bluuebunny/crossref_metadata_2025 huggingface dataset:
Bread staling. IV. Electrical properties of the crumb during staling
Authors: Kay M. , Willhoft E. M. A.
Published: November 2006

A new technique for studying the staling of bread is described based on conductance and capacitance measurements on the isolated centre‐crumb. It is proposed that the observed changes (up to 17%) in the electrical properties are due to retrogradation of the starch as well as the changes undergone by the transforming protein. Moisture redistribution is thought not to play a significant role during staling of the crumb at temperatures of less than about 10 °C. At 36 °C the first‐order rate‐constant for the protein transformation was estimated to be 0.7 day−1 and 0.3 day−1 for the rate constant for retrogradation of the starch fraction of the crumb. At 0 °C, the protein transformation was insignificant and the rate constant for the starch change was 1.03 day−1. The thickness of the gluten membrane surrounding the starch granules in bread was approximated to be less than 1 μm.
A semi‐micro method for the determination of lignin and its use in predicting the digestibility of forage crops
Authors: Morrison I. M.
Published: November 2006

The lignin content of dried grasses can be measured, after prior removal of interfering phenolic materials, by dissolving the residue in 25% acetyl bromide in acetic acid and determining the absorption at 280 nm. The absorption values can also be used to predict the nutritive value of dried grasses, hays and silages.
Physical and chemical changes in developing strawberry fruits
Authors: Woodward J. R.
Published: November 2006

Strawberry fruits of thevariety Red Gauntlet were harvested at 7 day intervals after petal fall. Changes in fruit weight, percentages survival on the plant, chlorophyll: carotenoid and anthocyanin, titratable acid, pH of extracts and sugar content were measured. Also changes in soluble and total pectic polysaccharides in alcoholinsoluble residues of harvested fruits were followed during development.

Fruit growth was not exponential and in later stages of growth the falling survival rate was correlated to fruit softening. Net synthesis of chlorophyll and carotenoid pigments took place up to 28 days and anthocyanin synthesis commenced 28 to 35 days after petal fall. The sugar content of berries increased with time and titratable acid concentrations increased slightly during development, falling in ripening fruits.

The specific viscosity of soluble pectic polysaccharides fell from 28 days after petal fall. There was net synthesis of polyuronide but not neutral polysaccharide during the development of fruits and the amount of insoluble pectic polysaccharide became small and relatively constant compared with the amount of soluble polysaccharide by 21 days after petal fall. Fruits undergoing senescence lost almost all their insoluble pectic polysaccharides.

The developmental processes taking place in growing fruits, especially with respect to changes in cell wall structure, and the relevance of results to fruit storage are discussed.
Chemical composition of Candida utilis and the biological quality of the yeast protein
Authors: Yáñez E. , Ballester Digna , Fernández Natividad , Gattás Vivien , Monckeberg F.
Published: November 2006

The chemical composition (moisture, ash, protein and non‐protein N, amino acids, ether extract, crude fibre, Ca, P, Fe) and biological quality (protein efficiency ratio and available lysine) were investigated in two batches of Candida utilis (Torula yeast). The samples (S1 and S2) were collected from a local factory. S2 was sterilised before drying. Protein, mineral and B‐complex vitamin contents were comparatively high. Amino‐acid analysis showed a high content of lysine and threonine, but a deficiency in sulphur amino acids. The biological quality measured as the protein efficiency ratio (p.e.r.) and available lysine gave values of 1.80 ± 0.05 and 6.6 g/100g of crude protein, respectively, in S1. These are higher than values reported in the literature. Sterilisation (S2) and storage for 1 year (S1(a)) significantly reduced the biological quality of the protein (p.e.r. 1.15 ± 0.12 and 1.34 ± 0.07, respectively). Supplementation of C. utilis with 0.3% DL‐methionine increased the p.e.r. value to 2.77 ± 0.03, close to that of casein. C. utilis appears to be a valuable material for human diets because of the high content and satisfactory quality of its protein and other nutrients.
Superficial scald, a functional disorder of stored apples VIII. Volatile products from the autoxidation of α‐farnesen
Authors: Anet E. F. L. J.
Published: November 2006

The main volatile product during the early stages of the autoxidation of α‐farnesene is 6‐methyl‐5‐hepten‐2‐one. Evidence that other unsaturated volatile ketones are also formed was obtained by catalytic reduction of the reaction mixture, when their more stable saturated derivatives were isolated. These ketones may arise by fragmentation of an α‐farnesene derivative at the central tertiary carbon atom in each of three possible ways.
A modified hypothesis for the structure and rheology of glutelins
Authors: Ewart J. A. D.
Published: November 2006

Cereal storage proteins, it is suggested, are more tolerant of genetic mutations than other proteins. Evolutionary tendencies may have been towards decreasing the cystine content and increasing the content of amino acids which are easily synthesised, especially those which are rich in nitrogen. The appearance of stress in molecular structure so that an intrachain SS bond is no longer able to close, thus creating interchain linkage, may have led to the origin of the glutelins.

It is argued that a viscoelastic dough can be formed only if protein particles, which originate in the form of protein bodies, are able to form a continuous structure whether maintained by covalent bonds or/and secondary forces.

