bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships between the critical concentrations of nitrogen, phosphorus and potassium in 17 different vegetable crops and duration of growth
Authors: Greenwood Duncan J. , Barnes Anthony , Liu Kit , Hunt John , Cleaver Trevor J. , Loquens Stephen M. H.
Published: October 2006

Fifty‐three field experiments were carried out to define the way in which the critical concentrations of nutrients in vegetable crops decline with increasing age so as to provide better criteria for diagnosing deficiencies and to provide inputs to models for fertiliser response. Each of 17 vegetable crops were grown with levels of nitrogen (N), phosphorus (P) and potassium (K) fertiliser that resulted in near maximum yields and little luxury consumption of nutrients. Between five and 20 individual plants were harvested at intervals (up to 13) during the growing period and analysed separately. A model was derived and used to summarise the data as curves of % organic‐N, P and K, and sum of cations (milli‐equivalents) in the dry matter with time. Mean plant dry weight‐time relations were also obtained. Unexplained variation about the best fitting curves was substantial and was not appreciably reduced by taking account of mean plant weight as well as time. Much of this unexplained variation was attributed to differences between plants within a harvest and some of it to harvest to harvest deviations from the model. However, little was associated with year to year variability. The net result is that 95% confidence limits were about ±25%. The significance of these findings to detecting nutrient deficiencies and providing inputs to models are discussed.
Variation in the concentration of major carbohydrates in the grain of some spring barleys
Authors: Torp Jan
Published: October 2006

A procedure adapted for rapid routine analyses was used to determine the content of starch, amylose, low molecular weight carbohydrates, and dietary fibre in grain from 37 barley genotypes grown in triplicate yield trials. Among 20 high‐yielding spring barley varieties grown in two subsequent years, the content of starch varied from 55 to 62% of the dry matter, while the content of amylose varied from 23 to 35% and averaged 30% of the starch. Among 17 exotic genotypes and mutant lines the content of starch and amylose in starch varied from 43 to 62% and from 17 to 48%, respectively. The amylose content was related neither to starch content nor grain yield. The content of low molecular weight carbohydrates was high in some starch‐deficient mutants but close to 2% in all other varieties and genotypes. There was a negative relation between grain yield and low molecular weight carbohydrates among the high‐yielding varieties. The content of dietary fibre varied from 18 to 25% in high‐yielding varieties, but was considerably influenced by environment. The content of dietary fibre was unrelated to grain yield or kernel weight. The exotic genotypes contained from 14 to 29% dietary fibre. Starch‐deficient mutants produced more dietary fibre per kernel than did normal varieties.
The effect of methyl bromide on esterase activity in wheat
Authors: Price Nicholas R. , Bunyan Peter J. , Loveder Christopher J.
Published: October 2006

Fumigation of wheat with methyl bromide causes a change in the polyacrylamide gel, isoelectric focusing profile of esterase proteins from aqueous extracts of wheat. The significance of this effect is discussed in the light of known reactions of methyl bromide in stored products.
Effect of Magadi soda treatment on the tannin content and in‐vitro nutritive value of grain sorghums
Authors: Muindi Pancras J. , Thomke Sigvard , Ekman Rune
Published: October 2006

Studies were conducted to investigate the possible use of raw Magadi soda (RMS), a sodium sesquicarbonate salt (Na2CO3NaHCO3. H2O) in the detoxification of the tannins associated with high‐ and low‐tannin sorghum grains and to establish the relative in‐vitro nutritive value of the treated grains. Treatment of grains with concentrations as low as 4 g litre−1 of RMS for 3 days, reduced the level of the assayable tannins in the grains by 40 to 57%. This reduction was accompanied with an increase in the in‐vitro digestibility of the organic matter and starch. Treatment of the hightannin sorghums increased the in‐vitro protein digestibility while no increase was observed for the low‐tannin sorghums. Use of solutions containing more than 37.5 and 9 g RMS litre −1, resulted in reduced protein digestibility of the high‐ and lowtannin containing sorghums, respectively.
Evidence for the osmotic dehydration theory of freeze damage
Authors: Grieve Peter W. , Povey Malcolm J. W.
Published: October 2006

Current views on freeze damage require that a reversal of osmotic flow occurs, on differential freezing across a membrane. This hypothesis has been tested using a variation of the traditional thistle‐funnel apparatus. Cellulose acetate membranes were used to retain sucrose solution within the thistle‐funnel and the arrangement was immersed in water. The sucrose concentration was measured refractrometrically whilst the water was slowly frozen. Once the water had fully frozen the sucrose concentration was observed to increase, reversing the steady dilution that had been observed before freezing of the water was complete. This concentration effect is consistent with a reversal of osmotic flow on differential freezing across the membrane. The effect was also observed in polyethylene glycol, retained with Amicon diaflo UMOS membranes.
The contribution of lead in water to dietary lead intakes
Authors: Smart Gloria A. , Warrington Marjorie , Evans William H.
Published: October 2006

