bluuebunny/crossref_metadata_2025 huggingface dataset:
The chemical oxidation of catechins and other phenolics: A study of the formation of black tea pigments
Authors: Bailey R. G. , Nursten H. E. , McDowell I.
Published: November 2006

The chemical oxidation of polyphenols has been used to produce black tea pigments. (+)‐Catechin, (−)‐epicatechin, (−)‐epicatechin gallate and (−)‐epigallocatechin gallate were isolated from convenient sources, their identity being confirmed by mass spectrometry and HPLC. The oxidation of a mixture of (−)‐epicatechin gallate and gallic acid gave an oxidation product of (−)‐epicatechin gallate in addition to epitheaflavic acid 3‐gallate. The catechins were oxidised chemically and the products analysed by HPLC, the chromatograms being compared with a black tea chromatogram. The reactions gave both resolved and unresolved pigments, and many of the resolved pigments had HPLC retention times close to black tea pigments. Each catechin behaved differently, the chromatograms of the oxidation products from each starting material being clearly distinguishable. Resolved pigments were obtained by the chemical oxidation of other phenolic compounds. This work provides a convenient method for studying the formation of resolved and unresolved black tea pigments.
Changes in enzymic activities after harvest and in early stages of botrytis cinerea infection of kiwifruit
Authors: McLeod Laurie C , Poole Philip R
Published: November 2006

Mature unripe kiwifruit were harvested on 19 May 1992, inoculated with Botrytis cinerea conidia, stored at 22°C and subsampled up to 168 h. Phenylalanine‐ammonia lyase (EC 4.3.1.5) activities in the stem end tissues peaked at 4 h with 4.0 and 7.3 times the initial values for control and inoculated fruit, respectively. Endochitinase (EC 3.2.1.14) activity increased in inoculated fruit only from 24 h after harvest, reaching 3.3 times the initial value at 168 h. A number of isoforms of endochitinase were detected at the time of harvest. Exochitinase activity was present in both inoculated and control fruit. Lipoxygenase (EC 1.13.11.12) activity increased at 4–8 h to 1.4 times the initial activity. Peroxi‐dase (EC 1.11.1.7) activities in inoculated and control fruit at 168 h were, respectively, 2.6 and 1.3 times the original values. Catechol oxidase (EC 1.10.3.1) activity increased from 2 h after harvest and peak values were 3.3 and 2.6 times the initial values for inoculated fruit and controls, respectively. The peroxidase and catechol oxidase activities of rotted stem end tissues were very low. High activities of pathogenesis‐related enzymes in fruit on the vine suggests that their expression is governed by environmental or maturity factors rather than by post‐harvest infection. The changes occurring in the early post‐harvest period appear to be related to the early post‐harvest decline in susceptibility to infection.
Metabolism and fate of dietary (U‐14C)‐labelled spinach cell walls in the rat
Authors: Buchanan Callum J , Fry Stephen C , Eastwood Martin A
Published: November 2006

Using uniformly 14C‐labelled spinach (Spinacia oleracea L) plant cell walls (PCW) the metabolism of PCW can be followed in a defined manner in the rat. Only 10% of the 14C was recoverable in the gut contents and faeces 18 h post‐gavage. Two percent of the 14C was excreted in urine and 25% excreted as CO2. 14C was found in all tissues of the body but was most concentrated in the adrenal glands, colon and caecum. The 14C was also present at moderately high concentration in the liver pelt, and owing to their larger size, these tissues accounted for a high percentage of the total 14C. In the liver the 14C was predominantly associated with phospholipid, whereas in the pelt it was present in protein and in fatty acid residues esterified to cholesterol. Dietary PCW material is extensively fermented in the caecum and colon. Also, the products of fermentation are a source of energy and important structural precursors of lipids and proteins for the animal.
Effect of staling on viscoelastic properties of pastes prepared from arabic bread
Authors: Toufeili Imad , Sleiman Ghada , Salman Rami Abu , Brockway Barbara
Published: November 2006

Dynamic testing detected differences in the rheological properties of pastes prepared from progressively aged Arabic bread. The storage (G') and loss (G″) modulii decreased at different rates upon storage. The progress of textural changes responsible for the generation of the sensory ‘stale’ response was marked by the transition of Arabic bread pastes from viscoelastic solids (G′>G″) to elastoviscous liquids (G″>G′).
Influence of nitrogen and sulphur on the glucosinolate profile of rapeseed (brassica napus l)
Authors: Zhao Fangjie , Evans Eric J , Bilsborrow Paul E , Syers J Keith
Published: November 2006

Clear influence of N and S applications on the profile of individual glucosinolates in the seeds of winter oilseed rape (Brassica napus L) was found in field experiments. The major effect of N was on the relative abundance of the four alkenyl glucosinolates. Increasing the N rate increased the relative proportion of 2‐hydroxybut‐3‐enyl at the expense of pent‐4‐enyl, and to a lesser extent, 2‐hydroxypent‐4‐enyl, in the double‐low (low erucic acid and low glucosinolates) variety Cobra, but at the expense of but‐3‐enyl in the single‐low (low erucic acid) variety Bienvenu. The results strongly suggest that a high N supply favours the hydroxylation step from but‐3‐enyl to 2‐hydroxybut‐3‐enyl. In contrast, the major effect of S appeared to be on the relative abundance of the alkenyl and indole groups as a whole. Sulphur deficiency decreased the concentrations of the alkenyl glucosinolates more than those of the indole glucosinolates, whereas S application to a S‐deficient crop resulted in a larger response in the alkenyl group than in the indole group. The more sensitive response of alkenyl glucosinolates to the plant S status is probably due to the requirement of methionine in their biosynthesis, as compared with the indole glucosinolates which are derived from tryptophan. Implications for changes in the glucosinolate profile in rapeseed are discussed.
Differences in accumulation of storage proteins between wheat cultivars during development
Authors: Johansson Eva , Oscarson Petter , Heneen Waheeb K , Lundborg Tomas
Published: November 2006

