Carbohydrate constituents of some nigerian maize varieties grown at three soil nitrogen levels

Of eight varieties of maize analysed, average values for constituent carbohydrates in g/100g dry matter were: soluble sugars, 1·61; starch, 62·04; water-soluble polysaccharides, 2·60; alkali-soluble polysaccharides, 6·85 and cellulose, 1·08. Lignin varied from 1·18 to 1·86%. Significant varietal differences (P < 0·05) were found for the carbohydrate fractions, although differences within varieties due to nitrogen fertilisation were not significant. Soluble sugars and starch, which contribute appreciably to the energy value of the maize, ranged between 56·68% for WCUI and 67·12% for Lag ABCD. Predicted digestible energy (DE) and metabolisable energy (ME) values for pigs were in the range 4005–4073 kcal/kg and 3881–3947 kcal/kg, respectively whilst metabolisable energy for poultry varied between 3692 and 4007 kcal/kg.     

The chemical composition of nigerian onions (Allium cepa, linn)

Four Nigerian cultivars of Allium cepa were analysed for the proximate chemical composition, i.e. carbohydrate constituents, mineral make-up and the amino acid pattern to provide basic information on their nutritive value. Crude protein ranged from 6·4% in ‘Kano’ to 19·6% in ‘Oyo’, ether extract from 1·7% in ‘Kano’ to 35·2% in ‘Oyo’, nitrogen-free extract (nfe) from 18·2% in ‘Oyo’ to 85·6% in ‘Kano’. Sugars identified in 80% ethanolic extracts of samples were glucose, fructose, sucrose and an oligosaccharide containing a ketose portion. Total sugars figures ranged from 13.·2% in ‘Oyo’ to 71·8% in ‘Kano’; hemicellulose, from 8·5% in ‘Zaria’ to 13·2% in ‘Oyo’; cellulose from 10·9% in ‘Kano’ to 24·6% in ‘Oyo’. Paper chromatography of hemicellulose hydrolystates of samples revealed the presence of galactose, arabinose, xylose, rhamnose and ribose. Nitrogen-free extract overestimated available carbohydrates by 19·26% to 40·04%. The onions were rich in calcium, magnesium and potassium; ‘Oyo’ was higher in iron (8·1 mg/100 g) and the essential amino acids than other cultivars.     

Carbohydrate composition of different varieties of cowpea (Vigna unguiculata)

Twenty varieties of cowpea with the following proximate composition: dry matter, 87–94%; crude protein, 24–33% ether extract, 1–2%; crude fibre, 2–5% and ash, 2–5% were analysed for sugar contents, starch, cell wall carbohydrates and lignin. The legume seeds exhibited a total carbohydrate content ranging from 56% to 68%, the major constituent being starch. Starch values as high as 45% to 48% were obtained for some varieties although most values ranged between 37% and 42%. Ethanol-soluble sugars were verbascose, stachyose, sucrose and raffinose in varying amounts but there were only traces of fructose and glucose. Samples had total soluble sugar contents of 6% to 13%. Values for unavailable carbohydrates for most samples were 11% to 13%. Lignin was very low and ranged from 0·6% to 1·8%.     

Effects of different processes on the carbohydrates of lima bean

Changes which occurred in the concentrations of free sugars, high-molecular weight carbohydrates (water-soluble carbohydrates, starch, hemicellulose, cellulose), and lignin in 3 differently processed varieties of lima bean have been studied. Samples were boiled, autoclaved or soaked in water and germinated for 3 days. Available carbohydrates (starch + sugars) which initially ranged from 53.3 to 54.8 g/100 g dry matter in the raw varieties, decreased very drastically with germination whilst raffinose disappeared and stachyose + verbascose were reduced to trace levels. Cooking as well as autoclaving brought about slight decrease in glucose, fructose and sucrose levels and increased oligosaccharide content of all the varieties. Changes in the content of the structural carbohydrates of all processed varieties were small. Cooking and germination, however effected some reductions in total unavailable carbohydrate content. The effect of these processes on improving the nutritional value of lima beans was discussed.     

