bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical methods for the reduction of the purine content of baker's yeast, a form of single‐cell protein
Authors: Trevelyan William E. 
Published: November 2006

AbstractChemical procedures, suggested by methods formerly used to prepare yeast RNA, or in the analysis of nucleic acids, were applied to the preparation of nucleic acid‐reduced baker's yeast. Water at 80–100°C extracted nucleotides but no nucleic acid from the cell, with a loss of 20% total solids and 16% total nitrogen. Water at 120°C removed part of the nucleic acid, and nearly all was extracted by 5% NaCl solution at 120°C. At room temperature, 0.5 N‐HC1 removed RNA from a suspension of heatkilled yeast. NaOH at a pH of about 12.5 extracted RNA from suspensions of fresh or of heat‐killed yeast. In both cases the cells lost 25–35% solids and a similar proportion of crude protein (Kjeldahl N). The RNA‐reduced yeast preparations may require further treatment, such as extraction with organic solvents, to improve appearance or palatability.
Evaluation of the ESCA technique as a screening method for the estimation of protein content and quality in seed meals
Authors: Peeling James , Clark David T. , Evans I. Marta , Boulter Donald 
Published: November 2006

AbstractThe ESCA (Electron Spectroscopy for Chemical Analysis) technique has been evaluated as an analytical screening method for the determination of protein content and quality of grain meals of some legumes and cereals. To this end the grain meals of a number of different species were analysed for total nitrogen, meals of varieties of cowpea (Vigna unguiculata) were examined for sulpho‐amino acid content, and the levels of basic amino acid in meals of some maize and barley varieties were measured by this technique; some amino acids, polyamino acids and pure proteins were also examined as standards.The results obtained for 15 grain meals by the ESCA technique, expressed as the ratio of the intensity of the N1s photoelectron signal to that of the C1s signal, were compared with %N as determined by a semi‐automated micro‐Kjeldahl method, and the correlation coefficient between the results from these two methods was r = 0.98. The binding energies of S2p electrons were determined for some amino acids and proteins, and the amino acid sulphur was differentiated from oxidised sulphur. The N1s/S2p intensity ratios for four pure proteins correlated very well with the calculated stoichiometric N/S ratios (r = 0.999). The N1s/S2p intensity ratios were also determined for seven cowpea varieties and the correlation coefficient between these values and the ratios N/Saa, measured by chemical methods, was r = 0.77.The N1s photoelectron peaks of some varieties of barley and maize meals showed a pronounced shoulder on the high binding energy side. On deconvolution into two components the main peak was assigned to nitrogen in the peptide bond and the smaller peak was assigned to the protonated nitrogen on the side chains of the basic amino acid residues.
Some changes in the composition of the fruit of the glasshouse cucumber (Cucumis sativus) during growth, maturation and senescence
Authors: Davies Jack N. , Kempton Ronald J. 
Published: November 2006

AbstractFemale cucumber flowers were tagged when fully open and the resultant fruit harvested for growth and chemical analysis at intervals of between 2 and 28 days. The growth curve relating fresh weight and time was sigmoidal approaching a maximum after about 14 days. Similar relationships were obtained for the total content per fruit of sugars, acids and the major nutrients nitrogen, phosphorus and potassium. The percentage dry matter and alcohol‐insoluble solids fell rapidly during the first 10 days of growth and then more slowly with increasing fruit age. In contrast, the percentage alcohol‐soluble solids changed little during the first 6 days and then decreased progressively. The major sugars, glucose and fructose, present in approximately equal amounts, increased rapidly for the first 6 days and then changed little until the onset of senescence. Traces of sucrose and myoinositol were present at all stages of development. The titratable acidity was extremely low and was closely correlated with the potassium content. On a dry weight basis, total and alcoholsoluble N and P increased slowly during the early stages of growth but more rapidly with increasing maturity. On the other hand, K concentrations tended to decrease.
A note on the properties of urine excreted by grazing cattle
Authors: Richards Ian R. , Wolton K. Margaret 
Published: November 2006

AbstractFifty‐eight urine samples were collected during the grazing season from cattle at North Wyke. N, K and Na contents, pH, specific gravity and osmotic potential were measured. Significant correlations were found between many of these variables. Wide ranges in N, K and Na contents occurred, indicating considerable variation in the rate of return of these nutrients between urine patches. The low osmotic potential of some samples suggested the involvement of an osmotic effect in urine scorch.
Single‐seed identification of wheat varieties: Use of grain hardness testing, electrophoretic analysis and a rapid test paper for phenol reaction
Authors: Wrigley Colin W. 
Published: November 2006