The concentration and composition of storage proteins in the developing kernels of five different wheat cultivars were investigated. The plants were grown in solution culture under strictly controlled conditions in climatic chambers and with long‐term limitation of external nitrogen availability. Thus, by growing these cultivars under the same defined treatments, reliable differences in the storage protein development could be determined. The total protein concentration was assayed using an automatic nitrogen analyser. The storage protein composition was examined by acidic polyacrylamide gel electrophoresis and sodium dodecyl sulphate polyacrylamide gel electrophoresis from 6 to 58 days after anthesis. The results showed that, in all stages of plant development, the ranking of the cultivars as to the storage protein concentration was the same as for mature field‐grown kernels. The differences in the storage protein concentration between the cultivars could not be explained by differences in protein composition. The start of storage protein formation during plant development did not differ between the tested cultivars, as determined by the electrophoresis pattern. The differences in the storage protein concentration between cultivars most likely depends on the relative balance between starch and nitrogen deposition in the grain, during the whole grain filling period.
Chemical composition of melia volkensii gurke: An unrealised browse potential for semi‐arid agroforestry systems
Authors: Milimo Patrick B
Published: November 2006

Results of chemical analyses of some nutritional characteristics of Melia volkensii browse, important for large wild and domestic herbivores in East Africa, are presented. Seeds, fruit pulp, leaves and twigs had high levels of crude protein, crude fat, minerals and fibre. Newly coppiced shoots (leaves and twigs), old shoots, fruit pulp and seed contained 230, 190, 130 and 320 g kg‐1 dry weight crude protein, respectively. The essential amino acid profile compared well with the FAO scoring pattern. Tyrosine was the first limiting amino acid in the coppice leaves and twigs, lysine in the cotyledons, and threonine and lysine in the endosperm. The concentrations of crude fat in the seed, fruit pulp, coppice shoots and old shoots were 480, 100, 80 and 50 g kg‐1, respectively. The fatty acids in the cotyledon and endosperm were mainly palmitic (110 and 109 g kg‐1, respectively), oleic (327 and 252 g kg‐1, respectively) and linoleic (487 and 573 g kg‐1, respectively). The levels of P, Na, K, Ca, Mg and the Ca/P ratio per kg dry weight were on average higher than the optimum recommended for ruminants. These results demonstrate that M volkensii browse, especially coppice leaves and twigs, have a high index for nutrient content, and the planting of this species should be promoted in the semi‐arid areas to supplement senescent grasses and cereal crop residues.
Volatile constituents of palm wine and palm sap
Authors: Uzochukwu Sylvia V A , Balogh Esther , Tucknot Owen G , Lewis Mervyn J , Ngoddy Patrick O
Published: November 2006

Palm wine and pasteurised palm sap volatiles were collected, concentrated on a Tenax GC and analysed by gas chromatography and gas chromatography‐mass spectrometry. Eighty‐two components were identified: 47 esters, 9 alcohols, 5 acids, 6 carbonyls, 2 acetals, 4 terpenes and 9 hydrocarbons. These had all been found previously in conventional wines. Odour evaluation of the separated palm wine components as they eluted suggested that no one compound is responsible for the characteristic palm wine odour. The acetates of higher alcohols and the ethyl esters of straight‐chain aliphatic C6‐C10acids seemed to be important and may play a big role in imparting the fruity nuances of characteristic palm wine odour. Their association with alcohols seemed also to be necessary for the expression of typical palm wine odour. The qualitative difference between palm sap aroma and palm wine aroma appeared to be due mainly to the presence of these esters and alcohols in palm wine and their apparent absence from palm sap, as well as to the presence of some low‐boiling esters and alcohols in palm sap and their apparent absence from palm wine.
Quality of cassava foods in Sierra Leone
Authors: Blanshard Alex F J , Dahniya Mohamed T , Poulter Nigel H , Taylor Andrew J
Published: November 2006

Gari and foofoo (fermented cassava foods) were purchased in the Freetown markets of Sierra Leone and analysed for factors associated with quality. Sellers were generally knowledgable about the source of the products which all originated from the country areas outside Freetown. The mean cyanide contents were higher (8.6 mg kg−1 DM for gari and 28.2 mg kg−1 DM for foofoo) than the amounts suggested by the Codex specification and, because of the distribution of the values around the mean, some samples necessarily contained unacceptable amounts of cyanide. Cyanogens were present as the cyanohydrin or as free cyanide; no glucoside was detected. Microbiological analysis of the samples showed high counts for total organisms, fungi and Enterobacteriaceae (106–107 g−1). The mean water content of gari was 119 g kg−1 which falls within the recommended limit of 120 g kg−1 but again, due to the distribution of values around the mean, some samples had considerably higher water contents than that limit. Titratable acidity and pH were measured and the mean pH values were 4.18 for foofoo and 4.55 for gari. The particle size and swelling power of gari samples were also measured as these relate to consumer acceptance. The data show the quality of current cassava foods marketed in a major urban centre in Sierra Leone. As centralised processing develops, improvements can be made to those quality parameters which have been identified as important.
A model of moisture‐induced plasticization of crunchy snacks based on fermi' distribution function
Authors: Wollny Mathis , Peleg Micha
Published: November 2006

