition of non-starch polysaccharides were available for 49 samples, but inclusion of these variables did not improve the performance of the model for predicting bread volume. Farinograph water absorption was largely explained by non-starch polysaccharide content, composition and structure, however.

Comparison of Different Methods for Determination of Dietary Fiber

Abstract Several methods are available for determination of dietary fiber. To increase insight into the relative merits of these methods, the acid-detergent fiber (ADF) and neutral-detergent fiber (NDF) methods of Van Soest et al., the Hellendoorn method, the method of Prosky et al. (AOAC method), and the Englyst method were compared with respect to the amount and the nonstarch polysaccharide (NSP) composition of dietary fiber determined in 4 food products. Our results show that the ADF/NDF detergent methods are inaccurate for the determination of cellulose, hemicellulose, and lignin, and that the NDF and Hellendoorn methods are less-suited for the determination of insoluble dietary fiber. There is a discrepancy between the amount and the NSP composition of the dietary fiber determined by the AOAC and Englyst methods. This is because of either overestimation of the amount of dietary fiber in the AOAC method (coprecipitation of oligosaccharides or Maillard reaction products) or to underestimation of the amount of dietary fiber in the Englyst method (loss of polysaccharides during hydrolysis or derivatization), or both. Differences in isolation methods lead to differences in amounts of soluble and insoluble dietary fiber found by different methods. For both the Englyst and the AOAC methods, calculation of the amount of soluble dietary fiber from the difference between total and insoluble dietary fiber is preferable, because large errors may occur in determining the soluble portion. We have shown that although different methods can yield comparable dietary fiber values, the NSP composition can vary greatly. Therefore, we recommend using those methods that determine specifically well-defined components of the dietary fiber. The chromatographic Englyst method is preferred for this reason, and because it gives insight into the type of polysaccharides present.

Texture of french fried potato: Chemical composition of non-starch polysaccharides

Non-starch polysaccharides of low (1.062 – 1.070) and high (1.102 – 1.106) specific gravity Netted Gem (Russet Burbank) potatoes and their fries were separated into high, intermediate and low molecular weight fractions by gel filtration and tested for their chemical composition. Polysaccharides in all three fractions were composed mainly of glucose (75.5 – 84.5%) and some fructose (9.5 – 14.5%) and galactose (6.0 – 11.0%). Results indicated that chemical composition of various molecular weight polysaccharide fractions, could not explain the differences in thermal stabilities between high and low specific gravity potatoes during frying.

Effect of cooking, pH and polyphenol level on carbohydrate composition and nutritional quality of a sorghum (Sorghum bicolor (L.) Moench) food, ugali.

1. The present work was undertaken to study the effects of cooking, pH and polyphenol level on carbohydrate composition and nutritional quality of sorghum (Sorghum bicolor (L.) Moench). Three different sorghum varieties; Dabar, Feterita and Argentine containing zero, intermediate to low and high levels of polyphenols respectively were used in the study. From these varieties uncooked, uncooked acidified, cooked, and cooked acidified diets were prepared. Diets were characterized with regard to resistant starch (RS), dietary fibre (DF), acid-detergent fibre (ADF) and amino acid content. Raw materials were further analysed for content and composition of non-starch polysaccharides and Klason lignin. The nutritional properties were studied in balance trials with rats. True protein digestibility (TD), biological value (BV), net protein utilization, digestible amino acids, digestible energy (DE) and digestible DF were used as criteria in the nutritional study. 2. Cooking at neutral and acid pH resulted in significantly higher assayed values for DF. Increase in DF could be accounted for by formation of RS. Approximately 50% of RS was recovered in the faeces. 3. In vitro values for protein associated with ADF and in vivo balance values using rats suggest that an endosperm protein fraction, kafirins, was made unavailable during cooking. This resulted in reduced TD and increased BV. It is assumed that unavailable kafirins serve as a nitrogen source for microflora in the hind-gut. 4. Dietary polyphenols changed the excretory route for N from urine to faeces. This resulted in lower TD and higher BV in Argentine (high in polyphenols) than in Dabar and Feterita (low in polyphenols), although dietary lysine (first limiting amino acid) was the same in the three varieties. 5. Variation in DE of the diets was attributed to DF, RS and the amount of faecal protein, which in turn were influenced by undigested kafirins and polyphenols.

Content and composition of non-starch polysaccharides in some norwegian plant foods

Analyses of non-starch polysaccharides have been carried out on plant material grown in Norway including potatoes, apples and some vegetables. A method which determined both amount and type of polysaccharides was used.