bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the use of shade in tea plantations in Kenya: Effects on chemical composition and quality of made tea
Authors: Owuor Philip O , Othieno Caleb O , Howard George E , Robinson Janet M , Cooke Rodney D
Published: October 2006

Tea was processed from leaves grown on un‐shaded, artificially shaded and Grevillea robusta Cunningh shaded plots at four different levels of nitrogen application (0 to 270 kg ha−1 year−1). Tea grown under artificial shade produced black tea with higher theaflavin and reduced thearubigin concentrations and with a better flavour index and tasters' evaluation than did tea grown without shade. The heavier (artificial) shading gave teas better than those derived from G robusta shaded teas. No statistically significant effects on the caffeine contents were observed. The data presented suggest that the removal of shade from tea gardens leads to a loss in quality. The need for a more complete economic evaluation is discussed.
Bracken (Pteridium aquilinum)—toxic effects and toxic constituents
Authors: Fenwick G R
Published: October 2006

Bracken (Pteridium aquilinum L Kuhn) is one of the most successful weeds of the world. In the UK it covers almost 700 000 ha, and is expanding its area by 1–3 % per annum. Not only does bracken limit the usefulness of marginal land but toxic principles in the plant may cause serious illness and even death in stock animals consuming its rhizomes or fronds. Bracken‐derived acute thiamine deficiency disorders occur in pigs and horses, and acute haemorrhagic syndrome, bovine enzootic haematuria and ‘bright blindness’ are all responsible for significant losses of livestock. A great deal of research has resulted in the isolation and identification of a number of natural components of bracken, and the evaluation of their biological effects using laboratory animal models and farm livestock has been carried out in detail. One compound contributing significantly to the toxicity of bracken is the carcinogenic and mutagenic norsesquiterpene, ptaquiloside. The effects on stock and laboratory animals of bracken, its extracts or ptaquiloside are discussed in this paper; the risk to human health from consumption of bracken fronds, milk and dairy products containing bracken carcinogens or their metabolites and drinking water supplies containing bracken leachates is considered from the standpoint of the UK and beyond. Options for the control of bracken are described briefly, and the final section indicates areas of bracken research deserving of further study.
Supplementary effect of aestivum wheat (Triticum aestivum L), bengal gram (Cicer arietinum L) and soya bean (Glycine max L) on protein quality of durum wheat (Triticum durum Desf)
Authors: Kaur Rup Davinder , Hira Charanjeet K
Published: October 2006

Chapatis and parathas were made from different combinations of durum (Triticum durum Desf) and aestivum (Triticum aestivum L) wheat to test for their organoleptic acceptability. The best accepted durum/aestivum (40:60) combination was supplemented at 10, 20, 30 and 40% levels with Bengal gram (Cicer arietinum L) flour and soya protein (Glycine max L) concentrate. Raw and cooked samples were analysed for some amino acids and trypsin inhibitor activity. The most acceptable cooked products were fed to growing rats for estimation of protein efficiency ratio, apparent digestibility and plasma proteins. Cooking resulted in considerable losses in cystine, available lysine and trypsin inhibitor activity. The losses were greater in paratha than in chapati. Protein efficiency ratio and apparent N digestibility of chapatis were significantly higher than those of parathas. However, protein quality of soya‐supplemented parathas was better than that of chapatis.
Identification of 1‐cyano‐2,3‐epithiopropane in volatiles of a model system from brussels sprouts (Brassica Oleraceae L var Bullata subvar Gemmifera DC)
Authors: Springett Mark B , Adams J Brian
Published: October 2006

Volatiles produced in model systems consisting of a crude enzyme preparation from Brussels sprouts (Brassica oleraceae L var bullata subvar gemmifera DC), sinigrin, ascorbic acid and 2‐mercaptoethanol were investigated using gas chromatography‐mass spectroscopy. 2‐Propen‐1‐yl isothiocyanate was the only breakdown product of sinigrin in the absence of 2‐mercaptoethanol but in its presence 1‐cyano‐2,3‐epithiopropane and small amounts of 2‐propen‐1‐yl cyanide also were formed. The identification of the 1‐cyano‐2,3‐epithiopropane was confirmed by comparison with a standard produced by autolysis of Crambe abyssinica L seed and with published mass spectra. The presence of 1‐cyano‐2,3‐epithiopropane in volatile extracts of unblanched, frozen stored Brussels sprouts is also reported.
Studies on fatty acid composition in tea Camellia sinensis
Authors: Bhuyan Lakshi Pd , Mahanta Pradip Kr
Published: October 2006

The proportions of fatty acids, viz lauric, myristic, palmitic, oleic, linoleic, and linolenic, in tea leaf, Camellia sinensis (L) O Kuntze, were determined at different stages of manufacture as well as in Mack tea. No significant variations were observed in the fatty acid contents of three major cultivars, Assam, China and Cambod. However, some variations were noticeable in leaf cropped in different months. Manufacturing stages have a pronounced effect on the relative proportions of the various fatty acids. Monthly distribution of total lipid was also followed in tea leaf, and the pattern of variation observed was identical for all the three cultivars.
The kinetics and mechanism of caffeine infusion from coffee: The hindrance factor in intra‐bean diffusion
Authors: Spiro Michael , Toumi Ralf , Kandiah Mangayetkarasy
Published: October 2006