AbstractFor varietal identification of grain samples containing a mixture of varieties, grains must be examined separately. A procedure is described for applying a range of tests to a single grain. The hardness and texture of the grain are checked by cutting a small piece from its brush end. The main part of the grain is ground and gliadin proteins are extracted from it for electrophoretic analysis. The phenol reaction of the grain can be determined by placing the grain end‐piece on paper moistened with 1% phenol or on catechol‐impregnated paper moistened with water. This phenol test takes less than an hour.
Influence of sinapine and p‐hydroxybenzylglucosinolate on the nutritional value of rapeseed and white mustard meals
Authors: Josefsson Egon , Uppström Bengt 
Published: November 2006

AbstractThe influence of sinapine on the nutritional value of rapeseed meal and white mustard meal, as well as the influence of p‐hydroxybenzylglucosinolate on the nutritional value of white mustard meal, was evaluated by feeding experiments with mice. The effect of sinapine was small, whereas p‐hydroxybenzylglucosinolate caused a highly detrimental effect on the nutritional value of white mustard meal. Preparations of sinapine and of p‐hydroxybenzylglucosinolate are described.
A treatment of grape wine distillation heads
Authors: Williams Patrick J. , Strauss Christopher R. 
Published: November 2006

AbstractThe development of a procedure to eliminate sulphur dioxide, acetaldehyde, acetals, and ethyl acetate from grape wine distillation heads is reported. This process, designed for use in a modified pot still, involves inert gas sparging of the diluted and acidified heads held at reflux until an acceptable concentration of acetaldehyde has been reached. The solution is basified and distilled, giving a treated product which, as shown by sensory evaluation, can be as good as high‐quality fortifying spirit. The ethanol recovery in this process is greater than that obtained by a comparable fractional distillation of heads.
Flavour quality of tomatoes
Authors: Dirinck Patrick , Schreyen Luc , Van Wassenhove Fredy , Schamp Niceas 
Published: November 2006

AbstractTomato volatiles present in essential oils obtained by steam distillation–continuous extraction and by head‐space condensation were identified and evaluated organoleptically. Flavour quality of different samples of fresh tomatoes, evaluated by a panel, could be related to the occurrence and concentration of n‐hexanal, trans‐2‐hexenal, cis‐3‐hexen‐1‐ol, 2‐isobutylthiazole and some unidentified compounds in the head space condensation essential oil.
Sulphur–nitrogen interaction effects on the yield and composition of the protein‐N, non‐protein‐N and soluble carbohydrates in perennial ryegrass
Authors: Bolton John , Nowakowski Tadeusz Z. , Lazarus William 
Published: November 2006

AbstractIn a controlled‐environment pot experiment sulphur fertilisers increased the yields of ryegrass when large dressings of nitrogen were also given. Yield responses to sulphur occurred when the dry matter contained less than 0.20% S. At the third cut, sulphur deficiency decreased concentrations of reducing sugars but had little effect on sucrose and fructosan in the grass dry matter. Only 44% of the nitrogen in the most sulphur‐deficient grass was protein‐N as compared to over 80% in non‐deficient grass. The non‐protein‐N accumulated predominantly as amides especially asparagine. The amino acid composition of the insoluble protein, including the proportions of cystine and methionine, was unaffected by acute sulphur or nitrogen deficiencies.
Manipulation of fermentation in the rumen
Authors: Harrison David G. , Beever David E. , Thomson David J. , Osbourn Dennis F. 
Published: November 2006

AbstractArtificial saliva (4 litres/day) was infused into the rumen of sheep fed a semi‐purified diet at hourly intervals. Dilution rate and the efficiency of synthesis of microbial protein in vivo were increased. The pattern of rumen fermentation was altered; the molar proportion of propionic acid decreased (32–20%) and acetic acid increased (58–66%) with infusion, and there was an increased flow of total amino acids into the duodenum.
Chemical composition of microbial matter in the rumen
Authors: Czerkawski Julian W. 
Published: November 2006

