bluuebunny/crossref_metadata_2025 huggingface dataset:
A preliminary report on the implication of RT–PCR detection of DAZ, RBMY1, USP9Y and Protamine‐2 mRNA in testicular biopsy samples from azoospermic men
Authors: Friel A. , Houghton J. A. , Glennon M. , Lavery R. , Smith T. , Nolan A. , Maher M.
Published: March 2003

In this study, reverse transcription–polymerase chain reaction (RT–PCR) was optimized to analyse the presence of DAZ, RBMY1, USP9Y, protamine‐2, SRY and actin messenger RNA (mRNA) in testicular cells of men suffering from idiopathic azoospermia. All samples (n=28), including five controls, showed normal expression of actin, SRY and USP9Y. Sperm was not recovered from eight patients after testicular biopsy. Of these, four patients showed altered mRNA levels for the fertility genes, DAZ, RBMY1 and protamine‐2. One patient, who was previously shown to be azoospermia factor region (AZF)b deleted, lacked RBM mRNA and presented with reduced amplification of protamine‐2 mRNA. This correlated with previous studies, which proposed that RBM expression is exclusive to AZFb and that the lack of testicular RBMY1 mRNA results in suppressed spermatogenesis. Two patients were each lacking DAZ mRNA but did show expression of RBMY1 mRNA at a reduced level, suggesting that there might be residual spermatogenesis in the absence of DAZ expression. Protamine‐2 mRNA was detected in one patient and was absent in the second patient. Finally, one patient lacked DAZ, RBMY1 and protamine‐2 mRNA. The 19 remaining azoospermic patients presented with normal expression patterns for each of the fertility genes studied. This study demonstrates that the expression of spermatogenesis‐specific genes varies in azoospermia. The study of the expression of such genes in a larger number of patients might be useful in characterizing and identifying subpopulations of azoospermic men.
The role of Na,K‐ATPase in human sperm motility
Authors: Koçak‐toker N. , Aktan G. , Aykaç‐toker G.
Published: March 2003

A fourth Na,K‐ATPase α isoform, which was found to be abundant in testes, was proved to be a catalytical subunit of the enzyme. Recently, it has been shown that the α 4 isoform along with α 1 is expressed in the midpiece of the flagellum of mature rat sperm and the inhibition of α 4 with ouabain led to sperm immotility. In this study, sperm from 135 males with normal semen profile and 50 males with oligoasthenospermia were treated with 10–5 and 10–2 M ouabain solutions to inhibit α 4, and α 4 plus α 1 isoforms, respectively. In males with normal semen profile, sperm motility has been demonstrated to decrease with time to almost the same level with both ouabain solutions. In oligoasthenospermic males motility was also found almost completely lost. These observations showed us that the α 4 isoform may be held responsible for human sperm motility.

When sperm plasma membrane Na,K‐ATPase activity was assayed for both normal and oligoasthenospermic males, a significant decrease in enzyme activity of males with oligoasthenospermia was observed (p < 0.05). In our recent study, sperm motility was found decreased by treatment with peroxynitrite (ONOO–). To investigate the effect of ONOO– on sperm Na,K‐ATPase activity, sperm plasma membranes were treated with 100 μM ONOO– and plasma membrane Na,K‐ATPase activity was observed to be significantly decreased (p < 0.05). Although total sulfhydryl (SH) content of sperm plasma membrane was also found significantly lower, no correlation was found between Na,K‐ATPase activity and SH content.
Modulation of androgen receptor protein by culture conditions of human skin fibroblasts
Authors: Palma Marcela M. , Fernandez Mireya , Vivanco XIMENA , Pino Ana M.
Published: March 2003

Cultures of skin fibroblasts show variation of androgen binding with culture conditions; binding variations are usually avoided by using confluent cultures. In this work, we analysed the effect of cell density and mitogenic agents on the level of androgen receptor (AR) of cultured human skin fibroblasts. Results demonstrated that in cultures of human skin fibroblasts, cellular binding of dihydrotestosterone was higher in cells grown at low than at high cell density. The reduction in binding resulted from a decrease in the number of high affinity receptors and not from a change in receptor affinity. Immunocytochemistry for AR showed greater staining intensity in cells grown at low than at high cell density. Additionally, immunoblot analysis demonstrated more AR protein in low cell density cultures. On the other hand, it was observed that cells grown at low cell density showed diminished androgen binding capacity after 24 h of treatment with insulin‐like growth factor (IGF‐l), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), or granulocyte‐colony stimulating factor (G‐CSF); this effect of growth factors was not observed in cells grown at high cell density.  In conclusion, we found that cell density of cultures and mitogenic agents can regulate AR binding activity in human fibroblasts. While we do not yet know how changes in cell density affect the amount of AR, we conclude that the mechanism could be mediated by activation of the tyrosine kinase pathway, as the effect was reproduced by mitogens.
Causes of gynaecomastia in young adult males and factors associated with idiopathic gynaecomastia
Authors: Ersöz Halil önder , önde Mehmet Emin , Terekeci Hakan , Kurtoglu Soner , Tor Hayati
Published: March 2003

