The extraction of radiolabelled inorganic sulphate from blood plasma

A study was conducted into factors governing the efficiency of the ion exchange method for extracting ³⁵S-labelled inorganic sulphate (SO) from blood plasma, using Dowex′1-X8 ion exchange resin. The study compared effects of trichloroacetic acid (TCA) strength as protein precipitant, different HCl strengths as resin eluent, sodium citrate/HCl (SC/HCl) versus HCl as eluents, and evaluated ultrafiltrated (UF) plasma upon the adsorption and recovery of added ³⁵SO. Both adsorption and release of ³⁵SO from the resin were inhibited by the presence of TCA, and HCl was not as effective as 1 M SC/2 M HCl in releasing ³⁵SO adsorbed to resin. The rates of ³⁵SO adsorbed onto resin and recovered were markedly increased by using UF plasma and 1 M SC/2 M HCl as eluent, with the values being 96.3 ± 0.11% and 91.1 ± 0.39%, respectively, where 1 g resin was used. Therefore, the use of UF for deproteinising and 1 M SC/2M HCl as eluent are recommended for extracting ³⁵SO from blood plasma when Dowex′1-X8 resin is used as the ion exchanger.     

Quantity/intensity relations in soils and the potassium nutrition of the strawberry plant (Fragaria SP)

In glasshouse pot experiments over two years, the strawberry plant used potassium primarily from sources which were in instantaneous equilibrium with the soil solution. Leaf potassium concentration at flowering and fruiting was highly correlated with the initial equilibrium potassium activity ratio (AR) of the soil, and a linear relationship existed between 1/Leaf-K and 1/AR Yield of fruit was less well correlated with AR than with the quantity of labile potassium in the soil. the gradient of the straight line part of the quantity/intensity (Q/I) graph was increased for 2 of the 5 soils after the period of intensive cropping; this could be related to an increase in the amount of exchangeable calcium+magnesium in the soil.     

Dissolution of various sources of gypsum in aqueous solutions and in soil

The dissolution of six sources of gypsum in water and 0.01 M CaCl₂ was examined in the presence and absence of soil. The gypsum samples included: analytical grade (AR), three sources of flue-gas desulphurisation (FGD) gypsum, phosphogypsum (PG), and mined gypsum (MG). Dissolution in aqueous solutions was monitored by measuring the concentration of calcium (Ca²⁺) and sulphate (SO) ions. In soils which adsorb small amounts of SO^?2₄, dissolution was estimated from the increase in the concentration of Ca²⁺ and SO in gypsum-treated soil over the control soil. However, in soils which adsorb significant amounts of SO, measurement of solution SO concentration underestimates the extent of dissolution. Gypsum dissolution was larger in water (15.20 mmol litre^?1) than in 0.01 M CaCl₂ (11.12 mmol litre^?1), and this was attributed to the Ca²⁺ common-ion effect. The rate of dissolution decreased in the order: AR > FGD > PG > MG. Dissolution was 2 to 10 times faster for powdered (< 500 .m) gypsum than for the discs obtained by pelletising. The differences in the rate of dissolution between the gypsum sources and between powder and disc samples were related to both surface area and the presence of CaCO₃, impurity. The rate of dissolution was 3 to 8 times faster in the presence than in the absence of soil. Whereas the dissolution of gypsum in the presence of soil followed first order reaction kinetics, it followed second order kinetics in the absence of soil. This difference in reaction kinetics resulted from the continuous removal of Ca2+ and SO by the soil.     

Intrinsic viscosities and apparent specific volumes of amino acids and sugars. ‘Effective size’ and taste of sapid molecules

Intrinsic viscosities ([η]) and apparent specijic volumes (V) are compared for a number of amino acids and simple sugars and their derivatives. While the sugars and their derivatives fit within a narrow range for both parametevs ([η])=2.27–2.61 cm³ g^?1; V=0.60–4.69 cm³ g^?1), the amino acids cover a much wider band ([η]) = 1.29–4.20 cm³ g^?1; V=0.562–0.712 cm³ g^?1). The intrinsic viscosity value of any particular amino acid is always greater than the corresponding apparent specijc volume, and ranges (at 10 mg g^?1) between two and seven times the value of the apparent specific volume. For the sugars and sugar derivatives, on the other hand, the intrinsic viscosities are always three to four times greater than the values of the corresponding apparent specijic volumes. When concentration is increased, all apparent specific volumes increase but they remain relatively constant if they are expressed as parachors (Vγ^1/4). Differences between the sugars and amino acids originate in the greater structural diversification of the latter molecules which in turn accords with their greater range of taste qualities.     

