bluuebunny/crossref_metadata_2025_split huggingface dataset:
Naturally occuring nitrate/nitrite in foods
Authors: Walker Ronald 
Published: November 2006

AbstractA review of the occurrence of nitrate in unprocessed foods showed that high concentrations are frequently found in vegetables. Spinach and lettuce commonly exceed 1000 parts/106 nitrate while, of the root vegetables, beets, turnips and radishes are similarly rich in nitrate. In general, the pulses contain less nitrate than leaf and root vegetables, and most fruits contain little nitrate. Fresh dairy produce is usually low in nitrate. Well waters in some agricultural areas may contain nitrate concentrations so high as to represent a hazard if used as the sole water source for infants, but municipal supplies in the UK rarely exceed 45 parts/106 although they frequently approach this. It is concluded that vegetables and water supplies make a greater contribution to the mean weekly nitrate intake than do cured meats. Nitrite concentrations are usually very low in fresh, undamaged fruits, vegetables and drinking water but adverse storage conditions can lead to (mainly microbial) reduction of nitrate. In these circumstances vegetables naturally rich in nitrate may accumulate nitrite at concentrations which can be toxic to infants.
Contribution of nitrite and nitrate to the colour and flavour of cured meats
Authors: Macdougall Douglas B. , Mottram Donald S. , Rhodes Douglas N. 
Published: November 2006

AbstractThe formation of nitric oxide myoglobin from nitrite and myoglobin involves a complex series of reactions not all of which are completely understood even now, and the stability of the cured colour, so important from the marketing point of view, continues to be investigated. The amount of nitrite necessary for complete formation of nitric oxide myoglobin is very small and the presence of no more than 25 mg/kg of nitrite in the cured meat is enough to ensure an adequately stable colour. At least four times this level is essential to produce a full development of the typical cured flavour. Very little is known of the mechanism of the reactions leading to the formation of cured flavours in cooked products or of the identity of the volatile substances responsible for it.
The microbiological role of nitrite and nitrate
Authors: Roberts Terence A. 
Published: November 2006

AbstractIn unheated products nitrite, together with sodium chloride and the pH value, contributes to the selection of the bacteria which grow during storage. Nitrate per se is generally believed to serve only as a reservoir for nitrite, but the commercial use of nitrate‐free cover brines in the Wiltshire bacon industry shows that such a reservoir is not always essential. Nitrate sometimes reduced the growth rate of bacteria in experimental Wiltshire collar bacon, but was of no benefit in back bacon. The clostridia occurring naturally in the bacon grew to higher numbers in collar cured without nitrate than that cured with nitrate. Clostridium botlinum (types A and B) was detected in these bacons, but did not grow in the bacon. In heated products the growth of surviving bacteria is controlled by the interaction of several factors including pH, sodium chloride, storage temperature and sodium nitrite or a substance derived from it upon heating. Further experiments are warranted to investigate the effects of dextrose, nitrate, ascorbate and polyphosphate.
The toxicology of nitrate, nitrite and n‐nitroso compounds
Authors: Swann Peter F. 
Published: November 2006

AbstractNitrate is essentially non‐toxic to mammals but it can be reduced to nitrite either in improperly stored food, in the rumen of cattle, in the gastrointestinal tract of the human infant, and by the microflora of the human mouth. The nitrite from these and other sources, including that purposely added to food, presents a toxic hazard both because of the direct toxicity of nitrite, and by the formation of carcinogenic N‐nitroso compound by reaction with amino compounds. Administration of toxic amounts of nitrite induces methaemoglobinaemia. The nature of this disease, its importance in human medicine and the reason for the particular sensitivity of the infant, are briefly discussed.The carcinogenic properties of N‐nitroso compounds are described. These compounds have been found in the environment and may be formed in the stomach from amines and nitrite. Our knowledge of the amount of N‐nitroso compounds to which man is exposed, is continually increasing but with the lack of epidemiologic evidence, the assessment of the significance to man of these traces of N‐nitroso compounds depends upon the interpretation of animal experiments and their extrapolation to man. This extrapolation would be more certain if there were a more clear understanding of the factors determining tissue selectivity by carcinogens and tissue sensitivity, and of the mechanism of cumulation of carcinogenic doses and of synergism between carcinogens. Recent experiments suggest that there may soon be a significant breakthrough in the understanding of this. These experiments are briefly discussed.
Volatile components of jute sacks
Authors: Seifert Richard M. , Buttery Ron G. , Guadagni Dante G. 
Published: November 2006