Gynaecomastia is a common clinical condition. Persistent pubertal or late onset idiopathic gynaecomastia is the leading cause of gynaecomastia in different series. The aim of this study was the assessment of the prevalence and characteristics of different causes of gynaecomastia in young adult males, and evaluation of the factors associated with idiopathic gynaecomastia. Fifty‐three male patients (mean age 22.04 ± 2.22, range 19–29), who had been admitted to our outpatient clinics with gynaecomastia as the main presenting symptom were enrolled in the study. Patients were evaluated with breast palpation, breast ultrasonography, anthropometric measurements and sex steroid levels. Secondary causes of gynaecomastia were ruled out. Thirty age‐matched healthy individuals were also studied as healthy control group. Idiopathic gynaecomastia was diagnosed in 31 of 53 patients (58%), with 17 (32%) persistent pubertal and 14 (24%) late onset course. Other causes of gynaecomastia were hypogonadism in 13 cases (25%), hyperprolactinaemia in five (9%), chronic liver disease in two (4%), and drug induced (prolonged use of H2 antagonists) in two (4%). Patients with idiopathic gynaecomastia, either pubertal or late onset, were compared with the healthy control group in order to find out associated factors. Anthropometric measurements revealed a significant increase in body weight and body mass index (BMI) in the patient group compared with healthy controls (72.4 ± 13.3 vs. 63.6 ± 7.9 kg, p = 0.0086 and 25.2 ± 4.0 vs. 21.5 ± 2.7 kg/m2, p = 0.0001). Total skin fold thickness (SFT) of four different regions were also higher in the patient group (50.9 ± 22.1 vs. 32.6 ± 10.2 mm, p = 0.0006) indicating a higher body fat percentage. Total serum testosterone (4.76 ± 1.31 vs. 5.70 ± 1.06 μg/mL, p = 0.0038) and luteinizing hormone (LH) (4.80 ± 1.92 vs. 7.32 ± 1.90 mIU/mL, p < 0.0001) levels were significantly lower in the patient group while oestradiol levels were similar. There was a significant correlation between total testosterone and LH levels (r = 0.27, p = 0.0445). Total testosterone and LH levels were negatively correlated with BMI and total SFT. As a result most common form of gynaecomastia is idiopathic gynaecomastia either as persistent pubertal or late onset forms in young adult males. Idiopathic gynaecomastia is closely correlated with generalized obesity, reduced LH and testosterone levels which may be the result of increased conversion of testosterone to oestradiol in increased adipose tissue mass.
Cytokines and their receptors in cardiovascular diseases — role of gp130 signalling pathway in cardiac myocyte growth and maintenance
Authors: Yamauchi‐Takihara  , Kishimoto
Published: March 2003

Interleukin (IL)‐6‐related cytokines share gp130 as the signal‐transducing protein. Cardiac myocytes produce various kinds of cytokines including IL‐6 and cardiotrophin‐1. Activation of gp130 transduces hypertrophic and cytoprotective signals in cardiac myocytes via JAK/STAT, MAP kinase and PI‐3 kinase pathways. Besides various well‐established mechanisms by which cardiac growth and myocardial remodeling are regulated, gp130 signalling may be a newly discovered mechanism that regulates these events in association with cytoprotective effect in myocardial diseases.
Upregulation of collagen VIII following porcine coronary artery angioplasty is related to smooth muscle cell migration not angiogenesis
Authors: Sinha Sanjay , Kielty Cay M. , Heagerty Anthony M. , Canfield Ann E. , Shuttleworth C. Adrian
Published: March 2003

Type VIII collagen is upregulated after vessel injury, and this collagen has been implicated in both smooth muscle cell migration and angiogenesis. This study examines the temporal and spatial pattern of expression of type VIII collagen in porcine coronary vessels at specific time points after balloon angioplasty.In situ hybridization studies demonstrated that collagen VIII messenger ribonucleic acid (mRNA) was markedly elevated in the neoadventitia at 3 days post‐angioplasty. By 14 days, elevated collagen VIII message was seen mainly in the neointima and this expression decreased to background levels by 90 days. The distribution of collagen VIII protein, detected using immunohistochemistry, was similar but the up‐regulation lagged behind the mRNA increase by a few days. Pre‐treatment of sections with pepsin highlighted variations in the organization and appearance of extracellular collagen VIII containing structures in both injured and normal vessels.New vessel formation was evident in the neoadventitia after 3 days, but there was no colocalization of type VIII collagen immunostaining with that of von Willebrand factor (a marker of endothelial cells) in the neoadventitia.These data show that up‐regulation of collagen VIII in the neoadventitia is an important early marker of the coronary arterial response to injury, and is not associated with new vessel formation.
Heterogeneity in the granulomatous response to mycobacterial infection in patients with defined genetic mutations in the interleukin 12‐dependent interferon‐gamma production pathway
Authors: LAMMAS D. A. , DE HEER E. , EDGAR J. D. , NOVELLI V. , BEN‐SMITH A. , BARETTO R. , DRYSDALE P. , BINCH J. , MACLENNAN C. , KUMARARATNE D. S. , PANCHALINGAM S. , OTTENHOFF T. H. M. , CASANOVA J.‐L. , EMILE J.F.
Published: March 2003