Interaction between cow slurry and 15N-labelled calcium nitrate as fertilisers for ryegrass production

A field-plot experiment with ryegrass was carried out to study the interaction between ¹⁵N-labelled calcium nitrate at 0, 25 and 50 kg N ha^?1 and cow slurry supplying 0, 33 and 68 kg NH-N ha^?1. Treatments were applied on a single occasion to a site where first-cut silage had just been removed. The effects of the treatments on dry matter yield, nitrogen offtake and % utilisation of calcium nitrate were measured in two cuts of herbage taken after 5 and 17 weeks. Increases in dry matter yield due to slurry were smaller at the 50 kg N ha^?1 rate of calcium nitrate than at the 0 and 25 kg N ha^?1 rates, possibly due to non-linearity of the yield response curve. Nitrogen offtake data indicated that the two sources of nitrogen were taken up additively by the ryegrass. Rate of calcium nitrate application or slurry treatment had no significant effect on the % utilisation of calcium nitrate in either cut. The average values for % utilisation of calcium nitrate over all treatments were 50 and 7% at cuts 1 and 2, respectively. There was no evidence for enhanced rates of denitrification in the presence of slurry. Recovery values of nitrogen (estimated by difference) were lower for NH-N in slurry than for calcium nitrate. Volatilisation of ammonia from surface-spread slurry is the most likely reason for the low efficiency of NH-N in slurry.     

Effect of nitrogen fertiliser on the nitrate contents of field vegetables grown in Britain

The nitrate and percentage organic nitrogen contents of 14 vegetable and two arable crops were measured after they had been grown with different levels of N-fertiliser. Foliage crops always contained substantial quantities of nitrate which increased with increase in the rate of N-fertiliser application. Grain of legumes and cereals, storage roots of carrots, parsnips and sugar beet, and onion bulbs and leeks contained no detectable amounts of nitrate even when N-fertiliser application rates were very high. Storage roots of red beet, swede and white turnip contained more than 3 mg NON g^?1 dry weight when grown with exceptionally high levels of fertiliser-N but contained very little when grown with the optimum amount of fertiliser-N or less. An equation was developed that linked NON to percentage organic-N for those parts of plants that could accumulate nitrate. It gave good fits to the data from seven crop species grown at a range of different levels of N-nutrition. It is estimated from the foregoing data and a survey of household food consumption that the average British person consumes about 60 mg NON week^?1 in field vegetables. If N-fertilisers were withheld consumption would be about 30 mg and if excess were applied it would be about 120 mg NON week^?1.     

Determination of plant iron,manganese and zinc by wet ashing procedures

The efficacy of HNOHClO₄ and HNOHClO₄-HF digestion mixtures for wet ashing of selected plant samples of field and greenhouse origin for Fe, Mn and Zn analyses was studied. The ternary digestion mixture was required for the determination of Fe, but not of Mn and Zn, in six unwashed field-grown samples, including four botanical Standard Reference Materials from the US National Bureau of Standards. The ternary digestion mixture was also required for the analysis of Fe in both washed and unwashed tops of field-grown flax (Linum usitatissimum L.). However, washing appreciably reduced plant Fe and Mn, presumably by removing soil contamination. In addition, the superiority of the ternary digestion mixture for Fe analysis was much less for the washed samples. The contents of Fe, Mn and Zn in washed tops of greenhouse-raised flax and soya beans (Glycine max L. Merr.) were similar with both digestion mixtures. It is recommended that in plant nutrition studies involving Fe, the efficacy of HNOHClO₄ digestion procedures be routinely checked by completely dissolving any siliceous residue with HF.     

