bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of fermentation, processing and storage on lipid composition of sauerkraut
Authors: Peng Andrew C.
Published: November 2006

The changes in lipid composition and fatty acid distribution of sauerkraut during fermentation, canning, processing and storage were investigated organoleptically and chemically. Treatments were significant throughout the experiment. pH, lactic acid, and moisture content did not reveal any substantial changes. Total lipids, neutral lipids, and glycolipids increased, whereas phospholipids were unaltered during fermentation and processing. Quantitative changes in nonpolar and polar lipids during storage were in opposite directions, and net lipid content did not change. The changes in fatty acid composition were primarily in the distribution of palmitic, stearic, oleic, linoleic and linolenic acids during fermentation, processing and storage. Total lipids did not relate to organoleptic evaluation. However, polar lipids, specifically phospholipids, were directly related to storage stability and increased amounts of general acceptability. The formation of phospholipids may be catalysed by a reaction between tin from the cans and polar lipids at the expense of neutral lipids.
A kinetic study of the competitive oxidation of oleic acid‐linoleic acid mixtures
Authors: Romero Alfredo J. Rosas , Morton Ian D.
Published: November 2006

The kinetics of the autoxidation of oleic acid‐linoleic acid mixtures have been investigated by the rate of oxygen uptake. Mixtures with different molar fractions were prepared, keeping the total number of moles constant. Oxidations were carried out at 30 °C and graphs were made of the percentage of oxidation against time, overall first order rate constant against molar fraction and overall second order rate constant against molar fraction. It was found that during the mono‐molecular decomposition of hydroperoxides, the reaction rates decrease with decreasing linoleic acid molar fraction. No prooxidant or antioxidant effects were observed during this period, the predominant effect being that of oleic acid acting as a diluent for the oxidation of linoleic acid. When the reaction enters the period of bimolecular decomposition of hydroperoxides, a slight antioxidant effect was found, for mixtures containing less than 25% oleic acid. With increasing oleic acid concentration this effect levels off and gives way to a more marked prooxidant effect when the oleic acid is above 75%.
Volatile amine production in uncured pork during storage
Authors: Patterson Ronald L. S. , Edwards Robert A.
Published: November 2006

The concentration of volatile amines and the bacterial counts were determined in pork meat stored at −20, +5 and +20 °C. Amine formation appeared to be independent of bacterial growth until the count reached 109/cm2. The meat spoiled before the dimethylamine/trimethylamine content reached a concentration likely to yield a detectable amount of N‐nitrosodimethylamine in a cured product.
Enzyme inhibition by polyphenols of sorghum grain and malt
Authors: Daiber Klaus H.
Published: November 2006

Enzyme production and activity in malt produced from birdproof sorghum cultivars were unaffected by the endogenous polyphenols present in the testa and nucellar layer of the grain. When the rigid segregation of tissues and substances in the malt grain is disrupted by milling, the polyphenols inhibit the endogenous enzymes in aqueous suspensions and reduce the brewing value of the ground malt. Sorghum beer made from malt of birdproof cultivars did not taste bitter. Bird‐proof sorghum cultivars differ widely in content and quality of polyphenols inhibiting enzymes. Enzymatic methods are proposed to determine the inhibiting fractions of the polyphenols in sorghum grain. The results of these methods correlate well with DMF‐extractable polyphenols assayed by ferric ammonium citrate in alkaline medium. The merits of enzymatic and chemical methods to determine biologically active polyphenols are discussed. Suggestions to protect the brewing industry against unsuitable grain sorghum cultivars of the birdproof class are made.
The application of regional geochemical reconnaissance data in areas of arable cropping
Authors: Jordan William J. , Alloway Brian J. , Thornton Iain
Published: November 2006

Copper, magnesium, manganese and zinc have been studied in stream sediments and soils in five representative areas of arable cropping in southern and eastern England. Results have been assessed on the one hand in relation to the geochemistry of bedrock and soil parent materials, and on the other to crop production. Stream sediment data closely reflected the total concentration of copper, magnesium and zinc in soils and at the same time were proportionately related to “available” levels of copper and magnesium in soils. On the basis of reported problems and field trials, concentrations of less than 7 parts/106 Cu and 600 parts/106 Mg in sediments are likely to delineate areas within which a proportion of soils are deficient in these elements, possibly leading to a reduction in yields in sensitive arable crops. Zinc data for sediments and soils were difficult to evaluate in the absence of recognised deficiencies in field crops in Britain. The marked effect of soil Eh/pH on the mobility of manganese in soils and on its availability to plants limits the use of this technique in predicting deficient areas. The possible importance of marginal soil deficiencies of copper leading to reduced yields in cereals is discussed together with the potential value of regional geochemical maps in delineating areas where such problems may be of economic significance.
Enzymatic determination of the indigestible residue (dietary fibre) content of human food
Authors: Hellendoorn Emile W. , Noordhoff Maria G. , Slagman Johan
Published: November 2006

