bluuebunny/crossref_metadata_2025 huggingface dataset:
Myosins from red and white bovine muscles: Differences measured by turbidimetric, calorimetric and rheological techniques
Authors: Egelandsdal Bjorg , Martinsen Berit K , Fretheim Kristen , Pettersen Marianne , Harbitz Ole
Published: November 2006

The aim of this study was to elucidate the functional performance of the most abundant protein component in meat, ie myosin, which is recognised as important for binding in meat products. As several genetic variants of skeletal myosin exist, myosins from two bovine muscles of different fibre type composition, M masseter and M cutaneus trunci were compared with respect to filament forming properties and denaturation characteristics. The principal methods used were turbidimetric measurements, which were used to monitor filament formation, calorimetry and rheology. The myosin systems were examined at two different salt levels (0.2 and 0.6 M NaCl) and at pH 5.5–7.0. The method of preparing myosin suspensions/solutions was also examined. Differences in the filament‐forming process for the two myosins were detected. Measurements of turbidity revealed that at conditions of low pH and low ionic strength white myosin had a higher ultimate turbidity compared with red myosin. Early in the transition from low to high turbidity, red myosin had a higher turbidity than white myosin corresponding to reduced solubility. The turbidity increased with time of storing the myosin suspensions/solutions. This change was attributed to formation of filaments and further association of filaments. White myosin had a smaller apparent enthalpy of denaturation than red myosin. The calorimetric measurements recorded in 0.2 M NaCl suggested that the head and the rod of white myosin were less stable than the corresponding parts of red myosin. However, exceptions to this rule were found at pH 6.0. In 0.6 M NaCl the identification of the transitions for red myosin was more difficult. The method of preparing myosin suspensions affected calorimetric and rheological measurements. In 0.6 M NaCl and pH 6.0 calorimetric thermograms of both myosins were affected by the preparation method. At pH 5.5 this change was interpreted as caused by denaturation promoted by the dilution/rapid titration technique compared with dialysing the systems to pH 5.5 from pH 7. Differences in the filaments formed might, however, also contribute to the variations seen in the calorimetric ther‐mograms. The gelling properties of white myosin were most sensitive to the preparation method used. Systems prepared by dialysis gave stronger heat‐induced gels than those prepared by ‘dilution’. White myosin always produced stronger gels than red myosin independent of the preparation technique. The rheological properties (at 80°C) of red myosin were less affected by the preparation method than were those of white myosin. At lower temperatures, however, there was more variation in the shapes of the rheological thermograms (Ǵ versus temperature) for red myosin than in the corresponding thermograms of white myosin.
Potentiometric titration studies on xanthan solutions
Authors: Young San‐Land , Martino Miriam , Kienzle‐Sterzer Carlos , Torres J Antonio
Published: November 2006

The potentiometric behavior of xanthan solutions was analyzed as a function of ionic strength, polymer concentration and temperature. For a given value of the polymer dissociation constant, α, pKawas linearly correlated withCs1/3(salt concentration). At polymer concentrations below 7.5 g liter‐1, pKawas a function of polymer concentration. However, when the polymer concentration was higher than this value, pKawas independent of polymer concentration. Potentiometric titration confirmed the significance of the hydrogen bond and the carboxylate group on the secondary structure of xanthan which suggested that the ordered xanthan conformation is stabilized mainly by hydrogen bonds. These can be disrupted by increasing the electrostatic potential of the molecule or by increasing the solution temperature. Neither the ionic strength nor the polymer concentration affected the secondary structure of xanthan at 25°C. However, ionic strength should reduce the repulsive force between charged groups in xanthan; this would explain the salt stabilization of the secondary structure observed at the higher test temperatures (35–70°C).
The use of continuous‐flow electrophoresis to remove pectin in the purification of the minor pectinesterases in lemon fruits (citrus limon)
Authors: Macdonald Helen M , Evans Roger , Spencer Wendy J
Published: November 2006

Continuous‐flow electrophoresis was used to separate pectin and coloured substances from extracts of lemon pectinesterase. Two minor lemon pectinesterases were subsequently separated from two major pectinesterases, using chromatography on Sephadex G‐75 and CM‐Sephadex C‐50. One minor pectinesterase was stable at low pH, showed the same initial pectinesterase activity at 88°C as at 25°C, and was active at 85°C for 9 min. This enzyme destabilised the cloud of single‐strength lemon juice. It is suggested that the minor pectinesterases might not be true isozymes, but could arise from association of a major enzyme with pectin.
Transformations of (14C‐lignin) cell walls of wheat by rumen microorganisms
Authors: Mosoni Pascale , Besle Jean‐Michel , Toillon Sylvie , Jouany Jean‐Pierre
Published: November 2006