Green and medium‐roast Kenyan arabica coffees were ground and sieved, and the 0·85–1·8 mm size fractions partially converted into two water‐swollen forms by an appropriate series of treatments. The first form still contained a mix of coffee solubles, the second only caffeine. The rates of caffeine infusion into water at 80°C were then measured for the dry coffee and for the two water‐swollen preparations. The caffeine was extracted two to three times faster from the solute‐free water‐swollen preparation than from the dry material Analysis of the results showed that counterflow of water the swelling of coffee particles, caffeine association with other solubes and physical restraints within the bean matrix all contribute to the low diffusion coefficient of caffeine inside the coffee particles. The behaviour of the green and the medium roast coffees was surprisingly similar.
Influence of food processing on iron availability in vitro from extruded maize‐based snack foods
Authors: Hazell T , Johnson I T
Published: October 2006

Samples of an extruded maize‐based snack food taken at various points during manufacture were digested in vitro under simulated physiological conditions. The proportion of iron diffusing across a semi‐permeable membrane was used as an index of bioavailability. Iron diffusibility increased from less than 3 % in raw whole maize to over 20 % in the finished product. Four processing stages were found to be responsible for this enhancement: (I) refining of raw maize, (2) product formulation, (3) extrusion cooking, (4) addition of flavourings. The extrusion cooking process itself was responsible for only a small part of the increase in iron diffusibility. There was a reduction in iron content due to refining, but a small increase in iron content due to product formulation and extrusion cooking. The various factors associated with each stage of snack food manufacture are discussed in relation to their potential influence on iron availability.
Effect of heat treatment of fish meals, fines and the addition of lysine as related to gizzard erosion in chickens
Authors: Wessels Jacobus P H , Post Bernard J
Published: October 2006

The effect was studied of certain properties of fish meal on their tendency to predispose chickens to develop gizzard lesions when used in starter diets. These properties relate to the degree of heat treatment to which the meals had been subjected, the fineness of the meal, and the fish species involved. The effect on gizzard erosion of addition of dietary lysine was also considered. The results suggest that the use of meals heated to 130°C or higher, but not of meals stored at lower temperatures, is more likely to result in the development of gizzard lesions, while the fineness of the fish meal had no effect on this phenomenon. In some instances added dietary lysine reduced gizzard erosion incidence. No relationship was found between chicken liveweight gain during the experimental period and gizzard lesion scores. A 7‐day biological test was used in these studies.
Flavone compounds in male and female asparagus (Asparagus officinalis) plants
Authors: Prickett Timothy C R , Walker John R L
Published: October 2006

Biochemical differences between male and female asparagus (Asparagus officinalis L) plants have been investigated. A compound termed ‘male sex factor’ (MSF) was found only in male shoots during flowering whereas a closely related ‘sex‐like factor’ (SLF) occurred in plants of both sexes. SLF was tentatively identified as 4′‐hydroxy‐5: 7‐dimethoxyflavone (5: 7‐dimethoxy‐apigenin). The possible role of MSF in asparagus breeding and cultivation is considered.
Indoleacetonitriles—thermal degradation products of indole glucosinolates in commercial rapeseed (Brassica napus) meal
Authors: Slominski Bogdan A , Campbell Lloyd D
Published: October 2006

Commercial low‐glucosinolate rapeseed (Brassica napus L) meal (LG RSM) was extracted with dichloromethane and subjected to chromatography on Sephadex LH‐20 to isolate indole‐containing compounds which were detected using TLC. Thin layer chromatography of dichloromethane extracts of various heat‐treated preparations of defatted low‐glucosinolate rapeseed cv Westar was also used to establish the origin of the major indole derivative. One of the minor components was identified as 3‐indoleacetonitrile (IAN) based on comparisons of GLC retention times and mass spectral data with authentic IAN. The major indole derivative was identified as 4‐hydroxy‐3‐indoleacetonitrile by comparison of mass spectral data with that for IAN and by establishing its precursor as 4‐hydroxy‐3‐indolylmethylglucosinolate.
Chemical and microbiological changes occurring in wheat silage maintained under modified atmospheres
Authors: Lisker Norberto , Taari Eli , Ashbell Gilad , Henis Yigal
Published: October 2006

In wheat silage maintained for 21 days at 26°C and 9‐9 kPa water vapour pressure under a continuous flow of modified atmospheres (MAs) containing 20% v/v O2 and different concentrations of CO2 (from 20 % v/v to 80 % v/v) there was a significant increase in pH and in the colony‐forming units (CFU) of aerobic bacteria, yeasts and moulds. In addition, water‐soluble carbohydrates (WSC) and acetic and lactic acids decreased considerably. Similar results were obtained with a continuous flow of 90 %, 95 % and 99 % v/v CO2 (supplemented to 100 % v/v with O2) and with 100 % v/v pure O2 Only with silage kept in an atmosphere of 100 % v/v CO2 or of 100 % v/v N2 were no changes observed.
A chemical study of lupinus hispanicus seed—nutritional components
Authors: Múzquiz Mercedes , Burbano Carmen , Rey Carmen , Cassinello Mar
Published: October 2006