Effects of cultivar,nitrogen fertilization rate and environment on yield and grain quality of barley

Ten barley cultivars, including covered and naked types, varying in their content of total starch, amylose, protein and β-glucan, were grown in different years, at various locations and nitrogen fertilization rates. The barley cultivars showed a large variation in yield (3250–6690 kg ha⁻¹), thousand kernel weight (40–50 g), bulk weight (660–815 g litre⁻¹), starch (51–67% of DM), protein (8–15% of DM), β-glucan (3·5–5·9% of DM) and ash (1·9–2·5% of DM). The naked cultivar SW 8775 had the highest starch content and the high amylopectin cultivar (SW 7142-92, waxy) had the lowest. The waxy starch barleys had the highest protein content, while the normal starch barleys (Golf and Lina) had the lowest protein content at each N-rate. Higher content of β-glucan was found in the waxy cultivars (5·0–5·9% of DM) and high amylose cultivars (5·6–5·9% of DM) than in the other barley cultivars (3·5–4·8% of DM). The results were evaluated by analysis of variance (ANOVA) and principal component analysis (PCA), and both confirmed that nitrogen fertilization rate was of great importance for the protein content. PCA revealed that protein and β-glucan were negatively correlated with starch and yield. The ANOVA showed that the cultivar factor was significant for all variables, but especially for the β-glucan content, which responded differently to the nitrogen fertilization rate during the 2 years. In this study, environmental effects were generally of less importance than the barley cultivars for the different variables. © 1998 Society of Chemical Industry.     

Chemical Composition of Pea Fibre Isolates and their Effect on the Endogenous Amino Acid Flow at the Ileum of the Pig

Pea starch, hulls and cotyledon inner fibres, isolated from pea seeds, were incorporated in N-free diets, on a NDF-content basis, in order to study their effect on the ileal endogenous amino acid (AA) excretion in the growing pig. Maize starch and wood cellulose were selected as references. The inner fibre-containing diet was also supplemented with enzymatically hydrolysed casein (EHC) in order to test the peptide alimentation method on a diet containing a fibre source with a high water-holding capacity (WHC=10·9 g water g⁻¹ DM). The fibres were also analysed by different methods (crude fibre, NDF, ADF, enzymatic–gravimetric method, Englyst method). The fibre content of the inner fibre fraction varied widely from one method to another and ranged from 109 g crude fibre to 480 g AOAC fibre kg⁻¹ DM. Compared to the ‘maize starch+wood cellulose’ diet (11·0 g AA excreted kg⁻¹ DM intake), pea starch had no effect on ileal AA losses (9·6 g), whereas pea hulls slightly increased them (14·2 g). The AA excretion dramatically increased with the incorporation of inner fibres (28·0 g), because of their very high WHC. The addition of EHC increased the output (48·0 g) further, at a level that can hardly be explained only by an increase of the endogenous secretions. The results suggest that the NDF content of grain legume products is not indicative of their effect on the ileal endogenous AA losses in pigs and that the physiological effects of fibres along the gastrointestinal tract are due to both their chemical and physical properties.     

Chemical studies on some Nigerian carbonated and alcoholic beverages

Carbonated beverages and different brands of lager beer bottled in Nigeria were analysed for carbohydrates, proteins, minerals, vitamins and alcohol, in order to provide basic data for the appraisal of their nutritive value. Seven carbonated beverages and five brands of lager beer were so analysed. The carbohydrate content of the carbonated drinks ranged from $\text{9·52–13·93}\text{g}\text{100}\text{g}$. They all contained sucrose, glucose and fructose. Calcium ranged from $\text{0·97–1·71}\text{mg}\text{100}\text{g}$; potassium, $\text{0·21–0·27}\text{mEq}\text{100}\text{g}$; sodium, $\text{1·58–5·20}\text{mEq}\text{100}\text{g}$. They contained no detectable amount of iron, traces of vitamin C, and negligible amounts of thiamin and riboflavin. The beers contained between 2·56 and $\text{4·17}\text{g carbohydrates}\text{100}\text{g}$. The main sugar was maltose. Alcohol (by weight) ranged from 3·77% to 5·20%. They were poor sources of minerals and vitamins. Some nutritional implications of these data are discussed.     

