bluuebunny/crossref_metadata_2025 huggingface dataset:
A quantitative comparison of the extraction of protein fractions from wheat grain by different solvents, and of the polypeptide and amino acid composition of the alcohol‐soluble proteins
Authors: Byers Marjorie , Miflin Benjamin J. , Smith Susan J.
Published: October 2006

Using several cultivars, whole milled wheat grain was first extracted with 0.5M NaCl to remove non‐protein N, albumins and globulins: the amount of protein subsequently extractable by either 70% ethanol, 55% propan‐2‐ol, or 50% propan‐1‐ol (with or without the addition of acetic acid), was then compared. All solvents were tested at 4, 20 and 60°C both with and without the addition of 2‐mercaptoethanol (2‐ME) as a reducing agent. Raising the temperature, including a reducing agent, and repeated extractions, all combined to maximise protein extractability; least was extracted by 70% ethanol at 4°C and most by 50% propan‐1‐ol containing acetic acid and 2‐ME at 60°C. The differing polypeptide compositions of these alcohol‐soluble fractions illustrated why N solubility alone is not a sufficient guide to protein extraction, e.g. 35% of grain N was extractable by either 70% ethanol at 60°C or 70% ethanol containing 2‐ME at 4°C, but high mol. wt polypeptides (>60000) were found only in the 60°C extract. In contrast, the complete range of alcohol‐soluble polypeptides was extracted by all solvent mixtures based on propan‐1‐ol, even at 4°C. Amino acid analyses of these alcohol‐soluble fractions confirmed the low levels of lysine in fractions free from high mol. wt polypeptides. More glycine was found in all fractions containing high mol. wt polypeptides, but only those extracted by propan‐1‐ol mixtures had an increased lysine content, the amount of which increased linearly as the extraction temperature was raised. Defatting the milled grain did not affect the extractability of alcohol‐soluble proteins, but the amount of protein soluble in 0.5M NaCl decreased. The protein rendered NaCl‐insoluble was not extracted by any of the alcoholic solvents tested, hence the N content of the residual material was increased. The inclusion of this denatured metabolic fraction in the residue will affect its amino composition. The problems arising from the retention of the classical nomenclature for Osborne‐type fractions are discussed.
Factors affecting the staling of madeira slab cake
Authors: Guy Robin C. E.
Published: October 2006

Cake staling, which is associated with changes in crumb firmness and moistness, has been shown to be related to two basic processes occurring in the crumb. These are an intrinsic firming process of the cell‐wall material of the crumb and the macroscopic migration of moisture from the central areas of the crumb to the dryer crust regions. The intrinsic firming process of the cell‐wall material of cake crumb is similar in character to that of breadcrumb and starch gels at temperatures up to 21°C. At higher temperatures it shows a significant deviation from the Avrami‐type polymer crystallisation kinetics used to describe the firming of starch gels and breadcrumb. The macroscopic migration of moisture is responsible for a secondary firming process which continues for periods of up to 5 weeks at ambient temperatures. It may also be responsible for the loss of moist‐eating quality in cake crumb.
Use of acid gel electrophoresis in the characterisation of ‘B’ hordein protein in relation to malting quality and mildew resistance of barley
Authors: Riggs Timothy J. , Sanada Matsuyoshi , Morgan Alan G. , Smith Derek B.
Published: October 2006

The ‘B’ polypeptides of the storage protein (hordein) of barley were studied in 84 varieties. On the basis of acid gel electrophoresis the varieties were classified into 13 distinct groups. Contrary to the suggestion that varieties preferred for malting tend to show less intensity of staining of the faster moving bands of the ‘B’ fraction of hordein, no consistent association was found in this study. Thus the malting potential of some varieties may be less affected by protein composition than by other factors. The genetic linkage between the Hor‐2 locus, specifying the ‘B’ group of polypeptides, and the Mlalocus, determining resistance to powdery mildew (Erysiphe graminis), was illustrated by the similar groupings of varieties carrying the same resistance alleles, but exceptions were observed. Examples of the inheritance of hordein patterns are illustrated and discussed.
Effects of soil compaction, seed depth, form of nitrogen fertiliser, fertiliser placement and manganese availability on barley
Authors: Holmes John C. , Donald Alistair H. , Chapman William , Lang Robert W. , Smith Keith A. , Franklin Michael F.
Published: October 2006

Investigations on light soils from 1977 to 1981 revealed important effects and interactions of husbandry methods and fertiliser placement on barley growth and yield which were largely due to their effects on Mn availability to the crop. Thus combine‐drilling an acidifying fertiliser (but not a non‐acidifying fertiliser) with the seed rather than broadcasting it, was very effective in controlling Mn deficiency and increasing yield substantially on Mn deficient sites. Soil compaction was beneficial where the fertiliser was broadcast, primarily because it forced shallow sowing of seed and thus kept the seminal roots near the acidifying fertiliser. Deep sowing of seed greatly reduced yield when fertiliser was broadcast but not when fertiliser was placed near the seed. These effects and interactions explain why poor crops were frequently associated with loose seedbeds, deep sowing and broadcast fertilisers.
Constitution of leguminous seeds. Polyacrylamide‐disc gel electrophoresis of acid soluble and acid precipitated proteins prepared from baby lima beans
Authors: Alli Inteaz , Baker Bruce E.
Published: October 2006