The constituent polypeptide chains of glutelins could be joined in a linear or a branched mode. A number of difficulties arise if the branched model is used to explain the properties of dough at the molecular level. In attempting to reconcile fact and theory, it is speculated that polypeptide chains of wheat, rye and barley glutelins form linear concatenations with two disulphide bonds connecting each chain to the next: continuity of structure in their doughs depends on entanglement and interaction by secondary forces. The glutelin molecules of oats and maize are unable to form a continuous network, hence the absence of viscoelasticity from doughs of these cereals. Two reasons are suggested: more probably the molecules are highly cross‐linked in the branched mode and are thus incapable of significant entanglement; or if the molecules were cross‐linked in the linear mode, poor solubility would ensure that protein‐protein contacts in protein bodies were maintained, thus preventing dispersal of the protein and subsequent molecular entanglement. The glutelin molecules of sorghum appear to be too small to create a network by molecular entanglement. The importance of the disulphide interchange reaction is thought to lie in stress relaxation, but not in the creation of a dough structure. It is suggested that SS groups in viscoelastic doughs are sterically protected except when exposed by stress and consequently stress relaxation by SS interchange tends to occur only when it is needed.
Pectinesterase activity of some Iraqi dates at different stages of maturity
Authors: Al‐Jasim H. A. , Al‐Delaimy K. S.
Published: November 2006

Changes in the pectinesterase (PE) activity in four Iraqi date varieties at different stages of maturity were followed. The enzyme activity was determined by titration of the carboxylic groups released by the hydrolysis of pectin. The results obtained show that there was an increase in PE activity in these varieties with ripening. The greatest increase occurred during the period when the fruit had passed the yellowish stage and turned soft. This increase in the enzyme activity was then followed by a general decrease as the fruit matured and ripened on the tree. The data also indicate that there was a qualitative difference in the behaviour of these varieties.
Metabolism of citric and malic acids during ripening of tomato fruit
Authors: Davies J. N. , Maw G. A.
Published: November 2006

Tomato fruit at various stages of ripeness were injected with 14C‐labelled citric and malic acids. The 14CO2 evolved by individual fruit was determined over a 72 h period and the fruit then analysed for the incorporation of 14C into sugars, amino acids and individual non‐volatile organic acids. In mature green tomato fruit citric and malic acids were found to be metabolised to a comparable extent. Appreciable interconversion occurred together with oxidation to CO2 and some labelling of glutamic acid and glutamine. In red fruit, citric acid was not as readily oxidised to CO2 and little conversion to malic acid was observed. On the other hand, malic acid was oxidised to CO2 and converted to citric acid as rapidly as in green fruit with, in addition, appreciable conversion to glutamic acid. These results are discussed in relation to the changes in concentration of the endogenous acids which take place during the ripening of tomato fruit.
Texture of canned potatoes: Use of new objective methods to separate the attributes of mouthfeel and breakdown
Authors: Woodman J. S. , Warren D. S.
Published: November 2006

New methods are described for the objective assessment of mouthfeel (mealiness) using a Kramer Shear Press and for the amount of breakdown by sedimentation of sloughed tissue. Their application to several hundred samples of canned potatoes is reported. These objective methods correlate significantly (P < 0.001) with their subjective counterparts and demonstrate a clearer separation of mouthfeel and breakdown than do subjective methods. Examination of partial correlation coefficients indicates that mouthfeel is more significantly related to the specific gravity of the raw material than is breakdown. In separate experiments, late planting was shown to affect mouthfeel but not breakdown and the addition of calcium chloride to affect breakdown whilst leaving mouthfeel unaltered. Evidence is presented that mouthfeel is a rheological property controlled primarily by solids content; in contrast breakdown is interpreted as a failure of intercellular adhesion.
An investigation on laboratory and field methods of determining the pH of soil suspensions
Authors: Farr E.
Published: November 2006

A comparison was made between the pH values of soil samples, measured with a pH meter in the laboratory, and those obtained by using colorimetric indicator solutions in the field. Of the indicators tested, BDH Soil Indicator and bromocresol purple provided the closest overall comparison with laboratory results for soils with pH values from 3.8 to 7.8. Bromocresol green was useful only over a limited range (less than 5.2). Differences in procedure and analysis sometimes produced compensatory errors but the results did not often agree exactly and the magnitude of the discrepancy for any given soil was predictable only within fairly broad limits—the average standard deviation was 0.34 units and there was about a 75% chance of the result determined in the field being within 0.3 units of the result determined in the laboratory.
Lucerne tannins. II. Isolation of tannins from lucerne, their nature and influence on the digestive enzymes in vitro
Authors: Milić Božidar Lj. , Stojanović Srdjan , Vučurević Nada
Published: November 2006

Tannic substances were isolated from dehydrated lucerne meal and it was found that they contained free gallic acid, gallotannins and flavanols. In the procedure for their isolation, cation and anion exchange resins, Amberlite IR‐120 and Amberlite IR‐45, were used. The isolated tannin was tested as an inhibitor of tryptic digestion of casein, L‐amylolytic digestion of starch and lipase enzymes. In in vitro studies it was found that the isolated tannin has a high inhibitory action on digestive enzymes.
Mercury levels in wheat and other cereals, oilseed and biological samples
Authors: Tkachuk Russell , Kuzina F. D.
Published: November 2006

Analyses of 80 samples of wheat showed a mean mercury content of 8 ng/g, with a range of 4 to 18 ng/g (ng = 10−9 g). Wheat flour contained the same amount of mercury as wheat. Other cereals and oilseeds contained 4 to 29 ng/g of mercury. Levels of mercury varied for other organic materials analysed.