Preliminary experiments have been carried out to determine the uptake of lead from both hard and soft waters used in the preparation of food and beverages. Lead concentrations in water for the range of 0.05‐0.5 mg litre−1 were used to prepare composite groups representing root vegetables, other vegetables and beverages whose composition reflected per capita consumption of these foods in the UK. The uptake of lead from water was highest for the composite group of other vegetables which comprises 70% by weight of green vegetables. For each of the composite groups and the particular water samples used there was little relative difference in uptake whether foods were prepared in hard or soft water. Calculations of the contribution made by lead in water used for preparation of foods and beverages to the total dietary lead intake indicates that at levels of lead of 0.02 mg litre−1, the contribution is about 10% but this can rise to about 40% as lead levels in the water approach 0.1 mg litre−1.
The influence of irrigation on the composition of soluble amino acids in developing wheat grain
Authors: Singh Umaid
Published: October 2006

Changes in the composition of soluble amino acids were determined in the endosperm of wheat at different stages of maturation grown under different soil moisture conditions. Significant differences were observed in the composition of soluble amino acids during the course of development. With the irrigated crop, the amount of proline decreased during developmental stages but it rapidly increased with development of grain until little beyond the half maturity stage. It then decreased towards maturity in the case of the unirrigated crop. Many soluble amino acids in the endosperm from the unirrigated crop were at lower levels than that in the endosperm from the irrigated crops during early stages of development, but in the later stages the size of the amino acid pool in the endosperm from the unirrigated field exceeded that from the irrigated field. Protein accumulation in the endosperm was also highly influenced by irrigation.
Free sugars and their relationship with grain size and starch content in developing wheat grains
Authors: Kumar Rakesh , Singh Randhir
Published: October 2006

Free sugars in wheat varieties, at different stages of grain development and differing in grain size and starch content per grain, were analysed to determine any relationship with grain size and starch content. Fresh and dry weight (mg per grain) of developing grain increased with maturity until 35 days after anthesis. Fresh weight declined after 35 days but dry weight remained almost constant. Water content increased until the 21 and/or 28 day stage and then decreased. Active starch synthesis started from 14 days onwards and continued until 35 days after anthesis. Free sugars (total sugars, reducing sugars, non‐reducing sugars and sucrose) per grain followed closely the changes in the rate of starch accumulation and, in general, were maximum at the 14 day stage followed by a decline up to 28 days, with no significant alteration afterwards. Presence of adequate amounts of soluble sugars in grain even when starch synthesis had stopped suggested that the supply of sugar precursors did not limit starch synthesis. None of the sugars was found to have a significant relationship with either grain size or starch content. A hypothesis explaining the termination of starch accumulation in developing cereal grains has been proposed.
Fractionation of wheat bran carbohydrates
Authors: Brillouet Jean‐Marc , Mercier Christiane
Published: October 2006

A procedure for the fractionation of wheat bran carbohydrates with an emphasis on non‐starchy polysaccharides is described. After a complete extraction using a chloroform‐methanol (2:1) solvent, bran was destarched using amyloglucosidase and extracted using ammonium oxalate. Then delignification by sodium chlorite followed by hot water extractions was applied. Small quantities of water‐soluble hemicellulosic polymers containing glucose, xylose, arabinose with lesser amounts of galactose and mannose were removed by these three steps. The remaining holocellulose (of a low protein content) was extracted using 1M sodium hydroxide, and hemicelluloses A1 and B1 were separated from the extract. Hemicellulose A1 (5.4% of native bran) was determined to be a xylan containing smaller proportions of arabinose and glucose, whereas hemicellulose B1 (12.6% of native bran) was a complex mixture of several types of polysaccharides, the major one being a highly branched arabinoxylan. Hemicelluloses A4 and B4, obtained by 4M sodium hydroxide extraction of the residue after 1M sodium hydroxide treatment, had lesser amounts of arabinose compared with the respective fractions from the preceding step. For hexoses, higher proportions of mannose and glucose were found. α‐Cellulose residue retains 19.8% of pentosans.
High‐pressure liquid chromatography of apple juice phenolic compounds
Authors: Wilson Eric L.
Published: October 2006

Apple juice phenolic compounds: (+)‐catechin, (‐)‐epicatechin, chlorogenic acid, phloridzin, phloretin xyloglucoside, and the polymeric procyanidins from the dimeric to the heptameric, were separated by high‐pressure liquid chromatography on a CN column, run in the normal phase, using an acidified tetrahydrofuran‐hexane solvent gradient. Individual procyanidin fractions, of different degrees of polymerisation, were collected from the CN column and the isomers from each fraction were then separated on a C18 column, using a methanol‐aqueous KH2PO4 solvent gradient.
Saponin content of soya beans and some commercial soya bean products
Authors: Fenwick Dorothy E. , Oakenfull David
Published: October 2006

Quantitative thin layer chromatography has been used to estimate the saponin content of whole soya beans (Glycine max L. Merrill, cv. Williams) and a number of commercial soya bean products such as protein isolates and lecithin. Saponins were present in all these materials at concentrations ranging from 56 g kg‐1 (on a dry weight basis) for whole soya beans to 3 g kg‐1 for the protein isolate ‚Promine‐D’︁. Previous estimates indicate a saponin content of whole soya beans of only about 5 g kg‐1. It is suggested that this is an underestimate resulting from loss of material during the extraction procedures used in earlier methods of analysis.
Identification and estimation of carotenoids in lyophilised meals of four Vicia species at five different stages of growth
Authors: Barro Carmen , González Gaspar
Published: October 2006