Acid soluble proteins (bipyramidal crystalline, 76.9% protein, 15% carbohydrate) prepared by citric acid extraction and acid precipitated proteins (amorphous, 64.2% protein, 11.3% carbohydrate) prepared by alkali extraction from baby lima beans (Phaseolus lunatus) were found to behave in a similar manner under alkaline conditions (pH 8.9) of electrophoresis (absence of urea). Striking differences were observed in the behaviour of the two types of protein preparations when electrophoresis was performed under acidic conditions (pH 4.5; absence and presence of urea and a mixture of urea and 2‐mercaptoethanol) and in the presence of sodium dodecyl sulphate.
Volatile constituents of feijoa—headspace analysis of intact fruit
Authors: Shaw G. John , Ellingham Peter J. , Birch Edward J.
Published: October 2006

The volatile constituents emanating from intact feijoa fruit during storage were concentrated on to Tenax GC using a headspace trapping technique. Analysis by gas chromatography and gas chromatography‐mass spectrometry led to the identification of 11 components of which myrcene, ethyl hexanoate, trans β‐ocimene, 2‐heptyl butanoate, cis hex‐3‐enyl butanoate and cis hex‐3‐enyl hexanoate are reported for the first time. Measurement of sequential changes in the aroma profile following natural abscission of the fruit suggests that ethyl benzoate may be an important compound in determining optimum ripeness of feijoa. Gas chromatographic sniffing trials on the headspace concentrate led to the conclusion that ethyl butanoate, methyl benzoate and ethyl benzoate are important in the aroma of intact feijoa fruit.
Analysis of tomato fruit: Effect of frozen storage on compositional values—an inter‐laboratory study
Authors: Buret Michel , Gormley Ronan , Roucoux Pierre
Published: October 2006

Tomato culturing trials often result in too many samples to analyse while fresh. The most common technique is to seal them in containers and preserve them by deepfreezing for subsequent analysis. An inter‐laboratory study has been made of the effect of freezing for various lengths of time on a number of compositional factors. Tests for soluble solids, dry matter content, electrical conductivity, titratable acidity, potassium, pH, glucose, fructose, sucrose, total N and Vitamin C in frozen tomatoes indicated that the levels of most of these constituents remained relatively constant during frozen storage and were similar to values found in the fruit prior to freezing. When the tomatoes were frozen as a purée it was essential to thaw them in the stabilising/ extracting solution used in the Vitamin C analytical procedure, otherwise there was a large loss in ascorbic acid.
Variations in the determination of the digestibility and metabolisable energy content of a maize silage
Authors: Phipps Richard H. , Fulford Rosemary J. , Cottrill Bruce R.
Published: October 2006

Maize silage which was freeze‐ or oven‐dried had 0, 2, 4, 6 and 8% or 0 and 8% by weight of pure maize starch added, respectively. The samples were analysed for invitro DOMD content at three different laboratories. There were significant differences (P<0.01) between laboratories and method of sample drying. Higher values were recorded for the freeze‐dried material. Nevertheless similar samples were generally ranked in the same order at different laboratories. The increase in in‐vitro DOMD values with increasing starch suggests that the technique is able to distinguish between maize silages of varying grain contents. Samples were also analysed for MAD fibre and and their ME content estimated from it and also by the gas production method now widely used in Germany. The gas production method produced higher ME values and these were closer to the results obtained from in‐vivo trials.
Nitrogen, sulphur and other mineral elements in white clover and perennial ryegrass grown in mixed swards, with and without fertiliser N, at a range of sites in the UK
Authors: Whitehead David C. , Barnes Ralph J. , Jones Lloyd H. P.
Published: October 2006

Perennial ryegrass (Lolium perenne L. cv. S23) and white clover (Trifolium repens L. cv. Blanca) were grown in mixed swards, with and without fertiliser N as ammonium nitrate, at 12 sites in the UK. Grass and clover separated from herbage harvested in May, July and September, have been examined for N, S and other major mineral elements, in relation to the nutrition of both the crop and ruminant animals. The total N content was greater in the clover than in ryegrass at each site, both with and without fertiliser N. The S content of the clover was similar to that of ryegrass at the first harvest in May, but was lower in July and September. There were large differences between the species in the ratio N:S, the average being 17.1:1 in white clover and 8.6:1 in ryegrass. The proportions of the total S present as sulphate were higher in ryegrass, with a mean of 48%, than in the clover, with a mean of 16%. The contents of Mg, and particularly of Ca, were higher in clover, while K was generally higher in ryegrass. Consequently, the ratio K: (Ca+Mg) was always at least twice as high in the ryegrass as in the clover. In some of the ryegrass, but none of the clover samples, it exceeded 2.2:1, the value above which there is an increasing risk of hypomagnesaemia in ruminant animals. The content of total cations (Ca + Mg + K + Na) was on average 37% greater in the clover than in the ryegrass, while the content of total inorganic anions (but including organic P) was much less in the clover. The content of organic anions, as calculated from the difference between the contents of total cations and inorganic anions, was at least twice as great in white clover as in ryegrass.
Changes in the levels of polyphenols in three pear varieties during bud development
Authors: Wilson Michael F. , Blunden Christine A.
Published: October 2006