The lower halves of apical internodes of wheat harvested at the flowering stage were labelled with [U‐14C] phenylalanine (phe) or with [O14CH3] sinapic acid (sin). Cell wall residues (CWR) and saponified residues (SR) were incubated in a fermenter simulating the rumen for 7 days with rumen fluid or without microorganisms (controls). PheCWR was labelled in all lignin units (measured as aldehydes from nitrobenzene oxidation), in phenolic acids and slightly in proteins. Labelling of pheSR was more lignin‐specific. SinCWR and sinSR were specifically labelled in syringyl units of lignin. The fermentation of CWR resulted in phenylpropane‐derived unit losses in the following decreasing order: ferulic acid>p‐coumaric acid>syringaldehyde>vanillin>p‐hydroxybenzaldehyde. If allowance is made for slight losses in controls, 61, 52, 61 and 63% of the phenylpropanes of pheCWR, sinCWR, pheSR and sinSR, respectively, were transformed into an acid‐precipitable fraction, an acid‐soluble fraction and 14CO2. The comparison of pheCWR and sinCWR degradation showed that syringyl units were solubilised into acid‐precipitable molecules to a greater extent than the other lignin units; demethylation of the syringyl units of lignins was also evident from the different productions of 14CO2. Alkali‐resistant lignins of SR were mainly transformed into acid‐precipitable molecules and were weakly degraded. Lignin solubilisation and degradation seem to be governed by different mechanisms which depend on both cell wall structure and rumen microflora.
A comparison of enzyme preparations to liberate folic acid for the microbiological assay of feed ingredients
Authors: Ryu Kyeong‐Seon , Eitenmiller Ronald R , Pesti Gene M
Published: November 2006

Microbiological assays were conducted to determine the level of total folate in feed ingredients using Lactobacillus casei (ATCC 7469). Fifty‐seven samples of feedstuffs were collected from several locations in the southeastern USA by a major broiler producer. Folic acid contents of samples pretreated before assay with three enzymes (conjugase, α‐amylase, a mixture of protease (Pronase®, were 22±86 ± 1.99 (μg per 100 g ± SD) for corn (N = 14), 22±01 + 1.18 for fish meal (N = 7), 29.34 ± 0.55 for milo (N = 4), 25.80 ± 6.93 for bakery meal (N = 5), 56.76 ± 4.97 for meat and bone meal (N = 4), 85.14 ± 2.56 for wheat middlings (N = 5), and 193.97 ± 11.19 for soybean meal (N = 18). Predigestion with conjugase, α‐amylase and Pronase® liberated folic acid and increased values by 22.3% compared to conjugase predigestion alone (P≤0.05). This study shows that the traditional conjugase pretreatment does not completely free folate from complex feed ingredients for microbiological analysis.
Aflatoxin B1 contamination of shrimp feeds and its effect on growth and hepatopancreas of pre‐adult Penaeus monodon
Authors: Bautista Myrna N , Lavilla‐Pitogo Celia R , Subosa Precilla F , Begino Edna T
Published: November 2006

A survey of aflatoxin B1 (AFLB1) levels in commonly used commercial shrimp finisher feeds in the Philippines showed a various range of values from not detected to 120 μg kg−1 using high‐performance thin‐layer chromatography. Six experimental diets were prepared to contain various levels of AFLB1 based on survey results to determine the effects of such contamination in pre‐adult shrimp Penaeus monodon (17.5 ± 0.6 g). Results showed that shrimps fed diets containing AFLB1 greater than or equal to 73.8 μg kg−1 gave comparatively poor growth rate and higher susceptibility to shell diseases. No AFLB1 residues were detected in sampled whole shrimp tissues after 62 days of exposure to AFLB1 containing diets indicating a low potential for transmission of the toxin from edible shrimp tissues to consumers. Histopathological alterations in the hepatopancreas of shrimp chronically exposed to AFLB, were observed in all samples. The degree of alterations correlated with the level of AFLB1. Based on growth performance, pre‐adult shrimps can tolerate AFLB1 levels of up to 52.3 μg kg−1 in the feeds although histopathological changes were already evident in the tissues of shrimps given diets with 26.5 μg kg−1 AFLB1.
Effects of some purified alfalfa (Medic ago sativa) saponins on transmural potential difference in mammalian small intestine
Authors: Oleszek W , Nowacka J , Gee J M , Wortley G M , Johnson I T
Published: November 2006

The effect of a range of structurally divergent alfalfa saponins on the potential difference (PD) across the rat small intestine has been examined in vitro Typically, there was an immediate reduction in PD, although there was considerable variation in response to particular compounds. Among the glycosides of medicagenic acid, bisdesmosides containing four sugar moieties had activities equal to the monodesmoside and to medicagenic acid itself. The exception was 3Glc, 28Glc‐medicagenic acid, which did not affect the membrane potential. Zanhic acid glycosides reduced the PD to a much greater extent than medicagenic acid derived compounds. The tridesmoside of zanhic acid was the most active compound tested. This compound is however not precipitated by cholesterol and hence would not have been present in the ‘biologically active’ fractions used in previous studies. The present data show that both the lipophilic aglyconc portion of saponins, and the sugar composition can influence the ability of these compounds to depolarized the intestinal mucosa. The observations are discussed in the light of anti nutritional properties of alfalfa saponins when fed to monogastric animals.
Evaluation of the seeds of selected lines of three Lathyrus spp for β‐N‐oxalylamino‐L‐ alanine (BOAA), tannins, trypsin inhibitor activity and certain in‐vitro characteristics
Authors: Aletor Valentine A , El‐Moneim Ali Abd , Goodchild Anthony V
Published: November 2006

Sixty eight lines comprising 36 Lathyrus sativus, 16 L cicera and 16 of L ochrus were analysed for crude protein (CP), the neurotoxin β‐N‐oxalylamino‐ L‐alanine (BOAA), protein precipitable tannin (PPT), catechin equivalents (CE), and trypsin inhibitor activity (TIA). Randomly chosen lines from each of the species were also evaluated for other chemical and in‐vitro characteristics including neutral detergent fibre (NDF), acid detergent fibre (ADF), in‐vitro dry matter and in‐vitro organic matter digestibilities (IVDMD, IVOMD), respectively.