The carotenoids from Vicia sativa, V. villosa, V. ervilia and V. monanthos at five different stages of growth, were identified and quantitatively determined. All of them showed significant quantities of carotene, lutein, zeaxanthin, violaxanthin, neoxanthin and traces of a pigment that was probably cryptoxanthin. V. villosa contained the highest amount of carotenoids. The four Vicia spp. showed higher levels of lutein and zeaxanthin than lucerne (alfalfa) meals.
Determination of free and loosely protein‐bound formaldehyde in the tissues of pigs fed formalin‐treated skim milk as a protein supplement
Authors: Florence Eric , Milner Douglas F.
Published: October 2006

Skim milk containing 0.1% formalin (0.4 g formaldehyde litre‐1) was fed to pigs and their growth rate compared with control pigs fed a formalin‐free meal diet. Formalin‐treated milk and tissues from control and experimental animals were analysed for residual formaldehyde, present as free and loosely protein‐bound, by a colorimetric determination using chromotropic acid. Some 20% of the formaldehyde added to milk was irrecoverable after 7 days' storage, probably due to irreversible binding to protein. Mean concentrations of residual formaldehyde in tissues taken from experimental and control pigs were 19.7 and 20.2 mg kg‐1, respectively. This indicates that excess residual formaldehyde is not present in tissues of pigs fed formalin‐treated skim milk.
Oxidation of cholesterol in heated tallow
Authors: Ryan Thomas C. , Ian Gray J. , Morton Tan D.
Published: October 2006

Preliminary thin layer and gas chromatography data indicate that tallow cholesterol is oxidised when tallow is exposed to high temperatures (180°C) for an extended period. This may be of some significance to human health since some of these oxidation products may be angiotoxic and/or carcinogenic and tallow is used as a deep‐fat frying medium in some fast‐food restaurants.
Carbon‐13 and proton nuclear magnetic resonance studies of wheat proteins. Spectral assignments for flanders gliadins in solution
Authors: Baianu Ion C.
Published: October 2006

The first proton and 13C nuclear magnetic resonance spectra of single wheat variety gliadins in solution are presented and assignments of the resolved 13C lines are proposed by comparison with the chemical shifts of the constituent amino acids in solutions. Proton magnetic resonance spectra are also presented for an extract of total wheat protein and partial assignments are proposed for these complex biochemical preparations. Further experiments on these materials of considerable practical importance are suggested and the non‐destructive character of the techniques is pointed out in relations to monitoring changes in protein conformation.
The thiocyanate ion (SCN−) content of eggs from hens (Gallus domesticus) fed on a diet containing rapeseed meal
Authors: Shuaib A. C. Ahmed , Beswick Gordon , Tomlins Richard I.
Published: October 2006

The antimicrobial effect of the lactoperoxidase‐thiocyanate‐hydrogen peroxide system has been recognised in milk and other biological fluids. In this study the main object was to determine whether the inclusion of 10% rapeseed meal (RSM) in layers' diet could enhance the levels of the thiocyanate ion (SCN−) in eggs to a level required by the LP system to promote bactericidal activity in egg products. Twelve ‚Abor Acre’︁ pullets were divided into two lots, separately housed and maintained under similar conditions. One lot was fed on a basal diet and the other on an experimental diet containing 10% RSM. Both diets were of known composition, isoenergetic and isonitrogenous. Throughout the feeding trials (15 weeks) a record was kept of egg productivity, individual egg weight and layers weight. Subsequently, the weekly‐lots of eggs were analysed for thiocyanate ions (SCN−) by gas chromatography. The colour of each yolk was measured using the ‚Roche Colour Fan’︁ and organoleptic assessments were made for the detection of trimethylamine taint since the feeding of RSM has been reported to influence these factors. No significant difference was recorded in the average weight of eggs obtained from both groups. However, egg production was 15% higher with RSM fed hens which lost a little weight. No taint was detected in either set of eggs and no significant variation in yolk colour was noted. After 4 weeks the levels of SCN− reached 1.6 mg kg−1 in the experimental eggs and then remained almost constant. The control set had an average of 0.5 mg kg−1 SCN−. Hence an enhancement of the SCN− levels can be achieved in shell eggs by incorporating 10% RSM in the layers' diet. This enhancement is of the order claimed necessary for the operation of this system.
Wheat starch granule protein: The isolation and characterisation of a salt‐extractable protein from starch granules
Authors: Lowy Gillian D. A. , Sargeant James G. , David Schofield J.
Published: October 2006

A salt‐extractable protein has been isolated and purified from large (A‐type) wheat flour starch granules (Triticum aestivum cv. Maris Huntsman). This protein was the major species extractable with NaCl and because of its ease of extraction it was tentatively concluded that it was associated with the surface of the granules. It had a molecular weight of approximately 30 000 as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS‐PAGE) and an isoelectric point (pI) in excess of 10 as judged by analytical isoelectric focusing in polyacrylamide gel. The amino acid composition of the protein was quite different from those of wheat gluten proteins. A protein with similar properties was present on small (B‐type) Maris Huntsman starch granules and it could also be detected on A‐type granules from another variety of hexaploid breadwheat (T. aestivum cv. Flinor) as well as on A‐type granules from tetraploid durum wheat (T. durum). This protein was not present on starch granules prepared from germinated grains (Maris Huntsman). The protein had neither α‐amylase activity nor inhibitory activity against either wheat or hog pancreatic α‐amylases. Several other proteins could be extracted from A‐type starch granules but only after gelatinisation of the starch granule in the presence of SDS. The electrophoretic behaviour of these proteins was quite different from that of the NaCl‐extracted protein and the rigorous conditions required to separate the latter proteins from the starch granules suggested that they are internal components of the granules.
The silica content of plant polysaccharides
Authors: Khalil Nabeel F. , Duncan Henry J.
Published: October 2006