The irregular force‐deformation relationships of commerical cheese balls and Zwiebacks at nine levels of water activity in the range 0.11–0.85 were recorded with a computer‐interfaced Universal testing machine. They were characterized by two empirical stiffness parameters, the force at 10 and 20% deformation, and two jaggedness measures, the apparent fractal dimension of the normalized force‐deformation curve and the mean magnitude of its power spectrum. The plots of all four parameters versus the water activity had a stable region followed by a substantial drop at a characteristic water activity level, of the kind expected when a material undergoes a glass transition. The phenomenon over the entire experimental water activity range, could be described by a model whose mathematical formal is a slightly modified version of Fermi' distribution function that is P(aw) = Ps/{1 + exp[(aw — awcp)]/bp} + cp where P(aw) is any of the stiffness or jaggedness parameters, Ps and cp constants whose sum is the magnitude of the parameter when the material is in the dry state (cp is the residual level after plasticization), awcp is a characteristic water activity level representing the region where the major textural changes take place, and bp a constant representing the steepness of the relationship at the transition region.
Copper bioavailability from breakfasts containing tea. Influence of the addition of milk
Authors: Vaquero M P , Veldhuizen M , van Dokkum W , van den Hamer C J A , Schaafsma G
Published: November 2006

The influence of drinking tea on copper bioavailability is unclear, particularly when tea is consumed with food. A breakfast meal containing white bread, margarine, strawberry jam, cheese and tea, with or without milk, was digested in; vitro and the dialysis of copper investigated. Reference breakfasts were prepared with water and water with milk. Copper dialysability (percentage of copper dialysed) was markedly increased by tea. The influence of adding milk to tea was not significant. A second study was carried out in rats using the breakfasts containing tea and water. They were spiked with 64Cu and given orally to the animals in a single dose. Whole‐body 64Cu retention was measured over a 4‐day period after administration. In order to determine the true absorption of 64Cu a control group of rats received the dose intraperitioneally. The results in vivo indicate a tendency to higher absorption and retention of 64Cu with tea. Liver 64Cu retention was significantly elevated by tea. Therefore, the presence of tea in a breakfast meal favours the formation of soluble low‐molecular‐weight ligands which can be absorbed and retained by rats. The concomitant increase in liver copper retetition may be associated with higher bioavailability and/or lower copper mobilisation.
Effect of drying on acidity and volatile fatty acids content of cocoa beans
Authors: Jinap S , Thien J , Yap T N
Published: November 2006

The objectives of the study were to evaluate the effect of drying on the pH, titratable acidity and volatile fatty acids (VTA), ie acetic, propionic, butyric, isobutyric and isovaleric acids content of cocoa beans, and on the flavour of the resultant chocolate. Freshly harvested cocoa pods from clones of PBC 123 and 128 (1 :1 ratio) were stored for 9 days and fermented for 5 days with a single turning at 48 h. Four drying treatments, ie oven‐drying at 60°C, air‐blow drying, shade‐drying and sun‐drying were carried out. Samples were taken periodically for pH, titratable acidity, and VFA analysis. Physical characteristics were also recorded. The resultant beans were made into dark chocolate for flavour evaluation. The results showed that wet beans held in shady areas for 120 h will not dry quickly enough to inhibit mould and yeast and other putrefactive activities; rapid oven‐drying of these still wet beans did not improve their flavour profile. There were no significant differences (P ⩾ 0.05) between samples that have undergone sun‐drying and air‐blow drying in the acidity and C3‐C5 VFA content; both were evaluated favourably by taste panellists. Oven‐dried beans contain a high concentration of VFA and produced chocolates with a high intensity of off‐flavour.
Dynamic rheological behaviour and biochemical properties of rabbit skeletal actomyosin during storage at 0° C
Authors: Ikeuchi Yoshihide , Tanji Hiroyuki , Kakimoto Takaaki , Suzuki Atsushi
Published: November 2006

The relationship between the dynamic rheological properties of heat induced gels of actomyosin (natural actomyosin) and the denaturation of actin in actomyosin during storage without ATP at pH 6.0 and 0°C was investigated using biochemical and dynamic rheological measurements. The complex modulus of gels after heating actomyosin containing 0.5 or 1.5 M KCl (pH 6.0) at 80°C increased with increasing storage time. The dynamic rheological behaviour during heat gelation of actomyosin in 1.5 M KCl indicated that the first rheological transition peak in the 50–53°C range induced by the presence of F‐actin gradually disappeared with increasing storage time. However, in 0.5 M KCl, this transition peak clearly remained even after 15 days. The time course of denaturation of actin in actomyosin treated with 1.5 M KCl at pH 6.0 showed an increase in the percent denaturation after the storage was started, and about 100% of the actin became denatured after 21 days. In the case of 0.5 M KCl, unlike 1.5 M, the denaturation of actin occurred quickly within the first 5 days and then did not proceed. A sigmoidal relationship was found between the percent denaturation of actin and the KCl concentration added, the greatest change occurring at KCl concentrations between 0.5 and 1.0 M. The data indicated that the change in the property of actin in actomyosin during storage at low temperature exerts a great influence on the viscoelasticity of heat‐induced gels of actomyosin.
Effect of soluble calcium of milk on fouling of ultrafiltration membranes
Authors: Rao H G Ramachandra , Lewis M J , Grandison A S
Published: November 2006