The species with the lowest and highest CP were L cicera(295.39 ± 18.69 g kg−1 DM) and L sativus(324.99 ± 13.40 g kg−1 DM), respectively. BOAA concentration, also, was least in L cicera (1.26 ± 0.18 g kg−1 DM) and highest in L sativus(5.63 ± 0.43 g kg−1 DM). There were higher intraspecies variations in BOAA levels among L sativus and L cicera than in L ochus genotypes. On average, BOAA levels in L ochrus and L sativus were about four to five times higher than those in L cicera. The PPT level in L sativus(4.54 ± 0.31 g kg−1 DM) was similar to that in the other species. However, there were some lines without detectable PPT in all the species. CE, which detects simple flavonoids as well as condensed tannins, was no more than 6.10 g kg−1DM in any accession, except in L ochrus in which CE ranged from 14.07 g kg−1 to 28.50 g kg−1 DM. There were high variabilities between and within species in CE values as shown by the high coefficients of variation. Mean TIA in all the L sativus lines (18.16 ± 2.38 g kg−1 DM) was similar to that in L ochrus and about twice the levels in L cicera. The coefficients of variation ranged from 10.93% in L ochrus to 17.13% in L sativus. The ash, organic matter and NDF content of the lines did not differ significantly. However, the ADF, IVDMD and IVOMD differed significantly (P < 0.05) between the species. The IVDMD and IVOMD of L cicera (88.55 ± 0.80% and 85.53 ± 0.85%, respectively) were significantly lower (P < 0.05) than in the other species. Seed weight correlated significantly (P < 0.05) with CE and TIA in both L sativus and L ochrus while CP correlated significatly (P < 0.01) with TIA in both L sativus and L cicera with respective r values of 0.70 and −0.75.
Agglomeration of ethyl esters in model spirit solutions and malt whiskies
Authors: Conner John M , Paterson Alistair , Piggott John R
Published: November 2006

Medium‐ and long‐chain ethyl esters were found to have a limited solubility when model spirits and malt distillates were diluted to 230 ml ethanol per litre for sensory analysis. At concentrations above this critical level the concentration of esters in solution remained constant, with the excess esters forming agglomerates. The saturated nature of the solution reduced the volatility of other esters, with a proportion of these compounds being partitioned into the agglomerate. The distribution was dependent on the mole fraction of each ester and its activity coefficient. Dissolution of wood extractives caused a number of changes in the solubility parameters of organic compounds; activity coefficients were increased and both the concentration and activity at which agglomeration occurred were decreased. This resulted in lower solution concentrations with increased concentrations in agglomerates. The reductions in free solution concentration could result in lower headspace concentrations, and thus have a direct effect on the flavour of the matured spirit.
Growth, yield and nodule activity of mungbean intercropped with maize and cassava
Authors: Sangakkara Ravi
Published: November 2006

A field study evaluated the influence of maize (Zea mays) and cassava (Manihot esculenta) on the growth, yield and nodulation parameters of individual plants of mungbean (Vigna radiata), established as an intercrop. The two systems were managed in a similar manner. Germination, establishment and growth of plants, and yield parameters of mungbean within the maize crop were reduced to a greater extent than that of plants grown with cassava. In addition, in both systems, growth and yields of mungbean plants in close promixity to the non‐legume were suppressed to a greater degree than in plants in the centre rows. In contrast, nodulation and nodule activity of plants in close promixity to maize or cassava was higher than in that of centre rows. The study revealed that shading of mungbean plants in close proximity to maize and cassava does not reduce nodule activity. While competitive relationships between the non‐legume and mungbean could affect the growth and yields of the legume plants in close promixity, the greater utilisation of nitrogen by the non‐legume is suggested to be the causal factor for increased nodule activity.
Rapid determination of chlorophylls in vegetable oils by laser‐based fluorometry
Authors: Tan Y A , Low K S , Chong C L
Published: November 2006

The presence of chlorophylls in vegetable oils is considered undesirable due to their adverse effects on oxidative deterioration, bleachability and hydrogenation. The usual methods for determination of chlorophylls in vegetable oils are absorption spectrophotometry, fluorometry and liquid chromatography using fluorescence detectors. This paper outlines a fluorometric method using a laser as the excitation source. The chlorophylls in crude palm oil, rapeseed oil, soya bean oil and olive oil were determined directly by laser‐based fluorometry using (a) a helium‐neon laser (632‐8 nm, 5 mW) as the excitation source and an optical‐multichannel analyser (OMA) with an intensified diode array as the detector, and (b) a helium‐neon laser and a photomultiplier tube as the detector. The method is especially suitable for the detection of chlorophylls in crude palm oil since no pre‐extraction step is required. The levels of chlorophylls measured in vegetable oils using the laser technique was also compared against values obtained by conventional spectrophotometric methods. The simplicity and rapid quantification of laser based fluorometry suggest that this technique can be readily applied to the detection or a wide variety of fluorescing species in vegetable oils.
Robust sensory evaluation of olive oil by a non‐parametric scoring system
Authors: Van Bruggen P C , Quadt J F A , L'Herminez P C , Vandeginste B G M
Published: November 2006

The quality grade of an olive oil is attributed on the basis of a number of chemical and physical parameters, and, in accordance with EC rules, additionally by the sensory evaluation by a taste panel. Evaluation of the statistics of the method of the Conseil Oléicole International (COI) as reported by Albi and Gutierrez (J Sci Food Agric 54 (1991) 255–267) revealed a number of limitations and weaknesses. An alternative test has therefore been developed. Oils are first tasted by a small panel which decides on acceptance, rejection or further sensory evaluation by a larger panel. The alternative conceptually simpler non‐parametric three‐point scoring system developed removes some drawbacks of the CSIC method. The method was applied to the panel results published by Albi and Gutierrez and the results of both methods were compared.
Occurrence of saponins and sapogenols in Andean crops
Authors: Cuadrado C , Ayet G , Burbano C , Muzquiz M , Camacho L , Cavieres E , Lovon M , Osagie A , Price K R
Published: November 2006

