Showing papers in "Journal of the Science of Food and Agriculture in 1958"
TL;DR: In this article, a method for the determination of carbohydrates in plant samples is described, in which the plants are frozen in dry ice as soon as they are cut and portions extracted with 80% alcohol in an Elco Homogenizer and the carbohydrate estimated by the anthrone reaction.
Abstract: A method for the determination of carbohydrates in plant samples is described, in which the plants are frozen in dry ice as soon as they are cut and portions extracted with 80% alcohol in an Elco Homogenizer and the carbohydrate estimated by the anthrone reaction. A few results are given for the uptake of sucrose by plant roots from a culture solution.
174 citations
TL;DR: It was found that by assaying certain myotomes freed from myocommata, rather than whole minced fillets, much of the variation in the results disappeared, especially that caused by changes in the body lengths of the fish.
Abstract: Considerable variations were observed in the percentage of total protein soluble in 5% sodium chloride (‘soluble protein’) of the minced whole muscle of North Sea cod. It was found that by assaying certain myotomes freed from myocommata, rather than whole minced fillets, much of the variation in the results disappeared, especially that caused by changes in the body lengths of the fish.
Determinations spread over a period of 14 months, however, have indicated that starvation and certain phases of the reproductive cycle can bring about changes in the amount of soluble protein of such myotomes from fish of different sizes, possibly as a result of a drain on the resources of the fish.
The observations made it possible to eliminate several causes of variation in the amount of soluble proteins obtained under standard conditions, and obtain material with less than 1% variation. This material will provide the basis for research on freezing and cold-storage of fish.
120 citations
119 citations
TL;DR: In this article, the relationship between phosphate sorption and soil properties has been examined for ten soils from each of four parent material groups in NE Scotland, including igneous and slate soils.
Abstract: Relationships between phosphate sorption and soil properties have been examined for ten soils from each of four parent-material groups in NE Scotland Aluminium extracted by the Tamm acid-oxalate method gives highly significant correlations in all groups, and except for the granite soils, where the highest correlation is with loss on ignition, it is the best single criterion of sorption Acid-oxalate-soluble iron also gives significant correlations, but in no case does addition of a term for iron significantly improve the estimate of sorption given by aluminium alone Iron extracted by dithionite-005N-HCl treatment gives very poor relationships, but again the aluminium extracted gives highly significant correlations, as does aluminium extracted with 25% acetic acid
Sorption in all groups is highly correlated with loss on ignition and organic carbon, indicating that the active iron and aluminium are closely associated with organic matter Clay and silt values, unconnected for organic matter, iron and aluminium lost in the normal treatment with H2O2 and HCl, are useless as criteria of sorption, and residues from the Tamm extraction sorb only about 10% as much phosphate as the original soils, indicating that apart from associated soluble iron and aluminium, clay minerals play a relatively minor role
The differences between soil groups are mainly quantitative, and the basic igneous and slate soils have relatively high sorption capacities and high iron and aluminium contents
97 citations
TL;DR: The brown acidic pigments and the yellow neutral pigments of black tea are provisionally named thearubigins and theaflavins respectively as discussed by the authors, and they are formed during the fermentation process, mainly as the result of the enzymic oxidation of ( −)-epigallocatechin and ( −-epigalocatechin gallate.
Abstract: The brown acidic pigments and the yellow neutral pigments of black tea are provisionally named thearubigins and theaflavins respectively. These and other substances characteristic of black tea are formed during the fermentation process, mainly as the result of the enzymic oxidation of (—)-epigallocatechin and (—)-epigallocatechin gallate. It is probable that the theaflavins are intermediates in thearubigin formation.
96 citations
TL;DR: In this paper, a scheme for the oxidation of these substances is developed which suggests that substances A, B and C are bisflavanols, and that theaflavin and the aflavin gallate are derivatives of purpurogallin.
Abstract: Many of the substances occurring in freshly plucked tea shoots are listed and the chemical changes taking place during withering and fermentation are discussed. In fermentation (—)-epigallocatechin and its gallate are the only polyphenols to undergo appreciable chemical change. A scheme for the oxidation of these substances is developed which suggests that substances A, B and C are bisflavanols, and that theaflavin and theaflavin gallate are derivatives of purpurogallin. Thearubigins are probably formed as a result of coupled oxidation of theaflavins. Structures are also suggested for the minor components P, Q, R and Z. It is probable that theaflavins and thearubigins account for the colour and strength of tea liquors, and that theaflavins also contribute towards quality and briskness.