Flux decline with time is a major problem encountered during the application of ultrafiltration in the dairy industry. Most work has put the emphasis on the role of casein, whey proteins, fat and colloidal calcium. These components either promote the build up of a concentration polarisation layer or are adsorbed on the membrane surface. The minor constituents have received little attention so far, probably because they do not contribute greatly to the mass of the gel layer. The role of soluble calcium on fouling of membranes is very evident as permeates obtained from four major dairy products fouled the membranes when applied as feed. Ultrafiltration of soft water, mains water and lactose solutions indicated that the presence of calcium brings about flux decline with time. Addition of 2 mM calcium chloride further reduced the flux rates to very low levels but addition of E.D.T.A. to the permeates improved the flux rates and reduced the fouling. Heating the permeates, followed by clarification also had beneficial effects on flux rates.
Thermal degradation of all‐trans‐β‐carotene in the presence of phenylalanine
Authors: Papadopoulou Kiriaki , Ames Jennifer M
Published: November 2006

Solutions of all‐trans‐β‐carotene in liquid paraffin were stirred under air at 210°C for 15 min in the presence and absence of various amino acids. After cooling, the absorbance values at 460 nm of model systems containing all‐trans‐β‐carotene and phenylalanine, cysteine or tryptophan were 34–58 times higher than that obtained on heating in the absence of an amino acid. Based on absorbance values at 420 nm, 86% of the coloured material present on heating the all‐trans‐β‐carotene‐phenylalanine model system at 210°C for 15 min was retained by the liquid paraffin on methanol extraction. The liquid paraffin phase remaining after methanol extraction was analysed by reverse‐phase HPLC and three major components were identified as all‐trans‐β‐carotene and two degradation products of all‐trans‐β‐carotene, ie 9‐cis‐β‐carotene and a furanoid diepoxy derivative. None could be detected on heating all‐trans‐β‐carotene alone, suggesting that its degradation was retarded on heating in the presence of phenylalanine.
Alteration of supplement nitrogen:Sulphur ratio by increasing sulphate supplementation affects the rate rather than the extent of fibre degradation in cattle fed a matured tropical grass hay
Authors: Morrison Mark , Boniface Anthony N , Murray R Maxwell
Published: November 2006

There is a need to understand how supplement N: S ratios can affect ruminal fermentation and ultimately, nutrient supply, in grazing animals. The following experiment was undertaken to describe the effect(s) of supplement N : S ratios upon the rate and extent of ruminal degradation of poor quality native pasture hay. Four rumen fistulated Brahman × Shorthorn (Drought master) steers, fed chopped Black Spear Grass hay, received either no intraruminal supplement, or urea plus sodium sulphate to give supplement N: S ratios of 23:1, 16:1, 11.5:1, 10:1 and 4:1. The level of urea supplementation was kept constant and maintained rumen ammonia concentrations in excess of 100 mg litre−1. No differences were observed in voluntary feed intake in response to different supplement N: S ratios. The extent of rumen fermentation as measured by the nylon bag technique and apparent organic matter digestibility in vivo were similar for supplement N : S ratios of 16:1 and lower, and total intake of digestible organic matter was maximal with a supplement N : S ratio of 10: I. Increasing levels of S supplementation were found to increase the rate of rumen fermentation.
Use of in‐vitro gas production to evaluate rumen fermentation of untreated and urea treated finger millet straw (Eleusine coracand) supplemented with different levels of concentrate
Authors: Prasad Cadaba S , Wood Christopher D , Sampath Koratikere T
Published: November 2006

Measurement of gas produced during in‐vitro fermentation was used to assess the ferment ability of urea treated and untreated finger millet straw to Which various levels of concentrate (maize/wheat bran/groundnut cake 35:32: 30) had been added. Data obtained from this technique were compared with in‐vitro digestibility data obtained earlier on the same feeds. Similar trends for the effect of supplementation on digestibility were observed in both in‐vitro and in‐vivo measurements. Linear correlation equations were obtained between gas produced and the proportion of dry matter disappearing, enabling in‐vitro gas production to be expressed in in‐vitro digestibility's. A single pool exponential equation was fitted to the gas production data enabling estimates to be made of the time when in‐vitro digestibility's best matched in‐vivo digestibility data. These times were 45.8 and 47.9 h of untreated straw, 43.5 and 61.0 h for treated straw for trials 1 and 2, respectively. Statistically significant (P < 0.05) interactive effects between supplement and both treated and untreated straws were observed. The digestibility of untreated straw was particularly stimulated by small quantities of supplement. The digestibility of treated straw was higher than that of untreated straw and less stimulated by supplementation. These findings are consistent with the hypothesis that fibre digestibility can be increased by providing a supplement which provides sufficient nutrients to stimulate the activity of rumen micro organisms.
The metabolism and fate of [methyl‐14C] and [uronate‐6‐14C]pectin‐labelled dietary plant cell walls in the rat
Authors: Buchanan Callum J , Fry Stephen C , Eastwood Martin A
Published: November 2006