The analytical method used is relatively rapid and simple when certain precautions are followed. The method consists of an oxygen‐bomb combustion of samples, reduction of the mercury in the bomb washings to elemental mercury and then analysis of the mercury by cold vapour atomic absorption spectrophotometry. The limit of detection of the method is approximately 1 to 2 ng of mercury/g of sample. The reliability of the method was verified by quantitative recoveries of added organic and inorganic mercury compounds from wheat and barley and by carrying out collaborative tests.
Changes in the carbohydrate constituents of cassava root‐tuber (Manihot utilissima pohl) during growth
Authors: Ketiku A. O. , Oyenuga V. A.
Published: November 2006

Sucrose formed the bulk of the sugars in cassava root‐tubers, accounting for more than 69% of the total sugars. Other sugars included fructose, glucose and maltose. Maltose was consistently present as the lowest amount. The highest concentration of sugars (5.7%) was attained nine months after planting. Starch accounted for the highest proportion of the carbohydrates. A peak value of 81% was observed eight months after planting. The decrease to 78% at nine months was accompanied by an increase in sugar concentration from 3.5% to 5.7%. The sum of cellulose and hemicellulose constituted the non‐available carbohydrate fraction to non‐ruminants. This was less than 7% of total carbohydrates. Paper chromatography of the neutralised hydrolysate of the extracted hemicellulose revealed the presence of glucose and xylose only. The amylose content of cassava starch varied between 16.2% and 17.4% during growth. This variation was significant at 1% F level. The separated amylose had an iodine affinity of 17.0% while amylopectin had 0.1%.
The distribution of some nitrogenous constituents in the tea plant
Authors: Selvendran R. R. , Selvendran S.
Published: November 2006

A survey was made of the various nitrogenous constituents of the tea plant using paper chromatography. The following parts of the plant were examined: leaves, bark and wood of stems and roots, feeder roots and fruits (pericarp and cotyledons).

Theanine was present in every organ except the fruit and tended to be the major amino acid of the plant. Glutamic acid, aspartic acid and glutamine also occurred universally and in relatively high concentrations, and serine, alanine and γ‐aminobutyric acid, though generally present, occurred in smaller quantities. The wood of stems and roots contained appreciable quantities of a ninhydrinreactive compound which streaked like histidine. Pipecolic acid was present in appreciable quantities only in the fruits.

The amino acids of the hot‐water‐soluble proteins of the various tissues have been determined and certain differences between them were noted.
Sulphite‐binding power of wines and ciders. I. Equilibrium constants for the dissociation of carbonyl bisulphite compounds
Authors: Burroughs Leonard F. , Sparks Arthur H.
Published: November 2006

The apparent Equilibrium Constants were determined at pH3 and 4 for the dissociation of the bisulphite compounds of acetaldehyde, pyruvic acid, 2‐ketoglutaric acid, L‐xylosone, D‐threo‐2,5‐hexodiulose, 2,5‐diketogluconic acid, 2‐ketogluconic acid and galacturonic acid. Determinations were also made over a wider pH range for acetaldehyde (pH 1 to 13) and pyruvic acid (pH 1.5 to 8).
The influence of chemical modification on the hydrolysis of fats by pancreatic lipase and pregastric esterase with reference to fat digestion in the pre‐ruminant calf
Authors: Hamilton Rosemary K. , Raven Alan M.
Published: November 2006

The hydrolysis of various dietary fats and pure triglycerides by pregastric esterase and pancreatic lipase was studied in vitro in conjunction with a series of digestibility trials to examine the effect of various chemical modifications to beef tallow on its digestibility in milk replacers for pre‐ruminant calves. Using pure triglycerides, it was shown that pregastric esterase preferentially hydrolyses triglycerides containing short chain fatty acids; the rate was highest with glyceryl tributyrate and decreased markedly with increase in chain length. Using butterfat, tallow and various modified forms of tallow, it was shown that the inclusion of butyric acid in tallow by interesterification, which markedly improved its digestibility, substantially increased its rate of hydrolysis by pregastric esterase. The initial rate of hydrolysis of tallow by pancreatic lipase was substantially less than that of butterfat. Little improvement in the rate of hydrolysis and solubilisation was obtained when the tallow sample was interesterified or when it was supplemented with the long chain fatty acids, myristic and oleic, or with the short chain fatty acid, butyric. A considerable increase in the initial rate of hydrolysis and solubilisation did occur with tallow samples with a reduced content of stearic acid.

The results suggest that hydrolysis by pregastric esterase is a major site of discrimination between different fats in the pre‐ruminant calf and an important factor in determining overall digestibility.
Effects of protein content on the distribution and properties of rice protein
Authors: Juliano Bienvenido O. , Antonio Alicia A. , Esmama Bernardita V.
Published: November 2006

The protein of brown rice became more evenly distributed as protein content increased. Kjeldahl protein content of brown rice provided a better indication of milled rice protein content than histological examination of individual grains because protein content varied among grains. The increase in protein content was mainly due to an increase in the number of protein bodies. Screening 10 493 varieties from the world rice collection for lysine content by dye‐binding capacity showed that lysine content of rice protein varied only by at most 0.5 % point at any protein level. A negative correlation between the lysine content of protein and protein content of brown and milled rice was observed only in samples with protein below 10%. As protein content increased water‐soluble nitrogen also increased as a percentage of brown rice.
Effect of delignification on the in vitro rumen digestion of polysaccharides of bagasse
Authors: Dekker Robert F. H. , Richards Geoffrey N.
Published: November 2006

Sugar cane bagasse was partially delignified by three different chemical methods, viz. sodium sulphide/hydroxide (Kraft process), sodium hydroxide and sodium sulphite.