The polyphenol content of three orchard pear varieties, Conference, Doyenne du Comice and Williams bon Chretien as determined between November 1981 and March 1982 as a preliminary part of a study to ascertain the basis of dietary self‐selection by bullfinches. The varieties most susceptible to bird damage, Conference and Williams, were shown to contain higher levels of extractable phenolic material than the partly bird‐resistant variety, Comice. There were no major intravarietal differences between buds of the same variety collected at different areas of the same site. The significance of these results is discussed.
The condensed tannin content of vegetativeLotus pedunculatus, its regulation by fertiliser application, and effect upon protein solubility
Authors: Barry Thomas N. , Forss David A.
Published: October 2006

The condensed tannin concentration inLotus pedunculatus(cv. Grasslands ‘Maku’) was 8–11% DM when grown in acid soils without fertiliser application and 2–3% DM when grown in high fertility soils. Application of P & S fertiliser to the acid soils increased DM yield and reduced condensed tannin content to 4–5% DM, with over 88% of the variation in condensed tannin content being explained by variation in DM yield; it also increased plant total N concentration and halved the molar ratio of condensed tannin: protein (MR). Condensed tannins quantitatively precipitated soluble protein in lotus and also effectively precipitated protein in mixtures of lotus with white clover. The minimum concentration of condensed tannin necessary to precipitate protein was 2–4% DM, corresponding to MR values of 6–13. However, protein from such mixtures could be deaminated by fermentations with rumen fluidin vitro, but potentially soluble protein in pure lotus (MR 29) was protected from deamination by condensed tannins. A portion of lotus tannin could not be bound by plant constituents in finely ground fresh herbage and was designated ‘free’ tannin. This fraction was linearly related to total plant tannin content, was predicted to be zero at 1.8% DM total tannin, and increased at 0.15 units per unit increase in total tannin content above this figure. Maximum ‘free’ tannin comprised 17% of total condensed tannin. Effects of total and ‘free’ tannin content upon the intake and digestion of lotus by sheep are discussed.
Pectic substances in developing and ripening plum fruits
Authors: Boothby Derek
Published: October 2006

The fresh weight of plum fruits increased throughout the growing season whilst the weight of ethanol insoluble material increased to a peak in the penultimate sample and then declined. Pectin content paralleled the change in weight of the insoluble residue. There were no significant changes in the proportional composition of monosaccharides in pectin or the total solids. Pectic substances were examined by gel permeation chromatography and high voltage electrophoresis. There was no evidence for extensive degradation of the pectic substances, but changes in the electrophoretic mobility were consistent with de‐esterification during ripening.
An enzyme‐linked immunosorbent assay for species identification of raw meat
Authors: Whittaker Robert G. , Spencer Terence L. , Copland J. W.
Published: October 2006

An enzyme‐linked immunoassay has been developed to differentiate between unprocessed beef, sheep, horse, kangaroo, pig and camel meats. Microtitre plates were coated with meat extracts at pH 5.5 and the bound meat proteins reacted with species‐specific rabbit antisera. The antisera were prepared by inoculating rabbits with serum from the required species and were purified by affinity chromatography on appropriate immobilised serum columns to remove cross‐reacting antibodies. Rabbit anti‐bodies bound to the meat proteins were detected using staphylococcal protein A conjugated to horse‐radish peroxidase. The assay is able to detect contamination as efficiently as the currently employed Ouchterlony immunodiffusion test. In addition it has the following advantages: (a) testing can be performed in approximately 3 h; (b) less volume of species‐specific antisera is required; (c) antisera can be mixed for simple screening procedures; (d) equipment is avilable to semi‐automate the assay procedure and the recording and reporting of results; (e) increased sensitivity, in the terms of amount of material required, allows use of simpler sampling techniques.
Effectiveness evaluation for a non‐absorbable antioxidant (Anoxomer) using a high pufa lipid system
Authors: Ke Paul J. , Cervantes E. , Robles‐Martinez C.
Published: October 2006

An investigation for the antioxidative effectiveness of a non‐absorbable, polymeric antioxidant, Anoxomer, with the PUFA mackerel skin‐model lipids has been evaluated by accelerated oxidation at 60°C. The oxidation rate of the tested samples was mainly followed by measuring the weight gain and changes of TBA value and FFA content. Effectiveness of antioxidation for Anoxomer in the mackerel skin lipids was also compared with other synthetic compounds, BHA, BHT and TBHQ. Overall, the order of effectiveness for inhibiting the oxidation was found to be TBHQ > Anoxomer > BHA > BHT at the concentration of 0.02% in the tested model lipids. In addition, Anoxomer was also shown to slightly reduce the formation of FFA and carbonyls. The effectiveness of Anoxomer at the level of 0.05–0.10% is recommended for the highly unsaturated lipids and related food products.
Effect of maturity on some chemical constituents of Sri Lankan pepper (Piper nigrum L.)
Authors: Jansz Errol R. , Balachandran Subramaniam , Packiyasothy E. Velupillai , Ratnayake Sunil
Published: October 2006