The metabolism of dietary plant cell walls (PCW) was followed in the rat using PCW isolated from spinach cell cultures which were14C‐labelled in the galacturonic acid residues (using D‐[6‐14C]glucuronic acid, ⩾85% of the 14C was confined to the C‐6 position of pectic galacturonic acid residues) or the methyl ester groups (using L‐[methyl‐14C]methionine, 90% of the 14C was confined to methyl ester groups and 10% of the 14C in methyl ether groups) of pectin. Eighteen hours after gavage, only 5‐10% of the 14C was recovered in the gut contents and faeces. Some of the 14C derived from the [methyl‐14C]pectin‐labelled PCW was present in the liver (2‐4%) and the pelt (6%). In the liver the 14C was mainly in phospholipids, whereas in the pelt the 14C was found in protein (mainly alanine residues) and fatty acids esterified to cholesterol. The livers from rats fed [uronate‐6‐14C]pectin‐labelled PCW contained less 14C (1%) but more 14C was found in the pelt (12‐15%). In the liver the 14C was found in phospholipid but in the pelt the label was exclusively found in amino acid residues. Pectin in intact PCW is extensively degraded in the caecum and colon and the products absorbed and metabolised by the host. These products may be important sources of energy and of precursors of structural compounds such as proteins and lipids.
Correlations among quality parameters of peach fruit
Authors: Génard Michel , Souty Michel , Holmes Susan , Reich Maryse , Breuils Liliane
Published: November 2006

The correlations among quality parameters of peach fruit (Prunus persica L Batsch) were studied for eight different cultivar‐shape‐site‐nitrogen‐season combinations (‘treatments’). Between 66 and 183 fruits were taken from each treatment and the quality parameters of skin colour, flesh firmness and taste were measured. Differences and similarities between treatments were analysed using a recent development in biplot multivariate analysis: the ACT method (Analyse Conjointe de Tableaux), which allows the study of several data tables in one unique analysis. Each treatment was characterised by a data table where records were the fruit and variables were quality parameters. A common pattern of correlation between quality parameters was found for all the treatments. Two main independent gradients were described. The first was a colour gradient and the second was a taste gradient. In the latter, the concentrations of sucrose and malic acid varied inversely with citric acid concentration. The firmness and the concentration of reducing sugars were independent of these gradients.
Mycoflora and aflatoxin contamination in shelled pistachio nuts
Authors: Heperkan Dilek , Aran Necla , Ayfer Mahmut
Published: November 2006

A total of 143 pistachio nut samples collected during harvest, storage and processing were examined for mould growth and aflatoxin production. The mould count was in the range of 103−104 cfu g−1 and 105−106 cfu g−1 for the harvest and storage samples, respectively. The growth of Aspergillus flavus was 38‐5‐39‐5% on the surface of the shells and 6–16% on the kernels without aflatoxin production. The contamination level of A flavus varied among samples collected from different regions. Peeling off the soft shell of pistachio nuts by hand reduced the contamination risk of A flavus to kernels. The predominant flora on stored pistachio nuts were Aspergillus, Penicillium, Cladosporium, Rhizopus, while the genera of Ulocladium, Trichothecium, Aureobasidium and Eurotium were less frequent. Thirty‐five percent of the A flavus isolates produced aflatoxins on synthetic media.
Cocoa hull: A potential source of dietary fibre
Authors: Martín‐Cabrejas María A , Valiente Cruces , Esteban Rosa M , Mollá Esperanza , Waldron Keith
Published: November 2006

Cocoa hull dietary fibre (DF) was evaluated by an enzymic‐gravimetric method. Insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) were subjected to acid hydrolysis and the resultant neutral sugars, uronic acids, and Klason lignin were quantified. Cocoa hull exhibited a high content of total dietary fibre (TDF), 504 g kg−1 on a dry weight (DW) basis, IDF being the main fraction found. Glucose was the major sugar constituent of the IDF fraction whereas the uronic acids were equally distributed in the IDF and SDF fractions. The chemical composition reveals that pectic polysaccharides and cellulose contributed in similar amounts to TDF (107 g kg−1 and 92 g kg−1 DW, respectively). Non‐starch polysaccharides accounted for 222 g kg−1 DW, while the content of Klason lignin was lower (161 g kg−1 DW). The main pectic substances in the insoluble fibre were low methoxyl pectins whilst those of the soluble fibre were high methoxyl pectins. Cocoa hull appears to be a good source of DF that might be used to supplement other sources of fibre or food products.
Estimating nitrate leaching and denitrification by simultaneous use of Br and 15N tracers
Authors: Bakar Rosenani Abu , Goulding Keith W T , Webster Colin P , Poulton Paul R , Powlson David S
Published: November 2006

Losses or nitrogen (N) by leaching were estimated in three experiments using bromide (Br) as a tracer. An estimate or denitrification was also made, by difference, by combining the estimate of leaching with a measure of total loss of applied N using 15N. This was compared with a direct measure of denitrification made using acetylene inhibition. Bromide proved to be a poor tracer for nitrate (NO3) leaching at two of the three sites, Brimstone and Hoosfield. Performance was rather better at the Broad Mead site. Problems in using Br were associated with (a) difficulties in measuring small concentrations of Br close to background in soil, and (b) reactions involving N such as immobilisation and mineralisation that rapidly change NO3 pools but do not affect Br. Use of Br in field experiments is unlikely to provide reliable estimates of NO3 leaching over timescales of several weeks as used here unless much more frequent sampling is done. Simultaneous measurements of total losses of N using a 15N tracer were combined with estimates of NO3 leaching using Br to calculate denitrification; these estimates were compared with measurements of denitrification using acetylene inhibition. Agreement was poor because of (i) the lack of reliability of the acetylene inhibition technique, and (ii) the very large errors associated with calculating denitrification as the difference between an estimate of NO3 leaching and total N losses.
Suitability of the linear relationships for predicting tryptophan of feedstuffs from nitrogen content: A critical study of literature data
Authors: Landry Jacques , Delhaye Sonia
Published: November 2006