AbstractThe vacuum steam volatile oil from jute sacks has been analysed by capillary gas chromatography and mass spectrometry. Thirty‐four compounds were characterised with some certainty, and some information obtained about an additional 36. The major volatile components were dimethylnaphthalenes. The odour thresholds of the volatile oil and some fractions were determined. These data and calculation of the amount transferred to a food contained in a sack, indicate that the jute sack could contribute an off‐flavour to the food.
Baking performance of egg‐yolk lipoproteins before and after surface modifications
Authors: Kamat V. B. , Jones A. A. , Graham G. , Yoell R. 
Published: November 2006

AbstractEnzymatically modified yolk or yolk plasma and succinylated yolk plasma gave unacceptable Madeira cakes but good fatless sponges of reasonable cell structure although somewhat inferior to the control. Modified yolk plasma showed variable degrees of aggregation in response to various treatments but the overall integrity of lipoprotein structure was unaffected. It is thought that in addition to the macroscopic integrity of yolk lipoproteins, their interfacial molecular anatomy has a marked influence on baking performance in both Madeira cakes and fatless sponges.
High‐ratio yellow cake. The starch cake as a model system for response to chlorine
Authors: Cauvain Stanley P. , Gough Brian M. 
Published: November 2006

AbstractStarch was extracted from wheat by wet milling, purified by differential centrifugation in water and substituted for flour in a high‐ratio yellow cake recipe. Carboxymethyl cellulose (1 % of the starch weight) was included to compensate for the poor water absorbing capacity of the starch. The cakes, in contrast to those prepared with flour (unchlorinated), did not suffer structural collapse on cooling. Further purification of the starch, accomplished by repeated shaking with toluene and water and removal of the emulsions so formed, led to cakes which did collapse. The collapse was prevented by chlorination of the toluenetreated starch and this system thus provides a potentially useful model for simulating the response of wheat flour to chlorine.
New constituents of the oxygenated fraction of pepper essential oil
Authors: Debrauwere Jack , Verzele Maurice 
Published: November 2006

AbstractThe oxygen containing compounds of black pepper oil were separated into free acids, esters, carbonyl compounds, alcohols and oxides using alkaline extraction, saponification, extraction with Girard T reagent and extraction with trichloroacetyl isocyanate reagent respectively for these fractions. Each fraction was investigated by gas chromatography coupled to a mass spectrometer using glass open‐tubular columns. Some compounds were preparatively isolated. Fifty‐one substances were identified of which 19 have not been recorded previously as occurring in black pepper oil.
Acid extraction of plant boron
Authors: John Matt K. 
Published: November 2006

AbstractOptimum extraction ratio, acid normality, and shaking conditions were established for HCl extraction of boron from plant materials. Within the range of low boron tissue levels (below 50 parts/106) encountered in diagnostic analysis for boron deficiency, the HCl extraction compared favourably with the dry ashing method for determination of total boron in plant materials. Although extraction was incomplete from samples with high boron content (above 80 parts/106), total boron determined by dry ashing was closely predicted from extracted boron. A rapid, yet consistent, HCl extraction for diagnostic plant boron analysis is proposed.
The role of formaldehyde as a protein crosslinking agent acting during the frozen storage of cod
Authors: Connell Jack J. 
Published: November 2006

AbstractFresh cod muscle treated with formaldehyde at concentrations approximating to those attained during frozen storage, is rendered partially inextractable in solutions of sodium dodecyl sulphate. This finding throws doubt on the role of formaldehyde as a methylene crosslinking agent acting during frozen storage of cod and similar species.
Determination of fatty acids in digesta: An improved method for the free fatty acids from c4: 0 to c18: 3
Authors: Edwards‐Webb J. D. 
Published: November 2006

AbstractA simple method is described suitable for the measurement of free fatty acids, from C4 to C18, produced by lipolysis of dietary fat in the calf. The method involves extraction of samples of diets and digesta with diethyl ether, and absorption of free fatty acids on to an ion exchange resin. After elution and conversion to methyl esters the fatty acids are determined by gas chromatography. By combining the values obtained with those for esterified fatty acids, estimated by an established procedure a complete analysis of the lipid classes in digesta can be obtained.
Changes in the amount of protein and lignocellulosic material accompanying the development of the field bean
Authors: Draper Simon R. 
Published: November 2006