A simple in vitro method using pepsin and pancreatin is proposed for the determination of the indigestible residue (dietary fibre) content of human food. Results of analyses of some groups of foods are given, e.g. legumes, cereal products, potatoes, some fruits and vegetables, and onions. The discrepancies between crude fibre and values for indigestible residue are great in leguminous seeds and whole cereal products. As far as vegetables are concerned, the discrepancy is greatest in potatoes, endive, curled kale and cassava leaves, and small in white cabbage, carrots and onions.
The determination of pyridoxine in enriched foodstuffs by direct spectrofluorometric measurement
Authors: Söderhjelm Petter
Published: November 2006

A new method for the assay of added pyridoxine in foods is proposed which is simple and rapid. The method utilises the natural fluorescence of pyridoxine and a blank value is obtained by the addition of an excess of borate which quenches the fluorescence of pyridoxine. Experimental values obtained are compared with microbiological determinations. The interference of pyridoxal and pyridoxamine is less than 5% for each when they are present in equimolar amounts to pyridoxine. The practical working range for the method is 0.1–20 μg pyri‐doxine/ml.
Pattern of crack formation in rice grain as influenced by shape and orientation of cells
Authors: Srinivas T.
Published: November 2006

Stress cracks usually develop across the grain in rice, although longitudinal cracks also develop occasionally on one axis. On examination of sections of rice grain it was noticed that orientation of elongated cells provided cell wall continuation across the grain and also along the length in the dorsiventral axis. Cracks were found to develop easily along these cell wall lines. Crack formation was difficult in the lateral axis along the length since cell wall continuity was absent. However, when severely dried grains were suddenly wetted cracks developed even in this axis by disruption of cells along the cleavage path.
Effects of form and amounts of nitrogen and magnesium fertilisers on the yield and on the inorganic and organic composition of italian ryegrass grown on magnesium deficient soil
Authors: Nowakowski Tadeusz Z. , Bolton John , Lazarus William
Published: November 2006

Italian ryegrass (Lolium multiflorum) S22, grown in Mg‐deficient soil in pots, was given 40 and 160 mg N/kg of soil as ammonium nitrate or as ammonium sulphate treated with a nitrification inhibitor and 0, 20 and 40 mg Mg/kg of soil as magnesium sulphate. Yields of grass given the larger dressing of N were greater with ammonium nitrate than with ammonium sulphate. The magnesium treatments significantly increased yields only of the third cut given the most N when concentrations of Mg in dry matter were 0.07% or less. Magnesium fertiliser had little effect on the production of reducing sugars and sucrose but markedly increased fructosan and percentages of chlorophyll in grass of the third cut given the larger dressing of N. Non‐protein nitrogen was much greater with ammonium sulphate than with ammonium nitrate nutrition. With both forms of N fertiliser, this fraction accumulated in grass grown without added Mg, but it decreased when Mg‐deficiency was corrected. The percentage distribution of N in the free amino acid pool varied with the form of N fertiliser and the Mg treatments. With grass given ammonium nitrate, free amino acids predominated over amides; the reverse was true for grass given ammonium sulphate. The main effect of adding Mg was to decrease glutamine and to increase the percentages of some free amino acids, especially alanine and γ‐aminobutyric acid. About half of the soluble organic N in grass given ammonium nitrate was unaccounted for as amino acids and amides with all the Mg treatments; this N fraction was much less in grass given ammonium sulphate, but it increased with increasing magnesium fertiliser.
Structural functions of taste in the sugar series: Binding characteristics of disaccharides
Authors: Lee Cheang‐Kuan , Birch Gordon G.
Published: November 2006