Ecotypes of the native Spanish species Lupinus hispanicus were analysed for seed nutrient composition. Comparisons were made between the two subspecies (ssp hispanicus (Boiss et Reut) and sspbicolor (Merino)). OtherLupinus species were also analysed. The seed protein content of Lupinus hispanicus is fairly high (420 g kg−1), and the tryptophan content is higher than that of other species (15–20 g kg−1). The oil content (30 g kg−1) is lower than that of Lupinus mutabilis and Lupinus albus. Of the sterols, β‐sitosterol and campesterol are high and cholesterol is low. The mineral content was similar for all species studied but some ecotypes of L hispanicus had high values of Mn though much lower than L albus (361 and 2396 mg kg−1, respectively).
Mechanism of seed lectin tolerance by a major insect storage pest of Phaseolus vulgaris, acanthoscelides obtectus
Authors: Gatehouse Angharad M R , Shackley Simon J , Fenton Katherine A , Bryden Julia , Pusztai Arpad
Published: October 2006

The bean weevil Acanthoscelides obtectus (Say) is a major storage peat of Phaseolus vulgaris L (kidney, haricot bean). The seeds of P vulgaris contain high levels (up to 30 mg g−1 DM) of lectin, which has been shown to be toxic towards larvae of the related bruchid storage pest of cowpea, Callosobruchus maculatus F. The lack of toxicity of this lectin towards larvae of A obtectus is demonstrated. Unlike the strong binding of lectin to the midgut epithelium observed in larvae of C maculatus, no binding of lectin molecules was found to occur in the gut epithelial cells of A obtectus. This observation provides the basis for a hypothesis explaining the lack of toxicity of P vulgaris lectin towards A obtectus. Assays of proteolytic activity in gut homogenates of C maculatus and A obtectus suggest that the difference in susceptibility of the two insects towards the toxic effects of the lectin is not due to differential inactivation by proteolysis. Besides its effects on larval development, the lectin has a further effect at pupation, causing disruption of adipose tissues in C maculatus but having no effect on A obtectus.
Apparent discrepancies between immunochemical methods used for ovalbumin recognition in food
Authors: Breton Christelle , Thanh Luu Phan , Dubray Gerard , Paraf Alain
Published: October 2006

The specificity of rabbit anti‐native ovalbumin antibodies against native ovalbumin (NOA) or heat‐denatured ovalbumin (HDOA) was studied by affinity chromatography, ELISA techniques, quantitative immuno‐precipitation and HPLC. Affinity‐purified antibodies were prepared either by passing antisera successively on an NOA column and an HDOA column, or vice versa. Antisera were found to contain about 85 % of antibodies directed against NOA, 7% specific for HDOA and 8% retained by both columns.

It is shown that antibodies specific for NOA fully precipitated NOA in liquid‐phase precipitation but were unable to bind NOA in ELISA using NOA‐coated plates, while recognising NOA trapped on the solid phase by a first layer of antibodies: ovalbumin was thus completely denatured during interaction with plastic as shown also by the fact that antibodies specific for HDOA reacted with NOA‐coated plates.

These results point out the need to modify ELISA tests for monoclonal antibodies selection and for structural studies of food molecules in complex mixtures. However, this observation, which holds true for ovalbumin, might not apply to all antigens.
Compositional and quality characteristics of paneer made from soya beans and buffalo milk under different heat treatments
Authors: Parmar Shantilal S , Singh Sukhminder , Sharma Radhey S
Published: October 2006

Soya—buffalo milk (SBM) paneer was prepared from an admixture (1: 1 w/w, wet basis) of buffalo milk and tofu, the latter made by two methods (boiling and pressure cooking). Calcium sulphate (20 g litre−1) and citric acid (100 g litre−1) were used as coagulants for tofu and SBM‐paneerpreparations, respectively. Significant differences (P0.05) were observed in the yield of okara and hulls of soya beans in the two methods. However, no significant differences were observed in the yield and composition of tofu. SBM‐paneer( unfried and fried) showed no significant difference in composition between the methods, excepting the moisture and fat levels in the unfried SBM‐paneer. Fried SBM‐paneer prepared by pressure cooking showed a significant difference in the sensory score. Comparative appraisal of the composition of tofu, SBM‐paneer ( fried and unfried) and whey obtained in the two methods are presented.
The role of a low molecular weight glutenin fraction in the cooking quality of durum wheat pasta
Authors: Kobrehel Kàroly , Alary Rémi
Published: October 2006

Durum wheat glutenin fractions, composed of two low molecular weight proteins DSG‐1 and DSG‐2 (durum wheat (Triticum durum Desf) sulphurrich glutenin fractions) were extracted from semolina samples using a low concentration of Na tetradecanoate after extracting albumins, globulins and gliadins. DSG proteins have a highSH plus SS content. A highly significant correlation was found between the SH plus SS content of this DSG‐rich fraction and the cooking quality of pasta (0.63, P <0.01 with firmness and 0.86, P <0.001 with the state of the surface of the cooked pasta) and this seems to be a functional relationship. The use of acetic acid at various molarities showed the presence of high molecular weight glutenin fractions with differing solubility properties. In this respect, differences were found between varieties which are placed in the same group according to the classification of durum wheats based upon the composition of high molecular weight glutenin subunits.
Utilisation of free and protein‐bound methionine sulphoxide by the chicken
Authors: Haaland Herborg , Arnesen Elisabeth , Njaa Leif R
Published: October 2006

The biological availability of free and protein‐bound methionine sulphoxide (MSO) was examined in nine growth experiments with chickens. The source of protein‐bound MSO was fish meals oxidised with hydrogen peroxide.

