Individual and combined effects of subclinical doses of deoxynivalenol and fumonisins in piglets

Scope: Deoxynivalenol (DON) and fumonisins (FB) are the most frequently encountered mycotoxins produced by Fusarium species and most commonly co‐occur in animal diets. These mycotoxins were studied for their toxicity in piglets on several parameters including plasma biochemistry, organ histopathology and immune response. Methods and results: Twenty‐four 5‐wk‐old animals were randomly assigned to four different groups, receiving separate diets for 5 wk, a control diet, a diet contaminated with either DON (3 mg/kg) or FB (6 mg/kg) or both toxins. At days 4 and 16 of the trial, the animals were subcutaneously immunized with ovalbumin to assess their specific immune response. The different diets did not affect animal performance and had minimal effect on hematological and biochemical blood parameters. By contrast, DON and FB induced histopathological lesions in the liver, the lungs and the kidneys of exposed animals. The liver was significantly more affected when the two mycotoxins were present simultaneously. The contaminated diets also altered the specific immune response upon vaccination as measured by reduced anti‐ovalbumin IgG level in the plasma and reduced lymphocyte proliferation upon antigenic stimulation. Because cytokines play a key role in immunity, the expression levels of IL‐8, IL‐1β, IL‐6 and macrophage inflammatory protein‐1β were measured by RT‐PCR at the end of the experiment. The expression of these four cytokines was significantly decreased in the spleen of piglets exposed to multi‐contaminated diet. Conclusion: Taken together, our data indicate that ingestion of multi‐contaminated diet induces greater histopathological lesions and higher immune suppression than ingestion of mono‐contaminated diets.     

Predictive model for inactivation of Campylobacter spp. by heat and high hydrostatic pressure

Campylobacter represents one of the leading causes of foodborne enteritis. Poultry and its products frequently transmit the pathogen. The objective of the present study was to model predictively the short-term inactivation of Campylobacter in a ready-to-eat poultry product to develop an economic high-pressure treatment. We inactivated baroresistant strains of Campylobacter jejuni and Campylobacter coli, grown to stationary phase on nutrient agar and inoculated in poultry meat slurry, by heat and high hydrostatic pressure. Incubation at ambient pressure at 70 degrees C for 1 min and at 450 MPa at 15 degrees C for 30 s inactivated more than 6 log CFU of this foodborne pathogen per ml of poultry meat slurry. Thermal and pressure inactivation kinetics of C. coli and C. jejuni in poultry meat slurry were accurately described by a first-order kinetic model. A mathematical model was developed from 10 to 65 degrees C and from ambient to 500 MPa that predicts the reduction in numbers of Campylobacter in response to the combination of temperature, pressure, and treatment time. We suggest the high-pressure treatment of foods to avoid health risks caused by Campylobacter. The nonthermal short-term treatment of the examined food model system represents a successful step to an economic high-pressure procedure.     

Eine verbesserte Methode zur Bestimmung der maximalen Emulgierkapazit?t von Proteinl?sungen

Zusammenfassung Am Beispiel der Milchproteine wird die Methode zur Bestimmung der maximalen Emulgierkapazität optimiert. Die Methode beruht darauf, daß am Inversionspunkt einer Emulsion der elektrische Widerstand sprunghaft ansteigt. Experimentell überprüft wurden die Parameter Proteinkonzentration, pH-Wert, Öl-Dosierungsrate, Ultra-Turrax-Drehzahl und Versuchsdauer. Ferner wurden Forderungen an die Ermittlungdes Leerwertes begründet. Durch Festlegen der stofflich und methodisch bedingten Einflußgrößen gelingt es, den Variationskoeffizienten auf Werte um 2,0% zu minimieren. Die vorgestellte Methode ist mit gutem Erfolg auf alle löslichen Proteine übertragbar und erfüllt die Anforderungen einer Standardisierung.

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An improved method for determining the maximum value of emulsifying capacity of protein solutions

Summary A method for the examination of the maximum value of emulsifying capacity was optimized using milk proteins. This method is based on a sudden increase in the electrical resistance at the inversion point of the emulsion. The following parameters were tested: protein concentration, pH value, rate of oil dosage, speed of the Ultra-Turrax, time needed for one experiment, and the requirements for preparing the blank. By fixing these parameters it is possible to minimize the coefficient of variation of about 2.0%. This method is successfully applicable for all soluble proteins and meets all the requirements for standardisation.