Patients with genetic lesions in the Type‐1 cytokine/cytokine receptor pathway exhibit a selective susceptibility to severe infections with poorly pathogenic mycobacteria and non‐typhi salmonella spp. These experiments of nature demonstrate that IL‐12‐dependent IFNγ production is critical for granuloma formation and therefore host immunity against such pathogens. The essential role of granuloma formation for protective immunity to these organisms is emphasized by the differing granuloma forming capabilities and resultant clinical sequelae observed in these patients which seems to reflect their ability to produce or respond to IFNγ (Fig. 9). At one pole of this spectrum, represented by the complete IFNγR1/2 deficient patients, there is a complete absence of mature granuloma formation, whereas with the less severe mutations (i.e. partial IFNγR1/2, complete IL‐12p40 and complete IL‐12Rβ1 deficiency), granuloma formation is very heterogenous with wide variations in composition being observed. This suggests that in the latter individuals, who produce partial but suboptimal IFNγ responses, other influences, including pathogen virulence and host genotype may also affect the type and scale of the cellular response elicited.

 Spectrum of genetic susceptibility to intracellular bacteria. At one pole of this spectrum complete IFNγR deficiencies are found; at the other pole are healthy resistant individuals. Partial IFNγR1 deficiencies, and complete IL‐12Rβ1 and IL‐12p40 deficiencies can be positioned in between, albeit closer to the former end of the spectrum, with clinical outcome also depending on pathogen virulence and host compensatory immune mechanism(s). Abbreviations: IFNγR – interferon gamma receptor, IL‐12Rβ1 – interleukin 12 receptor‐1 (modified from Ottenhoff et al. (1998)).

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Time course of bleomycin‐induced lung fibrosis
Authors: Izbicki G. , Segel M.J. , Christensen T.G. , Conner M.W. , Breuer R.
Published: March 2003

Intratracheal instillation (IT) of bleomycin is a widely used experimental model for lung fibrosis. In this study we describe the time‐course of bleomycin‐induced lung fibrosis in mice using computer‐assisted morphometry. C57Bl/6J mice were treated with a single IT dose of bleomycin or control saline. Animals were killed 3, 6, 14 and 21 days post‐IT. Lung injury was evaluated by analysis of bronchoalveolar lavage (BAL) fluid, hydroxyproline concentration in the lung, routine light microscopic examination resulting in a semiquantitative morphological index (SMI) of lung injury, and quantitative morphological measurements (fibrosis fraction and alveolar wall area fraction) aided by optimas image analysis software. Changes in BAL fluid attributed to bleomycin treatment include increased total cell count (days 14 and 21), and increased percentage of neutrophils (days 3 and 6) followed by a sustained increase in lymphocytes (days 6, 14 and 21). Hydroxyproline levels increased in bleomycin‐treated mice on days 14 and 21. Median SMI grades were significantly elevated on days 3, 14 and 21. Computer‐assisted morphometry demonstrated a 3‐fold increase in fibrosis fraction and a 1.3‐fold increase in wall area fraction in bleomycin‐treated mice on day 14, with no further increase on day 21. These data also demonstrate that the most suitable time point for assessing lung fibrosis in this model is 14 days after IT instillation of bleomycin, based on the observation that at 14 days the animals developed extensive fibrosis, but had less variability in the fibrotic response and lower mortality than later at 21 days. Computer‐assisted morphometry provides objective and quantitative measurements that are a useful tool for the evaluation of bleomycin‐induced lung injury.
Sensory analysis
Authors: Piggott John R. , Simpson Stephanie J. , Williams Simon A. R.
Published: March 2003

Sensory methods can be loosely separated into two groups: discriminant methods and descriptive methods. Simple models of difference tests rest on a number of assumptions, and not only are they not very good at showing that samples are the same, they are not good at detecting small differences. Quantitative Descriptive Analysis was developed from the Flavor Profile Method, and used an interval scale with emphasis on statistical evaluation of results. A variation of descriptive analysis is Free‐Choice Profiling, where data are normally examined by generalized Procrustes analysis. Initial suspicion of the results has been overcome by more rigorous testing of their reliability. Time‐intensity measurement is a special case of descriptive analysis, where a single characteristic is tracked as it changes over a period of time. Time‐intensity has only relatively recently achieved wide application, and there have been rather few methodological studies.
Chemical tainting of foods
Authors: Mottram Donald S.
Published: March 2003

Taints and off‐flavours in food are a major cause of consumer rejection of the food product, and consequently the occurrence of such flavour defects is of great concern also to the manufacturer. Unacceptable flavours in foods may develop within the food through chemical or microbial action on food components, or they may be inadvertently introduced into the food during processing or storage, by absorption of chemicals from airborne, waterborne or packaging‐related sources. The chemicals responsible for taints and off‐flavours are usually volatile organic compounds, which are frequently found at concentrations of less than 1 μg kg−1, and cause flavour problems because of their low odour‐threshold values. This paper discusses the possible origins of off‐flavours and taints in foods, and describes some incidents in which food taints have been caused by chemical contamination from the environment.
Physical chemistry of flavour
Authors: Taylor Andrew J.
Published: March 2003

The sensation of flavour occurs when certain flavour‐active molecules are released from food and are transported to stimulate sensors in the mouth and nose. The human brain integrates all the signals from the sensors and produces an overall flavour perception. The way in which flavour molecules are released from food during eating, and the manner in which they are retained during processing and storage, are all governed by various aspects of physical chemistry. This review describes some of the basic principles of partition, a key parameter in the physical chemistry of flavour. An overview of the theory and measurement of partition is given, along with some applications to model and real food systems.
The molecular biology of olfactory perception
Authors: Goodenough Peter W.
Published: March 2003