Effect of irradiation and germination on selected nutrients of corn

The effect of germination on potential nutrients (mineral matter, protein, lipids, fibre, carbohydrates and total energy) and an antinutrient (phytate) of corn, was studied. The influence of irradiation (5–20 krad) and germination on the vitamin contents (ascorbic acid, riboflavin) was also investigated. Comparison of the coefficients of variability revealed striking differences in the contents of these nutrients as a result of germination. Total mineral matter increased from 1·15% to 1·40%, protein from 9·6% to 14·0%, lipids from 4·36% to 4·60% and fibre from 0·71% to 0·82% whereas phytate decreased from 200 to $\text{105}\text{mg}\text{100}\text{g}$ and carbohydrates from 85·5% to 70·0%. Radiation and germination significantly affected the ascorbic acid and riboflavin contents of corn (p < 0.05). A maximum value of ascorbic acid ($\text{19·4}\text{mg}\text{100}\text{g}$) was observed in the 10 krad treated seeds as compared with $\text{14·3}\text{mg}\text{100}\text{g}$ in the control after 120 h of germination. Similarly, riboflavin increased from an initial value of 1·5 μg/g to 13·1 μg/g in the 20krad sample as compared with 6·0 μg/g in the unirradiated control.     

Changes in the non-structural carbohydrates associated with the field drying of oat forage

Two trials were conducted to determine the sugars, fructans and starch in oat plants (Avena sativa L) and the changes occurring in these carbohydrate fractions during field drying in the haymaking process. The composition of oat herbage in non-structural carbohydrates varied markedly between years; the contents of sugars, fractals and starch in both leaf blade and non-leaf blade materials being nether in 1990–1991 than in 1991–1992. Field drying produced a significant decrease (P < 0.05) in the amount of soluble carbohydrates. For the whole aerial plant parts, the decline in the fructans concentration ranged between 42.8 and 38.2% and that of sugars between 16.5 and 5.8%. The total losses of sugars and fractions in hay, expressed as losses of dry matter, ranged from 88 to 63 g kg^?1 depending on the year.     

The vitamin C content of some kiwifruits (Actinidia chinensis planch., variety hayward)

Skin, outer pericarp, inner pericarp and core, respectively comprised 4·8, 43·7, 45·0 and 6·5% of a mean whole kiwifruit weight of 111·3 ± 1·3 g. Kiwifruit weights ranged from 99·0 to 125·3 g. Vitamin C content per 100 g edible flesh ranged from 37·8 to 53·6 mg with means of 43·7 ± 1·7 mg for total vitamin C,41·9 ± 1·5 mg for ascorbic acid (AA) and 1·7 ± 0·4 mg for dehydroascorbic acid (DHA). Vitamin C contents were found to be at least half previously reported contents, possibly due to losses during storage and transportation from New Zealand. Total vitamin C concentrations per 100 g of skin, outer pericarp, inner pericarp and core were 41·7 ± 3·1 mg, 42·9 ± 2·0 mg, 45·5 ± 2·3 mg and 42·3 ± 2·6 mg, respectively. Outer and inner pericarp contained similar concentrations of both AA with 40·7 ± 1·7 mg and 42·7 ± 2·1 mg, and DHA with 2·1 mg and 2·8 ± 0·7 mg per 100 g tissue, respectively. Skin and core contained lower concentrations of AA with 28·1 ± 2·4 mg and 31·1 ± 2·2 mg, and correspondingly higher contents of DHA with 13·5 ± 2·4 mg and 11·2 ± 1·3 mg per 100 g tissue, respectively. Whole fruit weight correlated with DHA concentration in both skin (r = ?0·644) and core (r = ?0·693).     