The Kraft and alkali treatments each reduced the lignin content by about 55%, and increased the rumen dry matter digestibility (d.m.d., measured by an in vitro method) by over 170%. Treatment of the bagasse with sodium sulphite removed only 15% of the lignin and increased the d.m.d. by only 37%. The digestibility of hemicelluloses (measured as xylan and arabinan) and cellulose in delignified bagasse increased fourfold and twofold, respectively, for the Kraft and alkali treatments and twofold for the sodium sulphite treatment.
Measurement of non‐enzymic browning of dehydrated carrot
Authors: Baloch A. K. , Buckle K. A. , Edwards R. A.
Published: November 2006

Non‐enzymic browning of sulphited dehydrated carrot is measured by extracting brown materials with 2% acetic acid containing 1% formaldehyde, followed by precipitation of interfering pigments absorbing at 420 nm with 10% lead acetate and ethyl alcohol. The presence of sulphur dioxide is shown to reduce the absorption at 420 nm of a glucose—glycine browning solution and an extract of dehydrated carrot, the effect depending on time of incubation and exposure to light. The use of formaldehyde in the extraction solvent overcomes the effect of sulphur dioxide at concentrations up to 19 200 parts/million. The presence of carotenoids is shown to increase the absorption of browning extracts at 420 nm leading to high results. The interference from pigment materials is overcome by precipitation with lead acetate and ethyl alcohol. The use of both formaldehyde and lead acetate has no additional effect on browning determinations.

Comparative tests of the proposed lead‐alcohol precipitation method with an alcohol precipitation method, using both a glucose‐glycine browning mixture and an extract of dehydrated carrot, shows only the lead‐alcohol precipitation method to overcome errors due to carotenoid pigments either originally present in the extract or added as β‐carotene, while the additional use of formaldehyde during extraction is necessary to overcome errors due to sulphur dioxide.

Browning of dehydrated sulphited carrot stored for up to 20 days at 50 °C decreased with time of storage when measured by the alcohol precipitation method and in dehydrated non‐sulphited carrot, browning showed only a slight increase with storage time. When measured by the lead‐alcohol precipitation method, browning showed only a slight increase in stored dehydrated sulphited carrot, but a marked increase in stored dehydrated non‐sulphited carrot, in agreement with visual observations.
The effect of potassium sulphite on the recovery of micro‐organisms from dehydrated onion
Authors: Moussa R. S.
Published: November 2006

The addition of potassium sulphite to onion powder and onion flake homogenates improved the recovery of several microbial groups constituting the aerobic flora of many onion samples. The counts of sulphite‐reducing anaerobic spores were not affected. A correlation is found between each sample's content of the pungent principle and the degree to which the addition of sulphite recovers its aerobic microbial flora.

Aerobic spore‐forming bacilli, Gram positive and catalase negative streptococci, Gram and oxidase negative and occasionally pigmented bacilli and yeasts and moulds formed the greater part of the dehydrated onion flora. Escherichia coli was isolated in relatively low numbers from only 4 of the samples. All 243 samples showed a Staphylococcus aureus count of less than 10/g.
The effect of lipoxygenase action on the mechanical development of wheat flour doughs
Authors: Frazier P. J. , Leigh‐Dugmore F. A. , Daniels N. W. R. , Eggitt P. W. Russell , Coppock J. B. M.
Published: November 2006

The mechanical development of dough has been followed by measurement of the relaxation time of dough samples after mixing to various levels of work input. Parallel determinations of free and bound lipid have also been made. When doughs were mixed in air, addition of full‐fat, enzyme‐active soya bean flour (subsequently referred to as “soya flour”) resulted in an increase in relaxation time, particularly at higher work levels. The magnitude of this improvement increased with increasing work input and was dependent on the rate of work input. Addition of soya flour also enabled a higher level of mechanical work to be introduced before dough breakdown occurred. When doughs were mixed under nitrogen, or when the soya flour was heat denatured, no change in the rheological properties compared with the respective control doughs was found. The release of bound lipid, which occurred during dough development in air in the presence of soya flour, could also be induced by adding purified lipoxygenase to the dough, together with linoleic acid as a substrate. This resulted in rheological changes similar to those observed using soya flour. However addition of enzymically pre‐peroxidised lipid to doughs mixed in nitrogen was without effect on relaxation times. These findings suggest that lipid release is linked with structural changes in dough protein and provide further support for a mechanism of coupled oxidation of protein ‐SH groups by lipoxygenase.
The component fatty acids of chaulmoogra oil
Authors: Sengupta A. , Gupta J. K. , Dutta J. , Ghosh A.
Published: November 2006

The fatty acid composition of the seed oils of the species, Hydnocarpus kurzii, H. wightiana and H. odorata were determined by gas‐liquid chromatographic (g.l.c.) analysis. The percentages of individual fatty acids were found to be: hydnocarpic 23.0, 33.9, ‐; chaulmoogric 29.6, 35.0, ‐; gorlic 25.1, 12.8, ‐; lower cyclic homologues 0.3, 4.6, ‐; myristic 0.6, 0.8, 0.4; palmitic 8.4, 5.6, 11.8; stearic ‐, 0.6, 4.7; palmitoleic 6.0, 1.3, 0.5; oleic 5.4, 3.6, 21.8; linoleic 1.6, 1.8, 29.3; linolenic ‐, ‐, 31.2; respectively.
Thermal degradation of anthocyanins with particular reference to the 3‐glycosides of cyanidin. I. In acidified aqueous solution at 100 °C
Authors: Adams J. B.
Published: November 2006

Several highly purified 3‐glycosides of cyanidin were degraded at 100 °C in weak aqueous hydrochloric acid at various pH values between 1 and 4 under both nitrogen and oxygen atmospheres and it was shown that the aglycone‐sugar bond is the most labile of the glycosidic bonds at pH 2 to 4. At pH 1.0, however, all the glycosidic bonds are susceptible to hydrolysis.