Pepper (Piper nigrum L.) is traditionally harvested immature in Sri Lanka. The effect of maturity on starch content, volatile oil content and composition and piperine content is reported here. Although maturity affected the essential oil and piperine content, the oil composition remained largely unaffected. Most oil synthesis appeared to have taken place by 23 weeks. The piperine content reached a maximum (14.2%) at 19 weeks and then declined, although the total content per berry continued to increase until full maturity. As expected, starch synthesis dominated the second half of development, attaining a value of over 50% dry weight on ripening. Immature harvest alone cannot explain the relatively high levels of piperine and volatile oil in Sri Lanka pepper.
Descriptive analysis and quality ratings of 1976 wines from four bordeaux communes
Authors: Noble Ann C. , Williams Anthony A. , Langron Stephen P.
Published: October 2006

Twenty‐four wines from four communes in Bordeaux were evaluated by descriptive analysis by trained assessors. The same 1976 wines were assigned quality ratings by Masters of Wine (MW). The major aroma difference between the wines was attributed to variation in the intensity of the ‘green bean/green olive’ character by canonical variates analysis (CVA) of the aroma descriptor ratings across wines. The CVA of the flavour by mouth ratings showed the wines to be discriminated primarily on the basis of astringency and bitterness. By multivariate analysis of variance across regions, and by examination of the configurations derived from the CVA across wines, it was shown that the wines did not vary significantly between communes. No significant difference between the wines in quality ratings of the MWs was found.
Chemical and biological assay procedures for lysine in fish meals
Authors: Barlow Stuart M. , Collier Grant S. , Jurtiz June M. , Burt James R. , Opstvedt Johannes , Miller Eric L.
Published: October 2006

Sixteen laboratories from different countries undertook chemical tests to determine the lysine content of 8 samples of fish meal. The chemical tests were total lysine (gas liquid chromatography or ion exchange chromatography), dye binding capacity (DBC), dye binding lysine (DBL), and reactive lysine (FDNB). The same samples of fish meal were analysed for biologically‐available lysine in four laboratories by chick feeding experiments. Estimates of lysine by all methods except DBC differed significantly between laboratories, but generally meals were ranked similarly by each laboratory. The largest estimate of between laboratory variance, and also the poorest concordance of ranking of the meals by the different laboratories was shown by DBL. The chemical methods for measuring lysine gave means which were significantly different from the bioassay results. However, all the chemical methods gave values which correlated with the bioassay values. The DBC, DBL and FDNB methods gave similarly high correlation coefficients while total lysine was less well correlated. Use of the chemical methods to predict values for biologically‐available lysine gave wide confidence limits which are likely to encompass the variability in the majority of commercial fish meal samples. Consequently none of the chemical methods can be regarded as satisfactory for the purpose of distinguishing between normal commercial samples of fish meals in terms of an absolute content of biologically‐available lysine. The chemical methods may, however, be used in a more limited sense to detect differences in quality between meals of known history without indicating any absolute values for biologically‐available lysine. The dye binding methods appear suitable for process control within a fish meal factory where the analyses are carried out in a single laboratory and the nature of the raw material is known.
The effect of dietary‐induced changes in milk urea levels on the heat stability of milk
Authors: Banks William , Clapperton John L. , Muir D. Donald , Powell Anne K. , Sweetsur A. W. Maurice
Published: October 2006

Two experiments were carried out to investigate the relationship between milk urea content and the heat stability of the protein in the skim milk. In experiment 1, four cows were offered a diet of grass silage with different amounts of hay and a protein concentrate. Although there were individual differences between the cows in the relationship between coagulation time and milk pH, there was a significant correlation between milk urea content and the maximum coagulation time. In experiment 2, two groups of five cows were given a basal diet of hay with a supplement of either barley or soya bean meal. These diets were exchanged weekly over a 3 week period. A significant correlation between milk urea content and maximum coagulation time was observed, and a close relationship between milk urea content and the mean urea content of the blood found. It is concluded that, although milk urea content is not the sole determinant of coagulation time, there is considerable potential for manipulating the urea content of milk in order to increase the heat stability.
Determination of fructose and glucose in cucurbitaceae by h.p.l.c.
Authors: Salvo Francesco , Tripodo Maria Marcella , Dugo Giacomo
Published: October 2006

High performance liquid chromatography (h.p.l.c.) was used to characterise and quantify fructose and glucose in seven members of the Cucurbitaceae family. The h.p.l.c. system consisted of a μ‐Bondapak/Carbohydrate packed column, a solvent system of acetonitrile‐water (800 ml l−‐1) with a flow rate of 2.5 ml min−‐1, and a refractive index detector. The analysis, including sample preparation, was completed in less than 45 min. The quantities of fructose and glucose obtained were, except for one sample, <1% on a fresh weight basis, and the glucose: fructose ratios ranged from 0.41:1 to 0.93:1.
The effect of soil Ph on olsen bicarbonate phosphate values
Authors: Sorn‐Srivichai Puntipa , Tillman Russell W. , Syers J. Keith , Cornforth Ian S.
Published: October 2006

The effect of increases in soil pH by liming on Olsen bicarbonate phosphate (P) test values was investigated using two contrasting New Zealand soils: a highly P retentive Egmont soil and a Tokomaru soil with a low P retention capacity. After incubation with three rates of Ca(OH)2, soil pH was increased, and a reduction in the Olsen P values was observed. The amounts of 32P‐exchangeable P, however, increased with increasing soil pH, and there was very little change in water‐extractable P. The addition of lime had no significant effect on either the yield or uptake of P by ryegrass grown on the same soils in the glasshouse. It appears that the decline in Olsen P values in soils following liming is a result of an artefact in the Olsen procedure. High concentrations of Ca are involved in the decrease in Olsen P values in limed soils. It is suggested that the precipitation of calcium phosphates in the Olsen extracts of limed soils is responsible for the decrease in the Olsen P values. In a field experiment, increasing soil pH by lime addition also resulted in a decrease in the Olsen P values.
Compositional changes in chlorophylls and carotenoids during the four flushes of tea in North East India
Authors: Hazarika Mridul , Mahanta Pradip K.
Published: October 2006