83 citations
TL;DR: It is shown that the extreme shortening and loss of ‘drip’ characteristic of thaw rigor in isolated muscles will not occur if the muscles remain attached to the skeleton and thawing is not accelerated.
Abstract: The onset of rigor mortis in the longissimus dorsi muscle of the lamb has been studied, with particular emphasis on the effect of temperature on its time-course. With the introduction of faster-freezing techniques in the frozen lamb industry, part of the carcass may be frozen before the onset of rigor mortis. It is shown, however, that the extreme shortening and loss of ‘drip’ characteristic of thaw rigor in isolated muscles will not occur if the muscles remain attached to the skeleton and thawing is not accelerated.
69 citations
TL;DR: In this article, a comprehensive scheme using ion exchange and partition chromatography was described for the determination of nonvolatile organic acids of pome fruits, including malic, citramalic and citric.
Abstract: A comprehensive scheme using ion exchange and partition chromatography is described for the determination of non-volatile organic acids of pome fruits. The method is used to investigate changes occurring in the acids of the peel and pulp of mature Bramley's Seedling apples during storage at 15°. These changes involve not only the aliphatic acids malic, citramalic and citric, but also the alicyclic acids quinic and shikimic.
59 citations
TL;DR: Theoretical implications and synthetic mechanisms are discussed and lead to the conclusion that the tocopherols are interconvertible in plants.
Abstract: A study has been made of the tocopherol contents of the maize, wheat, barley and pea plants. The four plants have been germinated from seed in the laboratory and grown to maturity under field conditions. Using two-dimensional paper chromatography, detailed tocopherol patterns have been established at different stages of the life-history of each plant. The young growing plants all synthesise predominantly α-tocopherol, whereas non-α-tocopherols are mainly specific products of the seeds. Theoretical implications and synthetic mechanisms are discussed and lead to the conclusion that the tocopherols are interconvertible in plants.
53 citations
TL;DR: There was found to be a decrease in body and liver weights, liver fat content, and muscle ash, and an increase in muscle water and bile in the gall bladder, while the percentages of intercellular space and brain fat were not affected.
Abstract: Six cod were starved for 78 days in an aquarium at about 14°, and the effect on various constituents of the body were investigated. There was found to be a decrease in body and liver weights, liver fat content, and muscle ash, an increase in muscle water and bile in the gall bladder, while the percentages of intercellular space and brain fat were not affected. The limiting value for liver fat appeared to be about 2%.
51 citations
TL;DR: The absorption spectra of thearubigin fractions are all very similar and differ appreciably from those of the theaflavins as discussed by the authors, and the identification of P as a 5:7:3′:4′:5′-pentahydroxyflavylium salt is suggested.
Abstract: The absorption spectra of thearubigin fractions are all very similar and differ appreciably from those of the theaflavins. Theaflavin and theaflavin gallate have similar absorption spectra, which also resemble that of purpurogallin. Substances A, B and C have absorption bands at 275 mμ. The spectrum of Q differs from that of purpurogallincarboxylic acid. The identification of P as a 5:7:3′:4′:5′-pentahydroxyflavylium salt is suggested. Substance 1C absorbs similarly to gallic acid, and the presumed p-coumarylquinic acids to p-coumaric acid.
TL;DR: In this article, the iodometric determination of lipid peroxides was improved by using continuous de-aeration to reduce the errors caused by induced oxidation and the development of a micro-spectrophotometric method yielding accurate results at very low peroxide concentrations.
Abstract: Improvements concerning the iodometric determination of lipid peroxides are suggested. They relate to (a) the adoption of a procedure allowing continuous de-aeration to reduce the errors caused by induced oxidation and (b) the development of a micro-spectrophotometric method yielding accurate results at very low peroxide concentrations. The latter covers a range of samples containing 0-02 to 5 μmoles of peroxide.