This review discusses the anatomy of human odorant reception, with particular reference to the seven‐helical transmembrane‐protein superfamily of olfactory receptors, the concept of a novel multigene olfactory‐receptor family, the location of the olfactory‐receptor genes in the human genome and the characterization of the receptor proteins by cloning and overexpression. It then turns to the evidence for secondary message transduction following odorant binding, and the latest evidence on the structural analysis of G‐protein coupled signalling as well as how the binding of odorant molecules to the transmembrane olfactory receptors is transmitted through the neural pathways to the brain, including the remarkable success in generating cDNA libraries from single neurons.
Novel food products from genetically modified crop plants: methods and future prospects
Authors: Dunwell Jim M.
Published: March 2003

Using a variety of in vitro techniques, it is now possible to isolate a selected gene sequence from any source and introduce it into any major crop plant. Millions of hectares of such genetically modified (GM) or transgenic plants are already being grown commercially, mostly in North America. To date, the most widely grown GM crops (soybean and maize) are those with modified agronomic traits (herbicide or insect tolerance); the products from these commodity crops are now included in a wide range of processed foods. This review describes the methods used to generate these GM crops and then discusses the range of modified food products that can be generated using this new technology. Such products include those with altered protein, starch or oil quality, as well as examples of improved micronutrient or vitamin content. Much of this work, particularly that aiming to develop food with specific health benefits, is still at the experimental stage, but there is no doubt that many GM foodstuffs, with an increasing variety of qualitative changes, will reach the market in the coming years. The rate at which such products are developed commercially depends to a large extent on the public reaction to a technology still poorly understood by most consumers.
The optimization of a laboratory processing procedure for southern‐style Chinese steamed bread
Authors: Huang  , Quail  , Moss
Published: March 2003

A response surface methodology (RSM) design was used to optimize the laboratory processing procedure for southern‐style Chinese steamed bread (SSCSB). A screening test was applied to weak, medium and strong flours to establish critical variables. Consumer preference testing on the eating quality of southern‐style steamed bread (SSSB) established a scoring system for quality assessment of this product. For further RSM optimization testing, only the strong and medium flours were used. The following settings were established as optimal laboratory processing procedures for this style of steamed bread: farinograph mixer (300‐g bowl; speed 60 rpm); compressed yeast (1.5%); water addition [80% of farinograph water absorption (FWA)]; mixing time (50% of farinograph dough development time (FDDT); fermentation time (150 min); remixing time (180% FDDT); fermentation temperature (32°C); relative humidity (RH; 85%); sheeting time (20 passes); proving time (35 min); steaming rate (155 g of steam m−3 min−1); and steam time (20 min). The adequacy of the predictive models generated using the RSM procedure and reproducibility of the method for this style steamed bread were verified.
Mass transfer modelling of the osmotic dehydration of some fruits
Authors: Panagiotou Nicolaos M. , Karathanos Vaios T. , Maroulis Zacharias B.
Published: March 2003

An empirical model was developed to predict the water loss and solid gain during osmotic dehydration of apple, banana and kiwi fruit. The model is based on a first‐order kinetic equation, in which the rate constant is a function of the main process variables (speed of agitation, solute concentration, size of fruit and process temperature). This model was applied to a wide range of experimental data on the osmotic dehydration of apple, banana and kiwi fruit, and its parameters were estimated using non‐linear regression analysis. The results showed that all of the above process variables have a significant effect on the mass transfer phenomena during osmotic dehydration.
Effect of barrel temperature and screw speed on rapid viscoanalyser pasting behaviour of rice extrudate
Authors: Guha Manisha , Ali Syed Zakiuddin , Bhattacharya Suvendu
Published: March 2003

The effect of extrusion barrel temperature (80–120 °C) and screw speed (200–400 rpm) on the pasting and gelatinization properties of extruded rice products were studied. A twin‐screw extruder was used without using a die. A rapid viscoanalyser (RVA) was used for the pasting study; the parameters determined were the initial viscosity (IV), peak viscosity (PV), hot‐paste viscosity (HPV) and cold‐paste viscosity (CPV). The PV, HPV and CPV generally decreased with increasing barrel temperature and screw speed. The IV was high, 30–43 rapid viscoanalyser units (RVU), for extrudates compared with raw rice, 3–4 RVU. The extent of gelatinization (GE) of the extruded rice samples ranged between 93.8% and 99.0%, and an increase in screw speed enhanced the GE values. Regression equations (r > 0.991, P < 0.01) that relate pasting and gelatinization behaviour to temperature and screw speeds are reported.
Shear stiffness and density in potato parenchyma
Authors: Scanlon Martin G. , Day Andrea J. , Povey Malcolm J. W.
Published: March 2003