Analysis of several plant polysaccharides confirmed the presence of silica (Si) in all pectin samples analysed and revealed its presence in potato starch. In the latter case the Si was concentrated in the amylopectin fraction. The range of Si values found, based on dry weight of polysaccharide analysed, was: (a) for pectin 1.40‐2.30; and (b) for potato starch 0.47‐0.80 mg g−1. Other samples analysed contained less than 0.10 mg g−1. It would appear that most of the Si present in potato tubers is located in the starch grain where its distribution parallels that of phosphorus (P). The comparable range of values found for P in potato starch was 1.30‐1.60 mg g−1. It is thus possible that some of the distinctive properties of potato starch attributed to P could be influenced by the Si present.
The glycoalkaloid content of some edible solanaceous fruits and potato products
Authors: Jones P. Geraint , Fenwick G. Roger
Published: October 2006

The glycoalkaloid contents of three edible solanaceous fruits (aubergine, red and green peppers) have been found to be less than 10 mg 100 g−1 fresh weight. Commercial potato products, such as potato crisps, chips and tinned new potatoes, have been found to contain similar low levels which are within those accepted as safe by breeders of commercial potatoes.
Debittering and nutritional upgrading of enzymic casein hydrolysates
Authors: Cogan Uri , Moshe Michael , Mokady Shoshana
Published: October 2006

Commercially‐available proteolytic enzymes were used to prepare casein hydrolysates. Treatment of the hydrolysates with activated carbon resulted in the elimination of the bitter taste which developed during the course of hydrolysis. However, the debittering step was accompanied by a selective loss of tryptophan (63%), phenylalanine (36%) and arginine (30%). Consequently, the activated‐carbon‐treated hydrolysates exhibited poor nutritional quality in rat feeding studies. Supplementation of the treated hydrolysates with the proper amounts of tryptophan and phenylalanine greatly improved their nutritional quality. A simulated milk formula based on a partially debittered hydrolysate, resulted in a product of reasonably good nutritive value. The study demonstrates that an optimum balance between debittering by activated carbon and supplementation with tryptophan and phenylalanine is feasible. This will permit the production of casein hydrolysates of acceptable taste and of high nutritive quality.
A method for the determination of available fluoride from marine products using young chicks
Authors: Soevik Torleif , Braekkan Olaf R.
Published: October 2006

A method is described for the determination of available fluoride in biological materials. Groups of 1‐day‐old male White Leghorn chicks were fed a low fluoride diet for 14 days (2.3 mg F− kg−1) to which graded levels of fluoride were added as sodium fluoride, or in the form of fluoride‐containing foods. The drinking water did not contain any detectable amount of fluoride. Water and feeds were provided ad lib. The response was measured as the concentration of fluoride in the three bones of the third toe from both feet on a fat‐free dry matter basis. A linear accumulation was observed for the addition of up to 500 mg F− kg−1 to the diet. An experimental dose range between 0 and 8 mg kg−1 was chosen. The availability of fluoride was measured as the slope ratio between highly correlated regression lines for test material and a standard. The lines had a common intersection on the y‐axis. Relative to sodium fluoride, the biological availability of fluoride from different types of fish protein concentrate showed values of 110‐151%. The corresponding values for krill (Meganyctiphanes norvegica) and a fluoridated toothpaste containing sodium monofluoro‐phosphate were 112 and 145%, respectively.
Fatty acid composition and characteristics of the kernel fat of different mango (Mangifera indica) varieties
Authors: Van Pee Walter M. , Boni Luc E. , Foma Mazibo N. , Hendrikx Achiel
Published: October 2006

The kernels of 13 different mango varieties were examined. The kernels contained, depending on variety, from 6.8 to 12.6% fat, 5.2 to 6.3% protein (Nx6.25) and 1.4 to 2.0% ash on a moisture‐free basis. The fat was yellow‐coloured and melted at 32.5‐35.8°C. Stearic and oleic acids constitute about 85% of the total fatty acids. The ratio of stearic: oleic acids varied according to variety from 0.56 to 0.97. The remaining fatty acids are, in decreasing order, palmitic, linoleic, arachidic and lino‐lenic acids. Oleic and linoleic acids represented about 88 and 10%, respectively, of the fatty acids incorporated at the sn‐2‐position of the triglycerides.
Statistical properties of simple sensory difference tests: Confidence limits and significance tests
Authors: Smith Gordon L.
Published: October 2006

The Normal approximation to the binomial distribution is used to obtain confidence limits for the proportion of correct responses in a simple sensory difference test and the proportion of assessors able to discriminate between two products. Improved approximations, which should be considered with small panels or when the proportion of correct responses is close to 0 or 1, are discussed. To permit comparison of the discriminating ability of different panels, or investigation of the effect of a change in the products assessed, tests of the significance of the difference between two proportions are presented, based on the Normal approximation and the x2 statistic. The methods are illustrated with some data from an investigation on fish flavour.
Changes in the nitrogen fraction of sainfoin (Onobrychis viciaefolia) during growth
Authors: Treviño Jesús , Hernández M. T.
Published: October 2006