Samples of bitter seeds of local ecotypes and cultivars of lupin (Lupin mutabilis), white and yellow ecotypes of quinoa (Chenopodium quinoa Wild) and a local ecotype of amaranth (Amaranthus caudatus) grown in the Peruvian highlands were analysed for total saponin content and sapogenol composition. Sweet cultivars of L albus and L luteus cultivated in mild‐rainy lowlands of Chile were also analysed for comparison. Fast atom bombardment‐mass spectrometry (FAB‐MS) of the saponin extracts and gas chromatography (GC) analysis of the sapogenols after acid hydrolysis of the crude extract‐were used for the identification and quantification of saponins. It was found that L albus and amaranth had undetectable levels of saponins making them attractive for human consumption. The cultivars and ecotypes of L mutabilis contained saponin levels in the range of 229.8–390.5 mg k−1. FAB‐MS showed the presence of soya saponins I and II, whereas GC allowed the identification of soya sapogenols A and B. The same saponin composition was determined in L luteus whose total content was 55.3 mg kg−1. Saponin composition in quinoa seeds comprised oleanolic acid and three other sapogenols identified as hederagenin, phytolaccagenic acid and deoxyphytolaccagenic acid. Oleanolic acid saponins were found to be the main class of saponin in quinoa seeds sampled for this study. The yellow ecotype of quinoa presented a significantly higher content of saponins and of oleanolic acid as compared to white ecotypes. Since only one ecotype of amaranth was analysed, the nutritional significance of no detectable saponin needs further study. It was concluded that the environmental conditions in the Peruvian highlands are determinants of the amount and composition of saponins present in bitter lupine and quinoa.
Effects of explant source, culture medium: Strength and growth regulators on the in‐vitro propagation of three Jamaican yams: (Dioscorea cayenensis, D trifida and d rotundata)
Authors: Mitchell Sylvia A , Asemota Helen N , Ahmad Mohammad H
Published: November 2006

Explants of tuber, meristem and vines from three widely cultivated yam species in Jamaica—D cayenensis, D rotundata and D trifida—were examined for their responses to mineral media strength, inorganic ammonium and growth regulator supplements. Tuber pieces (5mm3) showed some positive growth responses but did not produce in‐vitro plantlets on all the media tested. Meristem tips of D trifida grew rapidly on basal media (BM) supplemented with either 0.1 mglitre−1 6‐benzylamino purine (BAP) and 0.01 mg litre−1indole butyric acid or 0.2 mg litre−1 BAP and 1.0 mg litre−1 naphthalene acetic acid (NAA) producing plantlets by 28 weeks. The nodal explants grew rapidly with plantlets obtained from all the cultivars within 4 weeks. Use of young, vigorously growing vines of 8 weeks or less, as explant source, gave low contamination levels (16–25%) in culture when sterilised for 30 min in 200 g litre−1 NaOCl in the case of D trifida and 300 g litre−1 NaOCl in the case of D cayenesis prior to culturing. Initiation of growth was optimal when explants were taken from monopodial vines grown in October or January and placed on BM supplemented with 0.5 mg litre−1 BAP (BM0.5BAP). Addition of 0.5 mg litre−1 kinetin to the BM or 0.05 mg litre−1 NAA to BM0.5BAP depressed shoot production, while 5.0 mg litre−1 kinetin increased swelling of the nodal region in explants from sympodial shoots and from vines grown in March. The results suggest that nodal segments excised from young, fast growing vines of these species are the best explant source for the purpose of commercial micropropagation.
Effect of lead ions on lipids and antioxidant complex activity of Capsicum annuum L leaves, pericarp and seeds
Authors: Stefanov Kamen L , Seizova Katya A , Pandev Stojan D , Yanishlieva Nedyalka V , Marinova Emma M , Tyankova Lina A , Kuleva Liliana L , Popov Simeon S
Published: November 2006

The composition of the main lipid classes in leaves, pericarp and seeds of pepper (Capsicum annuum L), and the effect of seedlings immersion in lead and sodium acetate nutrient solutions were investigated. Lead ions accumulated mainly in leaves; in pericarp and seeds the concentration of lead was more than 10 times lower. The influence of lead ions on the leaf lipid composition was expressed most in the last stages of plant development. Treatment with lead acetate caused a decrease in the activity of the antioxidative complex in pepper seeds.
Application of flow cytometric DNA measurements in the detection of irradiated onions
Authors: Selvan Emily , Thomas Paul
Published: November 2006

Nuclei from meristem tissue cells of onion bulbs γ‐irradiated (60–90 Gy) for sprout inhibition and non‐irrádiated control bulbs were isolated periodically during ambient (27–32°C) storage, stained with the fluorochrome 4′,6‐diamidino‐2‐phenylindole and their DNA distribution histograms measured by flow cytometry (FCM). Nuclei from irradiated onions showed a broader DNA distribution profile appearing as a wide (high) coefficient of variation (CV, 4–78%) of the G0/G1 peak as compared with non‐irradiated samples (CV, 2.39%). The DNA index (DI) of the diploid cells in control onions was 1 as against 0.74 in irradiated samples which indicated the presence of G0/G1 cells with abnormal DNA content in the meristem tissue cells of irradiated onions. The results indicate the potential application of quantitating changes in DNA content using FCM by determining CV of the G0/G1 peak as well as DI for differentiating irradiated from non‐irradiated onion bulbs.
Chilling injury development of ‘Tahitian’ lime, ‘Emperor’ mandarin, ‘Marsh’ grapefruit and ‘Valencia’ orange
Authors: Yuen Christopher M C , Tridjaja Nyoman O , Wills Ronald B H , Wild Brian L
Published: November 2006