AbstractDuring the development of plants of the field bean (Vicia faba L.) there was a rapid increase in protein, lignocellulosic material and total dry matter during a period extending from anthesis to a date 8 weeks later. Over the subsequent 10 weeks there was a much smaller increase in total protein and other components. The most important change during this period was a movement of nitrogen into the seeds. Throughout the experiment the major part of the total lignocellulosic material was associated with the stalks. The effect of the exclusion of this part of the plant on the chemical composition of a whole‐crop harvest is discussed.
Distribution of roots, water and nutrients beneath cabbage grown in the field
Authors: Goodman David , Greenwood Duncan J. 
Published: November 2006

AbstractDetailed measurements were made of the distributions of roots, water, nitrate, potassium and magnesium in the soil beneath summer cabbage that had been grown in the field for various periods of time. With few exceptions the concentration of water and nutrients did not vary with horizontal distance; the only detectable trends were in the concentrations of nitrate and potassium in the surface layer beneath large plants but these trends were much less than those of rooting density. The vertical distributions of nitrate and potassium ions were largely determined by rainfall which resulted in much loss of nitrate from the root zone and movement of potassium down the profile. Removal of water by evapotranspiration was more or less uniform down the profile despite rooting density declining sharply with depth. The significance of these findings to computer simulation of water and nutrient uptake by plants is discussed.
Role of ion‐selective electrodes in studies on vegetation, vegetables, fruits, juices and oils
Authors: Moody Gwilym J. , Thomas John D. R. 
Published: November 2006

AbstractIon‐selective electrodes constitute an important means of determining many of the ions, for example, nitrate, chloride, bromide, cyanide, fluoride, sulphate, ammonium, sodium, potassium, calcium, magnesium and boron, that occur in vegetation, vegetables, fruits, juices and oils. Their scope is outlined together with associated experimental problems and the results compared with those obtained by alternative analytical methods.
Roles played by bacterial and autolytic enzymes in the production of volatile sulphides in spoiling North Sea cod (Gadus morhua)
Authors: Herbert Rodney A. , Shewan James M. 
Published: November 2006

AbstractThe roles played by bacterial and autolytic enzymes in the production of volatile sulphides (hydrogen sulphide, methyl mercaptan and dimethyl sulphide) in spoiling iced cod have been investigated. The data show that the volatile sulphides arise as the result of the microbial degradation of cyst(e)ine and methionine. Thirteen Pseudomonas spp. have been investigated. All liberate hydrogen sulphide and methyl mercaptan. In addition to methyl mercaptan formation from methionine, six strains also produce dimethyl sulphide. There is no evidence to show that autolytic enzymes are directly involved in the production of volatile sulphides in chill‐stored North Sea cod.
Release of exchangeable and non‐exchangeable magnesium from nigerian soils on cropping with maize or chemical extraction
Authors: Lombin Ganyir , Fayemi Abraham 
Published: November 2006

AbstractA greenhouse experiment with maize (Zea Mays L.) using 12 representative soils of Western Nigeria indicated that the rate of release of non‐exchangeable Mg was too slow to meet crop requirements. Total Mg removed by four successive crops of maize (y) was well correlated with initial exchangeable Mg (x) (y = 6.34 + 1.06 x, r = 0.996***) suggesting that neutral N NH4OAc‐extractable Mg is the best measure of available Mg in these soils even under intensive cropping. The slow release of non‐exchangeable‐extractable Mg in the soils may be due to low percentages of silt and clay and their mineralogy.Total and non‐exchangeable Mg extracted by acidified N NH4OAc (pH 1.0) in 15 min at a soil extractant ratio of 1:5 correlated best with the total and non‐exchangeable Mg removed by cropping (r = 0.944*** and 0.734*** respectively). The use of such an acid extractant on these soils is, however, open to question in view of the relatively large amounts of non‐exchangeable Mg extracted by it compared with that extracted by cropping.Incipient Mg deficiency symptoms appeared in two‐week‐old plants when they contained 0.11–0.15% Mg. Persistent deficiency symptoms were associated with 0.1% Mg in the plants, 21–22 parts/106 exchangeable Mg and 5% (or less) Mg saturation of CEC.
Determination of S in extracted leaf protein
Authors: Byers Marjorie 
Published: November 2006

