bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of cooking on proteins from acha (Digitaria exilis) and durum wheat
Authors: Jideani Afam I , Apenten Richard K Owusu , Muller H G
Published: November 2006

The effect of cooking on proteins from acha and durum wheat was assessed from an analysis of protein extractability, gel electrophoretic profiles, in‐vitro protein digestibility (IVPD) and the amino acid compositions of wholemeal flour and residue proteins. Heating wholemeal flour samples at 100–140°C (t = 10–40 min) resulted in 0–30% and 45–55% decreases in acha and durum protein solubility, respectively. In general, high molecular weight (30–70 k Da) protein subunits were more susceptible to heat damage. For both cereals, sodium dodecyl sulphate (SDS; 10 g litre−1) and/or dithiothrcitol (DTT; 10 mM) increased protein solubility in unheated and heated samples. The IVPD index was 90–91% and was not significantly altered by cooking (100–120°C, t = 40 min). Cooking at extreme temperatures (140°C, t = 40 min) reduced the IVPD by 8% (P = 0.05). Osborne fractionation resulted in a durum or acha residue level of 7.8% or 55.2%. Treatment with solvent containing propanol, SDS and/or DTT at room temperature followed by SDS‐polyacrylamide gel electrophoresis of non‐solubilised proteins showed that the glutelin fraction of acha, with the exception of a 65 kDa subunit, was insoluble owing to strong inter‐subunit hydrophobic and disulphide interactions. Wholemeal acha flour and residue protein showed a significantly greater level of hydrophobic and sulphur amino acids as well as glutamine which is associated with H‐bonding. The possibility that cereal protein solubility is also dependent on protein‐carbohydrate links is discussed.
Mechanical assessment of texture of sweet cherries: Effects of freezing
Authors: Alonso Jesús , Canet Wenceslao , Rodríguez M Teresa
Published: November 2006

In this study the authors analysed which objective mechanical parameters, obtained by means of penetration, shear and Kramer shear cell tests, best explain the results obtained through sensorial assessment of the texture of six varieties of sweet cherry, and the changes undergone therein during the freezing process. The results suggest that the mechanical parameters selected should be independent of sample weight and volume, and that sample preparation should be as non‐destructive as possible. All the mechanical test parameters used in this work discriminate between varieties, but not all are useful for assessing the effect of freezing. The maximal force displayed on the shear‐test curve is the parameter that best reflects the firmness of the product whether fresh or frozen. The slope of the penetration‐test curve best reflects the variations in turgidity of the fruit as a consequence of freezing.
Determination of linamarin in cassava using enzyme‐sensitised microcentrifuge tubes
Authors: Yeoh Hock‐Hin , Tan Cheng‐Kim Catherine
Published: November 2006

Cassava leaf linamarase was covalently immobilised onto the inner surface of microcentrifuge tubes (1.5 ml). A large number of these enzymesensitised microcentrifuge tubes could be prepared in advance and stored at 4°C until needed. For determination of linamarin content, cassava root extract prepared in 0.1 M orthophosphoric acid was incubated in the microcentrifuge tube for 10 min at 30°C and pH 6. The cyanide released was then detected by a spectrophotometric method. Compared with other spectrophotometric procedures for determining linamarin, this method used less reagents and avoided unnecessary exposure to pyridine vapour. This system is also useful as a simple tool for rapid screening of linamarin content in cassava roots.
Identification of antimutagenic activities in the extract of an edible brown alga, Hijikia fusiforme (Hijiki) by umu gene expression system in Salmonella typhimurium (TA 1535/pSK 1002)
Authors: Okai Yasuji , Higashi‐Okai Kiyoka
Published: November 2006

A significant antimutagenic activity was found in the hot‐water‐soluble extract of an edible brown alga, Hijikia fusiforme (Hijiki in Japanese) which showed a significant inhibitory effect on the umu gene expression system in SOS response against DNA damage of Salmonella typhimurium induced by typical genotoxic substances such as N‐methyl‐N′‐nitro‐nitrosoguanidine (MNNG), furylfuramide (AF‐2), 2‐acetylaminofluorene(2AAF) and 3‐amino‐1,4‐dimethyl‐5H‐pyrido[4,3‐b]indole (Trp‐P‐1), This activity was divided into polysaccharide and non‐polysaccharide fractions and the former fraction showed a relatively high antimutagenic activity compared with that of the latter fraction. The polysaccharide fraction caused roughly equal inhibitory effects on MNNG‐, AF‐2‐, 2‐AAF‐ or Trp‐P‐1‐induced mutagenesis and the major portion of the antimutagenic activity of this fraction was estimated to have a molecular weight of more than 30 kDa. The non‐polysaccharide fraction also exhibited significant antimutagenic activities against MNNG‐, AF‐2‐, 2‐AAF‐ or Trp‐P‐1‐induced mutagenesis and the major activity or this fraction was associated with low‐molecular‐weight substances with less than 3.5 kDa. We discuss the biological significance of the antimutagenic activities from H fusiforme which were compared with those of Laminaria japonica and Undaria pinnatifida reported previously.
The proximate composition and some minor constituents of poppy seeds
Authors: Nergiz Cevdet , Ötles Semih
Published: November 2006