Sainfoin was harvested at four stages of increasing maturity. Samples were analysed for total N, true protein N, non‐protein N, nitrate and amino acids. Variations in the concentrations of these nitrogenous fractions throughout the growing period of plant are described.
Recovery of high quality oil from mackerel and sprat by the silage process
Authors: Reece Paul
Published: October 2006

Increases in the free fatty acid (FFA) content of oil from oily fish silage, recovered by centrifugation, have been shown to be principally associated with the release of FFA from solid material during liquefaction of the fish. Much of the initial FFA is present in the digestive tract of the fish prior to acidification. Pigmentation of the oil during ensiling is shown to be caused by the release of the acid hydrolysis product of haemoglobin, haemin. A 2% addition of 20 volume hydrogen peroxide has been shown to inhibit oil pigmentation and to reduce the FFA content in the recovered oil. Peroxide values of the oil, reduced by this treatment, can be further reduced by the addition of an oil‐soluble antioxidant to the silage.
Imitation milks from Cicer arietinum (L.), Vigna unguiculata (L.) walpers and Vigna radiata (L.) wilczek and other legumes
Authors: Caygill John C. , Jones Janis A. , Ferber Carol E. M.
Published: October 2006

Vegetable milks were prepared in the laboratory from mung bean [Vigna radiata (L.) Wilczek], cowpea [Vigna unguiculata (L.) Walpers] and chick‐pea [Cicer arietinum (L.)] by homogenisation of a filtered aqueous extract of the ground legume with soya bean oil. Emulsions stable to pasteurisation were made from the first two. Pigeon pea [Cajanus cajan (L.)] and black gram [Vigna mungo (L.) Hepper)] were found to be unsuitable as bases for milks prepared by simple processing. The nitrogen, oil, sugar and ash contents of the first three legumes, and of milks prepared from them, were determined. Imitation milks are intended to resemble animal milks nutritionally, and whilst the contents of potassium and phosphorus were acceptable, these vegetable milks were low in sodium, calcium and zinc. The trypsin inhibitory activity, whilst low in comparison with soya milk, was partially stable to pasteurisation. The amino acid composition indicated that it would be desirable to complement legume proteins with cereal proteins to prepare vegetable milks.
Fermentation patterns in ryegrass, red clover and maize silages treated with formaldehyde additives at ensiling
Authors: Kaiser Alan G. , Terry Ronald A. , Dhanoa Mewa S.
Published: October 2006

The influence of level of formaldehyde application at ensiling on fermentation patterns in ryegrass, red clover and maize silages was studied in three experiments using small‐scale silos. Formaldehyde was applied, together with formic acid at 2 litre t−1 fresh crop, over the range 0 to 166 g formaldehyde kg−1 crude protein (CP) in the crop. In ryegrass and red clover, but not in maize, low levels of formaldehyde application (<60 g kg−1 CP) induced clostridial‐type fermentations, as evidenced by increases in the content of volatile fatty acids and ammonia N. The concentrations of ethanol and 2,3‐butanediol were also increased. At higher levels of application, formaldehyde was particularly effective in restricting fermentation in ryegrass and red clover silages, there being little acid production above 120 and 80 g kg−1 CP, respectively. Only low levels of formaldehyde (ca 20 g kg−1 CP) were required to achieve this effect in maize silage. In each crop the insoluble N content of the silages increased with level of formaldehyde application. The recovery of formaldehyde in both the treated herbage and silage improved with level of application, but did not exceed 50% of that applied. As physical losses of formaldehyde would be expected to be minimal under the conditions of the experiments, it appears that chemical bonding was the main reason for the lack of recovery of formaldehyde.
Isoperoxidase changes in finger millet during development and blast disease
Authors: Ramachandra Geeta , Virupaksha Tumkur K. , Shadaksharaswamy M.
Published: October 2006

Patterns of cathodic and anodic isoperoxidases from finger millet varieties, which were either resistant or susceptible to blast disease, were obtained at different stages of seed germination. The isoperoxidase patterns showed marked changes during the course of germination and clear differences were found in the isoperoxidase patterns of three resistant and three susceptible varieties. Thus, it may be possible to use the electrophoretic method as a rapid screening technique to differentiate between finger millet varieties resistant and susceptible to blast disease.
Studies on peroxidases and vascular discoloration in cassava root tissue
Authors: Plumbley Richard A. , Hughes Peter A. , Marriott John
Published: October 2006

Extracts from discoloured cassava root tissue contained peroxidase activity in the soluble, covalently‐bound and ionically‐bound fractions. Extracts from non‐discoloured tissue lacked activity in the latter fraction and showed reduced activity in the other two fractions. Fractions from discoloured tissue showed nine soluble, two ionically‐bound and three covalently‐bound activity bands. Eight soluble peroxidase bands and one covalently‐bound band were detected by electrophoresis in fractions from non‐discoloured tissue. Some bands were less intensely stained than the corresponding bands detected in discoloured tissue extracts. Polyphenol oxidase showed increased activity only in the covalently‐bound fraction from discoloured tissue. Cassava roots produced ethylene in response to mechanical damage. Production commenced 6 h after injury and was only slightly affected by the accumulation of carbon dioxide. Neither the presence of carbon dioxide nor of exogenous ethylene had much effect on the electrophoretic pattern of soluble peroxidases.
The accumulation of lipids in developing seeds of white lupin (lupinus albus L.)
Authors: McGibbon Robert , Williams Watkin
Published: October 2006