The effect of varying levels of ethylene on the chilling injury (CI) development and the changes in the levels of putrescine, squalene and α‐farnesene of ‘Tahitian’ lime (Citrus latifolia Tanaka), ‘Emperor’ mandarin (Citrus reticulata Blanco), ‘Marsh’ grapefruit (Citrus paradisi Macf) and ‘Valencia’ orange (Citrus sinensis L Osbeck) stored at 0°C was investigated. It was found that different citrus fruits stored at 0°C had varying sensitivity to CI, and that low levels of exogenous ethyiene induced earlier and more severe CI in all citrus fiuits. The levels of endogenous putrescine, squalene and α‐farnesene varied between fruit, and was affected by the time of exposure at 0°C and the presence of ethylene. The patterns of change indicate that loss of squalene coupled with loss of α‐farnesene could be involved in induction of CI.
Nondestructive quality evaluation of fresh prunes by NMR spectroscopy
Authors: Zion Boaz , Chen Pictiaw , McCarthy Michael J
Published: November 2006

The potential for utilizing nuclear magnetic resonance measurements for evaluating the quality of fresh prunes was investigated. In a 2 T magnetic flux density, the chemical shift between proton hydrogens of soluble solids and those of water is less than 100 Hz. The band width of the water resonance spectrum of fruits is relatively large and therefore it is difficult to resolve between the spectral peaks of water and soluble solids. Measurements with a 100 mm Birdcage coil failed to resolve between the resonance peaks of soluble solids and water. Good resolution was achieved with a 20 mm diameter Surface coil. Signals (free induction decay) of 30 sugar prunes were acquired, and the spectra were calculated. Tuning and matching the coil before each measurement were not necessary, and the results were better when the magnetic field was not shimmed. The ratio of the soluble solids peak height to the water peak height correlated well (r = 0.907) with the soluble solids content of the prunes, as estimated by a refractometer.
Factors affecting the in‐vitro establishment of Jamaican yams (Dioscorea spp) from nodal pieces
Authors: Mitchell Sylvia A , Asemota Helen N , Ahmad Mohammad H
Published: November 2006

Factors such as inorganic ammonium, growth regulator supplements, propagule type and subculture period affecting the in‐vitro establishment of Dioscorea cayenensis and D trifida have been examined. The results indicate that for D cayenensis, transfer of whole plantlets to fresh initiation media prior to cutting into nodal segments and transfer to establishment media was beneficial. Addition of 800 mg litre−1 NH4NO3 to basal medium (BM) containing 0.5 mg litre−1benzylamino purine (BAP) caused a significant improvement in nodal numbers and resulted ir. 11.8 propagules per original explant after 8 weeks or 184.1 propagules after 16 weeks in‐vitro. Rapid establishment of D trifida cv Short Neck Yampie depended on the original explant source. Explants obtained from small tuber vines grew faster on establishment than those obtained from leafy cuttings. Initiation on BM supplemented with 0.5 mg litre−1 kinetin (BM0.5K) and establishment on BM supplemented with 0.5 mg litre−1 BAP (BM0.5BAP) produced the optimum result for the vines obtained from small tubers (24.0 propagules after 8 weeks of culture). For explants obtained from leafy cuttings, initiation on BM0.5BAP and establishment on BM0.5K gave optimum results (15.8). Quick establishment of initiated plantlets shown by increased shoot response and high multiplication rates were achieved in this study.
Residual glutamic‐oxaloacetic transaminase (GOT) activity in thermally processed poultry and poultry products as an indicator of end‐point temperatures
Authors: Senter Samuel D , Searcy Gayle K , Wilson Ruel L
Published: November 2006

Glutamic‐oxaloacetic transaminase (GOT) activities in chicken and turkey thigh and breast meat samples, thermally processed at 60–84°C in a model heat‐treating system, were evaluated for use as indicators of end‐point cooking temperatures (EPT). Wings, breasts, thighs and legs from commercially cooked, whole, roasted chickens and commercially processed products containing chicken and turkey meat were analyzed also to determine if residual GOT activities would indicate compliance with recent FDA/FSIS EPT recommendations. Activities of samples processed in the model system decreased logarithmically with increasing temperatures. GOT activities were higher (P < 0·05) in thigh meat than breast meat in both chicken and turkey samples; activities were higher in turkey than chicken. GOT values for chicken thigh and breast meat at 74°C, the FDA/FSIS recommended EPT for use by food handlers and retailers, were 735 and 164 Sigma‐Frankel units ml−1 (SFU ml−1), respectively. Values for turkey thigh and breast meat at this temperature were 1080 and 450 SFU ml−1, respectively. The range of activities was 7–13 SFU ml−1 in commercially prepared chicken products and 27–161 SFU ml−1 in turkey products. Analysis of these products showed adequate cooking and compliance with FDA/FSIS recommended EPT for retail sale. These data indicate that residual GOT activity in processed poultry has potential for use as an indicator of EPT.
A marine unicellular alga in diets of pregnant and lactating rats as a source of ω3 fatty acids for the developing brain of their progeny
Authors: Mokady Shoshana , Sukenik Assaf
Published: November 2006