To understand textural changes that occur during processing of potatoes, a more comprehensive understanding of the mechanical properties of potato tubers is desirable. Specimens of potato parenchyma had their turgor osmotically adjusted to be either fully turgid or flaccid. Control specimens at normal turgor were also studied. Density of the specimens was measured using Archimedes' principle. The storage (G′) and loss (G″) moduli of the complex shear stiffness were measured in a rheometer. A weak positive relationship between G′ and density was apparent, but only for the osmotically adjusted specimens. This was true regardless of whether specimens were fully turgid or flaccid. However, no such relationship was observed for the control (normal turgor) specimens, which was probably due to slight variation in turgor pressure affecting G′ independently of the effect of density on G′, and so masking the effect of density on shear stiffness. A positive relationship between G″ and density was observed, but only for flaccid specimens. This relationship was putatively assigned to shear strain energy dissipation by starch granule movement in a viscous protoplasm.
Emulsifiers affect the texture of pastes made from fermented and non‐fermented cassava flours†
Authors: Numfor Festus A. , Walter William M. , Schwartz Steven J.
Published: March 2003

The effects of glycerol monostearate (GMS) and sodium steroyl lactylate (SSL) on the rheological properties of native, naturally fermented (NF) and mixed culture fermented (MCF) cassava flour pastes were measured using instrumental texture profile analysis (TPA) and by finger cohesiveness (difficulty in separation). Fermentation reduced the TPA parameters, hardness, cohesiveness and gumminess, but not springiness/elasticity. These were reduced further when either GMS or SSL were incorporated into the pastes. Pastes made from native and naturally fermented flours were scored by a Cameroonian sensory panel as difficult to separate, whereas scores for native and fermented flour pastes treated with 1% or more of GMS or SSL were easy to separate. Increased internal stability of the cassava flour starch granules was suggested as the cause of the effects.
Characterization of rheological properties of systems containing sugar substitutes and carrageenan
Authors: Ozdemir Murat , Sadikoglu Hasan
Published: March 2003

The effects of addition of κ‐carrageenan to solutions containing 40% (w/w) sugar substitute on the rheological properties of these systems were investigated at 25 °C using a rotational viscometer at rotational speeds of 6, 12, 30, and 60 rev min−1. The flow behaviour of the solutions was adequately described by the power law model with or without yield stress. The consistency index (K) and the flow behaviour index (n) were determined from shear stress vs. shear rate data. The flow parameters of the solutions depended on the carrageenan concentration. The apparent viscosities of the systems decreased with increasing shear rate, indicating pseudoplastic behaviour. The final carrageenan concentration was found to be an effective factor controlling the degree of sliminess of the model food systems studied.
Effect of dry heat on the in vitro digestibility and trypsin inhibitor activity of chickpea flour
Authors: Márquez  , Fernández  , Alonso
Published: March 2003

The effect of a dry heat treatment on trypsin inhibitors, protein quality and molecular weight of products obtained from enzymatic hydrolysis of chickpea flours was analysed in order to use chickpeas as food protein hydrolysates. Chickpea flour obtained from dehusked seeds was processed under different conditions, either by heating or enzymatic treatment. Heat treatment at 140 °C for varying times (1–24 h) inactivated trypsin inhibitors and facilitated enzymatic treatment but showed an unacceptable loss in the nutritional quality of the protein for heating times longer than 6 h. Enzymatic treatment with a commercial protease, Alcalase 0.6L, at pH 8 and 50 °C, increased the protein nutritional value of the chickpea by breaking the protein chains into shorter peptide chains more suitable to human nutrition.
Functional properties of porcine blood globin decolourized by different methods
Authors: Yang Jeng‐Huh , Lin Chin‐Wen
Published: March 2003

The purpose of this study was to compare the functional properties of freeze‐dried porcine blood globin isolates, which were obtained after decolourization with sodium carboxymethylcellulose (Na‐CMC), acid‐acetone (A‐A), hydrogen peroxide (H2O2), or alcalase (an endopeptidase). Porcine red blood cell concentrates (RBCCs) without decolourization were freeze‐dried as controls. The proximate composition, solubility, emulsifying activity index, emulsifying stability, foaming capability, foam stability and gel strength of the globin isolates were determined. The solubility of the globin isolates was affected by decolourization treatment and pH (within the range 2–9). The globin isolates obtained by A‐A decolourization were particularly affected by pH. The solubility of the alcalase‐treated globin isolate was the highest of all the globin isolates, followed by the Na‐CMC‐ and H2O2‐treated globin isolates. The emulsifying activity index of A‐A‐treated globin isolate was unaffected by pH adjustment. The emulsifying stability of all isolates was not significantly different over the pH range 2–9. The foaming capacity was significantly different among treatments and pH levels (P < 0.01). The foaming capacity at pH 2–3 was greater than at pH 4–9, with the exception of the alcalase‐treated globin isolates. A‐A‐treated globin isolates had poor foaming capacity at pH 4 and 5, and foams produced at pH 8 and 9 from alcalase‐treated isolates had poor stability. The 10% solution of RBCCs (control) showed the greatest gel strength, followed by A‐A‐treated, Na‐CMC‐treated and H2O2‐treated globin isolates. The alcalase‐treated globin isolate solutions did not form gels. The decolourization methods surveyed in this study were all at least partially successful in ameliorating the dark‐brownish colour of RBCCs. However, the functional properties of the isolates, excluding gel strength, were generally comparable with those of RBCCs.
Bovine spongiform encephalopathy (BSE) – a review
Authors: Blanchfield J. Ralph
Published: March 2003

Bovine spongiform encephalopathy (BSE) incidence. The number of new cases continues to fall as forecast (from the peak of 37 487 in 1992 to 13 825 in 1995, to 7406 in 1996 to 3980 in 1997) and is on track to bring the epidemic to an end.