Oxidation and transformation of elemental sulphur in soils

The oxidation of ³⁵S-S⁰ (³⁵S-S⁰, sulphur flowers) added to four cultivated soils was well described using first-order kinetics. The half-life (t_l/2) of ³⁵S-S⁰ ranged from 12 days in a paddy soil to 176 days in an Ultisol. During the early phase of oxidation, a large proportion of the oxidised S was incorporated into organic fractions. After the first week any additional ³⁵S-S⁰ oxidised remained primarily as SO-S in most of the test soils. The amount of KH₂PO₄- extractable ³⁵S-SO-S as a percentage of total oxidised ³⁵S-S was at a maximum when approximately half of the added ³⁵S-S⁰ was oxidised. By the end of the 56-day incubation period, with the exception of the Ultisol, 54–70% of the oxidised ³⁵S-S in the test soils was present as ³⁵S-SO-S. The remaining oxidised S is presumed to have been converted into organic matter fractions. This ³⁵S-organic-S could be fractionated into the 0.1 M KH₂PO₄-extractable organic- S (5–13% of total oxidised ³⁵S-S) and the 0.01 M NaOH-extractable organic-S (14–23% of total oxidised ³⁵S-S). With the exception of the Ultisol where the undetermined organic S was about 36%, the amounts of unaccounted for S (not directly measured), in all soils were very small (typically less than 4%).     

Kinetics of coffee infusion: a comparative study on the extraction kinetics of mineral ions and caffeine from several types of medium roasted coffees

A comparative study of the equilibrium concentrations, rates of infusion and intra‐bean diffusion coefficients of caffeine, P (as H₂PO ), K⁺, Mg²⁺ and Mn²⁺ in Milli‐Q‐Water at 80 °C was carried out. Medium roasted coffees of particle size range 1.70–2.00 mm from six different countries—Special Kenya (Kenya), Santos (Brazil), Blue Mountain Java (Sumatra), Mocha (Ethiopia), Zimbabwe (Zimbabwe) and South African Grown (South Africa)—were used in the investigation. High‐performance liquid chromatography was used for the analyses of caffeine, and inductively coupled plasma atomic emission spectrometry for the chosen elements. The equilibrium concentrations of all the species and the trend were found to be independent of the various coffee beans. The order of the rate of infusion was found to be K⁺ > caffeine > P (as H₂PO) > Mg²⁺ > Mn²⁺. Examination of the rate constants clearly indicated that P (as H₂PO), Mg²⁺ and Mn²⁺ cannot be used for identification of the coffee origin, but the values for caffeine and K⁺ can be used. Diffusion coefficients of caffeine and mineral ions were calculated in two separate ways using rate constants and half‐lives of infusion. These were then compared with known diffusion coefficients of the same species in water for determination of hindrance factors. The hindrance factor for caffeine was found to be much smaller than the corresponding factors recorded at 25.5 °C. In general the hindrance factors in the bean were all of the order of 10, with Mn²⁺ being the most hindered species. This is an indication that the infusion of the various species through the coffee bean is a hindered process. This is because of the association of caffeine and mineral ions with other coffee solubles and the physical restraint within the bean matrix. © 2000 Society of Chemical Industry     

Ion chromatographic determination of inorganic anions in vinegar samples

An ion chromatographic procedure (IC) with chemical suppression is described for the simultaneous determination of the anions Cl^?, NO, HPO and SO at ppm levels in vinegar samples. The moderately strong eluent composed of NaHCO₃/Na₂CO₃ was chosen and sample pretreatment was required to reduce the influence of acetate on the chloride peak. The results obtained by IC were compared to those from standard methods.     