The proximate chemical composition of poppy seeds, along with minerals and water‐soluble vitamins content was investigated. The compositions of the fatty acids and tocopherols of the extracted oil were also determined. The proximate analysis of poppy seeds showed the following composition: (440 g kg−1), protein (211 g kg−1), moisture (50 g kg−1), ash (63 g kg−1), crude fine (62 g kg−1) and total carbohydrates (236 g kg−1). Potassium and calcium were the predominant elements in the poppy seeds. Linoleic acid was the major unsaturated fatty acid (750 g kg−1 total fatty acids) while palmitic acid was the main saturated one (86‐4 g kg−1). The amounts of α‐, β‐ and δ‐tocopherols found in poppy seed oil were 220 μg g−1, 40 μg g−1 and 20 μg g−1 respectively. Among the water‐soluble vitamins determined, pantothenic acid was found at the highest level followed by niacin and thiamin.
Antifungal proteins from sorghum endosperm and their effects on fungal mycelium
Authors: Kumari R Sunitha , Chandrashekar A , Shetty H S
Published: November 2006

Three antifungal proteins identified in sorghum endosperm act on the grain mould pathogen Fusarium moniliforme Sheldon causing inhibition of growth (Sunitha Kumari and Chandrashekar J Sci Food Agric 64 (1994) 357–364). Both morphological and biochemical changes in the fungal hyphae were observed on treatment with the antifungal proteins. The 18 kDa antifungal protein caused sloughing of cell wall polysacharides without much release of cytoplasmic material as seen by a slight increase in absorbance at 280 and 265 nm, and by microscopic examination. The decrease in pH or rise in electrical potential of the medium as the fungi respired was not altered by die presence of the 18 kDa antifungal protein in the incubation mixture. The 26 and 30 kDa protein fraction on the other hand caused leakage of cytoplasmic contents as observed microscopically without releasing polysaccharides from the cell wall. Addition of 26 and 30 kDa proteins to the incubation medium reduced the rate of the rise in pH or fall in electrical potential of the medium. Immunofluorescent microscopy indicated that the 18 and 26 kDa proteins bound to discrete areas or the fungal hyphal walls whereas, the binding of the 30 kDa antifungal protein was non‐specific.
Maillard reaction during the processing of ‘Doce de leite’
Authors: Pavlovic Suzana , Santos Rinaldo C , Glória Maria Beatriz A
Published: November 2006

‘Doce de leite’, a dairy product widely consumed in Brazil as a dessert or cake filling, is obtained from the heat treatment of milk and sucrose. On heating, the Maillard reaction occurs with the formation of desirable brown‐coloured products with a characteristic and pleasant flavour. However, the reaction can also lead to changes in nutritive value. In order to follow chemically the extension of the Maillard reaction and its effect on the nutritive value of ‘doce de leite’ its commercial processing was followed. Increases in the level of free 5‐hydroxymethylfurfural and in absorption at 420 nm by pigments attached to the protein were observed. The amino acid analysis showed a significant decrease in lysine levels (33%) as well as in arginine (11%) and histidine (10%). There was also a reduction in available lysine levels, as measured by the fluorodinitrobenzene (50.6%) and by the 2,4,6‐trinitrobenzenesulphonic acid (23.5%) methods. These results suggest a deleterious effect of the processing of ‘doce de leite’ on the nutritive value of the milk.
Performance of beef weaners on kikuyu silage supplemented with maize meal alone and in combination with protein of low degradability
Authors: De Figueiredo Maria C V , Stewart Iona B , Botha Willem A
Published: November 2006

A series of experiments were designed to evaluate the effect of supplementation of maize meal, alone or in combination with protein of low degradability, on the growth and voluntary intake of beef weaners.

Experiment 1: Maize meal (energy supplement) alone or in combination with fish meal (undegradable protein supplement) were evaluated as kikuyu silage supplements. Average daily weight changes of −312, 73, 300, and 635 g were obtained in weaners which were fed silage with no supplementation, 1.5 kg maize meal, 3 kg maize meal and 1.25 kg maize meal plus 0.250 kg fish meal each day, respectively.

Experiment 2: The effect of increasing levels of protein of low degradability, in the form of fish meal, as a supplement to kikuyu silage was evaluated. Voluntary intake increased with fish meal supplementation but not the level of supplementation. Weaners given 250 or 400 g of fish meal per weaner per day had higher liveweight gain than those not supplemented or supplemented with 100 g.

Experiment 3: Cottonseed meal, milled full‐fat soya beans and corn gluten meal were evaluated as replacements for fish meal. All diets were isocalorific and with the exception of the soya bean diet, which was lower in undegradable protein than the others, all diets had identical quantities of calculated undegradable protein. Neither voluntary intake nor liveweight gain were significantly affected by the replacement of fish meal with cottonseed or corn gluten meals.
A fourier‐transform infrared spectroscopic and microscopic study of the infection of potato tubers by Erwinia carotovora ssp carotovora in aerobic and anaerobic conditions
Authors: Stewart D , Lyon G D , Tucker E J B
Published: November 2006

The infection or potato tubers (Solanum tuberosum) by Erwinia carotovora ssp carotovora in aerobic and anaerobic conditions was studied using chemical analysis and Fourier‐transform infrared (FT‐IR) microscopy and diffuse reflectance spectroscopy. Analysis or the uninfected and infected residues following sequential extraction with diethyl ether, water (40°C), 90% dimethyl sulphoxide (DMSO) and digestion with amyloglucosidase showed that the principal effect of infection, particularly in anaerobic conditions, is starch degradation. This was substantiated by gel filtration chromatography of the 90% DMSO extracts. Extensive lignification was not found to be intimately associated with either infective condition. FT‐IR microscopical analysis of tissue sections showed that infection in both aerobic and anaerobic conditions caused starch and cell wall degradation, whilst extensive membrane degradation was only evident with anaerobic infection.
Impact of genotype and crop age on the breadmaking and physico‐chemical properties of flour produced from cassava (Manihot esculenta crantz) planted in the dry season
Authors: Defloor I , Leijskens R , Bokanga M , Delcour J A
Published: November 2006

