The aim of the study was to assay by PCR screening method whether the processing and the thermal stress have any influence on the feasibility of the detection of genetically modified DNA in different kinds of processed meat products such as sausages, liver cans, ready-to-eat hamburgers. The model meat products have been prepared with soybean meal spiked with RR (Roundup Ready) soybean meal in 0.5%, 1%, 1.5% and 2%. The samples were prepared under industrial circumstances. The assay was based on the detection of the specific part of the 35S promoter and the NOS terminator sequences. The modified PCR method was shown to be suitable for screening of GMOs in raw and also in moderately and highly processed meat samples when extreme heat treatment and pressure were used for the preparation of meat products. Half a percent RR soy contamination could be detected even if the food products underwent high temperature treatment.
Authors:K. Szekér, J. Beczner, A. Halász, Á. Mayer, J.M. Rezessy-Szabó, and P. Gálfi
The adhesion of twenty-six Lactobacillusstrains to two intestinal cell lines (Caco-2P and IEC-18) and 21 Bifidobacteriumstrains to Caco-2P cells was investigated. Non-specific adherence was determined on the surface of culture plates. The effect of short chain fatty acids (SCFA) on epithelial cells, and bacterial adhesion were investigated by Na-n-butyrate treatment. The adherence of LAB and bifidobacteria greatly varied in a strain-dependent manner. The adherence of LAB was better to IEC-18 cells than to Caco-2P cells, and bifidobacteria adhered better to Caco-2P cells than the LAB. Some strains adhered well or even better to the background than to the cells, which queries the specificity of adhesion of these strains. Na-n-butyrate treatment stimulated the differentiation of IEC-18 cells and therefore increased the number of adherent bacteria, probably because only the cell surface increased not the number of epitopes.
Authors:Katarzyna Fonteyn, Anouar Belahcen, and Antero Arkkio
The measurements done on magnetic bearings usually give higher losses than have been expected through the simulations. One of the reasons for the difference might be that the stresses introduced by mechanical or thermal treatments are not taken into account when a model is developed. In this paper, a core loss model of the magnetic bearings, taking the stresses in the laminations of the rotor into account is proposed. The model is used in the finite element analysis of radial magnetic bearings.
For colouring of foods anthocyanins are widely used, which are present in great quantity in black elderberry (Sambucus nigra). Experiments were done to study the anthocyanin content of several varieties and candidates, from which the highest value was found in the Haschberg cultivar. Further experiments were performed with this cultivar to study the anthocyanin stability ofS. nigraunder different circumstances (heat-treatment at various pH and temperatures). Our results revealed that anthocyanins react sensitively to temperature and pH increase.
Authors:E. Zsolt Horváth, A. Antal Koós, Krisztián Kertész, Zofia Vértesy, György Molnár, Mária Ádám, Csaba Dücső, József Gyulai, and P. László Biró
Gas sensing properties of different carbon nanotube (mostly multiwall,
MWCNT) mats, based on electrical resistance measurement were investigated in a
simple arrangement and found that the sensitivity for different gases or vapors
highly depends on the pre-treatment and functionalization of nanotubes. The
selectivity of the sensing was demonstrated by building a vapor recognition
system based on an array of multitube sensors made of differently
Authors:Y. Hassan, L. Mészáros, A. Simon, E. Tuboly, Cs. Mohácsi-Farkas, and J. Farkas
The total viable cell count of bacteria in vacuum-packaged chilled minced beef has been decreased equally, by approx. two log-cycles, as an effect of 1.5-2.0 kGy gamma radiation or 200-300 MPa high hydrostatic pressure (UHP) treatment for 20 min. Coliform bacteria could be eliminated to non-detectable levels by the same treatments. The shelf-life of both untreated and non-thermally pasteurised samples were limited mainly by growth of lactic acid bacteria. At about equal bactericidal effect, more drastic changes of texture and colour occurred in UHP-pasteurized minced beef samples than in the radiation-pasteurized ones. Whereas radiation pasteurisation caused minimal changes in appearance, texture and DSC-thermograms of minced beef, UHP-pasteurisation of the raw samples proved to be strongly discolouring by denaturing the muscle pigments and causing extensive denaturation of the myofibrillar proteins. The water holding capacity of irradiated samples decreased, while that of high pressure treated ones increased as compared to the untreated control. Near infrared spectrometry and electronic nose measurements gave promising results to make distinctions non-destructively on changes of various physical-chemical changes and quality parameters as a function of pasteurising treatments and/or storage.
Authors:A. Piga, B. Mincione, A. Runcio, I. Pinna, M. Agabbio, and M. Poiana
Olive fruit dehydration is always done locally in non-industrial ovens. This technology poses concern about the quality and safety of the end product. Most of the problems involved in this empirical technology may be solved by a proper control of process parameters. Olive fruits of fourteen Italian cultivars underwent hot air dehydration in mild conditions in a tangential airflow cabinet dryer. At the start, at regular intervals and at the end of the process, sampling was performed to calculate dehydration curves and quality loss. Pre-treatments such as blanching in hot brine, piercing of the skin and salting after blanching were applied. The drying kinetic is strongly affected by pre-treatments and olive characteristics: fruit size, flesh to pit ratio, dry matter. Results showed that mild drying temperature led to slow drying kinetics, even if pre-treatments reduced drying timeto a certain extent. Blanched olives showed, in general, the highest polyphenols content. The fastest drying was measured in the pierced olives, but the best taste was achieved for the salted product.
Authors:R. Ágoston, Cs. Mohácsi-Farkas, and S. Pillai
The food industry utilizes a variety of stressors such as heat treatment to inactivate or prevent the multiplication of
in foods. The aim of this study was to identify the extent to which pre-exposure to sub-lethal temperatures would induce temperature tolerance to 60 °C and result in increased D values.The D value of an avirulent
strain (4ab No 10) was initially determined in Tryptic Soy Broth at 55 °C, 60 °C and 65 °C. The cells were pre-exposed to sub-lethal heat stress of 46 °C (for 30 and 60 min), 48 °C (for 30 and 60 min) and 50 °C (for 30 and 60 min). Then they were exposed to 60 °C and the D
values were calculated. The pre-treatment at sub-lethal temperatures enhanced the D
value of the strain from 3.03 min to longer times. The D
values increased as a function of pre-treatment time at 46 °C: after 30 min exposure it was 5.24 min, and 16.18 min after exposure to 60 min. Similarly, the D
value after 30 min and 60 min exposure at 48 °C was 6.72 min and 14.83 min, respectively. The D
value after 30 min and 60 min exposure at 50 °C, was 13.88 min and 11.16 min, respectively. Heat injury was found to occur in this
strain under the experimental conditions.
Preservative qualities of caraway, known from ancient times, have regained importance as 21st century food safety issues predominate. Essential oil content and its composition of annual caraway varies significantly when row spacing and nutrient supply are manipulated under experimental conditions. During 2006–2007, Carum carvi var. annua cultivar ‘SZK-1’ was sown in small plots in three replications with two factors in split plot design. The row spacings were 24 cm, 36 cm, and 48 cm, and six nutrient application rates were applied (Control, N0K80, N80K0, N80K80, N80+70K0, N80+70K80). The results show that the percentage of essential oil content is influenced by the row space. Furthermore, our data show that increased potassium level enhances the amount of d-carvone in the oil. Every treatment of potassium produced higher d-carvone levels (53.34%) than those found in the control. In 2006, the first year of the two-year study, the highest carvone level (66.25%) was measured in the treatment of N80+70K80, whereas in 2007 the highest level occurred in the N80K80 (49.216%) treatment.