Effect of added glucose and xylose on the fermentation of perennial ryegrass silage inoculated with Lactobacillus plantarum

Perennial ryegrass (Lolium perenne L) was ensiled in laboratory silos after addition of glucose or xylose at rates of 0, 25, 35 and 45 g kg^?1 fresh grass. In addition, an inoculum of Lactobacillus plantarum, supplying 10⁶ organisms g^?1 fresh grass, was applied to all treatments. Silos were opened after 7, 21 and 100 days and the silage was subjected to chemical and microbiological analysis. AH silages were well fermented with pHs between 3·60 and 3·70 and low NH₃-N concentrations (<95 g kg^?1 total nitrogen) and an absence of butyric acid. Glucose was virtually completely consumed within 21 days but 0·30–0·50 of the xylose doses remained after 100 days. Lactic acid concentrations were not increased by the addition of sugars, but the glucose treatments were associated with very high concentrations of ethanol, 60–100 g kg^?1 DM, and the xylose additions produced very high concentrations of acetic acid, 60–135 g kg^?1 DM. Most(>0·80) of the glucose that disappeared could be accounted for in ethanol formation but the xylose consumed could be accounted for only if the lactic acid produced in its fermentation was metabolised further to acetic acid; indeed, for the two higher doses of xylose, the concentrations of lactic acid were reduced from the control value of 177 g kg^?1 DM to 140 and 120 g kg^?1 DM, respectively. The results indicate that the provision of extra sugar, as hexose or pentose, allows yeasts to assume a more prominent role in the fermentation with consequent wasteful fermentation of sugars. Furthermore, the suggestion is that xylose may indirectly, via a stimulation of lactate-assimilating yeasts, encourage further metabolism of lactic acid to acetic acid.     

FERMENTATION OF MINOR WORT CARBOHYDRATES BY BREWING YEASTS

Typical worts prepared from all-malt grists and from those using a proportion of adjuncts contain maltulose, maltotriulose, isomaltose, panose and isopanose at concentrations between 0·01 and 0·12%, and maltotetraose between 0·2 and 0·7%. Maltulose and maltotriulose are fermented by all brewing strains of Saccharomyces cerevisiae so far examined, soon after utilization of maltose and maltotriose respectively begins. Fast-fermenting strains absorb small amounts of panoses and certain of them remove some maltotetraose whereas slow fermenting strains fail to utilize these three sugars. The fast-fermenting strains utilize more isomaltose than do slow fermenting yeasts. Of the total (2–4 g/litre) minor sugars of wort, fast fermenting strains remove about 90% whilst slow fermenting strains absorb 70–80%.     

Analysis of the testaless seeds of chrysophyllum albidum: Nutritional aspects

The testaless seeds of Chrysophyllum albidum G Don from Nigeria were analysed and found to contain saponins with a foaming index < 100, 71 g kg^?1 crude fibre, 109 g kg^?1 total ash, 316 g kg^?1 carbohydrates, 364 g kg^?1 proteins and 52 g kg^?1 fixed oil on dry weight basis. They were also found to have appreciable amounts of K, Ca, P and Mg. Further analysis of the carbohydrates showed the presence of starch and the reducing sugars arabinose, galactose, glucose and mannose. The profile of amino acids showed the seeds to be rich in the essential amino acids lysine, threonine, leucine, isoleucine and phenylalanine. The fatty acids of fixed oil include 16–3% palmitic acid, 5–9% stearic acid, 41–3% oleic acid, 30–9% linoleic acid and 1–6% arachidic acid.     

Investigations of antinutritional factors of the winged bean (Psophocarpus tetragonolobus)

Twelve varieties of winged bean (Psophocarpus tetragonolobus) were analyzed for tannin, phytic acid, trypsin inhibitor, chymotrypsin inhibitor, α-amylase inhibitor and lectin. Tannin contents ranged from 1·35–6·75 mg/g of bean. Phytic acid contents ranged from 7·77–12·03 mg/g of bean and phytate-phosphorus represented a considerable percentage of the total phosphorus (44·3–54·8%). Chymotrypsin inhibitory activities were about twofold higher than trypsin inhibitory activities. α-amylase inhibitory activities could not be detected in any of the winged bean varieties used in this study. Hemagglutinating activities were observed with respect to all types of trypsinized human erythrocytes (A, B and O). However these activities disappeared completely after heating in a boiling water bath for 10 min.     