The breadmaking potential of cassava flour (in cassava flour/defatted soya flour/glyceryl monostearate recipes (80:20:3, w/w)) prepared from 10 IITA cassava genotypes harvested at the International Institute of Tropical Agriculture (IITA) at 6, 9, 12, 15 and 18 months after planting, was investigated. Bread quality in general was much more dependent on the age of the cassava at harvest time than on the effects of genotype. Thus, the quality of the bread (judged by the regularity of the crumb) produced from flour from crops harvested 12 months after planting was the best in general, with that from flour resulting from 9‐month plants superior to that resulting from 6‐month plants. Harvesting at 15 or 18 months led to a reduction in bread quality although the effects varied for different genotypes. Brabender peak viscosity varied widely within each set of flour samples harvested at any particular harvest time, but also with the harvest time itself. By differential scanning calorimetry (DSC) (moisture: dry matter ratio 2‐1 w/w), the 6‐month samples were characterised by two endothermic transition peaks, one at ca 72°C and one at ca 78°C. With increasing age at harvest time (up to 15 months), the 72°C peak became relatively more important, resulting in a ‘disappearance’ of the 78°C peak in the thermogram. The 18‐month samples again showed a 78°C gelatinisation peak or at least a shoulder thereof. The peak multiplicity of the 6‐month samples also occurred in DSC experiments with moisture: dry matter ratio of 6‐0 (w/w), showing that such samples have a unique gelatinisation pattern. Differences in the analytical values (α‐amylase activity, and starch, fibre and protein content) could not explain the differences in bread‐making potential.
Fatty acid profile of some cameroonian spices
Authors: Mbofung Carl M F , Gee Jennifer M , Knight Dorothy J
Published: November 2006

Spices are frequently used in the preparation of traditional Cameroonian dishes, but to date little is known about their nutritional characteristics. The work described in this paper revealed that some spices, notably Njangsang and Pebe have a high fat content (around 500 g kg−1) and that a substantial proportion of this lipid is polyunsaturated. Wide variations in the total lipid content (40–510 g kg−1) and in the PUFA : SAFA ratio (0 3‐3 8) were observed but the consumption of spices in general, and of certain varieties in particular, may provide a significant quantity of lipid having a beneficial fatty acid profile, together with some essential fatty acids.
A further investigation of the influence of dietary protected lipid supplements on the characteristics of cows' milk fat
Authors: Fearon Anna M , Charlton Colin T , Kilpatrick David J
Published: November 2006

Dairy cows were offered diets containing three commercially available lipid supplements to determine their effect on milk fat composition and melting properties. Changes in fatty acid composition were observed. These were similar irrespective of supplement and agreed with the general trends reported in the literature. Changes in triglyceride composition were also found and these again were similar irrespective of supplement. However, the melting behaviour of the milk fats was different and may possibly be explained by changes in triglyceride structure. Compatibility of the dietary modified milk fats in mixtures with cocoa butter was examined using iso‐solid diagrams produced by a computer‐aided modelling technique. The differences in compatibility observed were small in magnitude but may still be important to the chocolate manufacturer.
Fasting‐induced glycogen depletion in different fibre types of red and white pig muscles—relationship with ultimate pH
Authors: Wittmann Werner , Ecolan Patrick , Levasseur Pascal , Fernandez Xavier
Published: November 2006

The aim of the present work was to study the effect of fasting times (0, 24, 48 and 72 h) on glycogen level in different fibre types of a predominantly white (Longissimus, LD) and a predominantly red (Semispinalis, SS) pig muscle, and on ultimate pH (pHu, 24 h post mortem). Thirty two individually housed Large White castrates (eight pigs per treatment) were slaughtered individually under minimal stressful conditions. Muscle samples were taken during bleeding for enzymic determination of muscle metabolites and histological examination using computerised image analysis. Myofibres were classified by a combination of metabolic (W, white; R, red) and contractile (α, fast‐twitch; β, slow‐twitch) characteristics. The SS showed higher glycogen depletion after 24 h fasting than the LD (−55 versus −26%, respectively). No further significant changes in glycogen level were recorded with enhanced fasting times (up to 72 h), although in the SS a marked trend towards glycogen depletion was observed. Fasting for 24 h resulted in significantly increased pHu in the SS whereas for the LD, a significant increase in pHu occurred only after 48 h fasting. In response to fasting, significant decrease in histochemical staining intensity for glycogen occurred in the three fibre types of the SS. The βR fibres of the SS showed an almost complete glycogen depletion after 24 h fasting. With increasing fasting time, glycogen was further depleted in fast‐twitch fibres (αW and αR). In the LD, only fast‐twitch fibres exhibited significant decrease in glycogen level after 24 h fasting. However, this was of a much lower magnitude than that observed in the SS and furthermore, no further variation was recorded with increasing fasting time, regardless of fibre type. The present work is the first to report a significant interaction between muscle type and fasting‐induced glycogen depletion in pig. Furthermore, these results demonstrate that within each muscle, the extent of fasting‐induced glycogen depletion is strongly fibre‐type‐dependent.
In‐vitro and in‐vivo studies on digestion of dietary fibre components in a broiler chicken diet based on rye
Authors: Pettersson D , Frigård T , Åman P
Published: November 2006