The accumulation of lipid in embryos of lupin was found to be most rapid between 30 and 40 days after anthesis, coinciding with the stage of maximal dry weight increase of the developing seed. The percentage composition of oleic acid increased and that of linoleic acid decreased as the seed matured. Factors which cause premature cessation of embryo development are likely to affect adversely the oleate: linoleate ratio in the seed as well as the percentage oil content.
The polyphenolic content and enzyme inhibitory activity of testas from bean (Vicia faba) and pea (Pisum spp.) varieties
Authors: Griffiths D. Wynne
Published: October 2006

The polyphenolic content of the testa of two coloured flower varieties of beans grown in Wales was comparable with that of two coloured flower varieties of peas grown in eastern England. Testa tannins from both species had the same adverse effect on protein solubility, the inclusion of 15% testa producing a 7 unit reduction in protein solubility in 5% saline solution. Water extracts prepared from the testas also significantly inhibited in vitro the activities of trypsin, α‐amylase and fungal cellulase, and in all cases enzyme activity was restored on the addition of polyvinyl pyrrolidone, clearly indicating that the observed inhibition was due to the presence of tannins. Analysis of the whole grain revealed that, due to differences in the proportion of testa (approximately 13% in beans as compared with 10% in peas), peas had a significantly lower overall polyphenolic content. However, it is concluded that pea testa tannins may be of equal significance to bean tannins in animal diets since the formulation of isonitrogenous diets would require a greater proportion of peas due to their lower protein content.
An investigation of the experimental conditions which could affect water‐holding capacity of dietary fibre
Authors: Robertson James A. , Eastwood Martin A.
Published: October 2006

The water‐holding capacity (WHC) of various sources of vegetable and cereal dietary fibre has been measured under different experimental conditions. WHC was measured by centrifugation and filtration. The results obtained suggest that prolonged soaking has no effect on WHC. Fibre agitation, the presence of buffer (pH 7.5), and the presence of bile salt (deoxycholate) also had no effect on WHC, except for never‐dried potato fibre (NDPF) (fresh fibre concentrate). WHC, however, does vary with the method of measurement and the WHC determined by centrifugation was greater than that determined by filtration. The differences in WHC between NDPF and dried potato fibre are not due to gross chemical differences in the fibre. The conditions used for the preparation of dietary fibre and the measurement of its WHC, therefore, must be carefully controlled before the role of fibre in the diet can be better understood.
Rates of degradation of plant cell walls measured with a commercial cellulase preparation
Authors: Hartley Roy D. , Dhanoa Mewa S.
Published: October 2006

The relationship between the degradability, determined with a commercial cellulase preparation, of the cell walls of various plant parts of Italian ryegrass, maize and red clover can be expressed as Y = A ‐ Be−k1t‐Cek2t, where Y = percentage of cell walls degraded, t = reaction time, k1 and k2 are rates of degradation, and A, B, and C are constants where A = B + C. Degradability of the cell walls of Italian ryegrass or maize could be predicted accurately from the absorbance of the filtrate at λmax 282‐288 or 310‐324 nm. Treatment of cell walls of barley straw with 0.1 or 1M sodium hydroxide for 7 or 20 h degraded between 12 and 41% of the walls and led to the release of p‐coumaric and ferulic acids, the amount increasing with concentration of alkali and treatment time; the less concentrated alkali released more ferulic than p‐coumaric acid. Treatment with the cellulase preparation of the residues from alkali treatment showed that they were almost twice as degradable as the untreated walls.
Effect of maturity on some chemical components of cocoa
Authors: Packiyasothy E. Velupillai , Jansz Errol R. , Senanayake Upali M. , Wijesundara R. Chakra , Wickremasinghe Palitha
Published: October 2006

Immature harvest of cocoa to prevent losses due to pests and pilferage is common in Sri Lanka. The effect of maturity on the levels of some components of the Amelonado variety of cocoa grown in Sri Lanka is reported here. The major problem posed by immature harvest is the loss of fats which has been shown in this study to be of the order of 50% when the crop is harvested 1.5 months early, although the fatty acid composition does not vary significantly during this period. The pulp of immature cocoa pods contains less free sugars and produces less ethanol on yeast fermentation than pulp of mature pods but the methanol content of the distillate is higher in immature pulp. The pectin content of the pod endocarp declines as maturation proceeds.
Fermentation of tea in aqueous suspension
Authors: Millin David J. , Swaine Derwent
Published: October 2006

The fermentation of macerated tea leaf in aqueous suspension has been studied both manometrically and in a suitably controlled fermentation vessel. Oxygen consumption proceeded rapidly at a steady rate for an initial period, termed the primary fermentation, then decreased sharply as the availability of simple polyphenol substrates became rate limiting. Maximum reaction rates were observed at 20‐35 mg ml−1 total solids, as a result of substrate inhibition. At higher concentrations of solids reaction rates were also affected by diffusion effects within the leaf particles. At 50 mg ml−1 total solids and 25°C the system approximated to Michaelis‐Menton kinetics with Km02 = 5 × 10−5M and Vmax corresponding to a primary fermentation time (PFT) of 10‐15 min. The PFT corresponded with the attainment of maximum total colour and maximum level of theaflavins (TF) (often >30% of total colour). Beyond the PFT total colour remained constant, TFs decreased and non‐dialysable pigments increased with time. At fixed levels of dissolved oxygen and solids concentration > 60 mg ml−1 the proportion of TFs was inversely related to solids concentration. At 50 mg ml−1 total solids TFs increased to ca 60% of total colour as the dissolved oxygen level was increased to 0.175 mM. As temperature was increased from 15‐35°C the reaction rate increased, the proportion of TFs decreased slightly and thearubigins of intermediate molecular weight increased markedly.
Preservation of oil palm fruit and oil palm fruit mesocarp by gamma irradiation
Authors: Takyi Etor E. K.
Published: October 2006