AbstractMicrobial fractions, comprising protozoa, large and small bacteria and whole particulate matter, have been isolated from rumen contents of sheep given a mainly concentrate diet, a mixture of hay and concentrate, and hay only. Samples of rumen contents were taken before and 2 h after feeding. The main components determined were: protein, lipid, nucleic acids, carbohydrate and ash. The amount of cell wall was estimated in terms of known cell wall constituents (diaminopimelic acid (DAP) and glucosamine). The concentration of some of the constituents varied with diet and with respect to the time of feeding. Many of the differences disappeared when the results were expressed on a polysaccharide‐free basis. The amino acid composition of large and small bacteria was virtually the same. The amino acid composition of protozoa was similar except for the proportions of glutamic acid and lysine which were greater in protozoa, and alanine, glycine and DAP, the proportions of which were greater in bacteria. There were higher proportions of protein in large bacteria and protozoa than in small bacteria. Small bacteria contained more lipid, ash and DNA, and less RNA than the other two fractions. The polysaccharide content of protozoa and large bacteria increased from about 8% before feeding to about 30% after feeding, while the polysaccharide content of small bacteria increased only slightly after feeding.
Estimation of S‐methylcysteine sulphoxide (kale anaemia factor) and its distribution among brassica forage and root crops
Authors: Whittle Peter J. , Smith Ronald H. , McIntosh Alexander 
Published: November 2006

AbstractS‐methylcysteine sulphoxide (SMCO), kale anaemia factor, was quantitatively extracted from a variety of brassica crops by repeated maceration in water. It was separated from other components of the deproteinised extract by electrophoresis on silica gel impregnated glass‐fibre sheet; and after visualising with ninhydrin/cadmium acetate reagent, the SMCO spots were quantitated by reflectance‐mode densitometry. Values for SMCO contents of plants thus obtained agreed well with those obtained by ion‐exchange chromatography. The method is useful for rapid screening of a large number of plants, as well as for making fewer more accurate determinations. Ten varieties of kale and five of forage rape were grown on experimental plots and harvested at intervals between August and January. The SMCO content of the plants increased as they matured and secondary growth began. The flowers of kale contained twice as much SMCO per unit weight as the whole plant and were very toxic to cattle. Varietal differences in SMCO content were found in plants analysed before the onset of secondary growth, Maris Kestrel and Cauletta showing lower values than other varieties. Substantial amounts of SMCO were found in swedes, both in the “roots” and the “tops”, each structure being toxic to cattle. Other brassicas examined included Chinese cabbages, turnips, fodder radish and a Raphanobrassica.
The influence of an extract of orange peel on the growth and ascorbic acid metabolism of young guinea‐pigs
Authors: Wilson H. Kerr , Price‐Jones Chris , Hughes R. Elwyn 
Published: November 2006

AbstractYoung male guinea‐pigs receiving a maintenance dose of ascorbic acid (vitamin C) (0.1 mg/100 g body weight daily) received a daily supplement of a flavonoid‐rich extract of orange peel (5 mg/100 g body weight). The extract significantly increased the ascorbic acid concentration on the adrenals, spleen and leucocytes but not in the liver and brain. Hesperidin had a similar effect. The possible mechanisms of these changes are discussed. The orange extract and the hesperidin both produced a marked increase in the body weight of the guinea‐pigs; this effect was absent in ascorbic acid sufficient guinea‐pigs. The extract did not influence the survival time of the scorbutic guinea‐pigs. These indications of a partial vitamin C activity on the part of the flavonoids suggest that ascorbic acid is a multifunctional vitamin with its growth‐promoting function separate from (and presumably subordinate to) the prevention of scurvy.
Conditions affecting production of a protein isolate from lupin seed kernels
Authors: Ruiz Leonard P. , Hove Edwin L. 
Published: November 2006

AbstractConditions were investigated to determine the optimum processing parameters for preparation of a protein isolate from the ground, dehulled lupin seeds of Lupinus angustifolius. The extraction variables were: particle size (16–100 mesh); pH (2–11); extraction medium; solvent to lupin ratio (10:1 to 40:1); temperature (20–60oC) and time (15–60 min). The isoelectric point of the lupin protein was found to be pH 4.5 with a protein solubility of greater than 90% above pH 8.0. Using 60–100 mesh ground lupin and extracting at pH 8.5 for 30 min, a protein isolate was obtained on acidification to pH 4.8 which was 89.4% protein compared to 34.0% protein for the original dehulled lupin. This protein isolate represented 19.8% of the starting material and 52% of the starting nitrogen. Similar results were also obtained when hexane defatted lupin was used. In this case the protein isolate had a protein content of 92.5%. The yield of protein isolate could be increased to 25.7% of the starting material if the extraction was repeated. The protein efficiency ratio for the protein isolate was 2.90 when supplemented with methionine.
Effects of seed rate, nitrogen level and leaf age on the yield of extracted protein from five different crops in West Bengal
Authors: Matai Shyam , Bagchi Dipak , Chanda Sunanda 
Published: November 2006