In an in‐vitro system, endogenous enzymes, as well as an added enzyme preparation, degraded both soluble and insoluble dietary fibre components in a diet based on rye endosperm, insoluble arabinose and xylose residues were not as efficiently degraded in vitro by the endogenous enzymes as the insoluble glucose residues. Broiler chickens were fed on the diet with or without the supplementary enzyme. Enzyme supplementation generally improved the apparent ileal digestibility of the insoluble dietary fibre components while soluble dietary fibres, especially arabinoxylans, were enriched in the ileal digesta leading to negative digestibility values. 1H‐NMR spectra of arabinoxylans in digesta from chickens in combination with sugar analyses corroborated the results from the in‐vitro study which indicated that the enzyme preparation preferentially degraded the soluble mono‐substituted xylose residues while un‐ and disubstituted xylose residues were enriched.
Forage quality variation among maize inbreds: Relationships of cell‐wall composition and in‐vitro degradability for stem internodes
Authors: Jung Hans‐Joachim G , Buxtono Dwayne R
Published: November 2006

Forty‐five inbred maize (Zea mays L) lines were evaluated for genetic variation in stem cell‐wall concentration, composition and degradability, and for relationships among cell‐wall components and polysaccharide degradability. Cell‐wall neutral sugars, uronic acids, Klason lignin, and ester‐ and ether‐linked phenolic acids were measured on lower stem internode samples collected at the time of silking in 2 years. Twenty‐four and 96 h in‐vitro ruminal fermentations were used to determine the rapidly and potentially degradable cell‐wall polysaccharide fractions, respectively. Genetic variation (P < 0.05) was found for all measures of cell‐wall composition and many estimates of rapidly and potentially degradable cell‐wall polysaccharide components. Inbred line means varied by 50–300% for most traits. Three brown midrib mutant inbred lines included in the study were not the lowest in lignin content nor did they exhibit the greatest cell‐wall degradabilities in this population of inbred maize. Year of growth (environment) influenced (P < 0.05) cell‐wall traits even though reproductive physiological maturity at sampling was similar in both years. Degradability of the cell‐wall polysaccharide components were intercorrelated (P < 0.05) within the rapidly and potentially degradable fractions, but rate and extent of degradation of the cell‐wall components were not correlated (P > 0.05), except for uronic acids. A multiple regression model of principal components (R2 = 0.41, P < 0.05) indicated that cell‐wall lignification and substitution of wall polymers with phenolic and uronic acids were negatively associated, and pectic substances were positively related with rapid polysaccharide degradation. Very little of the variation (R2 = 0.15, P < 0.05) in potential cell‐wall polysaccharide degradation could be explained by this multiple regression analysis. There is a large degree of genetic variation among current inbred maize lines for stem cell‐wall quality traits, which should allow improvement of maize as a forage crop. Because of the complex matrix interactions in cell‐wall organization, however, no single cell‐wall component, or simple combination, can accurately predict degradability of maize cell walls.
Proximate composition and seed lipid components of some Prosopis (leguminosae) from argentina
Authors: Lamarque Alicia L , Maestri Damian M , Grosso Nelson R , Zygadlo Julio A , Guzmán Carlos A
Published: November 2006

Seeds of Prosopis chiiensis, P argentina, P nigra, P flexuosa, P caldenia and P alba were analysed for proximate composition, fatty acids and sterols. Protein content varied between 242 and 356 g kg−1 (DW), and oil content from 107 to 172 g kg−1 (DW). The seed lipids contained a relatively large proportion of unsaturated fatty acids with linoleic and oleic acids as the predominant fatty acids. β‐Stitosterol was the major component in all species studied.
Effect of frozen storage on the chemical and physical properties of black and silver scabbardfish
Authors: Dias Jorge , Nunes Maria L , Mendes RogéRio
Published: November 2006

Black scabbardfish (Aphanopus carbo) and silver scabbardfish (Lepidopus caudatus) were frozen and stored at −18°C for 8 weeks. Samples were withdrawn weekly and analysed for protein insolubilisation, electrophoretic profile, texture and colour. A considerable decrease in the percentage of protein nitrogen extractable in 50 g litre−1 sodium chloride was observed in both species during frozen storage, which was also reflected in the decrease of sarcoplasmic and myofibrillar fractions. On the other hand, the alkali‐soluble and stroma fractions tended to increase. This behaviour was considered as an indicator of protein denaturation. The analysts of the electrophoretic profiles only showed slight differences either between species or during frozen storage. A highly significant correlation (P < 0.05) was found between soluble protein and texture parameters. This correlation allowed the derivation of a statistical expression which permits the prediction of textural quality during frozen storage of both scabbardfish species from the soluble protein content.
Effect of drying method and condensed tannin on detergent fiber analysis of sericea lespedeza
Authors: Terrill Thomas H , Windham William R , Evans John J , Hoveland Carl S
Published: November 2006