BSE/nvCJD. Findings since 1996 indicate that the agents of BSE and new‐variant Creutzfeldt—Jakob disease (nvCJD) possess the same ‘fingerprint’. This is consistent with the transmission of BSE infection to humans. Although it remains possible that both BSE and nvCJD may have been triggered by some currently unknown cause, it is difficult to conceive what that might be.

nvCJD incidence. The UK Department of Health reported 24 cases of nvCJD up to the 6 April 1998. Assuming that nvCJD is the result of consumption of BSE infective materials before 1989, it is too soon to draw any conclusions about likely future incidence.

Infectivity of bovine materials. In its report dated 9 December 1997, the EU Scientific Steering Committee has set out the most up‐to‐date information and assessment of the infectivities of various bovine materials.

Beef, milk and bones. Assays in mice have not detected BSE infectivity in muscle meat (beef) or milk from confirmed cases. The more sensitive assay in calves is yet to be concluded, but to date results are negative. Thus, although low levels of infectivity cannot be excluded, the risk from beef or milk is currently considered to be extremely small. Calf experiments have detected infectivity in the dorsal root ganglia, the trigeminal ganglia and the bone marrow. The risk involved to people eating beef is extremely low, about one case of nvCJD in a billion years per person. However, this estimate has a wide range of uncertainty, and the UK government has responded by banning the sale of beef on the bone.

Galatin and tallow. In its report of 19–20 February 1998, the EU Scientific Steering Committee carried out risk assessments of various raw materials and production processes for gelatin and tallow, and has issued ‘scientific opinoins’ thereon.

Blood. Recent research on mice shows that the lymph system is involved in the passage of infectivity from gut to brain. This implicates the lymphoreticular system and suggests that circulating lymphocytes may carry infectivity. Infectivity has been found in the tonsils of nvCJD victims. Thus, the Spongiform Encephalopathy Advisory Committee (SEAC) has suggested the leucodepletion of blood supplies as a precaution.

Official Inquiry into BSE and CJD. The Institute of Food Sciecne and Technology (IFST) welcomed the official independent enquiry into BSE and has made a written submission.
Review of the public heath safety of products from aquaculture*
Authors: Howgate P.
Published: March 2003

This review collects and summarizes the published literature on chemical and biological public health safety hazards associated with aquacultured products and the degree of risk they pose compared with equivalent products captured in the wild.
Effects of meat piece size and phosphate on maximum slicing rate, cooking loss and sensory quality of a re‐formed pigmeat shoulder product
Authors: McDermott Martin , Mitchell Peter C. , Welch Robert W.
Published: March 2003

Summary Two pre‐tumbling treatment variables (meat piece size; raw product phosphate content) were evaluated for their effects on maximum slicing rate (MSR), cooking loss and sensory quality of a commercially produced, cooked re‐formed pigmeat shoulder product. At 0.457% phosphate, incremental reductions in meat piece size which increased specific surface from 0.60 to 0.93 cm2 cm−3 enabled MSR to increase from 300 to 400 slices min−1, reduced cooking losses from 0.875 to 0.60% and gave a more tender product. At 0.60 cm2 cm−3 specific surface, increasing phosphate incrementally from 0.457 to 0.532% produced similar positive effects on MSR and cooking loss but at phosphate above 0.482% sensory quality declined. Combination of optimal specific surface (0.93 cm2 cm−3) and phosphate (0.482%) permitted a MSR of 420 slices min−1, reduced cooking loss to 0.50% and gave an acceptable product. These process modifications can thus be advocated for improved production rate, yield and sensory quality.
Pilot scale isolation of proteins from field peas (Pisum sativum L.) for use as food ingredients
Authors: Tian Shaojun , Kyle William S. A. , Small Darryl M.
Published: March 2003

Summary The protein and starch fractions of field pea (Pisum sativum L.) are potentially a source of novel ingredients for food processing. As part of research to elucidate the functional properties of field pea proteins, the pilot scale extraction of proteins has been undertaken. Two different approaches have been used and the recoveries of protein compared. The first involved extraction with a salt solution followed by decanting and clarification to remove solids. The solution was then further concentrated and salt removed by ultrafiltration and diafiltration. The second procedure was based upon alkaline extraction followed by decanting and recovery by isoelectric precipitation and neutralisation. Both spray drying and freeze drying methods were employed. The protein isolates have been compared and characterised with respect to solubility, chemical composition and to electrophoretic patterns. Overall, the proteins extracted with salt exhibited better physical properties than proteins extracted with alkali, in terms of colour and particle size. The solubilities showed little variation and the electrophoretic patterns were similar. Freeze drying resulted in isolates with darker colour compared with spray drying.
Colour changes in thermally processed cupuaçu (Theobroma grandiflorum) puree: critical times and kinetics modelling
Authors: Silva Filipa M. , Silva Cristina L. M.
Published: March 2003