Investigations on the trypsin inhibitor,hemagglutinin, phytic and tannic acid contents of cowpea Vigna unguiculata

Ten cultivated varieties of mature dry beans Vigna unguiculata were analysed for trypsin inhibitor (TI) and hemagglutinating activities, phytic acid, phytic acid-phosphorus and tannic acid. The respective concentrations were: 19·6–28·2 TUI mg^?1 protein,¹ 33·5–98·9 HU mg^?1 protein,² 280–331 mg 100 g^?1, 131–200 mg 100 g^?1 and 0·42–0·78 g 100 g^?1 dry weight. Phytic acid-phosphorus as a percentage of total phosphorus was highest in Farv-13 (49·9) and lowest in Samaru local (29·8). Considerable variability in hemagglutinating activity was evident among the different varieties as indicated by the high percentage co-efficient of variation. Some of these differences may be genetic and may provide an opportunity for the genetic development of cowpea strains with superior protein quality, low in hemagglutinin content.     

Evaluation of nutritional and nutraceutical potentials of three wild edible mushrooms from Similipal Biosphere Reserve,Odisha, India

A variety of edible mushrooms are growing in Similipal Biosphere Reserve (SBR), some of which are used as ethno-medicine by indigenous tribals. In the present study, three wild edible mushrooms viz., Russula vesca, Russula delica and Termitomyces eurrhizus of SBR were analyzed for their nutritional and mineral contents along with antioxidant and antibacterial potential. The results showed that these three mushrooms are rich sources of nutrients (protein, carbohydrate, starch, reducing sugars and low fats), micronutrients (vitamins and carotenoids) and minerals (P, K, Mn, Co, Ni, Cd, Fe) with promising bioactive properties (antioxidant and antibacterial potentials). In general, these mushrooms revealed high amounts of proteins (22.82–35.17 g/100 g) and carbohydrates (45.68–63.27 g/100 g) and low contents in fats (2.03–4.62 g/100 g), while micronutrients (vitamins and carotenoids) and minerals were present in significant amounts. The antioxidant potentials of three different solvent extracts (ethanol, methanol and aqueous) of studied wild mushrooms showed strong antioxidant properties (ABTS, DPPH, H₂O₂ and metal chelating activities) with scavenging potential up to 89 % at concentration 100 μg/ml. Total phenol content was found between 21.92–41.99 mg catechol/g extract and flavonoid 2.53–7.52 mg quercetin/g extract. The studied mushrooms possess moderate antibacterial properties with zones of inhibition ranging from 13 to 30 mm against six human pathogenic bacteria which are comparable with Amphoxyllin standard. Being a source of nutrients and molecules with medicinal potential, the studied mushrooms can be used in human diet as nutraceuticals/functional foods for maintaining and promoting health, longevity and life quality.     

The effect of field drying on the non-structural carbohydrate composition in vetch hay

Common vetch (Vicia sativa L) was harvested and allowed to dry in the open air. The composition of fresh forage in non-structural carbohydrates varied markedly between years, the contents of sugars and starch in both leaves and stems being much higher in 1990-91 than 1991-92. Field drying produced a significant decrease in the amounts of these carbohydrates. The total losses of sugars and starch in hay, expressed as losses of dry matter, ranged from 28 to 15 g kg^-1, depending on the year.     

Characterisation of Lignin from CAD and OMT Deficient Bm Mutants of Maize

Internodes of the maize cell line W401 and bm₁ and bm₃ mutants expressed in W401 were harvested 5 days after anthesis (A5) and at silage (S) stage. The normal maize had a higher total phenolic (TP) content (80·5–90·5 g kg^-1 cell wall DM) than both bm₁ and bm₃ mutants (74·4–86·4 and 66·0– 84·2 g kg^-1 cell wall DM, respectively). TP were inversely related to cellulase digestibility with values of 85·4–91·5, 89·3–92·1 and 91·3–94·1% for normal, bm₁ and bm₃. Marked differences in p-coumaric acid concentrations were found ranging from 20·9 to 26·3 g kg^-1 cell wall DM for normal, 14·9 to 15·3 g kg^-1 for bm₁ to 10·1 to 14·4 g kg^-1 for bm₃. The ferulate pattern was entirely different with the bm₁ genotype providing the lowest total (9·1–10·7 g kg^-1) and etherified (1·9–2·3 g kg^-1) values. Although the bm₃ contained more total ferulate (11·5–13·1 vs 10·9–11·7 g kg^-1), the normal variety had a significantly greater amount of etherified ferulate (2·8–3·4 vs 3·2–4.1 g kg^-1) implying a greater extent of cross-linking between wall polymers. Recovery of guaiacyl and syringyl residues was greatest in the normal maize with the bm₁ occupying the middle position between the two extremes. Calculated S: G ratios from 4 M NaOH digestion and NMR were in good agreement with the normal line giving the highest ratio, bm₁ intermediate and bm₃ the lowest. Colorimetric analysis revealed a large increase in the aldehyde content of the in situ bm₁ lignin compared to normal and bm₃ genotypes although NMR failed to reveal significant numbers of aldehydic resonances. © 1997 SCI.     