The previous finding that only one half of a disaccharide molecule binds to the taste receptor site is fully substantiated but the linkage and the sugar residues of the disaccharide are important. The study is extended to the field of bitterness and it is observed that binding on to the bitter receptor is analogous to that on to the sweet receptor. With reducing disaccharides, it is the non‐reducing glycosyl unit that binds to the taste bud protein. Therefore, oligosaccharides constitute ideal models for this study despite their free anomeric centres.
Influence of cooking upon the nutritive value of potato and maize in diets for growing pigs
Authors: Whittemore Colin T. , Moffat Ian W. , Taylor Alexander G.
Published: November 2006

Diets containing 50% of the dry matter (DM) as barley, cooked flaked maize, ground maize, cooked flaked potato, or 22% of the DM as raw potato had metabolisable energy (ME) values of 14.5, 15.2, 15.1, 15.1 and 14.5 MJ/kg DM respectively, and efficiencies of N retention of 0.40, 0.41, 0.42, 0.42 and 0.31. Cooking potato had a positive effect upon the ME value and the efficiency with which ingested nitrogen (N) was retained. Any single nutritive value for raw potato was considered inappropriate due to the influence of raw potato on the digestibility of other diet components.

Pigs fed a diet containing cooked potato grew faster and converted feed to live weight more efficiently than pigs fed the same amount of a diet containing between 14 and 26% of the DM as raw potato. The presence of raw potato in diets was also found to reduce appetite. Cooking maize appeared to have only a small effect upon the nutritive value of maize. Pigs fed diets containing cooked flaked maize grew slightly faster than pigs fed ground maize.
Use of a centrifuging method to measure the drip of pork longissimus dorsi slices before and after freezing and thawing
Authors: Penny Ian F.
Published: November 2006

A method has been developed in which the drip from post‐mortem muscle is removed by centrifuging in tubes fitted with perforated teflon discs. Measurement of a number of samples showed that the weight lost after 1 1/2 h centrifuging correlated with the free drip of slices from the same muscle. There was also a good correlation between the free and centrifuged drip from frozen muscle slices. Thus the centrifuging method measures parameters which influence the water holding capacity of meat and offers a means of assaying, more quickly, the potential drip loss in meat slices both before and after freezing.
Effect of concentration process on cloud stability of reconstituted lemon juice
Authors: Epstein David , Mizrahi Shimon
Published: November 2006

The concentration process is a major factor in the low cloud stability of lemon juice reconstituted from a concentrate. A mechanism, based on the intermolecular bonding of pectin molecules, is suggested for this phenomenon, but actual proof of this has not yet been provided. It seems that the mechanism involved consists in reduction of the water activity below the critical level (inversely proportional to the pH of the system) necessary for maintaining the pectin in solution. This reduction favours an irreversible flocculation process through the intermolecular bonds of the pectin. This reduction favours an irreversible flocculation process through the intermolecular bonds of the pectin, thus resulting in the precipitation of the cloud particles trapped within the floes.
The use of activated charcoal for the concentration and analysis of headspace vapours containing food aroma volatiles
Authors: Clark Richard G. , Cronin Denis A.
Published: November 2006

The possibility of using very small quantities of activated charcoal for concentrating aroma volatiles from the headspace vapour over foodstuffs was investigated. Excellent recoveries of a range of organic compounds trapped on 2 mg of charcoal in a glass capillary tube were obtained when the components were desorbed rapidly at 260°C on to a gas chromatographic column, using a specially constructed injection device. In addition, the charcoal traps were found to be highly effective for concentrating volatiles at ambient temperatures from very large (18 litre) volumes of headspace vapour over raw walnuts, a foodstuff having a weak but characteristic aroma. Moreover, the aroma of the heat‐desorbed volatiles was judged by sensory evaluation to closely resemble that of fresh walnuts. The results suggest a considerable potential for charcoal in the headspace analysis of foodstuffs and of other substrates.
Interaction of gossypol with cottonseed protein: Potentiometric studies
Authors: Damaty Sayed , Hudson Bertram J. F.
Published: November 2006

Protein isolates, representing both structural and functional protein fractions, have been prepared from defatted cottonseed flour. In each case samples containing both normal and very low concentrations of bound gossypol have been studied. The pH of minimum solubility and the iso‐electric point of all fractions have been determined. The shift, in all cases, of these parameters to low pH values consequent on binding with gossypol is consistent with bonding taking place covalently with the formation of Schiff's bases from available free amino groups.
Chemical assessment of quality in tea and its relation to the market over an extended period
Authors: Hilton Peter J. , Palmer‐Jones Richard W.
Published: November 2006