The quantitative changes of two pigments, chlorophylls a and b, and four major carotenoids, β‐carotene, lutein, violaxanthine and neoxanthine, were investigated during four flushes of North East Indian plain teas from a deep skiffed area between April and October 1982. The tea flushes with different genetic properties were taken fromn from various Tocklai‐released clones: TV‐1 (Camellia sinensis (L.) O. Kuntze), TV‐2 (C. assamica (Masters) Wight), TV‐9 (C. assamica ‘Cambod’) and TV‐17 (C. sinensis, hybrid). They showed marked changes in these pigment constituents throughout the plucking period, which affected the organoleptic property of the black tea produced.
An automated enzymic assay for determining the cyanide content of cassava (Manihot esculenta crantz) and cassava products
Authors: Rao Poonam V. , Hahn S. K.
Published: October 2006

An automated enzymic method for the analysis of cyanide in cassava and cassava products is described. A total of 300 analyses a day can be handled easily. A wide range of free (nonglycosidic) or bound (cyano‐substituted glycosides) cyanides (0.4–40 μg HCN ml−1) can be assayed in the extracted solutions. The upper limit of detection for the bound cyanide can easily be increased by another three‐fold by assaying it under partial hydrolysis conditions. The two enzymic methods, manual and automated on Technicon's AutoAnalyzer, agreed well for the free and the bound cyanide in the leaf and the peeled storage root samples.
Effect of blanching and soaking on winged beans (Psophocarpus tetragonolobus)
Authors: King Richard D. , Puwastien Prapasri
Published: October 2006

The effects of blanching and soaking on the properties of two cultivars of winged bean (Psophocarpus tetragonolobus) seeds and flour were investigated. Blanching increased the rate of water uptake, total water absorbed and the percentage of beans rehydrated during soaking, but, decreased the protein solubility of the flour. Blanching for a short time, 1 min for Rajburi TIS 0172 and 10 min for the Suwan farm 2702 cultivars, inactivated almost all the lipoxygenase activity but had little effect on the trypsin inhibitor activity.
Stability of vitamin C in fruits and fruit blends
Authors: Mokady Shoshana , Cogan Uri , Lieberman Laurie
Published: October 2006

The levels of the two biologically active forms of vitamin C, ascorbic acid (AA) and dehydroascorbic acid (DHAA), were determined in individual fruits, in fruit blends and in model systems over a 3‐h incubation period at room temperature. There was essentially no reduction in the AA content in the orange juice sample and in the model solution of analytical l‐ascorbic acid. A rapid decrease in the AA content was observed in the banana, apple and guava samples and in blends consisting of orange juice‐banana‐apple or L‐ascorbic acid‐banana‐apple blends. However, the reduction in AA was concomitant with a quantitative increase in DHAA content.
Flour components affecting paste and noodle colour
Authors: Miskelly Diane M.
Published: October 2006

The influence of components contributing to the colour and brightness of flour, flour paste and Chinese and Japanese style noodles has been investigated. Differences in brightness and yellowness were attributable to wheat cultivar, milling extraction rate, protein content, starch damage and brown and yellow pigments.
Changes in the glucose: Fructose ratio during the growth period of the razaki grape
Authors: Soulis Theodossios P. , Avgerinos Asterios S.
Published: October 2006

The fructose content of table grapes is of importance, especially for cultivars growing in cold climates. The glucose: fructose ratio (G: F ratio) in the table grape Vitis vinifera L, cv. Razaki during the entire growth period was determined by polarimetric and volumetric methods, This ratio was found to be 1.95 at the beginning of the growth period and 1.55 in the final stage of growth (over‐ripe), with an excess of glucose throughout. The G:F ratio decreased until the middle of August and was almost constant thereafter, Acidity decreased until mid‐September, when the berries reached maximum weight.
Myrosinase activity of cruciferous vegetables
Authors: Wilkinson Andrew P. , Rhodes Michael J. C. , Fenwick Roger G.
Published: October 2006