Evidence is presented that phenolic aglycones, and glycosides of undetermined structure, are formed during anthocyanin degradation. An essentially colourless phenolic product, tentatively identified as the chalcone or α‐diketone of cyanidin, was observed during the breakdown of all the cyanidin‐3‐glycosides studied in the pH range 1 to 4. This compound is stable under anaerobic conditions but easily degraded in atmospheres of oxygen.

The rate of sugar formation was found to be similar to the rate of red colour loss and to the rate of anthocyanin disappearance in the pH range 2 to 4 showing that glycosidic hydrolysis and not opening of the pyrylium ring is the rate‐determining step of the principal reaction leading to red colour loss. At pH 1.0 (anaerobic conditions), the rate of red colour loss lags behind the rate of anthocyanin degradation because the red, cationic form of cyanidin is fairly stable at this low pH. Complete hydrolysis of the anthocyanin takes place at pH 1.0 in contrast to the partial hydrolysis observed in the pH range 2 to 4.

The qualitative and quantitative information reported in this paper led to the proposal of a mechanism for anthocyanin degradation and the red colour loss which accompanies it for the pH range 2 to 4.
Distribution of cell wall components in potato tubers: A new titrimetric procedure for the estimation of total polyuronide (pectic substances) and its degree of esterification
Authors: Warren Donald S. , Woodman John S.
Published: November 2006

Total esterified polyuronide in plant tissue can be assayed by titrating the uronic acid liberated from the alcohol‐insoluble fractions of the tissue by alkaline hydrolysis. The total polyuronide can be determined in a similar manner if the carboxyl groups are initially esterified with methanolic hydrochloric acid. Comparison of the two results gives the degree of esterification of the total polyuronide. The divalent metals present in the same alcohol‐insoluble fractions are assumed to be bound to the uronide groups and their assay gives a measure of the extent of interchain cross‐linking by metal salt formation.

Application of these procedures to samples from different parts of potato tubers showed that polyuronide generally had a low degree of esterification (about 40%) and was present in higher concentrations (about 4.6% a.i.s.) in the cortex and periderm than in the interior tissues (about 2.7% a.i.s.). The degree of crosslinking due to calcium and magnesium ions is lowest in the outer layers of the potato tuber and may be the reason that sloughing occurs in this area.
Energy changes during ensilage
Authors: McDonald P. , Henderson A. R. , Ralton I.
Published: November 2006

The energy changes occurring during ensilage have been examined using a theoretical model with data calculated from known biochemical pathways. Results of a laboratory experiment in which five grasses were ensiled in triplicate confirm that energy is recoverable in an anaerobic system in spite of gaseous losses in the form of CO2. These changes have a concentrating effect upon the gross energy value of silage. The importance of this increase in energy concentration is discussed.
Effect of differential maturity of paddy grains in a panicle on their milling quality
Authors: Desikachar H. S. R. , Bhashyam M. K. , Ranganath K. A. , Mahadevappa M.
Published: November 2006

Branches of paddy panicles were divided into four equal parts and grains collected from each part separately. Moisture content at harvest and milling breakage after shade drying of grains to 12 to 13% moisture were determined.

Average moisture content of grains gradually increased while milling quality generally suffered in grains from the top first quarter to the last quarter at the bottom. The same trend was found when the grains in the “top” quarter were compared with those from the “rest” of the panicle. The proportion of sun‐checked grains was highest in the “top” fractions at all stages of maturity. The grains at the “top” also had a tendency to shed easily from the panicle. At early stages of maturity milling breakage of grains in lower portions of panicles was high perhaps due to immaturity and softness.
(−)‐3t,4t‐Dihydroxycyclohexane‐1c‐Carboxylate, a new quinate metabolite of Lactobacillus plantarum
Authors: Whiting G. C. , Coggins R. A.
Published: November 2006

Lactobacillus plantarum, isolate No. 13a, reduces (−)‐quinate, shikimate and (−)‐dihydroshikimate to a new metabolite identified as (−)‐3t, 4t‐dihydroxycyclohexane 1c‐carboxylate. The absolute stereochemistry of the product is given and is shown to resemble that of (−)‐quinic and (−)‐dihydroshikimic acids.
Some examples of the effect of soil physical conditions on the tractive effort required during ploughing
Authors: Low A. James , Piper F. Joan
Published: November 2006

Some measurements have been made of the draw‐bar pull during autumn and late winter ploughing of soils of different texture and following different treatments. Periods under grass reduce the force required for ploughing. Farmyard manure applied at 75 t/ha annually was found to have lowered the draw‐bar pull on ploughing significantly after six years.
Nutritive value of processed Saccharomyces cerevisiae, Scenedesmus obliquus and Spirulina platensis as measured by protein synthesis in vitro in rat skeletal muscle
Authors: Omstedt Per T. , von der Decken Alexandra , Hedenskog Gudmund , Mogren Håkan
Published: November 2006

Rats were fed for six consecutive days on a diet containing the protein sources under test at a protein level of 20%. Protein synthesis by skeletal muscle ribosomes was measured in vitro. Synthetic activity was estimated per unit ribosomal RNA and per g of wet weight of muscle. In separate experiments the nitrogen efficiency ratio (n.e.r.) of the protein sources was determined after 21 days feeding at a 10% protein level.