The relationship between auction selling price and content of total theaflavins and total colour was investigated for teas sold on 25 occasions between June 1971 and December 1973. The extent to which price depended upon theaflavins and total colour varied according to the geographical area of origin of the tea and to the time of sale. While theaflavin content was generally the best explanation of price, total colour measurement added to the explanation on many occasions, particularly with teas from North East India. Possible ways in which seasonal market supply factors might influence the relationship are discussed.
rigor mortis in beef sternomandibularis muscle at 37°c
Authors: Locker Ronald H. , Daines Graeme J.
Published: November 2006

Beef Sternomandibularis muscle, restrained from shortening, was more tender if it entered rigor at 37°C than at 15°C. Raising the pre‐rigor holding temperature of unrestrained muscle above 15°C resulted in progressively greater shortening above 28°C, and greater tenderness, particularly between 34 and 37°C. Muscles allowed to shorten during rigor at 37°C were actually more tender than if restrained. In M. rectus abdominis, the muscles shortened at 37°C were a little tougher, but much less so than the degree of shortening would indicate. A study of the time course of tenderness changes, and other evidence, indicated that these effects were not due to ageing. Muscles which went into rigor at 37°C showed a slightly higher cooking loss than the 15°C controls and were softer, and usually paler in colour. There was an increased tendency of fibres to slip over each other. Loading experiments with raw muscle strips showed that where rigor occurred at 37°C, the strips yielded and “flowed” at lower loads than the 15°C controls. The various physical changes described indicate that rigor at 37°C differs considerably from rigor at lower temperatures. Some of the changes appear to be a mild form of the “pale soft exudative” condition seen in pork.
Naturally occuring nitrate/nitrite in foods
Authors: Walker Ronald
Published: November 2006

A 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

The 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

In 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

Nitrate 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

The 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

Enzymatically 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

Starch 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

The 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

Optimum 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

Fresh 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

A 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

During 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

Detailed 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

Ion‐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.
A rapid microdistillation method for the release of bound formaldehyde from treated feedstuffs
Authors: Van Dooren Paul H.
Published: November 2006

A rapid two‐stage microdistillation technique is described for the release of formaldehyde from tanned feed proteins. Quantitative recoveries are achieved for formaldehyde concentrations up to 1%.
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

The 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

A 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

The 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

A 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

The 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

The 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

Sausages 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

When 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

Young 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.
The measurement of cation exchange capacity of soils
Authors: Bache Bryon W.
Published: November 2006

The implications of the different methods available for measuring the cation exchange capacity (CEC) of soils are examined in the light of cation exchange mechanisms, and the issues involved in selecting a suitable method are discussed.
Some effects of nitrogen fertilizer on winter wheat
Authors: Batey Thomas
Published: November 2006

Between 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

Five 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.
Comparative evaluation of the enzyme multiplicity in a diploid, a triploid and a tetraploid sugar beet variety
Authors: Spettoli Paolo , Cacco Giovanni , Ferrari Giovanni
Published: November 2006

Specific activities and isoenzyme multiplicities of glutamic dehydrogenase, esterase, peroxidase, acid phosphatase, acid and neutral invertases were determined in a diploid, a triploid and a tetraploid sugar beet variety. The different ploidy status was accompanied by variations in the level of activity of glutamic dehydrogenase, peroxidase and invertase. Polyploidy induced a number of isoenzymes higher for peroxidase and lower for esterase, acid phosphatase and glutamic dehydrogenase. Specific isoenzyme bands characterised the invertase of the triploid variety.
Organic sulphur fractions in scottish soils
Authors: Scott Norman M. , Anderson George
Published: November 2006