Myrosinase activity in partially purified extracts of 12 cruciferous vegetables and an acetone powder preparation of Sinapis alba L. (white mustard) was determined by the initial rate of glucose formation from glucosinolate hydrolysis using a coupled assay. Of the species studied Raphanus sativus L. (radish, 12.8±0.7 μmol min−1g−1 powdered tissue) had the greatest myrosinase activity, and Brassica campestris L. ssp. rapifera (turnip) and Nasturtium officinalis R.Br. (watercress) (0.6±0.1 and 0.8±0.03 μmol min−1g−1 powdered tissue respectively) the least. The sub‐species of Brassica oleracea studied all had similar myrosinase activity (ca 2.5±0.2μmolmin−1g−1 powdered tissue) except B. oleracea L. var. gemmifera D.C. (Brussels sprouts) and B. oleracea L. var. capitata L. (white cabbage) which had higher activities (7.6±0.1 and 5.2±0.2μmol min−1g−1 powdered tissue respectively). The effect of ascorbate concentration upon the myrosinase activity of six of the crucifers studied and the white mustard preparation, revealed that the ascorbate concentration necessary to promote maximal activity varied with species. A concentration of 0.9mM ascorbate maximally activated radish and turnip myrosinase, while red cabbage, watercress, white mustard and Brussels sprouts were maximally activated at 2.0, 3.0, 5.0 and 0.7–1.0mM ascorbate respectively. Two peaks of maximal myrosinase activity, occurring between 0.9 and 1.0mM and at 3.0mM ascorbate, were found for B. oleracea L. var. botrytis L. subvar. cauliflora D.C. (cauliflower).
Observations on the determination of protein quality by the Thomas–Mitchell method
Authors: Eyre Michael D.
Published: October 2006

In the Thomas–Mitchell method for the assessment of protein quality, metabolic faecal nitrogen (MFN) and endogenous urinary nitrogen (EUN) are used to adjust faecal and urinary N excretion on test diets so that true digestibility (TD) and biological value (BV) can be calculated. Using an experimental technique where the urine and faeces from young growing rats were collected every 2 days for an experimental period of 28 days, trends in the estimation of MFN and in the determination of TD and BV were examined. A diet containing 20 g egg albumen kg−1 on an as fed basis (2.85 g N kg−1 dry matter) has previously been found to be most applicable for the estimation of EUN. This diet was also found to be appropriate for the estimation of MFN. To examine the effect of a change from an ad libitum intake of a stock diet (containing 150 g protein kg−1) to the restricted intake of a test diet (containing 80–100 g protein kg−1) on the determination of TD and BV, three protein sources (egg albumen, casein+1% L‐methionine and soya bean meal) were fed at two levels of intake: 9 and 15 g day−1. The time taken for the faecal N excretion to stablilise was very similar with all diets at both levels of intake. The TD of all three protein sources at both levels of intake increased gradually with increasing lengths of preliminary period. However, this increase was not great, and had little effect on the determination of the BV. Stabilisation of urinary N excretion with the three diets depended on the quality of the protein and the amount fed. This led to variation in BV with lengthening preliminary periods, especially at the lower level of intake. Urinary N excretion, and consequently BV, stabilised most rapidly with the highest quality protein (egg albumen) at the highest level of intake. However, stabilisation of BV with the lowest quality protein (soya bean meal) did not occur until after a preliminary period of 12 days, even at 15 g day−1. This preliminary period is considerably longer than that usually employed, and thus it appears that for many proteins the BV may have been assessed during a period before N retention has fully stabilised.
An estimate of the mean daily intake of glucosinolates from cruciferous vegetables in the UK
Authors: Sones Karen , Heaney Robert K. , Fenwick G. Roger
Published: October 2006

Samples (174) of cabbage, Brussels sprouts, cauliflower and swede‐turnip have been analysed for total and individual glucosinolate content in both the fresh and cooked form. Using data from the 1980 National Food Survey, the national mean daily intake is calculated to be 46.1 mg in fresh material, and 29.4 mg in cooked. There are large variations within the UK (for example in Scotland it is less than half that in south‐west of England), between income groups and over the year. National mean daily intake figures for the glucosinolates yielding goitrogenic products such as oxazolidine‐2‐thiones and thiocyanate ion are 6.7 and 14.7 mg respectively; the former figure is approximately doubled in the winter months. Based upon the above variations, arising from eating habits in the UK, together with the known large variation in glucosinolate content in cruciferous plants because of agronomic and environmental effects, it is likely that certain individuals will consume more than 300 mg total glucosinolates per day. The nutritional and toxicological consequences of such an intake are unknown at present.
Optimisation of the in‐vivo assay conditions for nitrate reductase in barley (Hordeum vulgare L. cv. Igri)
Authors: Sym Gordon J.
Published: October 2006

Assay conditions in vivo for determining nitrate reductase activity (NRA) in shoot and root tissues of winter barley (Hordeum vulgare L. cv. Igri) were studied. The composition, pH and temperature of the incubation medium, and the size of leaf slice were varied. Maximum leaf NRA was obtained with 5 mm transverse slices incubated at 32oC in a medium containing 0.1M phosphate buffer, pH 7.0, 0.02M KNO3, 30 ml litre−1 propan‐1‐ol and 0.1 ml litre−1 Triton X‐100. The optimum assay conditions for roots were similar to those for leaves, except that the pH was 7.5. There was negligible nitrite reductase activity in leaves incubated in the dark.
The effects of aminoethyoxyvinylglycine on maturity and post‐harvest changes in Cox's Orange Pippin apples
Authors: Child Robin D. , Williams Anthony A. , Hoad Gordon V. , Baines Christopher R.
Published: October 2006

Pre‐harvest spraying of orchard trees with aminoethoxyvinylglycine (AVG) suppressed ethylene production in apples at picking and during barn storage. Fruit firmness was not affected at harvest, but the fruit softened more slowly and remained greener longer after picking. Changes in volatile aroma components were noted and autocatalytic stimulation of ethylene was not possible. AVG did not reduce the acceptability of the fruit at harvest time: subsequently an increased preference for fruits from unsprayed trees was shown by a sensory assessment panel.
Soyasaponin I, a compound possessing undesirable taste characteristics isolated from the dried pea (Pisum sativum L.)
Authors: Price Keith R. , Roger Fenwick G.
Published: October 2006