     

Redox processes in pressurised smoked salmon studied by resonance Raman spectroscopy

Non-thermal food preservation technology is based on the application of high pressures up to 600 MPa. Here we report a resonance Raman (RR) spectroscopic analysis of smoked salmon meat after high pressure processing. High quality spectra, which can be obtained even from packed salmon without spectral interference of the packing foil, allow determining pressure-dependent irreversible changes of the main RR-active components of salmon meat, astaxanthin and myoglobin/haemoglobin. High pressure-treatment causes a decrease of the relative RR intensities of astaxanthin as probed with 514 nm excitation which is in line with a slight attenuation of the originally intense red colour of the salmon meat. 413-nm excited RR spectra indicate a heterogeneous broadening of astaxanthin bands accompanied by the formation of deoxy-myoglobin or deoxy-haemoglobin. The results suggest that pressure-treatment facilitates the oxidative degradation of astaxanthin coupled to the reduction of metmyoglobin (methaemoglobin).     

Phasengleichgewichte des Schnittes FeOn–CaO im Dreistoffsystem FeO–Fe2O3–CaO bei Eisensättigung

Überprüfung der Schmelzgleichgewichte des Dreistoffsystems FeO–Fe₂O₃–CaO auf der wüstitreichen, eisengesättigten Seite des Systems. Angaben über die Ergebnisse der thermischen Analysen, isothermen Halteversuche und mikroskopischen Untersuchungen. Aussagen über den quasibinären Schnitt Eisen-Kalkferrit bei Temperaturen unter 1150 °C sowie über den quasibinären Schnitt Calciowüstit-Kalk über 1150 °C.     

Antiviral activity of donkey milk protein fractions on echovirus type 5

Antiviral activity of Ragusano donkeys' milk proteins was investigated for the effect on echovirus type 5, known to infect the gastrointestinal tract of humans. Three protein fractions were tested; casein (CN), whey protein (WP) and a low molecular whey protein fraction (LWP; <30,000 Da). The antiviral activity of WP and LWP was tested on echovirus type 5 at three concentrations (1, 5 and 10 mg mL^?1); CN was assessed only at the lower concentration. All donkey milk protein fractions showed significant inhibition on virus replication at the concentration of 1 mg mL^?1, and both WP and LWP fractions showed significant inhibition on the virus replication at all concentrations tested. The strongest antiviral effect was observed for the WP fraction. These findings show that the different whey proteins in donkey milk, probably acting in synergy, exert antiviral activity on echovirus 5 and might contribute to prevent gastrointestinal virus infections in humans.     

The interaction of pulsed electric fields and texturizing ‐ antifreezing agents in quality retention of defrosted potato strips

The combination of pulsed electric fields (PEF) and texturizing and antifreeze agents on quality retention of defrosted potato strips were studied. Potato strips (10 mm thickness, 100 g) were placed in different solutions (1% w/v) of CaCl₂, glycerol, trehalose as well as NaCl and sucrose, treated with PEF (0.5 kV cm^?1, 100 pulses, 4 Hz). Then, all the samples were soaked in the same solutions for 10 min. After draining, samples were packed into polypropylene pouches and stored at ?18 °C for 12 h. Samples were thawed out at room temperature (20 °C) in 3 h. Untreated controls and PEF treated control samples were also frozen and thawed in similar conditions. To assess the potato strip quality, the thawed samples were analysed for moisture content, weight loss, firmness and colour attributes. The results indicate that PEF treatment by itself is not a suitable pre‐treatment method for frozen potato strips and should be assisted by CaCl₂ and trehalose treatment to prevent softening after defrosting. Firmness analyses determined that application of PEF alone results in 2.38 N. However, PEF in combination with CaCl₂ and trehalose result in 2.97 N and 2.99 N, respectively, which are both significantly firmer than the samples solely treated with PEF. CaCl₂ and trehalose were effective in not only maintaining the structural integrity of the cells, but also retaining colour attributes. The L* value was found to be higher (P < 0.05) in CaCl₂ and trehalose treated samples (58.95 and 57.21, respectively), as compared to PEF treated samples (53.97) denoting a darker colour. Application of CaCl₂ and trehalsoe in combination with PEF also resulted in significantly less weight loss after thawing.     

Purification and structural characterisation of lipid transfer protein from red wine and grapes

Lipid transfer proteins (LTP) play a major role in plant defence and are of particular interest due to their known ability to cause allergic reactions. These proteins are expressed in grapes and also remain detectable after vinification, especially in red wine. However, it remains unknown whether the protein undergoes any changes during the vinification process. Here, we present a purification method for LTPs from Dornfelder grapes and wine. By liquid-chromatography–mass spectroscopy (LC–MS/MS) we identified LTPs from two different species (Vitis vinifera and Vitis aestivalis). Additionally, the purified LTPs were characterised using spectrometric methods, confirming their high purity and structural stability during vinification. We conclude that LTPs are resistant to the alcohol content (13.5 vol%), acidic milieu of wine and other ingredients present during the vinification process, indicating that the allergenic potential of grape LTP is not diminished by the vinification process.