Bound MSO in oxidised fish meals was equally well utilised by the chicken as was bound methionine in unoxidised fish meals when the meals were the sole protein sources in the diet. When used as supplements to a low‐methionine diet, oxidised fish meals were slightly less well utilised than L‐methionine and unoxidised meals at the highest supplementation levels. At a low level there was no difference. Free L‐MSO was less well utilised than free L‐methionine when added to a soya bean meal diet and when used in purified diets. In the latter cystine was found to improve the utilisation of MSO.

High levels of MSO were found in muscle extracts of chickens even when no MSO was present in their diet.
Sensory characteristics of british sausages: Relationships with composition and mechanical properties
Authors: Jones Richard C , Dransfield Eric , Crosland Adrian R , Francombe Mariko A
Published: October 2006

The appearance, texture and flavour of cooked British sausages were assessed by 11 trained panellists using their analytical profile of 19 attributes, each of which was rated on an unstructured line scale. Five independent components were isolated, accounting for 86% of the sensory variation. ‘Saltiness’ was the only independent attribute. A map of sausage quality showed that ‘skin toughness’, ‘firmness’ and ‘meatiness’ were related closely to the principal sensory axis, and ‘juiciness’ and ‘fattiness’ to the second principal axis. The attributes of appearance describing the degree of doneness, and those describing comminution in appearance and in texture, were related to both principal axes. Mapping instrumental measurements into the sensory space showed that puncture and compressive strengths and nitrogen content were the best measures of variation on the first principal axis, indicating a toughness/tenderness component influenced by lean meat content. Fat increased juiciness, but, as salt or rusk increased, sausages were drier and more cohesive. Adhesion and cohesion were assessed as ‘cohesiveness’. ‘Fattiness’ and ‘saltiness’ were related poorly to fat and salt contents, respectively. ‘Fattiness’ decreased in tough, dry sausages of low pH, and ‘saltiness’ decreased as pH, fat and ‘dryness’ increased. In commercial sausages, the effects of comminution on eating quality could override those of formulation.
Amino acid composition of guineafowl's egg
Authors: Oguntona Tunde
Published: October 2006

Samples of eggs from two breeds (White‐breasted and Pearl) of guinea hens which were housed either on deep litter or in layer cages were analysed for their content of amino acids. The protein content of whole eggs ranged from 482 to 494 mg g−1, with a mean of 487 mg g−1. Concentrations of the various amino acids in the egg ranged from 118 mg (tryptophan) to 752 mg (glutamic acid) per g N. The mean concentration of total sulphur amino acids was 395 mg per g N. Overall the amino acid composition of guineafowl egg was not affected by either breed or housing system.
Comparison between wet and dry oxidation methods of sample preparation for copper and zinc analysis of grassland herbage
Authors: Christie Peter , Dickson E Leslie , Kilpatrick David J
Published: October 2006

Grassland herbage samples with a range of copper (3–11 mg kg−1)) and zinc (10–53 mg kg−1) contents were analysed for Cu and Zn following sample solution preparation by four methods. An acid digestion procedure incorporating chloroform extraction and a second digestion step was compared with micro and macro digestion methods (both without solvent extraction) and a dry ashing method. The residues were dissolved in HCl and the metals determined by atomic absorption spectrophotometry.

Results for Cu were much less variable than those for Zn. The dry ashing procedure gave higher analytical precision than did the acid digestion methods. However, when between‐plot field variation was included, the four methods gave similar coefficients of variation. Thus acid digestion, including the rapid micro method, appears to be suitable for routine analysis of herbage from field experiments. The double digestion procedure often gave low mean values for samples with high Cu and Zn contents, but it may be suitable for small numbers of samples with low Cu and Zn concentrations, while the higher precision of the dry ashing method may be useful for glasshouse or controlled environment studies with lower between‐plot variation.
Chemical and physical changes in the pulp during ripening and post‐harvest storage of cocoa pods
Authors: Biehl Böle , Meyer Bernd , Crone Gundel , Pollmann Lutz , Said Mamot Bin
Published: October 2006

Changes in the pulp during ripening and post‐harvest storage of cocoa pods were determined during numerous harvests in Malaysia (1984 to 1987) and Ghana (1985 to 1986), in order to gain a basis for understanding the influence of ripening and storage on acid formation during subsequent fermentation. Changes in the pulp during ripening of fully grown pods were the same but less pronounced than those during dry storage of harvested pods: the percentage of water in the pulp was not changed significantly, but the amount of water and of dry matter per seed was strongly reduced (by 40–50%) due to water evaporation and respiration of sugars. Sucrose was inverted completely. The result of these changes was an equally strong reduction of the pulp volume per seed and increase of the pulp surface to pulp volume ratio. The reduction of acid formation during fermentation with beans from stored pods is ascribed predominantly to these changes rather than to the reduction in the amount of sugars, and is explained not only by the facilitated mass aeration but, above all, by the significant increase in respiration at the pulp surface over ethanol fermentation in the pulp when the pulp volume is reduced prior to fermentation. Ghanaian pods at similar stages of ripeness revealed more advanced stages of the pulp compared with Malaysian pods and consequently less significant change during storage. Water evaporation and respiration during pod storage were significantly higher in the pulp than in the husk.
Effect of irradiation dose, storage time and temperature on the ESR signal in irradiated chicken bone
Authors: Stevenson M Hilary , Gray Richard
Published: October 2006