The effect of forage drying method on interrelationships between condensed tannins and fiber as determined by the detergent system of analysis was studied in a randomized block field experiment with three cultivars of sericea lespedeza (Lespedeza cuneata) (Dum‐Cours) G Don). Harvested forage was ovendried and freeze‐dried, and neutral detergent fiber (NDF) was determined with and without sodium sulfite added during the extraction. Acid detergent fiber (ADF), permanganate lignin, cellulose, and acid detergent insoluble nitrogen (N) were determined by separate and sequential ADF analyses. Without sodium sulfite, oven‐drying, compared with freeze‐drying, increased NDF, neutral detergent insoluble N, and sequentially‐analyzed ADF and lignin, due to precipitation of condensed tannins and protein in neutral detergent. Acid detergent fiber, lignin, and acid detergent insoluble N were higher in sequentially‐analyzed oven‐dried and freeze‐dried forages, compared with separate‐sample analyses, with a greater effect in oven‐dried samples. Neutral detergent fiber of both oven‐dried and freeze‐dried samples contained tannin‐protein complexes (precipitants), with more occurring in oven‐dried samples. When sodium sulfite was included in the neutral detergent extraction, all drying treatment differences in NDF, neutral detergent insoluble N, ADF, acid detergent insoluble N, and lignin were removed. Sequential NDF‐ADF analysis with sodium sulfite is recommended to minimize influence of condensed tannin on the detergent fiber system for sericea lespedeza.
Immunological characterisation of barley polypeptides in lager foam
Authors: Kauffman Juliet A , Mills E N Clare , Brett Gary M , Fido Roger J , Tatham Arthur S , Shewry Peter R , Onishi Akiko , Proudlove Michael O , Morgan Michael R A
Published: November 2006

Eight monoclonal antibodies (mAb) recognising barley polypeptides have been identified from a library developed to wheat prolamins. The specificity or the mAb has been determined using enzyme‐linked immunosorbent assay (ELISA) and immunoblotting. Six were of broad specificity, recognising D, B, C and γ‐hordeins to varying degrees by both techniques. IFRN 0610 preferentially recognised γ‐hordeins by ELISA but was highly specific for this hordein group by immunoblotting. Another mAb, IFRN 0624, bound to a Mr ∽ 18000 polypeptide belonging to the CM protein (trypsin/α‐amylase inhibitor) family by immunoblotting. This, or a related protein, was detected by 0624 in all hordein fractions using ELISA. These mAb, together with two others described previously and found to recognise the repeat motif of C hordein, were used in ELISA and immunoblot analysis of Octyl‐Sepharose fractions of lager foam. Hordein polypeptides were found in all foam fractions, indicating that much foam protein originates from the malt. The CM‐like protein was found present in a virtually unmodified form. In contrast, the repeat motif of C hordein was not detected, indicating that it had either been destroyed or masked by other beer constituents. The foam stabilising agent, propylene glycol alginate (PGA), increased the apparent hydrophobicity of hordein fragments suggesting that at least part of the activity of PGA is mediated by interactions with the hordein components of foam.
Supercritical fluid extraction of australian‐grown ginger (Zingiber officinale)
Authors: Bartley John P , Foley Philomena
Published: November 2006

The volatile compounds responsible for the flavour of Australian‐grown ginger have been extracted using supercritical carbon dioxide. Fluid densities above 0.8 g ml−1 result in the co‐extraction of significant amounts of triglyceride material. Analysis of the extract by GC‐MS indicates that the major components are neral and geranial, zingiberene, α‐bisabolene and β‐sesquiphellandrene which together account for 73% of the extract. The low concentration of gingerol degradation products attests to the mild nature of the extraction procedure.
Detoxification of jack beans (Canavalia ensiformis): I.—Extrusion and canavanine elimination
Authors: Tepal Justo A , Castellanos Rutilo , Larios Alfredo , Tejada Irma
Published: November 2006

In order to remove canavanine from jack bean (Canavalia ensiformis) the authors conducted extrusion and extraction experiments. In the extrusion experiments, using jack bean without testa and conditioned to 240 g kg−1 moisture content, different temperatures of the compression section of the extruder and screw rates were tried. Under these conditions the parameters measured were expansion, final moisture, haemagglutinins, urease activity, available lysine and soluble nitrogen index. The screw rate did not affect the extrusion of jack bean. The best temperature was 110°C. The extraction experiments were carried out with extruded jack bean (EJB) at 110°C and 70 rpm using one or two acid or formalin extractions. EJB amount, times and pH were evaluated with a surface response model in one acid extraction experiment. The best results were observed with 100 g kg−1 of EJB, at pH 55 for 2 h (1AEJB), which reduced the canavanine content to 8.5 g kg−1. In the same conditions using a second acid extraction (2AEJB) we obtained a product with 4.9 g kg−1 of canavanine. With the formalin extraction at pH 5.5 and 7.5, and a molar ratio of canavanine: formalin 1 : 1 and 1 : 2, we obtained a product with 8.2 g kg−1 of canavanine.
Thermal inactivation parameters for alkaline proteinases from north sea cod (Gadus morhua) and bovine α‐chymotrypsin
Authors: Amiza Mat Amin , Apenten Richard K Owusu
Published: November 2006

The heat inactivation of a mixture of alkaline proteinases from North Sea cod (Gadus morhua) viscera and bovine α‐chymotrypsin were compared at 40–60°C, pH 8.0. Fish digestive proteinases were at least 10‐fold less heat resistant than chymotrypsin mainly as a result of a lower apparent activation enthalpy (ΔH#) for the thermoinactivation of the former proteinases.
Effects of wheat pentosans on endogenous amino acid losses in chickens
Authors: Angkanaporn Kris , Choct Mingan , Bryden Wayne L , Annison E Frank , Annison Geoffrey
Published: November 2006