The relative merits of the presence of hull on the nutritional qualities of the African yam bean flour

The flour from three colour cultivars of hulled and dehulled seeds of the African yam bean (AYB) (Sphenostylis stenocarpa) was analysed for anatomical fractions; proximate, mineral, fatty and amino acids composition. The seed hull varied between 8.25% and 9.14%. Na, K. Ca, Mn, Fe, Zn are preferably found in the hulled samples. Essential fatty acids as well as essential amino acids are more enriched in the hulled samples than in the endosperm. Correlation coefficient results showed that proximate composition (r, r, r), mineral composition (r, r, r), fatty acids (r, r, r), fatty acids saturation (r, r, r) and amino acids (r, r, r) were significant at α = 0.05 in the samples shown in parentheses with values having high positive correlation coefficients ranging from 0.82 to 1.00. These results showed that dehulling of African yam bean seeds will lead to reduction in the nutritional qualities of the AYB.     

Reducing gaseous losses of nitrogen from cattle slurry applied to grassland by the use of additives

Losses of nitrogen (N) through ammonia (NH₃) volatilisation and denitrification were determined following the application of cattle slurry to grassland in autumn or spring. Denitrification was examined on two contrasting soils. A system of small wind tunnels was used to measure NH₃ loss and an acetylene inhibition technique for denitrification. Between 31 and 84% of the ammonium N (NH-N) applied in slurry was lost through NH₃ volatilisation. Acidifying the slurry to pH c 5.5 prior to application reduced these losses to between 14 and 57%. On a freely drained loam soil, denitrification from unacidified slurry applied in the autumn at 80 m³ ha^?1 was continuous throughout the winter, with the maximum rate of 0.91 kg N ha^?1 day^?1 occurring a few weeks after slurry application. The total denitrification losses were equivalent to about 29% of the NH-N applied for this treatment and 41% for the acidified slurry. The nitrification inhibitor dicyandiamide reduced the amount of N lost through denitrification by 70% when applied with the slurry at 25 kg ha^?1, by 55% at 20 kg ha^?1 and by 30% at 15 kg ha^?1. The nitrification inhibitor nitrapyrin did not appreciably reduce denitrification. Denitrification losses were consistently small from slurry applied to the freely drained loam soil in spring, or to a poorly drained, silty clay in autumn or spring. Neither nitrification inhibitor was of benefit in these situations.     

Analysis of proanthocyanidins in coffee pulp

Data are presented for the condensed tannins content of pulp prepared immediately from die cherries of three cultivars of freshly harvested coffee beans, and for the pulp after drying. The data have been interpreted with reference to purified quebracho profisetinidins (3.13–6.17% on a dry basis (db)) and to the E% values of the anthocyanin pigments formed by oxidative depolymerisation (0.60–1.19% db). Pulp from a yellow-fruited cultivar was significantly richer (P < 0.001) than pulp from the associated red-fruited cultivar. In contrast to previous reports the presence has been established of condensed tannin in the pulp at the time the cherry was harvested although an increase was observed on subsequent drying. Prodelphinidins could not be detected, but the presence of procyanidins was confirmed. Analysis of procyanidin dimer-rich and procyanidin oligomer-rich fractions suggested that while dimers dominate in undried pulp, dimers may be converted to oligomers during drying. Measurements of haemoglobin precipitation (relative astringency) were generally consistent with increased tannin content/polymerisation after drying but little interaction with methylene blue was detectable in any sample.     

Effect of Various lons on the Kinetics of Retrogradation of Concentrated Wheat Starch Gels

The effect of various ions on the mode and kinetics of concentrated wheat starch gels retrogradation was investigated. The anions SCN^-, I^-, NO, Br⁻, F⁻ and SO, and the cations K⁺, Li⁺ and Na⁺ were tested at 0,4-M concentration. Teh results, based on the Avrami theory, indicated that the mechanism of starch crystallization is instantaneous nucleation followed by rod-like growth of crystals regardless the ion present. The retrogradation rate for the halogens anions increased in the following order: I⁻, Br⁻, CI⁻ and F⁻. The retrogradation rate for the cations increased in the following order: K⁺, Li⁺ and Na⁺. The results obtained were dependent of the charge distribution of the anions studied.     