As measured by protein synthesis the nutritional quality of lyophilised baker's yeast Saccharomyces cerevisiae increased after mechanical disintegration. A further improvement was achieved by feeding yeast protein concentrates.

Judged by these determinations the nutritional quality of the three yeast preparations was higher than that of the low‐quality protein, wheat gluten but did not reach the level of the high‐quality protein, casein supplemented with methionine.

The metabolic utilisation of spray‐dried microalga Scenedesmus obliquus increased after mechanical disintegration from a value similar to that of wheat gluten to the level of methionine‐supplemented casein.

Lyophilised Spirulina platensis had a nutritional quality between that of wheat gluten and casein supplemented with methionine.

Addition of the limiting amino acid methionine to air‐dried baker's yeast or drum‐dried Scenedesmus obliquus and Spirulina platensis stimulated the metabolic utilisation of the micro‐organisms.

Supplementation of the diet with methionine increased the nitrogen efficiency ratio of air‐dried yeast and of drum‐dried Scenedesmus obliquus but had no effect on drum‐dried Spirulina platensis. The ratios were significantly lower than those of casein supplemented with methionine.

There was no difference in the nitrogen efficiency ratio between disintegrated yeast and yeast protein concentrate but the ratio of both was higher than that obtained with lyophilised yeast. The ratio was similar to that of casein without the addition of methionine.
A highly sensitive automated technique for the determination of ammonium nitrogen
Authors: Brown Michael W.
Published: November 2006

The catalytic action of nitroprusside on the phenol hypochlorite reaction has been utilised to design a more sensitive automated technique for determining ammonium nitrogen in soil extracts. The method gives reproducible results in close agreement with manual methods. Sensitivity is such that as little as 0.1 parts/ million of N in solution can be determined without the use of recorder range expansion.
Effects of storage treatments upon the ripening of conference pears
Authors: Knee Michael
Published: November 2006

Preliminary work established the pattern of changes in the amounts and properties of soluble pectic polysaccharides in Conference pears during ripening at 10 °C.

Conference pears were harvested on three dates and stored in air at −1 °C and in 2% O2 at −1 °C for various periods. They were ripened on removal from store at 18 °C. Chlorophyll and carotenoid concentrations in the fruit peel and soluble polyuronide concentrations in whole fruit as well as general storage data were recorded.

The lag in the ripening of pears at 18 °C after harvesting was abolished by storage at −1 °C. Softening and pectin changes were similar in all stored fruit samples irrespective of picking date, period of storage and whether stored in air or 2% O2. Storage in 2% O2 did retard breakdown slightly, however.

The main effect of 2% O2 was that it reduced the rate of destruction of chlorophyll during storage. Higher levels of chlorophyll were found during ripening in fruit which had been stored in 2% O2 than in fruit stored in air.
Fermented foods of common use in Egypt. II. The chemical composition of bouza and its ingredients
Authors: Morcos Sabry R. , Hegazi S. M. , El‐Damhougy Soraya T.
Published: November 2006

The nutrient content of different samples of bouza, either prepared in the laboratory or brought from the local market, were determined and compared with the individual ingredients.

Changes that occur in the pH values, diastatic power, alcohol and nutrient content of bouza when fermented for 24, 48 and 72 h were also studied.
Effect of some citrus juice constituents on taste thresholds for limonin and naringin bitterness
Authors: Guadagni Dante G. , Maier Vincent P. , Turnbaugh Jean G.
Published: November 2006

A panel of 20 to 27 screened judges was used to determine the threshold of pure limonin and naringin in distilled water, sucrose solutions, citric acid solutions adjusted to various pH values and in citrus juice model systems. Thresholds in distilled water were 1 and 20 mg/l for limonin and naringin, respectively. Sucrose, citric acid and combinations of these constituents in a model system increased the threshold of limonin and naringin several fold. The highest thresholds were obtained at low pH values in the absence of sugar. In a 1.2% citric acid solution containing 5% sucrose, 2.5% dextrose and 2.5% fructose the maximum limonin threshold of 11 mg/kg was obtained at pH 3.8. The maximum difference threshold for limonin in orange juice was 6.5 mg/kg and also occurred at pH 3.8. The optimum pH for limonin bitterness suppression (maximum threshold) was 3.8 in both model systems and natural orange juice. Thresholds on either side of this value were lower and limonin bitterness was more noticeable. No pH optimum was observed for naringin threshold in model systems. Individual thresholds showed a wide range of sensitivity to both limonin and naringin bitterness.
Storage of mushrooms in pre‐packs: The effect of changes in carbon dioxide and oxygen on quality
Authors: Nichols Royston , Hammond John B. W.
Published: November 2006

Mushrooms (Agaricus bisporus) were picked at the “button” stage (velum differentiated but unbroken) and stored for 3 to 5 days at 2 or 18 °C in styrene punnets (pre‐packs) overwrapped with one of a range of plastic films. Concentrations of carbon dioxide and oxygen were measured inside the pre‐packs at intervals. When the packs were opened, internal and external browning, loss of weight and diameter of the mushrooms were measured and subjective assessments of quality were made. These parameters were compared with those of mushrooms stored in unwrapped punnets.