The tryptophan contents of 20 samples of various feedstuffs, determined by using assay procedures which were proved to give quantitative results, were compared with those predicted from the relationships between nitrogen and tryptophan published by three laboratories. The ratio of predicted tryptophan to the observed tryptophan, expressed as percentage, ranged from 65% (pea) to 137% (fishmeal). These differences were shown to be related to a systematic underestimation of tryptophan regarding data from two laboratories associated with a variability of tryptophan content for a given nitrogen content and a given type of feedstuff.
Cultivation, preparation and consumption of ensete (ensete ventricosum) in Ethiopia
Authors: Pijls Loek T J , Timmer Arnold A M , Wolde‐Gebriel Zewdie , West Clive E
Published: November 2006

In Ethiopia almost 10 million people are dependent on ensete (Ensete ventricosum (Welw) Cheesrnan), also known as ‘false banana’. In the Gurage area in Central Ethiopia, agronomic and nutritional aspects of ensete were studied in 60 households in six villages. Ensete is propagated vegetatively and has a 6‐year growing cycle during which it is transplanted three or four times. Men harvest the plants; women scrape the pseudo stem in order to separate the starchy pulp from the fibre, and pulverise the corm. The pulp is fermented and stored for up to 5–7 years in earthen pits. The yield of ensete food (ko'cho) was found to be 34 kg per plant or 9.5 tons ha −1 per year. Compared with other foods grown in Ethiopia, the energy yield of ensete (6.1 MJ m −2 per year) was higher than that of all cereals, Irish potato, sweet potato and banana, but lower than that of cassava. The protein yield of ensete was higher (11 ± 4gm−2 per year) than all of the crops mentioned above, except for banana and Irish potato. To make ensete bread, fermented pulp is squeezed to make it drier, chopped to shorten the fibres and a 2 cm layer is baked for 15 min. Unfermented freshly harvested corm is also eaten after boiling. All foods have a low protein content (4–22 gkg−1). Bu'lla, white desiccated juice collected from the pulp, is more energy rich (8.5 MJ kg−1) than ko'cho (6.5 MJkg−1). A dietary survey, conducted in 39 households comprising 237 persons, showed that the average daily intake of 0.55 kg ensete provided 68% of total energy intake, 20% of protein, 28% of iron but no vitamin A. Energy intake from all food consumed was very low, being only 60% of requirements, while protein intake at 107% was ample. Since ensete can be stored for years, is readily available throughout the year and can withstand dry periods, its cultivation can significantly improve household food security in highland areas prone to drought and famine.
Genotype, environment and genotype × environment effects on trypsin inhibitor in peas
Authors: Bacon J R , Lambert N , Matthews P , Arthur A E , Duchene C
Published: November 2006

Amounts of trypsin inhibitor were determined in seeds from 11 pea cultivars grown at seven European locations during the 1990 season. Activities ranged from 0.42 to 4.25 trypsin inhibitor units per mg flour (TlU mg −1). Data analysis indicated a significant environmental as well as genetic effect on the activities detected. Cultivar NSA 89–0054 displayed the highest activities across the sites with a mean of 2.55 TIU mg −1, and the Cultivar Allure the lowest with a mean of 0.93 TILI mg −1 The site having the lowest mean activity was Chaläns in France with 0.98 TIU mg−1 and the highest was Roth well in the UK with 2.41 TIU mg−1. Some cultivars were more susceptible to environmental factors than others.
Changes in volatile compounds during maturation of some grape varieties
Authors: Gómez Encarna , Martínez Adrian , Laencina José
Published: November 2006

The evolution of volatile compounds in three Vitis vinifera varieties (Monastrell, Cabernet Sauvignon and Tempranillo) was followed during maturation to determine whether they could be used as a maturation index. The volatile compounds were extracted and analysed by gas chromatography and gas chromatography‐mass spectrometry. The volatile compounds of these non‐aromatic varieties generally occurred in very low concentrations and only the C6 compounds appeared in sufficiently high concentrations for their evolution to be followed and used to determine optimum maturity.
α‐Amylase inhibitor levels in seeds generally available in Europe
Authors: Grant George , Edwards Joan E , Pusztai Arpad
Published: November 2006

The α‐amylase inhibitor (αAI) levels in 18 seeds, which are generally available throughout Europe, have been determined. Kidney beans, haricot beans, pinto beans and runner beans had high contents of αAI (2–4 g equivalent kg−1 seed meal). Butter beans, blackeyed peas, chickpeas, field beans and sweet lupinseeds contained 0.1–0.2 g inhibitor equivalent kg−1 seed meal. No αAI activity was detected in samples of adzuki bean, lentils, mung beans, peas, soya beans, sunflower seeds or winged beans. The αAI activity present in whole kidney beans was relatively heat‐resistant. However, it could be completely abolished by aqueous heat treatment of fully imbibed beans at 100°C for 5–10 min.
Influence of the fermentation yeast strain on the composition of wine spirits
Authors: Lurton Luc , Snakkers Guillaume , Roulland Claudie , Galy Bernard , Versavaud Alain
Published: November 2006