Two‐hundred pairs of chicken bones (drumsticks) were irradiated at 2.5, 5.0, 7.5 and 10.0 kGy and stored for 0, 7, 14, 21 and 28 days at −20°C or + 5°C thus giving five replicates per treatment. Five unirradiated pairs of bones were stored at 5°C, one sample being analysed at each storage time. The samples were fragmented, freeze dried and ground prior to determination of the free radical concentration using electron spin resonance (ESR) spectroscopy. ESR signal strength increased significantly as irradiation dose increased, and decreased with storage time. Temperature alone had no significant effect on free radical concentration but, as the storage time increased, the bones stored at 5°C showed a significantly greater reduction in free radical concentration than those stored at −20°C. Correction of the ESR signal to a standard P or Ca concentration did not significantly reduce the variability of the results but did eliminate the interaction between storage temperature and storage time.
Characterisation of sour orange (Citrus aurantium) cultivars
Authors: Gogorcena Yolanda , Ortiz Jesús M
Published: October 2006

Twenty‐one cultivars of sour orange (Citrus aurantium L) and relatives selected in different areas of Spain were studied. Morphological determinations were carried out both in leaves and in fruits, including leaf size and area, number of oil glands, petiole length, fruit weight, number of seeds and others. Biochemical analysis included electrophoretic separations of proteins from leaves and fruit rind as well as peroxidases and esterases from some of the organs. Also chromatographic separations of rind oils were carried out in mature fruits. Quantitative and qualitative differences were detected for some of the cultivars. Enzyme differences were found to be adequate for distinction at the specific level. Two of the cultivars, ‘Bergamot’ and ‘Amargo clementino’, segregate from the main group, which indicates their belonging to a different species or to a hybrid. The validity of the present determinations for distinction and characterisation of material to be included in a citrus germplasm bank is discussed.
Effect of packaging and storage on the sensory quality of cooked chicken menu items served from chilled vending machines
Authors: Young Helen , Macfie Halliday J H , Light Nicholas
Published: October 2006

This study examined the effects of packaging on the sensory qualities of two cooked chilled foods (deep fried chicken drumsticks and chicken à la king) after extended chilled storage. Quantitative descriptive analysis was used with a trained taste panel to score the sensory attributes of the two products at various stages of chilled storage up to a maximum of 14 days at 0–3°C.

Storage had a significantly (P <0·05) deleterious effect on all the sensory attributes of chicken drumsticks. Just over half the sensory characteristics of chicken à la king were significantly affected and these effects were mainly concerned with appearance. Vacuum and modified atmosphere packaging extended the shelf life of both products in the sense that the changes in sensory attributes after 11–14 days were the same as in the cling‐film‐wrapped products after 4 days. The vacuum and modified atmosphere treatments were almost indistinguishable in their effects on the sensory attributes.
Treatment of milk by gamma irradiation—effect of anoxia on lipid peroxidation and the survival of Pseudomonas aeruginosa
Authors: Searle Andrew J F , McAthey Pamela
Published: October 2006

One of the causes of organoleptic changes in milk, lipid peroxidation, has been monitored by a sensitive assay newly applied to foodstuffs. It has been shown that even at medium radiation doses (up to 3600 Gy) negligible lipid peroxidation takes place, providing the milk is thoroughly gassed with nitrogen. Using a test spoilage microorganism, Pseudomonas aeruginosa (Schroeter), it was shown that the D10 was 35 Gy in air and 105 Gy under anaerobic conditions. Dose/survival curves indicate that 5 decades of killing needed 200 Gy in air and 600 Gy under nitrogen. However, even after receiving a dose of 1600 Gy, both aerobically and anaerobically treated milk failed the methylene blue test at 21 days post‐irradiation. The data indicate that, although the deleterious lipid peroxidation effects of irradiation can be minimised by the removal of air, this in turn results in a degree of protection being afforded to the bacteria, and that doses in excess of 1600 Gy are needed to effectively sterilise milk.
Aflatoxins in acid‐treated grain in Sweden and occurrence of aflatoxin M1 in milk
Authors: Pettersson Hans , Holmberg Torbjörn , Larsson Kjell , Kaspersson Anders
Published: October 2006

A survey of aflatoxins in acid‐treated grain and milk from farms using such grain was conducted in Sweden during 1986. Aflatoxins occurred most frequently (40%) in grain treated with a new formula of diluted (700 g litre−1) aqueous formic acid, but also in 31% of the samples of grain treated with 850 g litre−1 aqueous formic acid. The lowest incidence was found in grain treated with propionic acid, where aflatoxins were found in only one sample (3%). Aspergillus flavus/A parasiticus occurred in the same manner, but were more frequent than the aflatoxins. When cultivated on aflatoxin‐producing agar, positive reactions were more common (56%) among strains originating from grain treated with formic acid than among strains originating from grain treated with propionic acid (4%). Aflatoxin M1 in concentrations over 50 ng kg−1 was mainly found in milk from farms using formic acid, and in most of these cases aflatoxins were also detected in the grain samples. In some cases, milk from a single farm was contaminated enough to generate consumption milk from the dairy with aflatoxin M1 concentrations above or close to 50 ng kg−1.