TL;DR: The solubility and activity of the glycosidase, oxidase and proteinase enzymes in acetone-washed powders prepared from samples of cacao beans taken throughout a commercial curing have been determined.
Abstract: The solubility and activity of the glycosidase, oxidase and proteinase enzymes in acetone-washed powders prepared from samples of cacao beans taken throughout a commercial curing have been determined. The enzymes, and indeed all the proteins, are rendered insoluble by phenolic tanning immediately following the death of the bean. The relevance of this reaction to the quality of the processed bean is discussed. The enzymes, although insoluble, remain active but at much reduced rates. The necessity for slow drying becomes apparent when the degree of inactivation and immobilization of the enzymes is realized.
TL;DR: The organic acids of a number of berry fruits (soft fruits) have been examined qualitatively and quantitatively using the methods of paper chromatography, silica gel partition chromatography and ion exchange.
Abstract: The organic acids of a number of berry fruits (soft fruits) have been examined qualitatively and quantitatively using the methods of paper chromatography, silica gel partition chromatography and ion exchange. In blackcurrant, redcurrant, whitecurrant, loganberry, raspberry, strawberry and elderberry the predominant acid was citric acid, with smaller amounts of malic acid; in blackberry, malic acid was predominant with large amounts of lactoisocitric acid and isocitric acid also present. Gooseberry was examined at stages during growth; shikimic acid was the dominant acid in very young fruits, later citric and malic acids predominated. Both shikimic and quinic acids were detected in gooseberry, blackberry and elderberry.
TL;DR: In this paper, improved methods were described for the extraction of theogallin from unprocessed tea-leaf, which was shown to be a mono-galloylquinic acid.
Abstract: Improved methods are described for the extraction of theogallin from unprocessed tea-leaf. Gallic and quinic acids have been unequivocally identified as products of hydrolysis. Analytical data indicate theogallin to be a mono-galloylquinic acid. By analogy with 3-caffeoylquinic acid, it seems probable that the galloyl group is attached to the 3-position of the quinic acid.
TL;DR: In this paper, an examination of a sample of the eggs obtained over a year from four birds, each of four breeds, namely, White Leghorn, Black LeghORN, Rhode Island Red and Light Sussex, has been made.
Abstract: An examination of a sample of the eggs obtained over a year from four birds, each of four breeds, namely, White Leghorn, Black Leghorn, Rhode Island Red and Light Sussex, has been made. This examination included studies of percentage of cracked eggs, shell thickness and porosity, membrane thickness, total shell nitrogen and insoluble and soluble fractions. All these characteristics varied widely from bird to bird, but, despite this, all except porosity showed marked breed differences too, although on the basis of quantitative values, no one breed excelled in all characteristics. Shell thickness declined in the summer months and membrane thickness was very low in April, but no other characteristic appeared to be affected by the season. Shell thickness of itself was not a guide to the cracking of eggs but for any one bird the cracked eggs had the thinner shells. There was also a possibility that the cracked eggs had the thicker membranes. Thin-shelled eggs had a higher nitrogen content and this has been explained on the basis of shell structure. The close relationship between weight of true shell per unit area and shell thickness has been reaffirmed and it is suggested that weight per unit area is an easier, more reliable and quicker method of obtaining relative thicknesses of shells, than is the measurement of shell thickness using a micrometer screw gauge.
TL;DR: In this article, a method is proposed for a detailed summative analysis of roughages, in which the determinations of crude fibre and of nitrogen-free extractives are replaced by determining the sugars of which the soluble and structural carbohydrates are composed, of pure cellulose and of lignin.
Abstract: A method is proposed for a detailed summative analysis of roughages, in which the determinations of crude fibre and of nitrogen-free extractives are replaced by determinations of the sugars of which the soluble and structural carbohydrates are composed, of pure cellulose and of lignin.
TL;DR: It was found that the soluble protein content decreased at a steady rate when the fillets were stored at − 14°, in contrast to the findings of some other workers.
Abstract: Measurements have been made of the percentage of total myotome protein soluble in 5% sodium chloride (‘soluble protein’) of frozen cod fillets. It was found that the soluble protein content decreased at a steady rate when the fillets were stored at − 14°, in contrast to the findings of some other workers. When the limiting value had been reached, after about 15 weeks, no further decrease was observed even in fillets stored for over 4 years at this temperature. Freezing increased the variation in soluble proteins of individual fish in a given batch considerably over that found in an unfrozen batch. The speed at which the fish were frozen was found to have no effect on the soluble protein value provided that the fish were not stored in the frozen state.