Fifteen indigenous strains of Saccharomyces cerevisiae, differentiated by their genetic polymorphism, were compared in standard conditions for their respective ability to produce volatile compounds during the alcoholic fermentation of grape must. The results were processed using analysis of variance and of principal components. They exhibited significant differences between strains, in particular for the higher alcohols, fatty acid esters, acetates or acetaldehyde. On the basis of their analytical profile, five strains were selected and compared on the pilot scale. Overall, the pilot results confirmed laboratory findings. As the strain effect appears to be determinant on the aromatic composition of wine spirits, a programme of selection based on both intraspecific molecular characterisation and chromatographic analysis is carried out to obtain specific yeast strains for high‐quality spirits.
Effects of sucrose polyester coating on fruit quality of apricots (Prunus armenaica (L))
Authors: Şümnü Gülüm , Baymdirh Levent
Published: November 2006

Mature apricots were coated with different concentrations of a mixture containing sucrose polyesters (Semperfresh(tm) fruit coating) to determine the effect of that coating on shelf‐life, post‐storage life and quality of apricots. Respiration rates, weight loss, colour change, variations in soluble solids, ascorbic acid content, titratable acidity and pH of apricots were effectively reduced by both the 10 g litre−1 and 15 g litre−1 concentrations during ambient storage. After 10 days of cold storage both concentrations caused firmer fruit, higher pH, titratable acidity, soluble solids and ascorbic acid.
Formation of lysinoalanine following alkaline processing of soya bean meal in relation to the degradability of protein in the rumen
Authors: Nishino N , Uchida S , Ohshima M
Published: November 2006

Effects of sodium hydroxide (NaOH) treatment on the formation of lysinoalanine (LAL) and on in‐situ and in‐vivo utilisation of soya bean meal (SBM) protein were investigated. Defatted SBM was sprayed with 0 (water), 25, 50 and 100 g NaOH (kg−1 dry matter), dried at 80°C for 2 h and then fed to four rumen cannulated goats in a 4 × 4 Latin square as a mixed diet (9: 1 w/w) of sudangrass hay and the SBM. LAL was not detected in non‐alkaline SBM, but the cross‐linked amino acid increased according to the level of NaOH addition. The maximum concentration of LAL was 1.26 g per 16 g nitrogen when the highest level of NaOH was applied. The NaOH treatment did not alter the digestibility or the retention of nitrogen of the mixed diet. Addition of NaOH at 25 and 50 g (kg−1 dry matter) lowered the solubility of protein, while the highest level of treatment had little effect. Lag time and rate of degradation of protein decreased due to the increasing level in NaOH treatment. A significant correlation (r = —0.860, P < 0.01) between LAL content and rate of protein degradation suggested that the formation of cross‐linked amino acid would render protein more resistant to microbial degradation in the rumen.
Metal content and distribution in fenugreek cultivated in Pakistan
Authors: Naeem Sitwat , Khan Farooq Ahmed , Siddiqui Ishratullah , Mahmood Naeem
Published: November 2006

The metal contents in 42 fenugreek samples, cultivated in various agricultural areas of Pakistan, were determined using atomic absorption spectrophotometry. The concentrations of the metals—Cu, Mn, Cd, Ni, Co, Cr, Pb, Zn, Fe, Na and K—were found to be higher than those reported earlier. Particularly, the samples cultivated near the major industrial cities showed significantly higher levels of almost all the metals investigated in this study. The high concentration ranges of toxic metals, such as Cd 1·0–2·8, Pb 2·5–3·4, and Cr 17–19·8 mg kg−1, in a fairly large number of samples suggest a possible increase of the overall intake of these metals to potentially harmful levels.
Microspectrophotometric characterization of aromatic constituents in cell walls of hard and soft wheats
Authors: Akin Danny E
Published: November 2006

Cell walls of epidermis, hypodermis, nucellar epidermis, aleurone, and endosperm in hard and soft wheat (Triticum aestivum L) kernels were evaluated for aromatic constituents using ultraviolet (UV) absorption microspectrophotometry. Wheat varieties sampled were soft red winter Caldwell, hard red winter varieties Tam 200 and Karl, and hard red spring varieties Len and Yecora rojo. Spectra of cell walls of epidermis and hypodermis (beeswing cells) suggested larger amounts and a greater degree of polymerization of aromatic constituents in these walls compared to those of other cell types. Results also suggested the presence of ester‐linked ferulic acid. Nucellar epidermal walls also had polymerized aromatics and ferulic acid, but amounts appeared to be much less than in the walls of the beeswing cells. UV spectra of aleurone walls suggested that the predominant aromatic was ester‐linked ferulic acid; anticlinal walls had substantially more aromatic constituents than outer or inner periclinal walls. Endosperm walls lacked any indication of aromatics by this method. Grain hardness did not appear to be related to cell wall aromatics. UV absorption microspectrophotometry indicated significant variations in wall aromatics of different cell types of wheat grains.
Characterisation of bound flavour components in kiwifruit
Authors: Young Harry , Paterson Vivienne J
Published: November 2006

Glycosidically bound volatiles in kiwifruit have been studied. The compounds were isolated from kiwifruit juice by absorption onto a column of Amberlite XAD‐2 followed by washing with pentane and elution with methanol. Volatiles were released by enzymic hydrolysis with β‐glucosidase. Major components found and identified by GC‐MS were E‐hex‐2‐enal and benzaldehyde. Compounds not previously identified in kiwifruit include octan‐3‐ol, camphor, 4‐methylbenzaldehyde, 2‐hydroxybenzaldehyde, neral, geranial, methyl 2‐hydroxybenzoate, nerol, geraniol and 2‐phenylethanol.
The effects of antioxidants on changes in oils during heating and deep frying
Authors: Gordon Michael H , Kourkimskå Lenka
Published: November 2006