Summary Colour changes in thermally treated cupuaçu (Theobroma grandiflorum) fruit puree were modelled mathematically. Isothermal experiments in the temperature range of 80–115 °C were performed and colour was measured by a tristimulus colorimeter. At each temperature total colour difference (TCD*) increased and normalized L* decreased with processing time, both following a power law model. The power of the model was temperature‐dependent and described by the Arrhenius law. To estimate the model constants, a one‐step non‐linear regression was performed on all data. Activation energies of 31 and 36 kJ/mol were determined for TCD* and normalized L*, respectively. These results should prove useful in the design of pasteurization processes which minimize colour changes in cupuaçu puree.
Process–quality optimization of the vacuum freeze‐drying of apple slices by the response surface method
Authors: Hammami Chokri , René Frédéric , Marin Michèle
Published: March 2003

Summary Working pressure (P) and heating plate temperature (T) were considered to be the most important factors affecting the kinetics of the freeze‐drying operation for apple slices as well as the criteria of final product quality (appearance/shape, colour, texture, rehydration ratio). Freeze‐drying experiments involving a thick layer of slices under different processing conditions were designed according to a central composite rotatable system with two factors (P, T). Results were analysed by response surface methodology (RSM). By superimposing all quality criteria contour plots, the optimum levels of processing conditions yielding the best quality freeze‐dried apple slices were determined to be an operating pressure of 50 Pa, and a heating plate temperature of 55 °C. For a product loading of 17 kg m−2, the freeze‐drying time ranged from 48 to 50 h. The experimental values of the freeze‐drying time, appearance and colour of freeze‐dried apple slices obtained with these optimal conditions were very similar to those predicted by the corresponding second order polynomial model. The rehydration ratio of freeze‐dried apples was about 0.55 g g−1 of water removed and the texture loss of rehydrated apples was estimated to be more than 85%.
An ESR study on identification of gamma‐irradiated kiwi, papaya and tomato using fruit pulp
Authors: Jesus Edgar F. O. , Rossi Alexandre M. , Lopes Ricardo T.
Published: March 2003

Summary In this work we use paramagnetic defects induced by radiation in the fruit pulp to identify gamma‐irradiated kiwi, papaya and tomato. Pulp without seed, peels or stalks are treated by alcoholic extraction in order to remove water, soluble fractions and solid residue. The ESR spectra of pulp samples of irradiated fruit is composed of species A (g = 2.0045) and species C (g = 2.0201 and g = 1.9851), which are also observed in irradiated stalks and skins. In comparison with samples which are not submitted to alcoholic extraction, species C is stable enough to be used as a dose marker. Furthermore, the species C signal can be detected perfectly even in pulp samples irradiated with doses as low as 200 Gy. Irradiation doses of fruit, exposed to 200–900 Gy of a gamma rays, were estimated with an overall uncertainty of 15% using dried pulp samples. These results indicate that radicals induced in pulp have potential to be used in the identification and absorbed dose determination of irradiated fruit.
Water agar‐agar equilibrium: determination and correlation of sorption isotherms
Authors: Iglesias Olvido , Bueno Julio L.
Published: March 2003

Summary Water activity in hygroscopic solids determines the behaviour of many materials in storage as well as in drying and freezing operations. Available data concerning phycocolloid gels, such as those of agar‐agar and derivatives, are scarce in spite of their interest for pharmacology and the food industry. Thus, we have determined the isotherms of adsorption and desorption of agar‐water gels by means of a gravimetric procedure, at 25, 40, 60 and 80 °C, determining the effect of temperature on the heat of desorption by the isosteric heat method, using the Henderson model.
Concentration polarization modelling in the maple sap concentration by reverse osmosis
Authors: Bouchard Christian R. , Lebrun Rémi E.
Published: March 2003

Summary This research studied the effect of concentration polarization on the efficiency of reverse osmosis to concentrate maple sap. For these purposes, a commercial reverse osmosis spiral wound module was tested. A correlation of the variation of the sucrose mass transfer coefficient with the tangential velocity and temperature was experimentally determined from pure sucrose solution permeation tests. This correlation, together with a set of simple equations describing the reverse osmosis system, predicted the membrane sucrose concentration during maple sap concentration under a wide range of operating conditions. Good agreement was found between the predicted and experimentally determined value of the membrane concentration. Also, it was shown through some parametric studies, how the results of this work are helpful in the design and operation of a reverse osmosis system.
Effects of boiling, warm‐holding, mashing and cooling on the levels of enzyme‐resistant potato starch
Authors: Gormley Ronan , Walshe Thomas
Published: March 2003

Summary The effects of boiling, warm‐holding, cooling and mashing on the enzyme‐resistant starch (ERS) content of potatoes was studied together with inter‐tuber and inter‐cultivar variation in ERS content. Inter‐tuber variation in ERS content was small and mean values (on a dry matter basis) for boiled and raw potatoes were 10.7 and 74.2% (cultivar Rooster) and 10.8 and 74.3% (cultivar Anna). There was no significant difference between the ERS values of boiled potatoes of seven cultivars (range 10.0–10.8%). Warm‐holding mashed potatoes at 65–70 °C for 1 hr raised ERS values from 2.20 to 4.80%. In a separate test slow cooling over 2 hr to 21 °C raised the ERS content from 3.65 to 6.35%. Multiple cook‐cool (3×) gave ERS contents of 23.2 and 18.2% for boiled potatoes held for 24 hr at 4 or 20 °C. Mashing and freezing raised ERS values by 1–2%.
Microwave phase control heating
Authors: Bows John R. , Patrick Maria L. , Janes Ruth , Dibben David C.
Published: March 2003