TL;DR: In this article, it was found that fish originally frozen in about 60 min. formed more insoluble protein after storage for a given time than those frozen at other speeds: the effect was very pronounced at low storage temperatures and the cause of changes in the solubility in salt solution of fish muscle during cold-storage was inorganic salt present in liquid solution in the frozen fish.
Abstract: The proportion of protein soluble in 5% sodium chloride (‘soluble protein’) was measured in cod muscle which had been frozen at various speeds, after storage for different times at different temperatures. It was found that fish originally frozen in about 60 min. formed more insoluble protein after storage for a given time than those frozen at other speeds: the effect was very pronounced at low storage temperatures. As a result of the work, it is concluded that the cause of changes in the solubility in salt solution of fish muscle during cold-storage was inorganic salt present in liquid solution in the frozen fish. Possible mechanisms of protein denaturation under different conditions of freezing are suggested.
The limitations of the decrease in soluble protein content as an index of deterioration in frozen and cold-stored fish are discussed.
TL;DR: In this paper, established plots of four perennial grass species, rye-grass (two strains), meadow fescue, timothy and cocksfoot were dressed with a balanced fertilizer at the rate of 0, 2 and 4 cwt/ acre at the start of the growing season and after each cut at the height of 8-10 in.
Abstract: Established plots of four perennial grass species, rye-grass (two strains), meadow fescue, timothy and cocksfoot were dressed with a balanced fertilizer at the rate of 0, 2 and 4 cwt./ acre at the start of the growing season and after each cut at the height of 8–10 in. The soluble carbohydrate (free hexoses, sucrose and fructosan) and the crude protein contents of the grass at each cut were determined and estimates of the yield of dry matter recorded.
Increasing the amount of fertilizer led to (a, an increase in the weight of dry matter per acre and the number of cuts taken, (b, an increase in the protein content and the average weight of protein per acre at each cut and (c) a decrease in the content of soluble carbohydrates, particularly the fructosan fraction. The average weight of soluble carbohydrates produced per acre at each cut was least at the highest rate of fertilizer application. The stimulating effect of fertilizer appeared therefore to result in the utilization of sugars for leafy growth at the expense of carbohydrate storage in the form of fructosan.
TL;DR: Using a cold grinding technique followed by perchloric acid extraction, an iodine-staining polysaccharide can be obtained from fresh clover and rye-grass leaves, which is shown to contain 3-5.5% of starch on a dry weight basis.
Abstract: Using a cold grinding technique followed by perchloric acid extraction, an iodine-staining polysaccharide can be obtained from fresh clover and rye-grass leaves. Paper chromatograms of acid and enzymic hydrolysates show that the polysaccharide is starch. Clover leaves have thus been shown to contain 3-5.5% and rye-grass leaves 0.7% of starch on a dry weight basis. The effect of various factors including shading and wilting on the starch content of red clover leaves have been briefly examined.
TL;DR: In this article, Nitrate and ammonium-N levels in both the surface and subsoil of a heavy clay-loam were determined at intervals both on uncropped soil and under rye-grass.
Abstract: Concentrations of nitrate- and ammonium-N in both the surface (0–9 in.) and the subsoil (9–18 in.) of a heavy clay-loam were determined at intervals both on uncropped soil and under rye-grass. On uncropped land, high levels of nitrate were maintained through wet periods which caused percolation through 20 in. of bare soil. Only persistent and heavy rainfall in late summer reduced surface-soil nitrate to low levels. Ammonium-N provided by ammonium sulphate or by decomposition of urea was converted to nitrate quite slowly and the soil contained equal amounts of ammonium- and nitrate-N in July. No ammonium-N was transported into the subsoil. Little total mineral nitrogen was lost from the topsoil of uncropped land during June and July, but during August and September nitrate concentrations in the subsoil increased rapidly. Total inorganic nitrogen in the top 18 in. of soil remained roughly constant until the end of July, after which there was a loss of nitrogen from the profile as a whole. On unmanured plots, fluctuations in ammonium-N levels were much smaller than corresponding changes in nitrate.