The rheological properties of diluted solutions of 11 S-globulin isolated from soybeans by using selective thermal denaturation of 2 S- and 7 S-globulins

A simple and effective method of isolating 11 S-globulin (glycinin) from soybeans has been developed, which is based on the use of selective thermal denaturation of other components in globulin fraction. Glycinin content in the final preparation accounts for 97%, and its yield constitute about 1 g per 100 g of defatted flour (about 7% of glycinin content in flour). According to differential scanning microcalorimetry, the isolated preparation in terms of thermodynamics is identical with glycinin isolated by the method of THANH-SHIBASAKI with chromatography on hydroxyl apatite. The steady state viscosity of diluted solutions of the preparation was studied in four solvents: A - phosphate buffer pH 7.6, ionic strength 0.5; B - water pH 7.1, ionic strength below 0.001; C - 8 M guanidin - HCl; D - 8 M guanidine - HCl, containing 0.001 M 2-mercaptoethanol. Dependences of steady state viscosity on protein concentration (0.5 – 7.0 g/dl) and temperature (1 60 °C) were obtained. A study was also made on the fractional composition of the preparation in the indicated solvents by the sedimentation velocity method. According to the data of sedimentation velocity and viscosimetry, the molecular weights of various glycinin forms were determined. The values obtained are consistent with the published data. Analysis of the hydrodynamic properties of dodecameric and hexameric glycinin forms shows that they are similar to spheres of equal density, but of different size. In the investigated range of concentrations and temperatures, the intermolecular interactions play an insignificant role in the rheology of glycinin solutions (parameter of excluded volume according to MOONEY K α 0; excess effective activation enthalpy in viscous flow H. Only in water of about 4′ C, which is close to the temperature of glycinin precipitation, the role of intermolecular interactions is significant; this follows from the value H α 11 ± 7 kJ/mole.     

Colour score as a guide for estimating the protein value of corn gluten feed

BACKGROUND: Dry corn gluten feed (CGF) is a raw material commonly included in compound feeds, particularly for ruminant animals. Its colour can vary from yellow–light brown to dark brown. A general assumption is that darker CGF has a low nutritive value for animals due to heat‐damaged protein. This study aims to evaluate the use of colour as a practical guide for estimating CGF protein value. RESULTS: Results indicate great variability in the physical and nutritional properties among 28 sources of CGF. Principal component factor analysis was used to reduce a large number of variables into fewer numbers of factors. First factor aggregated 1/Z and acid detergent insoluble N content in opposition to X, Y, e^L, and L. Second factor aggregated a, a*, neutral detergent fibre and soluble crude protein (CP) contents in opposition to ash and CP contents, and digestible N and in vitro organic matter digestibility. Multiple regression analysis also showed that physical appearance (colour) was related to nutritional properties, stronger relationships being found between a, a* and L scores and digestible N. CONCLUSION: Colour could potentially be used to quickly predict the nutritive value of CGF, particularly digestible N, a key parameter when formulating rations. Copyright © 2011 Society of Chemical Industry     

Characterization of plasma membrane H+-ATPase from salt-tolerant yeast Candida versatilis

Plasma membrane was isolated from the salt-tolerant yeast Candida versatilis and the ATPase in plasma membrane was characterized. The ATPase was a typical H⁺-ATPase with similar properties to the Saccharomyces cerevisiae and Zygosaccharomyces rouxii enzymes. It was reacted with antibody (IgG) raised against S. cerevisiae plasma membrane H⁺-ATPase. The ATPase activity was not changed by adding NaCl and KCl to the assay solutions, but was increased by NH, especially by ammonium sulfate. In vivo stimulation of ATPase activity was observed by the addition of NaCl into the culture medium, as observed in Z. rouxii. No in vivo activation of H⁺-ATPase by glucose metabolism was observed in C. versatilis cells and the activity was independent of the growth phase, like Z. rouxii and unlike S. cerevisiae cells.     