One of the compounds contributing to the undesirable sensory characteristics (bitterness and astringency) of some cultivars of dried pea and their products has been identified by chemical and spectroscopic techniques as soyasaponin I, a sapogenin trisaccharide previously reported in soya.
The Glucosinolate Content of Some Fodder Brassicas
Authors: Bradshaw John E. , Heaney Robert K. , Macfarlane Smith William H. , Gowers Stuart , Gemmell Dorothy J. , Roger Fenwick G.
Published: October 2006

The glucosinolate contents of six kales and five cabbages (Brassica oleracea L.), four stubble turnips and six turnips (B. campestris L.), and six swedes and six fodder rapes (B. napus L.) were determined. As fodder brassica breeders wish to reduce the goitrogenicity of these crops, the concentrations of 2‐hydroxybut‐3‐enylglucosinolate (5‐vinyloxazolidine‐2‐thione is the goitrogenic hydrolysis product) and 3‐indolylmethylglucosinolate (the thiocyanate ion is the goitrogenic hydrolysis product) were of particular interest. High concentrations (mmol kg−1 dry matter) of 2‐hydroxybut‐3‐enylglucosinolate were found in stubble turnip leaf (8.12) and bulb (9.20), turnip bulb (9.97), swede bulb (5.66), and rape leaf (8.99) and stem (21.81) but not in kale or cabbage. In contrast, the concentration of 3‐indolylmethylglucosinolate was relatively high in cabbage head (6.39) and kale leaf (3.25) but not in the other crops.
Improved species identification of raw meat by double sandwich enzyme‐linked immunosorbent assay
Authors: Mark Patterson R. , Whittaker Robert G. , Spencer Terence L.
Published: October 2006

An improved enzyme‐linked immunosorbent assay (ELISA) has been developed to enable differentiation of unprocessed beef, sheep, horse, kangaroo, pig, camel, buffalo and goat meats to less than 1% level of detection. This double sandwich system utilises species‐specific capture antibodies raised in sheep or cattle and coated on to microtitre plates. Antibody coated plates are then used to immunoextract soluble protein from prepared meat samples. Bound meat proteins are detected by the addition of species‐specific rabbit antisera followed by staphyloccocal Protein A conjugated to horse‐radish peroxidase (HRPO), or by antisera directly conjugated to HRPO. Adoption of a capture antibody provides a number of advantages over previously described ELISA systems. Sample preparation is not critical because colour production is approximately constant between sample dilutions of 1000 and 10 g litre−1. Increased sensitivity and selectivity allows the bulking of samples for screening purposes. In addition, the assay is faster; testing may be carried out in less than 2 h.
Acid‐ageing of lignocellulosics to improve ruminant digestibility—application to bagasse, wheat and rice straw and oat hulls
Authors: Crosthwaite Caroline , Ishihara Mitsuro , Richards Geoffrey N.
Published: October 2006

Lignocellulosic agricultural wastes were impregnated with small amounts of hydrochloric and sulphuric acids and aged under varying conditions of temperature and time. Hydrochloric acid was added as vapour and sulphuric acid as a dilute aqueous solution and the fibres subsequently air‐dried. The acid‐aged fibres became more digestible to rumen fluid (in vitro) and to cellulase, with improvements up to four‐fold (for 1.1% hydrochloric acid in oat hulls). The increases in rumen fluid digestibility were always associated with increases in water‐solubility. The effects are attributed to acid hydrolysis, especially of hemicelluloses and perhaps to some extent of lignin–carbohydrate linkages. The procedures may have some potential for low‐cost, small scale exploitation in upgrading lignocellulosic agricultural wastes for cattle fodder.
Effect of drought and irrigation on the fate of nitrogen applied to cut permanent grass swards in lysimeters: Experimental design and crop uptake
Authors: Dowdell Rodney J. , Webster Colin P.
Published: October 2006

The effect of drought and irrigation on the yield and fertiliser nitrogen uptake by cut permanent grass swards was investigated using lysimeters containing monoliths (80 cm diam., 135 cm deep) of two soil types (Salop series, clay loam and Bromyard series, silt loam). Over the five summers 1977–81 swards were treated with four dressings of calcium nitrate at rates of 0 and 100 kg N ha−1 after each cut; in the first year, the nitrogen was labelled with 15N. Rainfall equivalent to the long‐term average gave mean yields of 12.9 t dry matter ha−1 for Salop and 14.3 t dry matter ha−1 for Bromyard. Irrigation (to 120% of average summer rainfall) gave a non‐significant increase of 8–9% in herbage yield on both soils. When the average rainfall distribution was modified to create periods of drought for 4 weeks duration immediately before each cut and fertiliser application, yields were significantly depressed, by 12% on Salop soil and 20% on Bromyard soil. Adjustment of the drought so that cutting and nitrogen application fell mid‐way in the dry period resulted in only a small non‐significant depression of yield on both soils (yield 95–96% of average rainfall treatment). The recovery of applied 15N labelled fertiliser in herbage during the first year of the experiment was in the range 45–47% for the Salop soil and 39–52% for the Bromyard soil. In the Salop soil the recovery of the labelled nitrogen was not significantly affected by imposition of drought conditions or by irrigation. However, in the Bromyard soil the drought treatment resulted in a significant reduction in the recovery of fertiliser nitrogen to 79% of that of the average rainfall treatment and irrigation increased the recovery to 106%. The contrasting results from the two soils was due to the imposed drought treatments which were more effective in creating differing soil water status in the Bromyard soil. This was due to its good drainage and lower water holding capacity. On both soils, fertiliser nitrogen constituted 53–60% of the total nitrogen content of the herbage. This experiment indicates that on clay soils with poor drainage status, the pattern of rainfall distribution has relatively little impact on the productivity of the sward and its utilisation of fertiliser nitrogen. On freely‐draining soils, however, heavy rainfall after drought following cutting and nitrogen application can substantially depress yield and fertiliser use.
Purification and properties of pectinesterase from papaya
Authors: Lourenco Euclides J. , Catutani Adelaide T.
Published: October 2006