Under grass, soil nitrate levels fell quickly in warm wet weather when growth was rapid. In the same period, on plots receiving ammonium sulphate or urea, grass removed ammonium-N quickly and there was no increase in soil nitrate. When a first cut of grass was taken in July, four-fifths of the total supply of nitrate- or ammonium-N present in the soil at the beginning of the experiment had been removed. While the second crop was growing there was little nitrate (or ammonium-N) in the surface soil, but the harvested grass ‘recovered’ as much of the applied nitrogen as the first crop. It is suggested that nitrogen used in growth by the second crop was either taken up earlier and stored in the plant, or that it was taken from the subsoil.
TL;DR: In this paper, the phytate phosphorus and total phosphorus contents of oat grain have been studied, and it has been shown that there are very significant differences between varieties of Avena sativa on the one hand and of A. strigosa X A. brevis on the other.
Abstract: The phytate phosphorus and total phosphorus contents of oat grain have been studied, and it has been shown that there are very significant differences between varieties of Avena sativa on the one hand and of A. strigosa and A. strigosa X A. brevis on the other. The ratio of phytate P to total P is, however, remarkably constant in mature grain. Changes in phytate and total P accompanying maturation of the grain and germination have also been studied. The calcium and magnesium contents of the grain are considered in relation to their presence in phytin, and some of the evidence suggests that the phytin of different cereals may differ in chemical composition.
TL;DR: The action of intercellular ice on muscle cells was studied by means of the deoxyribose nucleic acid method in fish fillets frozen at different speeds and found that in very slow freezing the strong salt solutions created by the freezing out of water from the weakly saline interstitial fluids exercised considerable solvent effects on the fibres, without actually breaking them open.
Abstract: The action of intercellular ice on muscle cells was studied by means of the deoxyribose nucleic acid method in fish fillets frozen at different speeds. It was found that there was a zone of minimum damage at a freezing time of about 115 minutes, the most rapid freezing time at which all ice was able to form in the intercellular spaces. Since the ice masses were relatively small (little bigger than the muscle cells) they did not deform or damage the cells to any great extent. With slower freezing, cell damage was found to increase to a maximum value at 200–500 minutes (‘Peak C’), and the manner by which this was brought about is discussed; thereafter it decreased again. It was also found that in very slow freezing the strong salt solutions created by the freezing out of water from the weakly saline interstitial fluids exercised considerable solvent effects on the fibres, without actually breaking them open. The concentration of protein in the interstitial fluid tended therefore to increase in very slow freezing (freezing time about 750 minutes).
TL;DR: In this paper, the relationship between carbonyl compounds and flavour deterioration of fats is discussed and methods of estimating total carbonyls contents are described, with consideration given to their significance with respect to flavour deterioration in the presence of antioxidants.
Abstract: Evidence for the relationship between carbonyl compounds and flavour deterioration of fats is discussed and methods of estimating total carbonyl contents are described. Examples of the carbonyl contents of vegetable oils at different stages of processing are presented and consideration given to their significance with respect to flavour deterioration in the presence of antioxidants. Distinction is made between the non-volatile, tasteless, carbonyl compounds and the volatile, breakdown products of fat oxidation, which are responsible for rancid flavours.
TL;DR: In this article, an extract of fresh ox-muscle was prepared in the laboratory under conditions designed to minimise any chemical change, and a complete analysis was made of this extract and compared with that of commercial meat extract.
Abstract: An extract of fresh ox-muscle was prepared in the laboratory under conditions designed to minimise any chemical change. A complete analysis was made of this extract and compared with that of commercial meat extract.
Despite the different methods of extraction and subsequent treatment, the two extracts showed remarkably similar composition. The major difference was the loss of free amino-acids and sugars from the muscle extract and the formation of brown pigmented substances, presumed to be of the Maillard type, in the commercial material.
A substance reducing triphenyltetrazolium chloride, believed to be a sugar derivative, was found in the muscle extract but not in the commercial meat extract.
A method is described for the estimation of carnitine.