The risk of aflatoxin formation after inadequate treatment of grain with formic acid is very high and is considerably lower with propionic acid. Formic acid has now been prohibited for use as a preservative of high moisture grain in Sweden.
Potential of probiotic organisms to prevent diarrhoea and promote digestion in farm animals – A review
Authors: Sissons John W
Published: October 2006

This review examines the scientific basis for claims that commercial probiotics prevent diarrhoea and increase digestive performance in young farm animals. Suppression of pathogenic coliforms in the stomach and intestine by competitive growth and bacteriocidal secretions of lactic acid bacteria justifies the use of lactobacilli in probiotics. However, there is as yet insufficient evidence to support the notion of a beneficial digestive role for this gut microflora.
Natural occurrence of zearalenone and trichothecene toxins in maize‐based animal feeds in zambia
Authors: Siame Bupe A , Lovelace Cheryl E A
Published: October 2006

A year‐long collection of maize‐based animal feed samples from the National Milling Company and mouldy maize collected from farmers fields near Lusaka were analysed for Fusarium mycotoxins. In the survey, 148 samples were tested for zearalenone, deoxynivalenol and nivalenol, and 60 samples for T‐2 toxin and diacetoxyscirpenol. Zearalenone was present up to 0.6 mg kg−1 in 17% of the feed samples, and deoxynivalenol was found at I‐0 mg kg−1 in 1.4 % of these samples. This is the first report of these toxins in animal feeds in Zambia. Zearalenone was also found in 57.6 % of the 33 mouldy maize samples collected at levels ranging from 0.08 to 6.0 mg kg−1 (mean concentration 1.11 mg kg−1), and 49.5% of these samples contained deoxynivalenol at levels ranging from 0.5 to 16.0 mg kg−1 (mean concentration 5.56 mg kg −1). T‐2 toxin and diacetoxyscirpenol were not detected.
Effect of redfish meal enriched diets on the taste and n‐3 pufa of 42‐day‐old broiler chickens
Authors: Ratnayake Walisundera M N , Ackman Robert G , Hulan Howard W
Published: October 2006

Broiler chickens were fed diets supplemented with redfish meal at levels of 4,8 and 12 %. A control group was fed with an all‐vegetable protein diet. After 42 days the birds were slaughtered and edible tissues (white, dark and skin) were analysed for lipid content and composition. The white and dark meats were tasted organoleptically for the possible presence of ‘fishy’ off‐flavours. There was no change in the content or class composition of the lipids with diet or sex of the bird, but in meats an increase in fish meal in the diet caused an increase in the level of n‐3 polyunsaturated fatty acids present, especially 20: 5n‐3 eicosapentaenoic acid, 22: 5n‐3 docosapentaenoic acid and 22: 6n‐3 docosahexaenoic acid at the expense of n‐6 fatty acids. The enrichment was most pronounced in white meat of both male and female birds and could make a contribution of n‐3 polyunsaturated fatty acids to the human diet quantitatively similar to that of an equal portion of lean white fish. Taste panel results showed that there was no significant difference in flavour or taste among any of the samples. There was a tendency for the 12% dietary group birds to be the least preferred, but no panelist detected ‘fishy’ flavours or objected to the taste of the meat.
In‐situ pectin de‐esterification of alkali‐treated fruit waste materials
Authors: King Karen , Norton Grenville , Mitchell John R , Caygill John
Published: October 2006

Waste peel and pulp materials from orange, lime and mango fruits were treated with sodium carbonate which increased the pH and resulted in the de‐esterification of pectin in situ. Chemical and enzymic (pectinesterase) de‐esterification occurred in each of the treated fruit waste materials. A specific carbonate enhancement of pectinesterase activity which was clearly demonstrated in orange peel was found to a lesser extent in lime pulp but not at all in mango peel. During treatment of the dispersions with Na2CO3, each of the three fruit waste materials gelled. The pectin degree of esterification of the orange and lime dispersions was below 50% (low methoxyl pectin) on gelling but the mango peel dispersions gelled at pectin degree of esterification levels above 50% although the gelation mechanism was that of a low DE pectin. The degree of esterification of the soluble pectin in the mango dispersion was, however, found to be very much lower than the overall pectin degree of esterification determined. It is suggested that in‐situ pectinesterase activity is restricted to the soluble pectin in mango peel whereas in the citrus residues both soluble and bound pectin are de‐esterified.
Textural characteristics of tomato fruits (Lycopersicon esculentum) affected by suns
Authors: Adegoroye Adegoke S , Jolliffe Peter A , Tung Marvin A
Published: October 2006

Six textural characteristics, deformation, epicarp strength, locular resistance, firmness, compliance and toughness, were calculated from force/ deformation curves obtained by punch testing tomato friuits (Lycopersicon esculentum Mill cv Vendor) in which sunscald had been induced by radiation stress. Sunscalded portions of unstored fiuits had higher compliance and lower firmness values than the uninjured portions. For the stored fruits, the magnitude of the ripening‐induced decrease in epicarp strength, locular resistance and firmness associated with storage was significantly reduced by ‘incipient’ injury and eliminated by ‘advanced’ injury.