AbstractThe yield of leaf protein from five different crops grown at different seed rates and nitrogen levels was studied. Bajra (Pennisetum typhoideum Rich.) and mustard (Brassica nigra Koch) gave large protein yields. Harvesting just before the initiation of flowering produced the highest yield except with hybrid Napier (P. typhoideum x P. purpureum) and turnip (Brassica rapa L.). With the latter, maximum yield was obtained 45–52 days after sowing, and with the former 62 days. Seed rates of 120–150 kg/ha (4–5 times normal) were used with bajra and ragi (Eleusine coracana Gaertn), 30 kg/ha with mustard and 8 kg/ha with turnip. The yield of extracted protein was not increased by giving mustard more than 60, ragi more than 160 and bajra more than 240 kg N/ha. The N level for maximum response was not reached with turnip and hybrid Napier. More of the leaf protein was extracted from mustard and turnip than from the other species; mustard and turnip also gave the largest yields of protein (7.6 and 5.7 kg/ha/day respectively).
Changes in biochemical components during the germination of spores of Penicillium roqueforti
Authors: Fan Tsai Y. , Kinsella John E. 
Published: November 2006

AbstractGermination of spores of Penicillium roqueforti consisted of three stages, i.e. swelling, germ‐tube emergence and hyphal elongation which occurred at 4, 12 and 16 h respectively after initiation of incubation of resting spores in the germination medium. The swelling phase represents the period during which the germinating spore assembled required synthetic enzymes though there was only a small increase in dry weight (2 mg h−1 per 109 spores). Nuclear division occurred since DNA multiplied rapidly during spore swelling. The percentages of RNA and proteins reached their maxima at the end of this period. The unsaturated fatty acids, e.g. linoleic and linolenic acids, were synthesised. Germ‐tube emergence represented a transition phase during which growth was moderate (at a rate of 9 mg h−1 per 109 spores) as compared to hyphal elongation phase (34 mg h−1 per 109 spores). The percentage of RNA, proteins and carbohydrates decreased. The percentage of unsaturated fatty acids was highest at the middle of this period and then declined. The hyphal elongation phase represented a period of rapid growth. The relative contents of proteins and DNA remained constant while the percentage of carbohydrates and saturated fatty acids increased, reflecting the proliferation of cellular and membrane materials.
Autolytic methods for the reduction of the purine content of baker's yeast, a form of single‐cell protein
Authors: Trevelyan William E. 
Published: November 2006

AbstractWhen a suspension of baker's yeast was incubated at 50°C, the cells became permeable to H+, a process completed in about 4 h. Cellular constituents of low molecular weight then diffused into the medium, but only after a long lag period were cell nucleic acids and proteins degraded by intracellular enzymes. The lag period was shorter at higher temperatures, when RNase and proteinases suffered some thermal denaturation. It was abolished if, before autolysis at 50°C, yeast was plasmolysed by ethyl acetate, or heated to 70°C for 1 min, treatments which, it is thought, disorganised the membrane of the yeast cell vacuole, within which the enzymes are located. Heat treatment, when effective, was sufficiently severe to disorganise the yeast cell plasma‐lemma, with the consequence that a single adjustment of pH immediately following heat treatment served to maintain a constant pH, without addition of buffer, during the subsequent incubation at 50°C. Autolysis was not found to be an entirely suitable procedure for the reduction of the nucleic acid content of baker's yeast, because of the concomitant and severe loss of protein.
An automated colorimetric method for determining oxalic acid in plant material
Authors: Cooke David T. , Sansum Linda L. 
Published: November 2006