AbstractThe oxygen‐combustion technique for converting organic S to sulphur oxides, absorbing these in hydrogen peroxide, and determining the sulphate formed by measuring the amount of chloranilic acid it releases from an excess of barium chloranilate, was found to give satisfactory recoveries of S from methionine and cystine. This method for determining S was then applied to extracted leaf protein concentrates, almost all of whose S is derived from methionine and cyst(e)ine.
2‐methoxy‐3‐sec‐butylpyrazine—an important contributor to carrot aroma
Authors: Cronin Denis A. , Stanton Philip 
Published: November 2006

AbstractA concentrate obtained by concurrent solvent extraction‐steam distillation of carrots, Daucus carota L. gave complex chromatograms with more than 100 peaks. Attention was focused on a region of the chromatogram judged to be of sensory importance even though it contained components present only in very low concentrations. Procedures based on the use of glass porous layer open tubular (PLOT) capillary traps, a nitrogen selective detector and mass spectrometry led to the isolation and identification of 2‐methoxy‐3‐sec‐butylpyrazine. The possible significance of this highly potent odorant in carrot aroma is discussed.
Fatty acids of boal fish oil by urea fractionation and gas–liquid chromatography
Authors: Ghosh Amitabha , Ghosh Anita , Hoque Mominal , Dutta Jyotirmoy 
Published: November 2006

AbstractThe fatty acid composition of body and liver fats of boal, Wallago attu (Schn.), a cat fish, belonging to the family Siluridae and commonly known as fresh‐water shark has been determined by urea fractionation and gas–liquid chromatography (g.l.c.). The percentages of major component acids were found to be, 16:0, 10.5; 16:1 ω9, 7.6; 18:0, 7.2; 18:1 ω9, 17.4; 18:2ω9, 8.4; 18:3ω3, 6.1; 20:4ω3, 3.7 and 22:6ω3, 4.4. In addition, a number of minor component acids have been detected and estimated. The liver oil fatty acids have also been determined without fractionation and the percentages of major component acids found were 16:0, 23.5; 18:0, 12.7; 18:1ω9, 7.0; 20:4ω3, 13.7; 22:6ω3, 11.2.The oil has been studied for the first time for its fatty acid composition.
Triglyceride composition of Sesamum indicum seed oil
Authors: Sengupta A. , Roychoudhury S. K. 
Published: November 2006

AbstractThe fatty acid composition of Sesamum indicum seed oil was determined by gas–liquid chromatography. The percentages of individual acids were found to be: palmitic, 11; stearic, 6; arachidic, 1; oleic, 43; linoleic, 39. Triglyceride composition was calculated from the fatty acid compositions of the native oil and of the monoglycerides produced from it by pancreatic lipase hydrolysis. The oil is composed of 8, 41 and 51%, GS2U, GSU2 and GU3 respectively. Analysis by special thin‐layer chromatography combined with densitometry also indicated similar triglyceride composition for the sesame seed oil. Changes effected on the triglyceride composition by randomisation were also determined by both methods of analysis.
Nutritional value of soya protein and milk coprecipitates in sausage products
Authors: Skurray Geoffrey R. , Osborne Christopher 
Published: November 2006

AbstractSausages containing 60% of meat proteins replaced with soybean or milk calcium coprecipitates were prepared. Growth rates and plasma amino acid levels in rats fed diets based on these products, together with vitamin and available amino acid analysis indicated that the nutritional values of the non‐meat proteins were similar but were both markedly lower than meat sausages. Nutritional damage to the protein in the sausages during cooking was only apparent in the all‐meat sausage.
Effects of ageing and cooking on the tenderness of beef muscle
Authors: Davey C. Lester , Niederer Alan F. , Graafhuis Arie E. 
Published: November 2006