Preferential ripening of the uninjured portions increased deformation and toughness beyond expected values. Various sunscald symptoms such as inhibition of fruit softening, the production of tough tissues, the localisation of sunscalded tissues and the differential ripening of uninjured parts relative to the sunscalded portions can be detected by determining force‐deformation characteristics of the sunscalded tomato fruits.
An improved, rapid, ELISA technique for detection of pork in meat products
Authors: Ayob Mohammad K , Ragab Awad A , Allen John C , Farag Radwan S , Smith Christopher J
Published: October 2006

The demand for analysts to determine the purity, quality and safety of food products is increasing. Adulteration of meat products with meat form other species is a particular problem. Determination of species of origin is possible using immunological assays. This paper reports a novel approach to the problem and discusses improvements and modifications of such immunologically based assays. These increase the sensitivity to 10 my g −1 of the adulterant species (pork) and permit automation and standardisation of the assay, increasing the reliability and rapidity compared with other methods.
Morphological and physiological variants among isolates of saccharomyces cerevisiae from palmwine and other sources
Authors: Ayanru Dafe K G
Published: October 2006

Using 34 carbon and four nitrogen compounds, and 12 standard yeast identification tests, eight isolates of Saccharomyces cerevisiae Hansen from Raphia Beaur (Palmae) palmwine and other sources were evaluated comparatively for morphological and physiological characteristics. Differences among the isolates were found mainly in their formation of pseudomycelium and blastospores, and in the fermentative utilisation of galactose, maltose, melibiose, raffinose, trehalose and α‐methyl‐D‐galactoside. The wine isolates varied primarily in their assimilatory capabilities for lactic acid and maltose. Observed fermentative and assimilative differences among the wine isolates confirmed the presence of physiological races of S cerevisiae in Raphia palmwine, and suggest that physiological races of S cerevisiae in palmwine may influence the wine's organoleptic and aromatic qualities.
Differences between wines fermented with and without sulphur dioxide using various selected yeasts
Authors: Herraiz Tomas , Martin‐Alvarez Pedro J , Reglero Guillermo , Herraiz Marta , Cabezudo Maria D
Published: October 2006

Comparisons were made between wines resulting from the fermentation of a single grape must of the Verdejo cultivar with various yeasts, namely the indigenous must microflora, pure cultures of Kloeckera apiculata, Torulaspora delbrueckii and Saccharomyces cerevisiae, and mixtures of these cultures, all with or without the addition of SO2. There were major differences in both volatile and non‐volatile compounds. Principal component analysis and cluster analysis showed that these differences were due mainly to the effects of the sulphur dioxide upon the yeasts.

Analytical data on the wines demonstrate that the nature of a wine depends upon the particular yeasts present during the fermentation in the absence of SO2. On the other hand, if the fermentation is carried out in presence of SO2, similar wines are produced despite differences in the microflora.
Nutritional value of stored fish silage as a protein source for young rats
Authors: Espe Marit , Raa Jan , Njaa Leif R
Published: October 2006

Silage was produced from 75% whole herring (Clupea harengus L) and 25% herring offal from a commercial fillet production line by addition of 2.5% (by weight) of formic acid. The silage was stored at room temperature for 180 days and sampled for chemical analyses after 0,1, 4,8,15,30,60,90,120,150 and 180 days. The changes seen were increased degree of autolysis and increased N H3 production during the first 90 days of storage. The nutritional value of the stored silage was studied in balance experiments with rats. The digestibility and utilisation of protein of a freshly prepared silage were higher than those of raw material and of silages stored for some time. When stored for more than 90 days the quality of the silage was significantly reduced, as shown by poor protein utilisation by rats. This quality reduction was probably due to a combination of autolysis and rancidity in the silage. This may indicate that the degree of hydrolysis may be used as a chemical quality criterion for fish silage.
Dephosphorylation of phytate compounds by means of acid phosphatase from Aspergillus niger
Authors: Żyla Krzysztof , Kujawski Maciej , Koreleski Jerzy
Published: October 2006

A non‐purified preparation of intracellular acid phosphatase (EC 3.1.3.2) from a waste mycelium of Aspergillus niger was utilised for dephosphorylation of phytate compounds present in food and feed ingredients. The enzymic hydrolysis of p‐nitrophenylphosphate was used for assaying acid phosphatase activity, expressed in standard units (u).

The hydrolysis of phytate phosphorus in wheat bran, soya bean meal and fully formulated feedstuffs for broilers (Galus galus; ‘Cornish’ × White Rock') was carried out at 40°C, a pH value of 4.5 and an enzyme dosage ranging from 12 to 30 u g−1. Complete dephosphorylation of soya bean protein isolates was performed at 60°C, a pH value of 4.5 and an enzyme dosage of 12 u g−1. In the gastrointestinal tract of broilers the in‐vivo dephosphorylation of phytates present in feed was observed when the preparation of acid phosphatase was added to the diet.
Zinc/Chromium (II) reduction for nitrate determination in agricultural materials by colorimetry or ion‐selective electrode
Authors: Hepher Michael J , Alexander Ronald H , Dixon James
Published: October 2006

To phase analytical pathways within this laboratory, recent approaches to nitrate analysis have been studied; of particular interest were the U V spectrophotometric approach (Heanes 1982, 1986) and zinc/chromium (II) reduction procedure (Pruden et al 1985). By combining and modifying various aspects of the aforementioned procedures with an adaption of an indophenol blue colorimetric procedure (Mitchell 1972) it was possible to measure nitrate‐nitrogen 0.10‐8.00 g kg−1 DM routinely on a range of agricultural materials (at present hays, straws, grasses, calabrese, potato leaves, cereals, soils and perlites) on a sophisticated high‐volume‐throughput microprocessor‐controlled auto‐sampler/spectrophotometric system.
Biochemical changes during the natural fermentation of the african oil bean (Pentaclethra macrophylla) for the production of Ugba
Authors: Njoku Henry O , Okemadu Chinwe P
Published: October 2006