Experiments were conducted to determine the potential of gamma radiations in the extension of the shelf‐life of oil palm fruit and oil palm fruit mesocarp. In the course of the experiment, it was observed that even though palm fruits in their harvested form, went bad within 3 days post‐harvest, their shelf‐life can be extended to at least 2 months through preparation of dry oil palm fruit mesocarp. Furthermore, despite the fact that gamma radiation cannot be used to prolong the shelf‐life of oil palm fruit proper, it can be used to drastically reduce the mould load in the dry palm fruit mesocarps, thereby further enhancing their keeping quality and consumer acceptance. Chemical and organoleptic analyses of fat extracted from irradiated, dry oil palm fruit mesocarp show that there is practically no radiation effect. The significance of these observations is discussed in relation to the possible acceptance of radiation‐preservation of oil palm fruit mesocarp commercially.
Effect of diet on protein degrading activity in the sheep rumen
Authors: Siddons Rodney C. , Paradine John
Published: October 2006

Comparative studies on the effect of diet on ruminal protein degrading activity were made with sheep fed either maize or timothy and with sheep fed either barley or lucerne. In both studies the levels of proteolytic activity and deaminase activity in the rumen, measured as non‐protein nitrogen and ammonia production, respectively, during in‐vitro incubation of rumen liquor and casein, were higher when cereal was given than when forage was given. The rate of casein degradation after intra‐ruminal infusion was also higher with the cereal diets, whereas outflow rate from the rumen was lower. However, with all diets the fractional hydrolysis rate of casein was considerably greater than its fractional outflow rate and the calculated proportion of protein escaping ruminal breakdown was low. The effect of diet on the degradation of the protein of natural feedstuffs was examined by measuring N disappearance when samples of the four feeds and of three protein supplements (soya bean meal, groundnut meal and fish‐meal) were incubated in dacron bags in the rumen. In contrast to the findings with casein, the rate of N disappearance for all feedstuffs, except maize which was similar on the two types of diet, was lower when sheep were given cereal than when given forage.
Estimation of starch and total fermentables content in storage roots of cassava (Manihot esculenta Crantz.)
Authors: Keating Brian A. , Evenson John P. , Breen Alan R.
Published: October 2006

The relationships between the percentage of dry matter (DM), specific gravity, percentage of starch and percentage of total fermentables in cassava storage roots have been examined in detail. The results confirm the findings of earlier workers that specific gravity can provide a reliable estimate of storage root DM in the absence of drying facilities. A curvilinear relationship of the form 1/y = a + bx was found to exist between storage root DM and percentage of starch or fermentables within one cultivar over a range of ages and seasonal conditions. This relationship shows that the proportion of total DM present as starch or fermentables increases for samples of higher DM percentages. A similar relationship was shown to exist between specific gravity and percentage of starch or fermentables. A linear relationship was also developed between the percentage of DM and of fermentables based on 28 cultivars harvested at the same age and under the same seasonal conditions. More information is required on cultivar differences in these relationships over the entire range of DM and fermentable percentages, before widespread use is recommended. Once correctly established, relationships based on DM or specific gravity provide a simple and reliable method of estimating percentage of starch or total fermentables in the storage roots of cassava. Comparisons are made between these results and those reported earlier in the literature, using less precise methods of starch measurement.
Some observations on the effect of grassing‐down, nitrogen fertilisation and irrigation on the growth, leaf nutrient content and fruit quality of young golden delicious apple trees
Authors: Haynes Richard J.
Published: October 2006

In a 3 year trial the growth and leaf nutrient content of newly planted Golden Delicious/MM 106 apple trees was compared under grassed‐down and clean cultivated conditions. With no fertiliser applications grassing down, compared with cultivation, decreased shoot extension and trunk girth increment in all three seasons and total dry weight of both tops and roots of trees at the end of the 3 year period. Grassing‐down generally decreased total N and increased concentrations of P, K and Ca in the leaves. Generally, in the third season, the mineral composition of the fruit paralleled that in the leaves. Application of fertiliser N to cultivated plots in the second and third seasons had no significant effect on tree growth; N fertilisation significantly increased tree growth and total leaf area per tree under grassed‐down conditions, particularly in the third season. During the third season irrigation had only a small effect on the growth of trees from the grassed‐down non‐fertilised plots. However, there was a large positive interaction between N fertilisation and irrigation on tree growth, total dry weight of both shoots and roots of trees and on fruit size.
Kinetics and equilibria of tea infusion. Analysis and partition constants of theaflavins, thearubigins, and caffeine in koonsong broken pekoe
Authors: Spiro Michael , Siddique Shama
Published: October 2006