The effects of wheat pentosans on protein digestibility and endogenous amino acid losses in precision‐fed chickens was investigated using the homo‐arginine marker technique. Addition of pentosans equivalent to 15 g and 35 g of wheat arabinoxylans per kg diet significantly depressed (P < 005) the overall digestibility of amino acids and increased (P < 0‐05) endogenous losses of amino acids, but the inclusion of cellulose or polyethylene polymer (92 g per kg diet) had no measurable effects.
Lead content in grapefruit juice and its uptake upon storage in open containers
Authors: Stilwell David E , Musante Craig L
Published: November 2006

The lead contents of 52 samples of grapefruit juice, 14 packaged in glass, eight in waxed paperboard, and 30 in tin‐coated carbon steel containers, were determined. Only those juices packaged in metal cans contained measurable amounts of lead, (< 1–27 μg litre‐1) averaging 7‐7 μg litre‐1. Leaching studies were carried out on juices stored, under refrigeration, in opened containers for up to 30 days. The lead content increased considerably with time in juices stored in tin‐coated cans. For example, after 6 days of storage the lead contents of these juices ranged from 3 to 90 μg litre‐1, and averaged 30 μg litre‐1. The lead content did not increase in juices that were stored in glass, paperboard or polyethylene containers. The source of lead in the cans was traced to lead impurities in the tin coating. Higher lead impurities in the tin coating produced higher lead contents in the juice. The implications of these findings are discussed.
Production of a horse‐specific monoclonal antibody and detection of horse meat in raw meat mixtures by an indirect ELISA
Authors: García Teresa , Martín Rosario , Morales Paloma , Haza Ana I , Anguita Gonzalo , González Isabel , Sanz Bernabé , Hernández Pablo E
Published: November 2006

A stable hybridoma cell line (DD3) has been produced secreting a monoclonal antibody specific for horse muscle proteins. The DD3 monoclonal antibody (mAb) did not show significant cross‐reactivity when tested against beef, chicken, pig and soya proteins or bovine caseins, gelatine and bovine serum albumin. The DD3 mAb was used in an indirect ELISA format for the detection of defined amounts of horse meat (10–500 g kg‐1) in beef meat mixtures. Immunorecognition of monoclonal antibodies adsorbed to horse meat adsorbed onto the ELISA plate was made with rabbit anti‐mouse immunoglobulins conjugated to the enzyme horseradish peroxidase. Subsequent enzymic conversion of the substrate gave clear optical density differences when assaying mixtures of minced beef containing different amounts of horse meat.
The variation of glucosinolate concentration during a single day in young plants of Brassica oleracea var Acephala and Capitata
Authors: Rosa Eduardo A S , Heaney Robert K , Rego Francisco C , Fenwick G Roger
Published: November 2006

Changes in the total and individual glucosinolate concentrations of Portuguese leaf type cabbage (Brassica oleracea var acephala cv Galega) and white cabbage (B oleracea var capitata cv Predena) were monitored throughout the day. In the first experiment (experiment 1) conducted during two hot days, plants of Galega were grown to the four‐leaf stage, harvested at 06:00 h, 10:00 h, 14:00 h, 18:00 h and 22:00 h and analysed for glucosinolate concentration. In a second experiment (experiment 2) in milder circumstances, Predena and Galega were grown and harvested similarly. Five glucosinolates were detected using a high‐performance liquid chromatography method. In experiment 1 the major compound found in Galega was 3‐methylsulphinylpropyl glucosinolate (glucoiberin) followed by allyl‐ (sinigrin) and indol‐3‐ylmcthyl (glucobrassician) glucosinolates whilst in experiment 2, indol‐3‐ylmcthyl‐ was the major compound in both cultivars, followed by allyl‐ and 4‐methoxyindol‐3‐ylmethyl glucosinolates. A significant decrease in total glucosinolate concentration was noted between 10:00 h and 14:00 h, and the highest concentrations occurred at 18:00 h in experiment 1 and between 06:00 h and 10:00 h in experiment 2. For the total glucosinolate concentration and each of the detected glucosinolates there were very high significant differences (P < 0‐001) across the five sampling times in experiment 1. In experiment 2, Galega showed significant differences for total glucosinolate (P < 001), allyl glucosinolate(P < 005), indol‐3‐ylmethyl‐ (P < 0‐05) and 1‐methoxyindol‐3‐ylmethyl‐ (P < 0‐05), whilst in Predena only 4‐methoxyindol‐3‐ylmethyl concentrations were significantly different (P < 0‐01) across sampling times.
Determination of free fatty acids in foods by flow injection
Authors: Puchades Rosa , Suescun Alicia , Maquieira Angel
Published: November 2006

A flow injection manifold has been developed for the spectrophotometric determination of free fatty acids (FFA) at 716 nm after continuous extraction into an organic phase of soaps formed by the reaction of copper acetate with the analytes. The carrier system stream was toluene and the reagent stream aqueous copper acetate‐pyridine (50 g litre−1). The calibration graph was linear over the range 1 × 10−4 to 5 × 10−3 M oleic acid using an injection volume of 115 μl. The injection rate was 75 samples h−1 with a precision of 109% (RSD). Though this procedure does not permit the total recovery of short‐chain fatty acids it is very effective in reflecting the total concentration of FFA. The system has been applied to the determination of total FFA in olive oil, milk fat and cocoa butter. Although the values obtained by the proposed method are lower than those obtained by the reference method (titration) and by chromatography, their comparison shows good linearity.
Toxicity of the Alternaria spp metabolites, tenuazonic acid, alternariol, altertoxin‐i, and alternariol monomethyl ether to brine shrimp (Artemia salina L) larvae
Authors: Panigrahi Shantanu , Dallin Stephen
Published: November 2006