Gross composition,amino acid,phytic acid and trace element contents of thirteen cowpea cultivars and their nutritional significance

Thirteen cultivars of cowpea (Vigna unguiculata (L) Walp) were analysed for their proximate composition, amino acid, trace element and phytic acid contents. Crude protein values ranged from 206·8 to 283·8 g kg^?1 DM. The mean contents (g kg^?1) of other major nutrients were ether extract, 18·6; ash, 38·8; total dietary fibre, 121·8 and carbohydrates, 573·4. When compared with the provisional amino acid scoring pattern of FAO, all cultivars were low in methionine and high in lysine, isoleucine, leucine and phenylalanine plus tyrosine. Values for threonine and valine were variable compared with the pattern. The range of values for the chemical score was 0·61–0·74. Phytic acid values ranged from 5·10 to 10·27 g kg^?1, and the phytate: zinc molar ratios were all higher than that (15:1) above which zinc deficiency can be induced. Most of the trace elements showed wide variation in their occurrence among the cultivars. The values for zinc and iron showed less variation. The toxic elements mercury and selenium were present in varying amounts in more than half of the cultivars while tin was found in only one variety.     

Changes in cell-wall composition and degradability of sorghum during growth and maturation

Samples of sorghum (Sorghum bicolor Moench × Sorghum sudanense Stapf, cv ‘P 988’) were harvested at five growth stages. Quantitative methylation and acetalation–methylation methods were used to examine changes during growth of cell-wall polysaccharides, their association with phenolic compounds and the effects of changes on rumen degradability. Cellulose degradability, as measured by a nylon-bag method, decreased from 82·5% at the youngest stage to 36·5% at the milk-ripe stage, at a greater rate of change than degradability of dry matter. Among the monosaccharides contributing to cell-wall polysaccharides, the degradabilities of arabinose and uronic acid residues were consistently higher than those of xylose and glucose, the main components of structural carbohydrates. Recovery of parent neutral sugars from cell wall polysaccharides, calculated as the sum of partially methylated alditols, was in good agreement with the values obtained by direct estimation of individual sugars as their alditol acetate derivatives. Total non-starch polysaccharide content increased from 31·1% to 45·1% between the first two growth states, with little change evident thereafter. The relative proportion of individual to total sugars remained consistent throughout growth. The values for arabinose, xylose and glucose residues accounted for 4·9%, 27·9% and 63·0% of total neutral sugars, respectively. The pattern of glycosidic linkages detected could be mainly ascribed to the presence of (1–4)-β-D -glucans (cellulose), arabinoxylan, (1–3)(1–4)-β-D -glucans, (1–4)-β-D -galactan, (1–3)(1–6)-β-D -galactan, rhamnogalacturonan and, possibly, xyloglucan. The cellulose content of the five sorghums was, in order of growth, 14·3%, 21·8%. 22·3%, 21·2% and 22·0% of dry matter. The ratio of the mixed-linked g1ucan:cellulose decreased during growth. Arabinoxylan, the predominant hemicellulosic polysaccharide, was estimated to comprise about 33% of total neutral sugars consistently for all sorghum samples. Arabinose, found largely as terminal residues in the cell walls, carried various amounts of alkali-labile substituents, particularly at position 0–5, depending on the growth stage of sorghum. The extent of 0–5 substitution was closely correlated with both the lignin content (total phenolics minus phenolic acids, r = 0·903) and with cellulose degradability (r = 0·915).