AbstractWhen beef sternomandibularis muscle was subjected to prolonged cooking, toughness, measured by shearing force across the grain, was reduced by about 50%. The shortened state of the muscle determined the final shear‐force value attained as in normal cooking, being considerably higher in meat at 40% shortening, than in either unshortened meat or in meat shortened by 60%. The tenderising effect of ageing was additional to that from long cooking. Ageing reduced the tensile strength of the myofibrils as measured by resistance to the shearing stresses of homogenisation. Cooking tenderising resulted from a breakdown in the collagen of the interstitial connective tissue. In cooked meat distinct linkages were shown to exist between Z‐lines of adjacent myofibrils. The mechanical strength of cooked meat is ascribed to the tensile strength of the fibrous components of muscle and these lateral linkages.
Distribution and identity of labelled products following autumn application of 15N‐labelled urea or potassium nitrate fertilisers to apple trees
Authors: Cooper Denise R. , Hill‐Cottingham Dennis G. , Lloyd‐Jones Charles P. 
Published: November 2006

AbstractYoung apple trees growing in pots of soil were treated in October with 15N‐labelled urea on the foliage or with K15NO3 via the soil. Whole trees were sampled in the following February and May and the tissues extracted to determine the concentrations of the major nitrogenous constituents and their 15N enrichments. At the February samplings following both treatments half the 15N was in the insoluble fraction, and the soluble part consisted almost entirely of arginine and asparagine. But the two treatments gave quite different distributions of 15N between the two amino acids Urea applied to the leaves resulted in over four times as much 15N in arginine as in asparagine; in contrast, from the soil nitrate treatment the distribution was almost equal. When sampled in May the new leaves and blossoms contained a large proportion of the total 15N in the tree. Comparison of these results with those from the February sampling leads to the conclusion that the nitrogen for this new growth had come from the insoluble N and arginine reserves and that the asparagine reserve had made little contribution to growth up to this time.
Some effects of nitrogen fertilizer on winter wheat
Authors: Batey Thomas 
Published: November 2006

AbstractBetween 1966 and 1969, 44 experiments on winter wheat tested five rates of N applied as spring top dressings of NH4NO3. There was a marked seasonal variation in the response of grain yield to N with a large response in 1969 (mean optimum 97.5 kg/ha N) and a small response in 1968 (mean optimum 49.2 kg/ha N); the mean optimum N rate for all experiments was 73.1 kg/ha N. The response curves for N and grain yield were classified into 4 types; there were 22 sites with positive curvilinear relationships, 7 were indeterminate, 4 with positive linear and 11 with negative linear relationships. At several of the latter sites substantial yield losses occurred when N was applied.The rate of N that would have been recommended using ADAS prediction methods based on previous cropping and manuring at each site was calculated. At 18 sites the rate of N recommended by prediction methods was within 40 kg/ha of the actual optimum obtained by experiment; at 29 sites it was within 50 kg/ha N but at 8 sites it differed by 75 kg/ha or more. The optimum grain yield obtained by experiment was compared with that obtained when the “recommended” rate of N was given; on 21 sites the difference in yield was less than 300 kg/ha but at 7 sites it was over 900 kg/ha. The results show that the ADAS prediction method accurately assessed the N status at almost half the sites overall. At 11 site (25%) yield differences between the optimum and recommended N rate were greater than 600 kg/ha but if the results for 1969 were excluded because of the unusually high response to N, at only 5 sites (15%) were yield differences greater than 600 kg/ha.Samples of soil from 17 sites were analyzed by 8 methods to assess available N; in 1966 several methods showed promise but in 1967 no method was of value, when correlated with N response.Tiller numbers were counted in 1968 and 1969; there was a strong tendency for more tillers to survive at high N rates. The effects of N on grain size were clear and consistent each year, the highest proportion of the large grain was obtained at low rates of N; each increment of N decreased grain size, irrespective of the optimal N rate.
Effects of volatile bacterial metabolites on the growth, sporulation and mycotoxin production of fungi
Authors: Barr John G. 
Published: November 2006

AbstractFive toxigenic fungi were grown in the presence of pure cultures of a number of different bacteria. Alterations in the gaseous environment resulting from bacterial growth produced changes in the growth, sporulation and toxin production of the fungi. Different fungi varied in their response to any one bacterium, and different bacteria produced a variety of responses from each individual fungus. The growth, sporulation and toxin production of most fungi were normally inhibited by the presence of bacteria; in a few cases toxin production was stimulated. Toxin production was able to proceed in the absence of sporulation.The implications of bacterium–fungus interactions in certain environments are considered.