Koonsong Broken Pekoe tea leaf was equilibrated with water at 79.5 and 94.0°C using water: leaf ratios from 25:1 to 100:1. The concentrations of theaflavins, thearubigins, and caffeine were measured in the aqueous extracts. Analysis of the results by a simple two‐phase model gave the concentrations of the three constituents in the original leaf without the necessity for the usual assumption of complete extraction. The theory also yielded the partition constants (distribution coefficients) of the three constituents between swollen leaf and aqueous solution, and the enthalpy changes for their extraction.
Identification of the component responsible for the effects of added dietary copper sulphate in the female domestic fowl
Authors: Jackson Norman , Stevenson Mary H.
Published: October 2006

Sulphate, as sulphuric acid, was fed to Shaver 288 and Warren Studler SSL laying hens for 280 days at levels equivalent to 0.2, 0.4, 0.6, 0.8 and 1.0 g sulphate kg−1 diet. The results obtained were compared with those found using similar diets to which the sulphate was added as copper sulphate pentahydrate (CuSO4·5H2O). Addition of H2SO4 had no effect on food intake, food conversion efficiency, body‐weight or egg production. The addition of CuSO4 caused adverse effects on food intake, egg production and body‐weight. The H2SO4 had no effect on liver, kidney, oviduct, ovary and gizzard weight per unit body‐weight. CuSO4 decreased ovary and oviduct weights and increased gizzard weight. H2SO4 had no significant effect on liver copper (Cu) concentrations but CuSO4 increased liver Cu. The highest level of CuSO4 addition depressed liver lipid concentration in the Shaver 288 birds. Both the H2SO4 and the CuSO4 affected the levels of individual fatty acids.
Purification, identification and quantification of an egg‐weight‐depressing factor (vicine) in fababeans (Vicia faba L.)
Authors: Olaboro Gershon , Marquardt Ronald R. , Campbell Lloyd D. , Fröhlich Andrzej A.
Published: October 2006

An egg‐weight‐depressing factor in fababeans was isolated in pure form from a white precipitate which had been shown in a previous study, to contain a concentrated form of this factor. The analytically pure compound was obtained in colourless, needle crystals. Its melting point was 242‐244°C, it contained 17.4% nitrogen but did not react with ninhydrin. The spectra had adsorption maxima at 274, 276 and 269 nm in acidic, neutral, and alkaline solutions, respectively. These and other properties were identical to those of vicine [2,6‐diamino‐4,5‐dihydroxy pyrimidine,5‐(β‐D‐glucopyrano‐side)] a compound known to be present in fababeans. Vicine and convicine [2,4,5‐trihydroxy, 6‐aminopyrimidine,5‐(β‐D‐glucopyranoside)]; compounds having similar chemical and probably physiological activity, were resolved on a cation‐exchange column and were detected by monitoring at 280 nm. Quantitative results obtained with the procedure was shown to be similar to those obtained with two other procedures. This method, however, was superior to other methods as it gave individual values for both vicine and convicine rather than a composite value; sample preparation was simple and the method could readily be adapted to automatic analysis.
Studies on black gram (Vigna mungo) trypsin inhibitor
Authors: Kamalakannan Vedhachalam , Sathyamoorthy Arcot Venugopal , Motlag Dinkar Bhagwant
Published: October 2006

The trypsin inhibitor fraction from black gram was isolated by ammonium sulphate fractionation (0‐75%). It exerted maximum inhibition on trypsin and to a less extent on the endopeptidases, chymotrypsin, papain, pronase and pepsin in vitro, In‐vitro digestibility of the raw black gram was found to be lower than autoclaved black gram and autoclaved black gram supplemented with native black gram trypsin inhibitor. Haemagglutinating activity was absent in the black gram extract as well as in the black gram trypsin inhibitor fractions. During the last 48 h of germination there was a steep decline in trypsin inhibitory activity and an increase was observed later. Trypsin inhibitory activity was greater in the leaves than the cotyledons during the fourth, fifth and sixth days of germination.
A third β‐Gliadin from Cappelle‐Desprez wheat
Authors: Ewart John A. D.
Published: October 2006

A third β‐gliadin has been isolated from Cappelle‐Desprez wheat. It is the middle member of a triplet of almost equally spaced bands that appears on starch‐gel electro‐phoresis. Surprisingly, it has no very close affinity with the fastest of these three bands. Although conforming to the amino acid composition expected in gliadins, the content of (His + Arg) is four less than in the fastest component, but the small molecular weight of only 27 000 compensates for this, so that the mobility at acid pH is only a little less than that of its faster companion. The protein appears to be single‐chain and free from SH groups and carbohydrate. Of the (Glx+Asx) content, 96% is amidated. Published analyses of β‐gliadins have been calculated to the same basis and compared.
The effect of emulsifiers, sugar, shortening and soya flour on the staling of barbari flat bread
Authors: Maleki Morteza , Vetter James L. , Hoover William J.
Published: October 2006

A standard method has been developed to bake barbari flat‐type bread. Instron was used to measure the hardness of the crumb of bread samples as a criterion of staling. Different combinations of emulsifiers, sugar, shortening and soya flour were added to the formula of barbari bread to find their effect on the retardation of hardness. Addition of soya flour increased the loaf weight but decreased its total organoleptic score. Added amounts of different additives tried in this experiment improved the hardness approximately to the same level. The best result was obtained by the addition of sodium stearoyl‐2‐lactylate and shortening.