Over 90% of the sulpher in some acid surface soils derived from different parent materials in north‐east Scotland was in organic combination. N:S ratios in the majority of the soils fell within the narrow limits of 6.0–7.5, and showed less variation than C:S ratios. Organic sulphur was poorly correlated with organic phosphorus, and high correlations with categories of soluble aluminium and iron seemed to reflect similar relationships between these elements and the whole organic matter. A group of calcareous soils derived from shelly sand deposits contained a lower proportion of organic sulphur. An average 64% of organic sulphur in the acid soils occurred as organic sulphate, compared with only 23% in the calcareous soils. Organic sulphate was less well correlated with carbon and nitrogen than was total organic sulphur. Total carbon‐bonded sulphur was best determined as the difference between total organic sulphur and organic sulphate, because direct measurement by Raney‐nickel reduction underestimated the amount present in most of the soils, due to the presence of chemically unreactive compounds. Good correlations between the reactive carbon‐bonded sulphur and carbon, nitrogen and organic sulphur, suggested that a well‐defined group of compounds was being measured. There were no consistent effects of drainage conditions on organic sulphur contents, or on the amounts and proportions of organic sulphur present as sulphate or in carbon‐bonded form. The freely drained soils derived from basic igneous drift, however, contained more organic sulphur than poorly drained samples, but this is attributed to differences in the organic matter content.

Several features of the results indicated that organic sulphur, unlike organic phosphorus, was predominantly an integral part of the soil organic matter.
Effect of irrigation on the lipid composition of taramira seed
Authors: Sukhija Pritam S. , Kaur Narinder , Bhatia Iqbal S.
Published: November 2006

The effect of irrigation on the lipid composition in maturing taramira (Eruca sativa, Mill) seed was studied. Decreasing the number of irrigations had an adverse effect on oil setting. Restricted irrigations affected adversely the biosynthesis of erucic acid in the oil at initial stages, though at later stages of seed development, irrigation had no such effect.
Influence of ethylene on the ripening of stored apples
Authors: Knee Michael
Published: November 2006

When preclimacteric apples were stored in air at 3.3°C rapid ethylene production usually began after 5 to 10 days. Treatment with ethylene caused earlier softening of apples, especially at the highest concentrations tested, 1–2 ml/litre. No effects on soluble polyuronide or peel chlorophyll levels were observed. It was not possible to induce earlier softening or compositional changes by ethylene treatment of apples stored in 2% O2:98% N2 at 3.3°C. Ethylene removal, by permanganate, delayed softening and increase in soluble polyuronide in preclimacteric, but not in postclimacteric, apples, stores in 2% O2:98% N2 at 3.3°C. Peel chlorophyll degradation was slow and unaffected by ethylene removal or fruit maturity. Loss of galactose residues from the cell wall was similar at high and low ethylene concentrations.

Removal of ethylene from apples stored in 5% CO2:16% O2:79% N2 at 3.3°C did not affect their ripening, but delayed softening of apples stored in 9% CO2:12% O2:79% N2 at 3.3°C.
Effects of storage at chilling temperature on ion absorption, salt retention capacity and respiratory pattern in yam tubers
Authors: Olorunda Ayodele O. , Macklon Alan E. S.
Published: November 2006

Yams, like most tropical crops, are subject to chilling injury when stored at temperatures below 10°C. Membrane permeability changes are considered to be among the causative factors. Some physiological parameters associated with the cell membranes were therefore examined in yam tuber tissue. It was established that incipient chilling injury could be rapidly detected by changes in ion absorption and salt retention capacities of tuber disks. Chilling effects were also reflected by changes in respiratory rate. It is proposed that these techniques can be used for rapid screening of tubers of a wide range of yam varieties, to establish optimum and minimum safe storage temperatures.
Stability of lipids and proteins in leaf protein concentrates
Authors: Hudson Bertram J. F. , Karis Ioannis G.
Published: November 2006

Although freeze‐dried leaf protein concentrate (l.p.c.) contains as much as 15–20% of lipids in which linolenic acid (60%) is the predominating component fatty acid, it appears to be unexpectedly stable when stored under ordinary conditions, i.e. at room temperature and exposed to air. Linolenic acid, in the form in which it occurs in l.p.c. is less prone to destruction than in the form of total lipid isolate, or in the form of more conventional linolenic‐containing vegetable oils. Rates of disappearance of linolenic acid and also loss of protein quality as judged by dye‐binding capacity, on heat treatment appear to follow a progressive trend as temperature is increased, without displaying a well‐defined order of reaction. With increasing temperatures, increased moisture levels result in an increase in the rates of both lipid and protein transformations. In heat treatments involving temperatures below 100°C, the presence of the lipid fraction does not affect protein transformation. At higher temperatures, when the lipid itself undergoes substantial oxidation, protein quality as judged by dye‐binding capacity is considerably affected.