Pectinesterase (PE) was partially purified from papaya pulp, and its biochemical properties were studied. The enzyme was eluted in a single peak after DEAE‐cellulose and Sephadex G‐100 chromatography. The PE had a molecular weight of 53000 and showed an optimum pH of 8.0. Its activity was dependent on an NaCl concentration of 0.2M. The enzyme was heat stable: approximately 80% of the original activity remained after 60 min of heating at 50°C but completely inactivated by incubation at 80°C for 1 min. The activity was linear with time and protein concentration. The maximum reaction in 3 min was found at 60°C and the initial rate increased 9‐fold from 20 to 60°C. The estimated Km was 0.12g litre−1 with citrus pectin as the substrate. The kinetic study revealed that polygalactur‐onic acid is a competitive inhibitor, and a Ki value of 0.07 g litre−1 was determined. On the basis of this study, papaya PE properties resembled those of pectinesterase from other sources.
The composition and consistency of pig backfat as it affects the quality of vacuum‐packed rindless bacon rashers
Authors: Enser Michael , Dransfield Eric , Jolley Paul D. , Jones Richard C. D. , Leedham Michael
Published: October 2006

Samples of adipose tissue from unsatisfactory, soft, vacuum‐packs of rindless bacon rashers were compared with satisfactory harder samples to determine the factors responsible for the difference in consistency. Lipid from unsatisfactory packs contained significantly higher mean concentrations of unsaturated fatty acids, lower mean concentrations of saturated fatty acids and had a lower mean melting point and mean slip point. Discriminant analysis revealed that the samples were best differentiated according to their proportion of linoleic acid or by the ratio of stearic acid to linoleic acid. Linoleic acid was the best discriminator although stearic acid and palmitic acid were correlated best with the melting point and slip point of the lipid and with the force required to puncture the intact adipose tissue by a probe attached to an Instron materials testing machine. Samples which would give satisfactory firm packs, based on the data from discriminant analysis, required a puncture force greater than 7N. In terms of the spectrum of backfat consistency in British pigs, satisfactory bacon comes from hard backfat whereas the unsatisfactory packs come from backfat of medium consistency.
An assessment of commercially available reagents for an enzyme‐linked immunosorbent assay (ELISA) of soya protein in meat products
Authors: Griffiths Neil M. , Billington Melvyn J. , Crimes Andrew A. , Hitchock Christopher H. S.
Published: October 2006

An enzyme‐linked immunosorbent assay (ELISA) procedure based on a limited supply of specially prepared experimental immunoreagents and designed to measure levels of soya protein in raw or processed mixed meat products has already been published. This report describes a modified method with commercially available immunoreagents suitable for routine use; its response to a range of commercial soya ingredients has been checked using a particular soya protein isolate (Unisol, Unimills BV) as arbitrary standard. Individual soya components and possible cross‐reacting food materials have also been investigated. Both the original and modified methods have been applied to a set of model beefburgers containing known levels of Unisol. There was good agreement between observed and calculated levels in raw and heat‐set beefburgers; sterilised samples gave a decreased but linear response. The procedure is recommended for the examination of meat products in non‐specialised laboratories.
Variation in the oil content and fatty acid composition of field beans (Vicia faba) and peas (Pisum spp.)
Authors: Welch Robert W. , Wynne Griffiths D.
Published: October 2006

Oil content has been found to range from 1.2–1.9% in a wide range of diverse field bean (Vicia faba) cultivars, populations and selections and from 1.4–2.8% in a narrower range of pea cultivars. The ranges in fatty acid composition for beans and peas respectively were palmitic, 13.9–21.0% and 12.0–16.6%, stearic 2.2–3.5% and 2.5–4.2%, oleic 15.0–33.0% and 14.2–33.3%, linoleic 41.3–59.7% and 43.7–60.9%, linolenic 2.6–4.9% and 6.4–13.4%. Environment exerted a significant effect on the oil content of field beans but cultivar differences remained apparent. The analysis of whole or milled field beans stored for up to 5 years showed only minor losses of oil and component fatty acids. In both species over 90% of the total oil content was found in the cotyledons. Cultivar differences in whole grain oil content were associated with the concentration of oil in the cotyledons and appeared independent of the relative proportions of either embryo or seed coat. The interrelationships between oil content and other seed characteristics were also determined and the significance of these results in relation to plant breeding are discussed.