As a result of the mushroom respiration, the internal atmosphere of the prepack was rapidly modified until, after about 24 h, a rough equilibrium concentration of CO2 and O2 was established in the range 4 to 10% CO2 and 11 to 17% O2 at 2 °C or 8 to 15% CO2 and 1 to 2% O2 at 18 °C; the mean concentration was dependent on the type of film. An equation, applicable to five out of six films that were tested, is proposed to describe the relationship between the equilibrium CO2 concentrations at 18 °C and the permeability data of the film.

At 18 °C, the gas changes inside the pre‐packs prevented opening of the pileus and, in combination with prevention of water loss by the film, slowed down deterioration of the mushrooms. However, concentrations of CO2 much above or below 10 to 12% were associated with increased internal browning. At 2 °C overwrapping generally caused slight external browning of the pileus.

The relevance of the results are discussed in relation to the commercial marketing of pre‐packed mushrooms.
Protein quality of some Nigerian feedstuffs. II. Biological evaluation of protein quality
Authors: Fetuga B. L. , Babatunde G. M. , Oyenuga V. A.
Published: November 2006

The protein quality of some Nigerian protein concentrates were studied by conventional protein quality techniques using weanling albino rats of the Wistar Strain.

The true digestibility of the concentrates were between 90 and 98% for most of the feedstuffs examined, except the cashew nut scrap kernel meals I and II, (84.6 and 84.3%); the African locust bean seed only (75.9%); the African locust bean seed and pulp (81.6%); and the palm kernel meal (74.2%) which showed significantly lower values than the others.

The animal protein sources examined (milk powder, casein, fishmeals and egg) were found to show superior p.e.r., n.p.r., p.r.e., n.p.u. and b.v. values to those observed for the cashew nut samples, African locust bean seed, groundnut and palm kernel meal. Blood meal, however, could not support the growth of rats and showed poor protein quality indices: −2.46, 0.83, 16.1, 18.9 and 19.3 for the p.e.r., n.p.r., p.r.e., n.p.u. and b.v., respectively.

The cashew nut scrap kernel meal samples I and II with protein values in the range 0.76 to 1.12, 2.86 to 3.13, 45.7 to 50.1, 41.3 to 46.7 and 48.9 to 55.3 for p.e.r. n.p.r., p.r.e., n.p.u. and b.v., respectively, were poorer compared to the good grade kernel meal with values of 2.01, 4.01, 64.2, 63.0 and 68.6 for p.e.r., n.p.r., p.r.e., n.p.u. and b.v., respectively, probably as a result of more severe heat damage.

The African locust bean seed samples could not support the growth of rats, gave negative p.e.r. (−3.19 to −2.54); low n.p.u. and b.v. (19.8 to 20.9 and 22.3 to 23.7). The palm kernel meal, despite its apparent balance of amino acids showed poor protein quality indices: 1.27, 2.62, 42.0, 44.1 and 56.7 for p.e.r., n.p.r., p.r.e., n.p.u. and b.v., respectively, attributable to its high fibre content and a concomitant lowering of the digestibility.
A gel consistency test for eating quality of rice
Authors: Cagampang Gloria B. , Perez Consuelo M. , Juliano Bienvenido O.
Published: November 2006

A rapid, simple test, complementary to the test for amylose content, was developed based on the consistency of a cold 4.4% milled‐rice paste in 0.20 N‐KOH. Consistency is measured by the length in a test tube of the cold gel held horizontally for 0.5 or 1 h. The consistency values are correlated with amylograph setback viscosity and can differentiate into three consistency types–low, medium, and high–even rice samples of similar amylose contents as long as they are between 24 to 30%.
Chemical methods suitable for screening for protein content and quality in cowpea (Vigna unguiculata) meals
Authors: Evans I. Marta , Boulter Donald
Published: November 2006

Several chemical methods have been tested for their suitability as screening procedures for estimation of the protein content and quality of cowpea (Vigna unguiculata) meals.

Preliminary estimates of crude protein can be obtained by the UDY dye‐binding procedure, followed by the automated microKjeldahl (% N × 6.25) method using, for example, Carlo Erba equipment. Total amino acid nitrogen was estimated also with the Carlo Erba apparatus and for the cowpea varieties examined a positive correlation between the total amino acid nitrogen and total nitrogen contents was found. Total sulphur was evaluated as a measure of the sulpho‐amino acids in cowpea meals. Total sulphur was determined by wet digestion and subsequent turbidimetric estimation of barium sulphate. Methionine was determined in meal hydrolysates by a Locarte Autoanalyzer. Cysteine was determined either as cysteic acid on the Locarte Autoanalyzer or as bismuth sulphide.