The effect of antioxidants on the stability of rapeseed oil during heating at 80°C and during deep‐fat frying of potato chips (French fries) was assessed by measurement of the formation of polymers and increase in peroxide value, supported by determination of the increase in mass during heating and changes in tocopherols during frying. The Rancimat was also used to assess the stability of the oil containing antioxidants at 100°C The order of antioxidant activity during heating was: TBHQ > lecithin > ascorbyl palmitate > rosemary extract > BHT, BHA and D‐δ‐tocopherol. Minor deviations from this order of activity were observed depending on the method of assessment used, with the main difference being the low stability of the oil samples containing lecithin or ascorbyl palmitate in the Rancimat test. Ascorbyl palmitate gave a lower rate of increase of mass and peroxide value, but gave a similar rate of dimer formation compared to the rosemary extract. The rosemary extract and ascorbyl palmitate both retarded formation of dimers during deep‐fat frying and retarded losses of natural tocopherols in the oil. The stability of oil used for deep‐fat frying fell as the tocopherols were consumed and this was reflected in an increase in hydroperoxides generated in oil samples after frying. Oil extracted from the chips was similar to the bulk oil in polymer content.
Comparative characterisation of dioxane‐soluble lignins released by ball milling and by sheep digestion from forage grasses
Authors: Kondo Tsuneo , Watanabe Takashi , Ohshita Tomoko , Kyuma Tadashi
Published: November 2006

Faecal soluble lignin (FSL), extracted from the faeces of sheep that received orchardgrass and timothy, were compared with 90% dioxane‐soluble lignins released by ball milling (MHL) and by subsequent enzymatic hydrolysis (EHL) from the same grasses. FSL contained much less carbohydrate and esterified p‐coumaric and ferulic acids than MHL and EHL. Although no considerable differences were found in the yields of vanillin and syringaldehyde produced by nitrobenzene oxidation, the molar ratio of syringaldehyde to vanillin was higher for FSL than for MHL and EHL. Such differences in chemical properties among the lignin preparations were confirmed by 13C‐NMR spectroscopy. FSL had a lower molecular size compared with MHL and EHL. Results indicated that syringyl‐rich lignin fragments with less phenolic acid esters, probably depolymerisation products of the grass lignins, were released by digestion in sheep from the forage grasses.
Effect of condensed tannin in cottonseed hulls on endogenous ileal amino acid loss in the growing rat
Authors: Yu Feng , Moughan P J , Barry T N
Published: November 2006

The effect of condensed tannin (CT) in cottonseed hulls (CSH) on endogenous ileal amino acid flow in the growing rat was evaluated. CSH contain around 900 g kg−1 fibre and 52 g kg−1 total CT. Twenty‐four rats were allocated to four semi‐synthetic diets, which contained enzymically hydrolysed casein (EHC) as the sole source of dietary nitrogen and chromic oxide as an indigestible marker. Two of the diets contained no CSH while the remaining two contained 50 g kg−1 CSH. At each level of hull inclusion (0 and 50 g kg−1), polyethylene glycol (PEG: MW 3500) was added (6 g kg−1) to one of the diets. The effect of CT was assessed by determining endogenous ileal amino acid loss in the presence or absence of PEG, which binds and inactivates CT. The rats were given their respective experimental diets ad libitum for 14 days. Samples of digesta were collected at slaughter from the terminal 15 cm of ileum. The digesta samples were centrifuged and the supernate ultrafiltered. The precipitate plus retentate (MW > 10000) fraction affords an estimate of endogenous loss. Inclusion of CSH in the EHC based diet increased ileal flow of total nitrogen (1387 versus 1623 μgg−1 dry matter intake; P ≤ 0.05), increased ileal flow of total amino acids (23%; P ≤ 0.01), and significantly increased ileal flow of several individual amino acids. There was no significant effect of PEG and no PEG × diet interaction; showing that the CSH effects could not be explained by action of CT. The presence of hulls in commercial cottonseed meal would appear to contribute to the reported low apparent ileal amino acid digestibility coefficients for cottonseed meal by increasing endogenous ileal amino acid flow, but this effect is not due to the CT component of the hulls.
Effect of liming on calcium and magnesium concentrations in herbage
Authors: Riggs Katherine S , Syers J Keith , Rimmer David L , Sumner M E
Published: November 2006

The effects of adding calcitic and dolomitic limestone on the Ca and Mg concentration of perennial ryegrass grown in two acid UK soils were investigated in a greenhouse experiment. Additions of calcitic limestone and subsequent cropping caused decreases in exchangeable Mg of some soils to values considered to be deficient for many agricultural crops (<50 mg Mg kg‐1). However, such decreases in the predicted availability of Mg did not lead to Mg‐deficient herbage (<2.00 g Mg kg‐1) or reduced yields in most cases. In one of the soils, additions of dolomitic limestone increased soil exchangeable Mg to concentrations adequate for plant growth at the higher application rates and resulted in significantly (P<0.05) higher herbage Mg concentrations (2.05‐3.55 g Mg kg‐1) than were obtained with calcitic limestone (1.63‐2.93 g Mg kg‐1). Thus, the use of dolomitic limestone is more likely to provide adequate Mg concentrations for grazing animals than is calcitic limestone. No significant correlations were obtained between either exchangeable Mg or Ca : Mg ratios in the soil and Mg concentrations in the herbage following calcitic limestone treatments. This suggests that plants may be able to take up soil Mg which is not readily exchangeable and, therefore, soil exchangeable Mg may be a poor measure of the plant availability of Mg.