Summary Food processors are increasingly looking towards new microwave‐based technologies to deliver competitive advantage in the market place, reduce operational costs, allow greater product innovation and increase flexibility without the need for large capital investments. The technical barriers to the widespread exploitation of microwave heating, and opportunities for microwave heating in food processing, are discussed in the context of the need to understand the microwave field/material/process interaction. It is shown how a new application of interference techniques, called phase control microwave heating, may offer opportunities for enhanced heat transfer in food processing, especially for direct control of the spatial power deposition within a foodstuff. Simulations of phase control heating using a 3D FETD microwave model, validation of experimental findings and examples in other applications are presented.
The kinetics of browning measured during the storage of onion and strawberry
Authors: Manuel Sá Maria , Sereno Alberto M.
Published: March 2003

Summary The kinetics of non‐enzymatic browning of onion and strawberry during storage at different temperature (5, 15, 25, 35, 45 °C) and equilibrium relative humidities (33%, 44%, 53%) was measured. Colour formation in onion was observed by measuring absorbance versus time in aqueous extract solutions. Experimental results of colour formation of onion as a function of time for each level of water activity were best represented by a zero order kinetics, while anthocyanin degradation in strawberry followed a second order kinetics. Rate coefficients obtained in both cases showed an increase in the rate of the reactions with both temperature and water activity. With regard to temperature dependence of rate coefficients, statistical evidence suggest that in the case of colour formation in onion, the Williams‐Landel‐Ferry model is a better representation than Arrhenius. In the case of strawberry it was not possible to reach such conclusion in spite of a lower summation of residuals obtained with the WLF model.
Three‐dimensional MRI mapping of microwave induced heating patterns
Authors: Nott Kevin P. , Bows John R. , Patrick Maria L.
Published: March 2003

Summary Magnetic Resonance Imaging (MRI) has been used to map in three dimensions, non‐invasively, the complex heating patterns induced by microwave heating. Comparisons with infra‐red thermal imaging of the surface heating patterns are demonstrated. The effects of the differential heating properties have been characterized for a model food sample. The potential applications of MRI temperature mapping to optimizing the domestic and industrial use of microwaves for heating of foods is discussed.
Whey protein aggregation under shear conditions – effects of lactose and heating temperature on aggregate size and structure
Authors: Spiegel Thomas
Published: March 2003

Summary Whey protein concentrates with different lactose contents were heat‐ and shear‐treated in a scraped surface heat exchanger at various temperatures. The properties of the resulting protein aggregates are closely correlated with the denaturation kinetics of β‐lactoglobulin and the different mechanisms – unfolding and aggregation – which determine the overall reaction rate. At temperatures below 85 °C, unfolding is slowed down especially if there is a high content of lactose. A loose, porous aggregate structure is formed and the particle size and the serum binding capacity increase. The smallest aggregates are produced when heating takes place between 85 and 95 °C. In the temperature range above 100 °C aggregation is the rate‐limiting step and the aggregate structure is very dense and compact. The particle size increases and is no longer dependent on the concentration of lactose.
Foaming properties of β‐Lactoglobulin: impact of pre‐heating and addition of isoamyl acetate
Authors: Marin Isabelle , Relkin Perla
Published: March 2003

Summary Foaming properties of solutions of β‐lactoglobulin alone or in a mixture with isoamyl acetate were investigated through a conductimetric method. It was observed that addition of isoamyl acetate to β‐lactoglobulin at molar ratios, R = 1 and 2 led to enhanced foaming properties in comparison with β‐lactoglobulin alone. In regards to the observed changes in tryptophan fluorescence properties, it is suggested that β‐lactoglobulin + isoamyl acetate might form a complex with a specific surface activity.
Adsorption of β‐Lactoglobulin variants A and B to the air–water interface
Authors: Mackie Alan R. , Husband Fiona A. , Holt Carl , Wilde Peter J.
Published: March 2003

Summary The adsorption of proteins to interfaces is a vital and complex process for the formation and stabilization of multiphase food systems (emulsions and foams). The process of protein adsorption is generally understood only at the phenomenological level, as the complexity of protein unfolding during adsorption is very difficult to predict and model. By comparing proteins with very similar structures, it is possible to attribute observed changes in adsorption behaviour. The A and B genetic variants of β‐lactoglobulin (β‐lg) differ by only two amino acids (Asp‐64, Val‐118 in A, and Gly‐64, Ala‐118 in B), thus making them ideal candidates for this type of comparison. In this study we monitored the surface behaviour of β‐lg A and B, measuring the surface tension and surface dilational modulus of adsorbed protein, and the compression behaviour of spread protein films. At pH 7, variant B lowered the surface tension and increased the surface dilational modulus more rapidly than variant A. Raising the pH to 7.8 should increase the level of dissociation into monomers. Indeed, this was confirmed by the rate of adsorption, which increased in both cases. Also, the surface tension of both variants was much lower than at pH7. Variant B was less sensitive to the change of pH than A. Regardless of pH, after 3 h adsorption the difference between the variants in surface tension or surface dilational modulus was negligible. The differences in surface behaviour between the variants are discussed in terms of interactions between monomers at and with the interface, and the dimer : monomer equilibrium in the bulk solution.