Changes in the activities of major enzymes and in the proportion of the principal chemical components during the nataral fermentation of ugba from African oil bean (Pentaclethra macrophylla Bentham) were studied. The activities of the enzymes were related to changes in chemical composition. α‐Amylase, proteolytic and lipolytic enzyme activity remained detectable throughout the 72‐h fermentation period, and reached a maximum at 24‐36 h. The levels of amino nitrogen, ammonia nitrogen, reducing sugar, titratable acidity and pH increased with time. A seven‐fold increase in the amino nitrogen level occurred during the fermentation. The temperature of the fermentation and the moisture level reached maximum values at 24 h and 48 h of fermentation respectively. These results could provide useful indices for the improved evaluation of ugba fermentation.
Sugar content of swedes for stockfeeding
Authors: Bradshaw John E , Griffiths D Wynne
Published: October 2006

The sugar content was determined of 19 cultivars of swede (Brassica napus ssp rapifera L) grown in rows 50 and 75 cm apart. Sugar concentration ranged from 54.3 to 78.7 g kg−1 fresh weight and was positively correlated with dry matter content which ranged from 90.4 to 138.7 g kg−1 fresh weight. The average concentration of fructose, glucose and sucrose in the dry matter was 225.0, 328.4 and 34.5 g kg−1 DM, respectively. The high‐dry‐matter cultivars tended to have less fructose and more sucrose than the low‐dry‐matter ones, but total sugar concentration in the dry matter was not associated with dry‐matter content. Row width had little effect on sugar content compared with the differences between cultivars. The implications for the feeding value of swedes are discussed.
A study of weight loss of stored yam (Dioscorea cayenensis) as affected by the ventilation of the storage locations
Authors: Ajayi Omolayo A , Madueke Levi U
Published: October 2006

Investigation of the effect of ventilation on the storage losses of yam (Dioscorea cayenensis L) was carried out. The tubers were stored in three ventilation locations (1.4%, 3.8% and exposed ventilation) in two storage environments. It was found that the higher the ventilation level, the greater the weight loss. Exposed tubers that were subjected to direct heating and cooling of the sun and rain, respectively, rotted away; the high temperature involved preventing the sprouting of the tubers. Tubers in the 1.4% and 3.8% ventilation levels outside took a longer time to sprout than those stored inside.
Volatile flavour constituents of feijoa (Feijoa sellowiana)—analysis of fruit flesh
Authors: Shaw G John , Allen John M , Yates Martin K , Franich Robert A
Published: October 2006

The volatile flavour fraction from the flesh of ripe feijoa fruit (Feijoa sellowiana Berg cv Mammoth) has been isolated by high vacuum steam distillation and subsequent liquid‐liquid extraction of the volatiles. Analysis by capillary GC and GC‐MS led to the identification of 15 constituents of which (Z)‐hex‐3‐enal and isopropyl benzoate are reported for the first time. Methyl benzoate constituted 82% of the volatile flavour extract.
Composition and odour of volatiles from autoxidised methyl arachidonate
Authors: Taylor Andrew J , Mottram Donald S
Published: October 2006

Methyl arachidonate was subjected to autoxidation at room temperature either alone or in a water emulsion. Volatiles in the headspace were collected on Tenax and analysed by GC‐MS, and the amounts and identities of the major and minor volatiles were compared. Generally, the same compounds were formed in both systems, but whereas the amounts varied the changes were consistent with the role of water in lipid oxidation. Twelve volatiles accounted for 90% of the total, with oct‐l‐en‐3‐ol (30–40%), hept‐2‐enal (10–17%) and hexanal (6–17%) most prominent. Over 40 other volatiles were detected. The odour of individual components in both systems was assessed using a GC equipped with a sniffing port.
Influence of rooting medium pH and shoot and root temperature on the nitrate reductase activity of winter barley
Authors: Klessa David A , Hall David A , Sym Gordon J
Published: October 2006

In three separate experiments, the effects of rooting medium pH (pH 4.0, 5.3 and 6.5), root temperature (5, 10 and 15 C) and shoot temperature (6 and 17 C) on the growth, in‐vivo nitrate reductase activity and nitrogen status of winter barley were investigated. Except where temperature was specifically studied, air and/or root temperatures were maintained at 10 C to simulate the typically cool conditions which prevail during the early growing season for cereals in northern Europe.

Although growth, nitrate uptake and nitrate reductase activity were markedly affected by variations in temperature and pH. the Nitrogen Response Index, which is the quotient of in‐vivo induced and endogenous nitrate reductase activities in shoot or root material, was unaffected and uniquely reflected the N status of the plant.
Effect of lactobacilli inoculation on cassava (Manihot esculenta) silage: Fermentation pattern and kinetic analysis
Authors: Saucedo Gerardo C , González Pedro B , Revah Sergio M , Viniegra Gustavo G , Raimbault Maurice
Published: October 2006

The major effect of Lactobacillus inoculation on laboratory cassava (Manihot esculenta Crantz) silage was a change from a heterofermentative pattern observed in natural silage to a homofermentation. Small amounts of starter culture (1% v/w) were required to produce a high level of lactic acid (> 28 g kg−1 DM) and to reach a pH of at least 4. The Gompertz model was used to evaluate the effect of inoculation level on the lactic formation based on kinetic criteria. Also an empirical pH lactic acid correlation was proposed to monitor the progress of ensiling, based solely on pH measurements. The simulation model may be used to improve guidelines for silo safety and to evaluate the effect of lactobacilli inoculants.