The period of brain development in rats occurs during the late pregnancy and early lactation periods. During that time a large quantity of omega‐3 (ω3) long‐chain polyunsaturated fatty acids, mostly decosahexaenoic acid, is deposited in the brain lipids of the developing and growing pup. A dietary source of ω3 fatty acid should be provided during this period to the dams' diet to assure sufficient of ω3 fatty acids to the developing progeny. Although a wide variety of lipids from plants and marine animals was examined in this respect, we provide herein for the first time, experimental data that indicate that the marine unicellular alga Nannochloropsis can be efficiently used as a dietary source of the ω3 fatty acid eicosapentaenoic acid for pregnant and lactating dams. Furthermore, the dietary ω3 lipids of the alga are efficiently transferred to the developing foetus and pups to support the requirements for normal brain development.
In vivo breakdown of dietary [methyl−14C] and [uronate‐6−14C]pectin‐labelled spinach cell walls by rat intestinal microorganisms and incorporation of 14C into host tissues
Authors: Buchanan Callum J , Fry Stephen C , Eastwood Martin A
Published: November 2006

The metabolism of dietary plant cell wall (PCW) pectin was followed in the rat using PCW isolated from spinach cell cultures 14C‐labelled in the galacturonic acid residues or pectic methyl ester groups. 14C‐PCW were rapidly broken down in the caecum and colon of the rat and generated several groups of soluble products. [14C]Methanol was released from [methyl−14C]pectin‐labelled PCW and some of the methanol was converted to 14C‐labelled volatile acids. 14C‐Labelled volatile acids were also generated from [uronate‐6‐14C]pectin‐labelled PCW along with soluble but non‐volatile material. 14C derived from both cell wall types was taken up by the caecal and colonic mucosa and transported to the liver, pelt and other body tissues. Some 14C was excreted as 14CO2 and in urine.
Bitterness of cassava: Identification of a new apiosyl glucoside and other compounds that affect its bitter taste
Authors: King Neville L R , Bradbury J Howard
Published: November 2006

Compounds extracted by methanol from cassava parenchyma and cortex have been separated on a preparative HPLC column and identified by 1H and 13C NMR spectroscopy. A new compound isopropyl‐β‐D‐apiofuranosyl‐(1 → 6)‐β‐D‐glucopyranoside (IAG, structure I) has been found as well as small amounts of phenylalanine and tryptophan. The composition of another HPLC fraction has not been elucidated. The amounts of the identified compounds and of linamarin, lotaustralin, citrate, malate and the various sugars present in cassava have been determined by HPLC methods. The threshold levels of bitterness of aqueous solutions of linamarin, lotaustralin and IAG, have been determined and together with published data on L‐phenylalanine and L‐tryptophan have allowed our evaluation of their contributions to the bitterness of cassava. Linamarin is the sole contributor in the parenchyma but (with two cultivars out of six studied) IAG contributes more to the bitterness of the cortex than does linamarin. The perception of bitterness of linamarin solutions is confounded in the presence of neutral citrate and malate which have a sour taste. These modify the taste of cassava tubers. There are many compounds that contribute to the taste of cassava tubers, hence it is not surprising that the bitterness of cassava is not always correlated positively with the cyanide potential.
Effect of hot‐air drying on flavour compounds of bell peppers (Capsicum annuum)
Authors: Luning Pieternel A , Ebbenhorst‐Seller Truke , de Rijk Theo , Roozen Jacques P
Published: November 2006

The influence of hot‐air drying on the composition of both volatile and non‐volatile flavour compounds of different Dutch bell pepper cultivars was investigated. Contents of glucose, fructose, ascorbic, citric, and oxalic acid decreased significantly after drying, while the levels of sucrose, malic, fumaric, and cis‐aconitic acid increased. Glucose, fructose and ascorbic acid probably participate in Maillard reactions during heating. Different effects of drying could be distinguished on the composition of volatile compounds. The majority of these compounds evaporated during drying. Some compounds were partly retained in the dried bell peppers, whereas others disappeared completely. Gas chromatography‐sniffing port analysis revealed that compounds with mainly “fresh” odour notes like lettuce/grassy/green bell pepper ((Z‐2‐3‐hexenal), fruity/almond ((E)‐2‐hexenal), fruity (octanal), lettuce/green bell pepper ((Z)‐3‐hexenol), and grassy/green bell pepper ((Z)‐2‐hexenal) decreased or disappeared after drying. Another group of compounds increased or were formed during drying, like 4‐octen‐3‐one, (E)‐2‐heptenal, (E)‐2‐octenal, (E,Z)‐ and (E,E)‐2,4‐heptadienal, decanal, and (E)‐2‐nonenal; most are known as autoxidation products of unsatu‐rated fatty acids. The increased levels of 2‐methylpropionic and 2‐ and 3‐methylbutyric acid, 2‐metlhylpropanal, and 2‐ and 3‐methylbutanal seemed to be due to Strecker degradation. Gas chromatography‐sniffing port analysis showed that the latter three compounds had distinct cacao, sweaty, and spicy odour characteristics.
Identification and biological activity of lectins of different subunit composition isolated from Phaseolus vulgaris L var athropurpurea
Authors: Martínez‐Aragón Ana , Cavallé Carmen , Frühbeck Gema , Tosar Alicia , Santidrián Santiago , Stewart James C , Rubio Luis , Pusztai A
Published: November 2006