The toxicities of several Alternaria spp metabolites to brine shrimp (Artemia salina L) larvae were determined using the disc method of inoculation and an exposure period or 18 h. The 50% lethal concentration dose of tenuazonic acid, alternariol, altertoxin‐I and altenuene were around 75, 100, 200 and 375 μg ml−1, respectively. Although alternariol monomethyl ether was found not to produce any mortality, its poor solubility in the common solvents posed testing difficulties, making assessment of its toxicity unreliable.
Correlation for pigment content through colour determination using tristimulus values in a green leafy vegetable, swiss chard
Authors: Ihl Mónica , Shene Carolina , Scheuermann Erick , Bifani Valerio
Published: November 2006

The relationship between colour parameters of the chlorophylls and carotenoids in the green leaves of Swiss chard was studied. Using the Hunter colour parameters (L*, a*, b*, chroma and hue angle) we found a correlation coefficient r2 = 0.9264 for the chlorophylls and r2 = 0.8595 for carotenoids. The chlorophyll a, b plus chlorophyllide a, b extraction and the carotenoid extraction were carried out on the whole tissue using N,N‐dimethylformamide as solvent. Using between 10 and 50 mg tissue, the extractions with 3 ml solvent for 14–16 h at 4°C in darkness were quantitative for the chlorophylls; for the carotenoids, the same procedure indicated a content approximating to the level of provitamin A present in the leafy vegetable.
Mechanical and optical assessment of the ripening of tomato fruit with reduced polygalacturonase activity
Authors: Langley Keith R , Martin Alan , Stenning Robert , Murray Angus J , Hobson Graeme E , Schuch Wolfgang W , Bird Colin R
Published: November 2006

The ripening characteristics of modified tomatoes (Lycopersicon esculentum Mill cv Ailsa Craig), which express antisense RNA to polygalacturonase (PG) and thus have very low activity of this enzyme, were compared with control fruit. Previous studies of these fruits showed that although PG activity was reduced to approximately 1% of that in untransformed tomatoes, this reduction had no effect on softening. Further detailed mechanical assessments have now been performed which revealed small, but significant differences in the fruit ripening characteristics between control and antisense fruits. Compression along the polar axis of the PG antisense fruit was significantly reduced relative to the control. Deformation at failure (h), ‘modulus’ (M), coefficient of compression (Kc), and coefficient of shear (Ks) values from probe tests along the equatorial axis also indicated that the antisense fruit was firmer. Although these significant differences in texture properties were observed between the antisense fruit and the control, they were quite limited in extent, as compared to the normal evolution observed during ripening. Scanning electron microscope studies on the sub‐exocarpic region of the pericarp showed that cell wall separation was reduced in the ripe antisense tomatoes, and this may explain the change in mechanical properties. Optical measurements made with both Hunter Color Difference (Hunter Lab Ltd, Fairfax. VA, USA) and Micromatch 2000 (ICS Texicon Ltd. Altrincham, UK) spectrophotometer systems showed that the ‘a’ (green/red) component of colour of the antisense tomatoes was increased relative to that of the control samples. The effect of PG on softening and of cell wall breakdown on mechanical and optical properties is also considered.
Response of some black tea quality parameters to nitrogen fertiliser rates and plucking frequencies
Authors: Owuor P Okinda , Odhiambo Herman O
Published: November 2006

The effects of the rate of application of nitrogenous fertiliser and frequency of plucking (harvesting) on various black tea quality parameters and yields were compared on done 6/8. High rates of nitrogen application and long plucking intervals reduced the theaflavin content and brightness of black tea liquor. The caffeine content of the black tea increased with increasing rates of nitrogen application but decreased with increase in the plucking interval. The Group I volatile flavour compounds increased with nitrogen application rate and long plucking intervals while the Group II volatile flavour compounds and the flavour index decreased. Tasters preferred teas from shorter plucking intervals and low rates of nitrogen application. Yields increased with increasing rates of nitrogen but were lowered by long harvesting intervals. The rate of nitrogen application did not change the distribution of leaf into different standards.
Effect of pH on the colour formed by Fe‐phenolic complexes in ripe olives
Authors: Brenes Manuel , Romero Conceptión , García Pedro , Garrido Antonio
Published: November 2006

The effects of the pH in the flesh of ripe olives processed for table olive production, the type of acid used to correct it, the heating process used and the iron content of the flesh on the colour of the final product were studied. The best colour was obtained by bottling the fruits at pH 7. Additions of acids, especially citric acid, always caused discoloration when olives were bottled at a pH of around 7. On the other hand, when the fruits were packed at a pH higher than 7 the addition of certain amounts of acids produced darker olives. Darker colours are related to higher iron contents in the flesh, but treatment of olives with ferrous gluconate before neutralising the pH of the flesh yielded better colours than those treated after neutralising for the same iron concentration in the olives. Results obtained after adding iron to the oxidation solutions did not show the same pattern as those obtained using fruits. These results suggest that the fixation of the colour formed is not only due to the phenol‐iron complexes.
The influence of seed size on digestibility and growth performance of broiler chickens fed full‐fat rapeseed
Authors: Liu Yong‐Gang , Jensen S K , Eggum B O
Published: November 2006