AbstractA simple, automated colorimetric method for determining oxalic acid in plant material is based on the quantitative reduction in colour of a zirconium/3,4‐dihydroxyazobenzene‐2′‐carboxylic acid complex by microgram quantities of oxalic acid. It is suitable for use over a wide range of oxalic acid concentrations. Interference from phosphate, sulphate, citric acid and malic acid was encountered but by appropriate sample dilution this problem was resolved.
Freeze–thaw gelation of hen's egg yolk low density lipoprotein
Authors: Kamat Virendra , Graham Gillian , Barratt Martin , Stubbs Morris 
Published: November 2006

AbstractThe freeze–thaw gelation of hen's egg yolk low density lipoprotein (l.d.l.) has been examined by viscometry, agarose gel filtration, electron spin resonance spectroscopy, electron microscopy and differential scanning calorimetry. The data indicate that the core lipids, the hydrocarbon chains of interfacial lipids of l.d.l. and the sulphydryl, imino, amino and tyrosine groups in the side chains of l.d.l. peptides are not directly involved in the gelation mechanisms. The gelation is caused by non‐specific aggregation due to cross‐linking of peptides and/or phospholipid polar head groups of adjacent l.d.l. particles. During freezing, interparticle contacts are formed and strengthened as transformation of solvent water into ice increases the concentration of the particles. Salt and sugar additives inhibit large increases in concentrations of l.d.l. during freezing and prevent gelation by helping to increase solvation of interfacial regions of the l.d.l. particles. Agents that induce large viscosity increases in the l.d.l. sols before freezing may act by producing a local conformational change in l.d.l. protein and/or disrupting lipid–protein bonds.
Effects of fertilizer on the seedling emergence of vegetable crops
Authors: Hegarty Terence W. 
Published: November 2006

AbstractIn a field experiment on fertilizers applied at 0, 100 and 200 units/acre to the seedbed only nitrogen fertilizer caused a reduction in seedling emergence, though nitrogen, phosphate and potassium fertilizers did cause delays in crop emergence (calabrese, carrot, onion and red beet). In a pot experiment investigating the effects of the equivalent of 0, 125, 250, 375 and 500 kg/ha of nitrogen incorporated to a depth of 100 nm in soil, high fertilizer levels and low soil moisture resulted in reduced seedling emergence. Carrot was most sensitive and calabrese least sensitive to moisture stress. The rate of seedling emergence in carrot and onion was linearly related to water potential. Where absolute levels of seedling establishment and uniformity of crop establishment are considered to be important in vegetable growing it is recommended that inorganic nitrogen fertilizer be omitted from broadcast seedbed fertilizer dressings.
Determination of volatile fatty acids C1–C6, and lactic acid in silage juice
Authors: Jones Dilys W. , Kay James J. 
Published: November 2006

AbstractA method for the determination of volatile fatty acids, C1–C6, and lactic acid in silage juice is described. The procedure is simple and capable of application to large numbers of samples. It involves separation of the free acids by ion exchange, formation of their benzyl esters by the addition of benzyl bromide to a solution of the tetrabutylammonium salts in acetone and ultimate determination by gas liquid chromatography.
Improved separation of the major water‐soluble proteins of soya meal by a single‐step chromatographic procedure
Authors: Fisher Christopher E. , Leach Ian B. , Wilding Peter 
Published: November 2006

AbstractA method is described in which the major water‐soluble proteins of soya meal—the storage globulins, glycinin and γ‐conglycinin, and the anti‐nutritional factors, Kunitz trypsin inhibitor and soya bean haemagglutinin—are resolved from one another in a single‐step chromatographic procedure. The method can be used as a basis for the preparation of these components, and also as an analytical tool for examining soya protein‐containing materials.
Rapid separation and analysis of Nϵ‐(γ‐glutamyl)‐L‐lysine‐and Nϵ‐(β‐aspartyl)‐L‐lysine in protein digests
Authors: Otterburn Michael S. , Sinclair William J. 
Published: November 2006

AbstractThe separation and resolution of the isopeptides Nϵ(γ‐glutamyl)‐L‐lysine and Nϵ(β‐aspartyl)‐L‐lysine formed in heated proteins has been successfully achieved. The method demands a well‐characterised ion‐exchange column and the use of pH 3.40 lithium citrate buffer (0.2 N Li+). Due to the variations in particle size and cross‐linkages in the ion‐exchange resin a computer‐assisted buffer gradient system has been developed. This system effects resolution of both isopeptides in 7 h. The use of leucyl‐glycine as an internal standard facilitates quantitative estimation of the isopeptides.