Protein concentrate, albumin (AF) and globulin fractions (GF) (60.2, 42.3 and 69.7% of protein content, N × 5.40, respectively) were obtained from raw seeds of Phaseolus vulgaris var athropurpurea (PHVa) cultivated in northern Spain. SDS‐PAGE analysis revealed that the isolectins were present solely in the AF while the GF was entirely lectin‐free. Affinity chromatography and SDS‐PAGE were used to separate and identify lectins of different subunit composition: E4 + E3L, E2L2, El3 and L4 (in g: 0.12, 0.03, 0.03 and 0.44, respectively, from 2.9g of PHVa meal). In this cultivar the amount of E4 was negligible. With the methodology followed in this study the L4 isolectin could not be isolated from the AF and it was determined by densitometry. The biology activities of these PHVa phytohaemagglutinins—erythroagglutinating and lymphocyte transformation activities—were assessed in rat and human cells. There was a direct correlation between the erythroagglutinating activity and the E subunit composition of the isolectins using rat red blood cells. The lymphocyte transformation activity of the isolectins with human peripheral blood lymphocytes was correlated with the L‐subunit content in the lectins. However, the relationship between lymphocyte transformation activity and lectin profile with rat lymphatic node lymphocytes was not as straightforward as expected.
The influence of pea seed trypsin inhibitors on the in vitro digestibility of casein
Authors: Al‐Wesali Mohammad , Lambert Nigel , Welham Tracey , Domoney Claire
Published: November 2006

The influence of pea seed trypsin inhibitors on the digestion of casein has been compared with that of soya bean trypsin inhibitors, using an in vitro digestion system, based on porcine pepsin and pancreatic enzymes. The data obtained suggest that pea trypsin inhibitors are much less effective inhibitors of digestion than the two soya bean inhibitors tested. The different behaviour of the inhibitors in the system used is not due to a differential sensitivity to pepsin, but may, in part, reflect a differential modification of the inhibitors by pancreatic enzymes.
Comparisons of good‐ and poor‐cooking lentils
Authors: Bhatty R S
Published: November 2006

Good‐ and poor‐cooking Canadian cultivars of lentils, CDC Richlea, Rose and Laird, were compared for shear force, seed phosphorus (P), phytic acid (PA), water uptake and for seed coat composition and structure. Good‐cooking CDC Richlea and Rose lentils (shear force 4.9 kg g−1) contained 24–33% more P and 48% more PA than poor‐cooking lentils (shear force 7.0–8.1 kg g−1). The poor‐cooking CDC Richlea lentil (shear force 8.1 kg g−1) had smaller hydration coefficients, solids lost, and water absorption than the good‐cooking ientil (shear force 4.9 kg g−1), but differences disappeared in dehulled good‐ and poor‐cooking lentils of the same cultivar. Regression analysis showed that the good‐ and poor‐cooking lentils absorbed water at the same rate. Therefore, smaller water‐uptake was not responsible for the poor‐cooking condition. Seed coat compositions of good‐ and poor‐cooking Laird lentils were generally similar; the major components of the seed coats were cellulose and hemicellulose, forming about 56% of the non‐starch polysaccharide and lignin fractions. Light microscopy of isolated seed coats showed a more tightly packed epidermis layer and a larger, thicker cell‐walled hypodermis layer in the poor‐cooking lentil than in the good‐cooking lentil.
The use of cumulative gas production to determine the effect of steam explosion on the fermentability of two substrates with different cell wall quality
Authors: Williams Barbara A , Van Der Poel A F B , Boer Huug , Tamminga Seerp
Published: November 2006

Wheat straw, ammoniated wheat straw and corn silage, were treated under constant conditions of steam explosion, differing only in the time for which the material was subjected to steam, prior to discharge from the vessel. The three feedstuffs were evaluated for their fermentability by measurement of cumulative gas production with time. Fermentation curves were fitted to a model and the resultant parameters tested for significant differences by an analysis of variance (using the Tukey test). Neutral detergent fibre and neutral detergent insoluble nitrogen were analysed before and after both steam treatment and fermentation. The substrates were significantly different from each other in terms of gas production parameters. Generally, there was an effect of the time of steaming, which tended to be negative in the case of straw. A significant interaction was found between type of substrate and duration of steam injection. The results suggest that steam explosion, under these conditions, was not a practical approach as a pretreatment for animal feed particularly of poor quality cell walls such as those from wheat straw.
A comparison of Karl Fischer titration with alternative methods for the analysis of silage dry matter content
Authors: Kaiser Alan G , Mailer Rodney J , Vonarx Margaret M
Published: November 2006

Eight methods for determining the dry matter (DM) content of silages were compared using a diverse set of 14 silages. The methods were oven drying at 80°C and 100°C, microwave drying, freeze‐drying, toluene distillation using large or small distillation apparatus, Karl Fischer titration, and chemical saponification. There were significant differences between silages (P <0.001) and methods of analysis (P <0.001) and a significant silage × method interaction (P <0.001). The Karl Fischer and saponification methods gave higher DM values than the other methods, and differences between the methods increased with reducing silage DM. A simple multiplicative model fitted to the data showed that most of the silage × method interaction could be attributed to the volatile content of the silages, and the differences between the methods in the proportion of volatiles retained after DM analysis. In a comparison of sample preparation methods, chopped silages and silages ground with dry ice gave similar DM values when using the Karl Fischer and oven drying (80°C) methods. The Karl Fischer method allows the direct chemical determination of silage water content, and is a simple and rapid procedure well suited to the routine analysis of large numbers of silages.
Determination of condensed tannins in complexes with fibre and proteins
Authors: Makkar Harinder P S , Singh Bhupinder
Published: November 2006

