bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipids of potato tubers. Effects of storage temperature on total, polar and sterol lipid content and fatty acid composition of potato tubers
Authors: Galliard Terence , Berkeley Howard D. , Matthew Jennifer A. 
Published: November 2006

AbstractPotato tubers (Majestic and Bintje varieties) were stored at 5 and 20 °C for up to 24 weeks. Only minor differences were observed in lipid composition of tubers stored at the two temperatures. Linolenic acid levels were slightly lower in the 10 °C stored tubers, although no significant differences were found in the proportions of the total polyunsaturated fatty acids of tubers at 5 and 20 °C. The effects on the fatty acid composition of Pentland Crown potatoes of short term storage at 30 °C are reported. It is concluded from this and from previous papers in this series that neither the choice of potato variety, nor of storage temperature for a given variety, is likely to reduce the polyunsaturated fatty acid content of potato sufficiently to avoid the problems experienced commercially in the oxidative degradation of polyunsaturated fatty acids to produce off‐flavours in potato products. The large changes in the proportions of the different classes of sterol lipids which have been reported to occur in potatoes during storage were not confirmed by the present studies.
Amino acid changes associated with the development of cold hardiness in perennial ryegrass
Authors: Draper Simon R. 
Published: November 2006

AbstractDuring the development of cold hardiness in Lolium perenne there is a progressive increase in the free amino acid content of leaves, mainly due to an accumulation of glutamine and proline. These changes are largely reversed within 8 days if plants are transferred to higher temperatures which allow dehardening to occur. It is suggested that amino acid analysis could be used as a means of comparing the response of grass varieties to changing temperature regimes.
Composition of Saccharomyces fragilis biomass grown on lactose permeate
Authors: Delaney Rory A. M. , Kennedy Robert , Walley Bernard D. 
Published: November 2006

AbstractSaccharomyces fragilis (NRRL y 1109) was grown on a medium composed of Cheddar cheese whey ultrafiltration permeate, supplemented with inorganic nitrogen. The biomass had a crude protein content of 49.5% and an ash content of 7.6%. The “true protein” content, based on a N fractionation procedure was 37.2% and the total nucleic acid content was 5.7%. Qualitatively, the amino acid composition of S. fragilis was similar to that reported for other whey‐yeasts. The quantity of individual essential amino acids was greater in the permeate grown S. fragilis. The sulphur containing amino acids, methionine and cyst(e)ine were present at a combined level of 3.2 g/16g N, compared with 2.2g/16 g N in a commercial whey‐yeast product. The chemical score (CS) and essential amino acid index (EAAI) were 58.2 and 76.0 respectively. Rats fed on a diet containing S. fragilis biomass as the sole source of dietary protein showed a net weight increase. NPUcarcass for S. fragilis protein was 67.0±3.9 compared with a value of 75.3±3.0 for a casein control. Supplementation of S. fragilis biomass with DL‐methionine(2 g/16 g N) raised the NPUcarcass value to 84.4 ± 2.8.
Influence of glucosinolates and high‐molecular factors on the nutritional value of low‐glucosinolate rapeseed meal
Authors: Josefsson Egon 
Published: November 2006

AbstractIn order to ascertain the reason for the prominent growth‐inhibiting effect of unheated low‐glucosinolate rapeseed meal, the nutritional value of various fractions of the meal was evaluated in growth experiments using mice. A meal containing myrosinase activity was not growth‐inhibiting after the low‐molecular compounds had been removed by dialysis. A hydrolysis of glucosinolates to isothiocyanates and oxazolidinethiones would probably not explain the marked antinutritional properties of the low‐molecular fraction. Heat treatment after autolysis did not improve the nutritional value of the meal. The harmful factors present in an autolysed meal could be extracted with methylene chloride. This extract contained nitriles, but no isothiocyanates or oxazolidinethiones. Thus, together with other information, the results suggest that the growth‐inhibiting effect of unheated, low‐glucosinolate rapeseed meal is mainly due to the presence of factors that direct the hydrolysis of glucosinolates towards nitrile production.
Physiological aspects of nitrate utilisation in a barley variety exhibiting high seed protein content
Authors: Edgar Kenneth F. , Draper Simon R. 
Published: November 2006

AbstractA barley variety (Hiproly) which exhibits high seed protein content, was compared with the commercial variety, Ymer. Plants were raised to the seedling stage using a sand culture system. The effects of humidity, nutrient NŌ3‐N level, and stage of development, on leaf and root protein and NŌ3‐N contents, were assessed. The major difference between varieties was observed when the regression of leaf NŌ3‐N (mg/plant), on root NŌ3‐N (mg/plant) was examined. Unit increase in total root nitrate results in a larger increase in leaf nitrate in Hiproly than in Ymer. Possible explanations for this difference are discussed.
Polyphenol oxidase activity and browning of three avocado varieties
Authors: Kahn Varda 
Published: November 2006

AbstractA comparison between the in vitro total and specific activity of polyphenol oxidase of three avocado varieties, Fuerte, Horeshim and Lerman, showed clear differences that were correlated with the in vivo rate of browning of the corresponding freshly cut mature fruit; Fuerte had the highest values, followed by Horeshim and then Lerman. A good correlation existed between the PPO activity in the crude homogenate of the fresh fruit and the crude enzyme extracted from the acetone powder prepared from each variety. The possibility that the relatively low PPO activity in the crude enzyme of the Lerman avocado was due to the presence of an inhibitor and to factor(s) degrading the enzyme, or that the relatively high activity of the Fuerte enzyme was due to an activator, was tested in various ways and ruled out. It was therefore concluded that the differences in the rate of browning of the three avocado varieties studied were directly related to the PPO activities as expressed in the crude enzyme fraction.
Effect of fermentation, processing and storage on lipid composition of sauerkraut
Authors: Peng Andrew C. 
Published: November 2006

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractEnzyme 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

AbstractCopper, 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

AbstractA 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

AbstractA 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

AbstractStress 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

AbstractItalian 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

AbstractThe 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

AbstractDiets 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

AbstractA 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

AbstractThe 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

AbstractThe 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

AbstractProtein 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

AbstractThe 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

AbstractBeef 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.