Effect of root zone pH and form and concentration of nitrogen on accumulation of quality‐related components in green tea

Green tea quality is greatly influenced by concentrations of free amino acids, polyphenols (mainly catechins) and caffeine. The present study investigated the principal relationship between selected nutritional factors (form and concentration of N supply, root zone pH) and accumulation of these quality‐related components of tea (Camellia sinensis (L.)) plants. Tea plants were hydroponically cultured with NH , NO and NH NO at pH 4.0, 5.0 and 6.0 in one experiment and supplied with varying N concentrations (0.75, 2.0 and 4.5 mmol L^?1, NH /NO^?₃ = 3:1) in another experiment. Concentrations of free amino acids were considerably higher in NH ‐ than in NO ‐fed plants. This was attributed to the much greater absorption of NH compared with NO . Furthermore, the relative allocation of absorbed N to free amino acids, particularly theanine and glutamine, was substantially increased by NH nutrition, suggesting that NH was more readily assimilated than NO into theanine. The concentration of caffeine was increased in NH ‐ and (NH NO )‐supplied plants, whereas concentrations of catechins were reduced in (NH NO )‐fed plants. Root zone pH did not influence concentrations of most free amino acids in young shoots, with the exception of theanine, which increased at low pH (4.0) irrespective of N form; this likely stemmed from an accumulation effect, as growth decreased more strongly than N absorption. Raising the N supply increased plant N allocation to free amino acids. The increase was most striking for arginine, while theanine was only marginally affected. This may have adverse consequences for green tea quality, as less favourable taste characteristics have been attributed to arginine. Copyright © 2007 Society of Chemical Industry     

Near‐infrared transmittance spectroscopy: a potential tool for non‐destructive determination of oil content in groundnuts

The oil content of 64 samples of groundnut kernels, representing 47 genotypes, was determined by the conventional Soxhlet extraction procedure (Oil^SOX). The values of Oil^SOX ranged from 403 to 536 g kg⁻¹. The optical densities (ODs) of these samples were determined at 12 wavelengths (918, 928, 940, 950, 968, 975, 985, 998, 1010, 1023, 1037 and 1045 nm) in the near‐infrared (NIR) region using a food composition analyser (essentially a filter‐based NIR spectrophotometer). The instrument also recorded the temperatures of the sample (Temp^S) and the air (Temp^A) surrounding it. A sample holder (75 mm × 150 mm; optical path length 25 mm) was used for optical density measurement. The data obtained were subjected to multiple linear regression analysis using the ODs at 12 wavelengths, Temp^S and Temp^A as the independent (predictor) variables, and Oil^SOX as the dependent variable. The multiple linear regression equation comprising 14 predictors showed a significant relationship between predicted values of oil content (Oil^NIR) and Oil^SOX. The standard error of calibration and the coefficient of determination for calibration (R) were 3.54 and 0.821 respectively, while the standard error of prediction and the coefficient of determination for prediction were 5.82 and 0.865 respectively. The ratio of standard error of calibration and standard error of prediction was 0.608. The differences between Oil^SOX and Oil^NIR were less than ± 20 g kg⁻¹ for samples having oil contents in the range from 480 to 510 g kg⁻¹. However, for samples having Oil^SOX lower than 480 g kg⁻¹ or higher than 510 g kg⁻¹, differences greater than ± 20 g kg⁻¹ were observed. There exists scope for further refining the regression equation by using a larger number of samples for generating optical data. The results demonstrated the potential of NIR transmittance spectroscopy for determining the oil content of groundnuts in a non‐destructive manner. © 2000 Society of Chemical Industry     

Magnetic resonance imaging of connective tissue: a non‐destructive method for characterising muscle structure

A magnetic resonance imaging technique based on susceptibility‐induced contrast was used to visualise the spatial distribution of connective tissue in meat. Magnetic resonance imaging of bovine meat samples was carried out with a high‐field 4.7 T imager. Magnetic resonance images obtained with spin‐echo and gradient‐echo sequences were compared to elucidate the role of connective tissue in the additional signal losses observed in the gradient‐echo images. maps were reconstructed from the multiple gradient‐echo images, which provide quantitative information. Comparison with histological pictures indicates that these maps exhibit the overall organisation of the primary perimysium at the scale of the whole muscle. The distinct perimysial organisation shown between the Gluteo biceps and Pectoralis profundis muscles illustrates the potential of magnetic resonance imaging for characterising the muscle connective tissue structure. © 2000 Society of Chemical Industry