The levels of condensed tannins in tannin‐protein complexes dried at 50°C or at 100°C for 2 h, 4 h and 24 h, determined by butanol‐HCl reagent, were significantly lower compared to those in freeze‐dried or undried complexes. On the other hand, condensed tannins in the fibre fractions (neutral detergent fibre and acid detergent fibre) were statistically similar in samples freeze‐dried or dried at 50°C. Significantly lower levels of condensed tannins were observed in fibre fractions dried at 100°C as compared to freeze‐dried fibre fractions. The results suggest that for accurate determination of condensed tannins bound to fibre fractions or present as tannin‐protein complexes, the fibre fractions or the samples containing tannin‐protein complexes should be freeze‐dried.
Semi‐sweet biscuits: 1. The influence of sodium metabisulphite on dough rheology and baking performance
Authors: Oliver Ged , Thacker David , Wheeler Robert J
Published: November 2006

The influence of sodium metabisulphite (SMS) on the performance of single wheat varieties in the production of semi‐sweet biscuits has been studied. In general doughs produced with SMS required a shorter mixing time, produced shorter dough extrusion times and lower elastic and viscous moduli than doughs produced at the same water level without SMS. Doughs were also produced at a higher water level in the absence of SMS to give similar rheological properties to the corresponding doughs containing SMS. However, dough pieces from doughs containing SMS showed less contraction on processing than dough pieces from all doughs without SMS, including those with similar rheological characteristics to doughs containing SMS. It is believed that this is due to the rheological properties of the dough being achieved through different mechanisms. In the presence of SMS the gluten proteins undergo chemical modification whereas the increased water in the absence of SMS causes a reduction in the magnitude of the rheological parameters through a dilution process. The inclusion of SMS, or increasing water content, caused a reduction in the hardness of biscuits from the varieties Galahad and Riband. The hardness of biscuits from other varieties studied was not affected by a reduction in dough strength. Measurements of flour protein quality were able to rank varieties in order of their likelihood to exhibit dough contraction on processing. However, the measurement of the rheological parameters of dough gave a better prediction of the dimensions of the baked biscuit.
Protein‐enriched yoghurt by ultrafiltration of skim‐milk
Authors: Brazuelo Agustin , Suárez Elena , Riera Francisco A , Alvarez Ricardo , Igesias José R , Granda Juan
Published: November 2006

Ultrafiltration (UF) and reverse osmosis (RO) have been used to increase the total solids of skim‐milk in order to produce a protein‐enriched yoghurt. Milk concentrated by either process can be fermented adequately, but RO does not change the proportions of milk components. Ultrafiltration with 10 kDa cut‐off membranes, allows us to obtain concentrated milk with different protein/lactose ratios. Ratios of 1–2–1–3 lead to a good textured yoghurt with up to 35% more proteins than commercial products.
Changes in the dry matter, sugar, plant fibre and lignin contents of swede, rape and kale roots in response to turnip root fly (Delia floralis) larval damage
Authors: Hopkins Richard J , Birch A Nicholas E , Griffiths D Wynne , Morrison Ian M , McKinlay Roderick G
Published: November 2006

Plants from two genotypes of swede (Brassica napus var napobrassica), kale (B oleracea var. acephala) and rape (B napus var napus) were each inoculated at the three to four true leaf stage with 10 eggs of the turnip root fly, Delia floralis. After 8 weeks the damage caused by the resultant larvae significantly reduced the weight of leaves, stems and roots compared with uninoculated plants, with the greatest reduction (26–46%) being found in the roots. Dry matter content, which did not differ between either crop type or cultivar, was unaffected by larval damage. Ethanol‐soluble sugar content was reduced in all cases by larval damage, but only significantly in one rape and one swede cultivar. The effect of D floralis damage on the concentrations of individual sugars (glucose, fructose and sucrose) was crop type and cultivar dependent. The neutral detergent fibre and lignin contents of the undamaged swede roots were significantly lower than in either the undamaged kale or rape cultivars studied. In all crop types the neutral detergent fibre and lignin content significantly increased following D floralis damage. The six Brassica genotypes studied fell into two groups on the basis of host status for D floralis. The two kale cultivars and the forage rape Hobson were considered poor hosts for D floralis, with low percent age pupation (38–41%) and low pupae weight (12.5–14.4 mg). The two swedes and the oilseed rape Ariana were considered good host for D floralis, with both higher percentage pupation (51–59%) and pupae weights (19.8–20.0 mg). The possible relationships between the root composition of undamaged and attacked roots, and D floralis resistance are discussed.
Measurement of protein in whole plant samples with ninhydrin
Authors: Barbehenn Raymond V
Published: November 2006

The ninhydrin method has been used widely for measuring amino acids in hydrolysed purified proteins. It is also a useful method of measuring the total amino acid or protein content of hydrolysed plant samples. In this study the conditions used in a modified ninhydrin method were found to incompletely hydrolyse protein. Therefore, standard conditions for protein hydrolysis (6 M HCI at 110† C) were tested. The accuracy of protein measurements using the standard ninhydrin method was evaluated using pure proteins, protein‐carbohydrate standards and plant samples augmented with known amounts of protein. Standard hydrolysis conditions completely hydrolysed proteins, but protein content was overestimated when these conditions were used on whole plant samples and standards containing carbohydrates. This error may be quantified and corrected easily in plant samples, however, by measuring the recovery of protein added to control samples before hydrolysis.