Two double low rapeseed varieties were separated into small and big seeds to study their nutritive value for broiler chickens. The seed weights for small and big seeds of spring rape variety Jaguar were 3.6 and 4.9 mg, and of winter rape Impala were 4.1 and 5.3 mg, respectively. Analytical results showed no significant differences in protein and fatty acid content between the big and small seeds. The small seeds contained more fibre constituents, eg lignin 13.7% higher for Jaguar and 3.4% higher for Impala, the other dietary fibre components show ed a similar trend. The big seeds, however, tended to be higher in fat and gross energy, but also in total glucosinolates. A 2 × 2 × 3 factorial design was performed on 24 broilers, to investigate the apparent digestibility and growth performance during three successive periods of balance trials, using diets consisting of 350 g kg−1 full‐fat rapeseeds and 650 g kg−1 remainder feed mixture identical for all treatments. The diets with big seeds clearly showed higher digestibility for all measured dietary components. The surpluses as absolute percentage units respectively for dry matter were 2.8 (P < 0.001); gross energy 3.8 (P < 0.001); fat 7.9 (P < 0.001) and protein 1.6 (P = 0.045). The same trend was also found in the digestion of fatty acids and vitamin E. The big seeds displayed 7% higher (P = 0.071) growth rate and 8% higher (P = 0.002) feed conversion, respectively. Greater nutritional superiority of the big seeds was observed on the earlier growth ages, indicating the young birds are more sensitive to the seed size difference. It is concluded that the big seeds are more digestible than the small seeds and that a selection towards Digger seed size or a mechanical separation during processing will be beneficial.
Kinetics of the decolouring of carotenoid pigments
Authors: Minguez‐Mosquera M Isabel , Jaren‐Galan Manuel
Published: November 2006

The decolouring reaction of carotenoids was studied using β‐carotene, di‐esterified capsanthin and capsanthin. The study was designed to determine what effects the increase in temperature, the nature of the reaction medium and the presence of light have on the kinetics of the reaction. The reactions that take place in an anhydrous medium follow a zero‐order kinetics, while those that take place in an aqueous medium follow a first‐order kinetics. Light and temperature accelerate the degradation reaction without changing the formal aspects of the reactions. The values for the thermodynamic parameters (activation energy and enthalpy of activation) of each reaction were different according to the conditions used, but this variation was due to a compensation effect. However, the existence of this effect confirms that the decolouring reaction is the first step of the carot‐enoid degradation, and this step is identical for all of the pigments irrespective of the reaction conditions, although the formal aspects and kinetics of this first step are strongly modulated by the nature of the pigment and the experimental conditions used.
A mycological survey on mixed poultry feeds and mixed rabbit feeds
Authors: Bragulat M Rosa , Abarca M Lourdes , Castellá Gemma , Cabañes F Javier
Published: November 2006

The mycoflora of 55 samples of mixed poultry feed and mixed rabbit feed were studied. Differences in the mycoflora between the two kinds of feed were studied. Fungal counts ranged from < 10 2 to 10 5 cfu g−1, the lowest counts being in the samples of rabbit feeds. Seventy‐three fungal species belonging to 28 genera were identified. The predominant species were Aspergillus flavus, A candidus, A amstelodami, Penicillium chrysogenum and Fusarium moniliforme. Aphanocladium album, ranking sixth in the samples overall, showed exceptional incidence compared with published data. Fusarium moniliforme, A flavus and A amstelodami had the highest individual percentage counts. The F. moniliforme and A candidus percentage counts were significantly higher in mixed poultry feeds than in mixed rabbit feeds, quite the reverse of the A amstelodami and P chrysogenum percentage counts.
The effect of leaf protein concentrate from red clover on plasma cholesterol level in rats
Authors: Szymczyk Beata , Gwiazda Stanislaw , Hanczakowski Piotr
Published: November 2006

The effect of native and defatted leaf protein concentrate (LPC) from red clover on plasma cholesterol level in rats was studied. Fat‐free casein was used as a control protein. The native LPC contained 212 g kg−1 of ether extract and oleic acid (C18: 1) was its main fatty acid. LPC protein was relatively poor in sulphur‐containing amino acids. Each protein studied was given to rats with or without soya bean oil. It was found that total cholesterol level in plasma of rats fed with the oil‐containing diets was higher than that of rats fed with the oil‐free diets. Original fat present in the native LPC though rich in unsaturated fatty acids had no hypocholesterolaemic effect. LPC was hypocholesterolaemic compared with casein in diets not containing added soya bean oil, although the difference did not reach statistical significance.
Rapid detection of polymorphism in yams (Dioscorea sp) through amplification by polymerase chain reaction and rDNA variation
Authors: Muzac‐Tucker Ingrid , Ahmad Mohammed H
Published: November 2006

Ribosomal DNA (rDNA) from rice (Oriza Sativa) was used to examine polymorphism in 12 yam (Dioscorea sp) cultivars. Restriction enzyme digests of total yam DNA was probed with the pRR217 probe containing the entire repeat unit of rDNA from rice. The polymerase chain reaction was also used to amplify genomic DNA of six of the 12 cultivars studied using random primers. The amplification patterns of D rotundata‐cayenensis cv tau suggested that ‘tau’ is more closely related to D rotundata sp than it is to the D cayenensis sp. The results showed polymorphisms among the different yam cultivars.