The results obtained for cowpea meals showed that there was a relatively small variation in the total sulphur and in the sulpho‐amino acid contents. Although the relation between total sulphur and sulpho‐amino acids was found to be significant at the 95% confidence level, the confidence limits were wide and at this stage a definite recommendation cannot be given as to the probable usefulness of the total sulphur‐screening procedure. A strong negative correlation was observed between both methionine and sulpho‐amino acids/16 g of N and % crude protein. Similarly, a negative relationship was observed between total sulphur/16 g of N and % crude protein.
A rapid radioactive method for determination of thiaminase activity and its use in the diagnosis of cerebrocortical necrosis in sheep and cattle
Authors: Edwin E. E. , Jackman R.
Published: November 2006

Methods available for the assay of thiaminase are discussed, and a new method based on the cleavage of [14C]thiazole‐labelled thiamine is described. Due to the rapidity and simplicity of its operation, it is especially recommended when large numbers of assays need to be carried out. Its application in understanding the aetiology of cerebrocortical necrosis of cattle and sheep is reported.
Changes in onion (Allium cepa L.) flavour components resulting from some post‐harvest processes
Authors: Freeman George G. , Whenham Robert J.
Published: November 2006

The effect of the following processes on the flavour of the product as compared with that of fresh onion has been investigated: pickling, canning, boiling and frying under domestic conditions, dehydration in hot air and by freeze‐drying and freezing. Flavour assessments were based on determination of pyruvate, thiolsulphinate and volatile components in headspace, gas‐liquid chromatograms as well as sensory testing in certain cases. All the methods of flavour assessment led to the conclusion that these processes were accompanied by large flavour losses. Quantitative estimates of the losses, varied with the analytical method in question, but were in general of the order of 90 to 95%. Freeze‐drying gave a product which retained more of the characteristic flavour components of fresh onion, as judged by sensory tests, than the other processes and in this case the taste threshold test indicated a flavour loss of 95%, pyruvate (PE) a loss of 25%, thiolsulphinate 26% loss and gas‐liquid chromatography a loss of total peak area of 57%. Evidence that onions are consumed mainly for their flavour rather than as a source of nutrients in the classical nutritional sense is discussed and other factors which influence the flavour strength of the vegetable are reviewed.
Surface‐active principle in black gram (Phaseolus mungo) and its role in the texture of leavened foods containing the legume
Authors: Susheelamma N. S. , Rao M. V. L.
Published: November 2006

A surface‐active principle of the nature of a globulin and an arabogalactan type polysaccharide have been shown to occur in the black gram. The polysaccharide does not exhibit surface activity, but confers thermal stability on the foam formed by the protein and prevents its disruption by heat. Together, these two components appear to be responsible for the characteristic soft, spongy texture of leavened foods containing the legume.
Effect of parboiling on thiamin, protein and fat of rice
Authors: Padua Adoracion B. , Juliano Bienvenido O.
Published: November 2006

Parboiling decreased the thiamin content of rice. Nevertheless, milled parboiled rice contained more thiamin than milled raw rice at the same degree of milling because parboiling caused thiamin to diffuse inwardly. Both the degree of loss and the degree of diffusion depended on the severity of the heat treatment. Bran‐polish of parboiled rice had a higher fat and protein content than bran‐polish of raw rice at the same degree of milling because the starchy endosperm of parboiled rice had a greater resistance to milling and so the bran and the germ were more effectively removed. Milled parboiled rice tended to have lower protein content than milled raw rice. Starch content was lower in bran‐polish from parboiled rice.
The lipids of the alga Spirulina
Authors: Hudson Bertram J. F. , Karis Ioannis G.
Published: November 2006

The blue‐green alga, Spirulina maxima, examined in the form of a spray‐dried powder, contains 11% of lipid, which has been analysed in detail with a view to establishing both the classes of lipid present and their fatty acid profiles. The dominant lipids are mono‐, di‐ and probably higher galactosyldiglycerides and phosphatidyl glycerol. Unlike other algae, Spirulina synthesises cis‐6‐cis‐9‐cis‐12 octadecatrienoic acid in contrast to its 9–12–15 isomer.
The use of fatty acids as grass silage additives
Authors: McDonald P. , Henderson A. R.
Published: November 2006

The effects of a range of fatty acids (C1‐C18) on silage fermentation in laboratory silos have been examined. When acids were applied to ryegrass in equimolar concentrations (50 mM) in the C1‐C6 range, only the C6 acid (hexanoic) had a marked effect in inhibiting lactate production. When hexanoic acid was examined in a second experiment over the concentration range 9 mM to 50 mM, concentrations below 50 mM did not prevent acid production, and at the lower levels production of lactate was stimulated. When higher fatty acids hexadecanoic (16:0), octadecanoic (18:0) and octadecenoic (18:1) were added at similar concentrations (8 to 9 mM) and octadecadienoic (18:2) added at concentrations ranging from 8 mM to 29 mM to ryegrass samples, lactic acid fermentation was not inhibited.
Effect of mode of cutting on cooking loss in beef
Authors: Locker Ronald H. , Daines Graeme J.
Published: November 2006

Cooking loss has been studied in beef rectus abdominis and sternomandibularis muscles. The form of these muscles, the first a flat sheet and the second a rod of elliptical cross‐section, both bounded by intact surfaces, has allowed systematic patterns of cutting, giving differing distances along the fibre between cut ends. The cooking loss increases as the distance between cut ends is reduced, and is similar in both muscles. Mince has a lower cooking loss than 1 cm or 2 cm slices. The evidence strongly suggests that loss is almost exclusively along the fibres to the cut ends. The greatest loss is in the 2 cm adjoining the cuts. The large variation in loss with length is not reflected in the shortening along the fibre during cooking, which remains close to 25% irrespective of length.

The lower loss in longer pieces of M. sternomandibularis is associated with a slightly higher level of tenderness. Freezing increases cooking loss in 4 to 16 cm lengths but not in shorter pieces or mince.