TL;DR: In this paper, the levels of nitrate and total mineral nitrogen increased appreciably on incubation; corresponding changes in ammonium levels were smaller, were irregular and were not related to other soil characteristics.
Abstract: ‘Mineralizable-N’ values were determined by incubating at 18° a series of 27 soils of medium and heavy textures at 50% of their moisture-holding capacity for 30 days. Increases in nitrate levels following incubation of soils which had been previously air-dried were, on average, three times as great as increases given by incubating corresponding freshly-sampled soils. In all soils the levels of nitrate and total mineral nitrogen increased appreciably on incubation; corresponding changes in ammonium levels were smaller, were irregular and were not related to other soil characteristics. Increases in nitrate and in total inorganic nitrogen on incubating air-dried soils were approximately related to the initial levels of nitrate present in the soils when they were sampled, and to their percentages of total nitrogen.
TL;DR: In this paper, a special examination has been made of lucerne saponins, which appear to be mixtures, probably varying both in glycosidic and sapogenin structure.
Abstract: Triterpenoid saponins from various plants have been subjected to paper electrophoresis and paper chromatography and a special examination has been made of lucerne saponins. These bulk saponins and those from a number of other plants appear to be mixtures, probably varying both in glycosidic and sapogenin structure. An explanation is suggested for some striking differences between paper chromatographic and paper electrophoretic results given by certain saponins.
TL;DR: The processes of mineralisation and immobilisation of nitrogen are defined, and the contribution of mass isotope (15N) studies to our knowledge of these simultaneous transformations in soil is briefly reviewed.
Abstract: The processes of mineralisation and immobilisation of nitrogen are defined, and the contribution of mass isotope (15N) studies to our knowledge of these simultaneous transformations in soil is briefly reviewed
Studies of immobilisation of nitrogen in soils treated with organic materials are reviewed with particular reference to the nitrogen content and carbon/nitrogen ratio of the added substances Laboratory studies on carbon/nitrogen relationships in glasshouse soils incubated with mixtures of sucrose and inorganic nitrogen are summarised, together with comparative data for a wide range of other soils The amounts of nitrogen immobilised in acid ‘maiden’ soils on incubation with sucrose were increased by the addition of lime and phosphate, but did not reach the levels of activity of old glasshouse soils; these findings are discussed in relation to the carbon/nitrogen ratios of the untreated soils and to their rates of evolution of carbon dioxide
Recent studies on the simultaneous mineralisation of carbon, nitrogen and phosphorus are briefly described Data are presented for 32 soils showing relationships between initial soil pH and the percentages of the total soil nitrogen mineralised after liming or hydrolysed by autoclaving with acid The observation that acid soils appear to contain a reserve of nitrogenous constituents which is readily mineralised on liming is discussed with reference to recent views on the chemistry of the nitrogenous components of soil organic matter
Reference is made to some recent work on laboratory incubation tests as a guide to the availability of soil nitrogen and the prediction of crop response to nitrogenous fertilisers
TL;DR: In this article, the authors compared the results of direct acid hydrolysis of extracts of soils made using water, aqueous NaOH or Na4P2O7 and 30% ethanol.
Abstract: The carbohydrates found after hydrolysis of extracts of soils made using water, aqueous NaOH or Na4P2O7 and 30% ethanol were compared with those found in a direct acid hydrolysate of these soils. The soils used included a Sassafras loam as control, a Sassafras loam amended with lucerne, a Pocomoke sandy loam from a field area, and a Pocomoke sandy loam from a virgin area covered with pines. Some carbohydrates were found in all hydrolysates but the direct acid hydrolysis gave the highest yields.
Glucose, galactose, mannose, arabinose, xylose, fucose, rhamnose, 2-O-methyl-D-xylose, 2-O-methyl-D-arabinose, two other methylated sugars and galacturonic and glucuronic acids were among the carbohydrate materials found. Glucosamine, N-acetylglucosamine, inositol and mannitol were other carbohydrate compounds present in the hydrolysates.
Quantitative differences were also noted in the amounts of these carbohydrates. In the lucerne-amended soil, the carbohydrate materials measured were about 0–092% compared with 0–078% for the control soil. The Pocomoke field soil contained larger amounts of these materials than did the virgin soil. Differences in quantities of individual sugars in the soils were also found.