Authors:M. Molnár, L. Hornyák, R. Nagy, E. Márki, and Gy. Vatai
Our experiments were based on a model solution containing five of the main pineapple aroma components. Both sweeping-gas pervaporation and vacuum-pervaporation methods were carried out. Measurements were performed at different temperatures and feed flow rates. The purposes of this study were to examine applicability of the two pervaporation methods in reference to the pineapple aroma recovery, the effects of the operating parameters on the process, and modelling the pervaporation process by resistance-in-series model. Higher enrichment could be reached with vacuum-pervaporation than the sweeping-gas method. The separation process is determined by the diffusion of compounds in the membrane, thus the resistance in the boundary layer at liquid side is negligible. Based on performed experiments, the pervaporation process can be applied in beverage industry for aroma recovery.
Authors:A. Szabó, A. Gyepes, Á. Nagy, L. Abrankó, and J. Győrfi
Vitamin D2 is essential for the human body and mushrooms are proved to be one of the best sources of it. In our experiment biologically active, pre-harvest white and cream type button mushrooms and oyster mushroom were treated with UVB light in order to increase their vitamin D2 level, by transforming their natural ergosterol content into vitamin D2. UVB lamps (operating on 312 nm) and six time periods of irradiation (15 to 90 min) were used. After three consecutive days of treatments the yield were measured and samples were taken for vitamin D2 analysis. Data showed considerable increase in vitamin D2 levels at every time period in each cultivar.
Authors:A. Nagy, L. Jędrychowski, É. Gelencsér, B. Wróblewska, and A. Szymkiewicz
In recent years, research related to studying the effect of gut microflora on the human health has become of major economic importance. The main objective of our study was to examine whether or not the orally administered Lactobacillusstrains (LB) as an oral adjuvant can improve the mucosal immune protectionviaan enhanced IgA secretion to a co-administered marker antigen ovalbumin (OVA). We adapted a murine (BALB/c) model to demonstrate beneficial adjuvant effects of probiotic LB strains. Orally sensitised mice with OVA, which were prefed with native or heat denatured (HD) Lactobacillus salivarius (Ls) or Lactobacillus casei (Lc) responded better or with the same efficiency to a vaccination with antigen (OVA) than mice that had been sensitised only with OVA or not sensitised at all. Antibody (IgA) responses in the gut were increased in response to vaccination with OVA in mice that had been prefed with native or heat denatured Ls or Lc followed by Ls or Lc and OVA feeding. In prefed groups, the OVA feeding alone primed for specific immune response, while adjuvanted OVA has increased the immune exclusion potential of the gut.
Authors:E. Nagy, I. Éliás, L. Körmendy, and J. Czeglédi-Jankó
Development of rapid methods is often needed for the in-line process control of the proximate composition (e.g. fat or moisture content) of meat in the meat processing plants. This paper reports on the continuous wave nuclear magnetic resonance (CW-NMR) technique applied for determining fat content in fresh meat. The interfering moisture content in meat was removed by microwave drying and the dried residue was transferred quantitatively into the NMR-tubes. The total analysis time was about 35 min. Experiments were performed with pork (with a fat content from 1.7% to 21%), beef (with a fat content from 1.0% to 16.1%), lard (rendered pork fat) and tallow (rendered beef fat) samples and with their combinations: lard-tallow, lard-lean pork, tallow-lean beef and lard-tallow-lean beef-lean pork. The regression (prediction) equations (NMR-signal vs. fat content determined with the Soxhlet reference method) of pork and beef did not differ significantly. However, there was a noticeable difference between the regression lines of pure lard and pure tallow. Moreover, the latter ones differed from the regression equations of pork, beef and of the various meat-fat combinations. The variability of the fatty acid composition of the fat also seems to influence the stability of the calibration curves, because the sensitivity of the CW-NMR signal to the fatty acid composition interferes with the quantitative determination of fat content in meat.
Authors:L. Kredics, Zsuzsanna Antal, Ilona Dóczi, L. Manczinger, F. Kevei, and Elisabeth Nagy
Cefditoren is the active form of cefditoren pivoxil, a new, broad-spectrum oral cephalosporin with strong in vitro activity against penicillin-susceptible and resistant Streptococcus pneumoniae. In this study, the minimum inhibitory concentrations (MICs) of cefditoren were determined for a special selection of S. pneumoniae isolates known to be susceptible, moderately susceptible or fully resistant to penicillin; these isolates originated from the lower respiratory tract of adults with pneumonia or the upper respiratory tract of children with or without symptoms of infection. Some of this latter group of isolates exhibited extremely high MICs to penicillin (³32 mg/l), whereas the MICs of cefditoren did not exceed 2 mg/l. The MIC50 and MIC90 of cefditoren proved to be 0.25 and 1.0 mg/l, respectively, with a range of MICs £0.015-2.0 mg/l for all the tested S. pneumoniae isolates. Its good activity suggests that cefditoren is expected to be a potent drug in infections caused by penicillin-resistant and multidrug-resistant S. pneumoniae.
Authors:L. Kredics, Zsuzsanna Antal, A. Szekeres, L. Manczinger, Ilona Dóczi, F. Kevei, and Elisabeth Nagy
Species belonging to the filamentous fungal genus Trichoderma are well known as potential candidates for the biological control of plant pathogenic fungi and as cellulase producers of biotechnological importance. Several data were published in the last decade also about the clinical importance of this genus, indicating that Trichoderma strains may be potential opportunistic pathogens in immunocompromised patients. However, there is a lack of information about the potential virulence factors of clinical Trichoderma strains. This study was designed to examine the extracellular proteolytic enzymes of six clinical T. longibrachiatum isolates. Supernatants from induced liquid cultures of the examined strains were screened for proteolytic enzyme activities with 11 different chromogenic p-nitroaniline substrates. The production of trypsin-like, chymotrypsin-like and chymoelastase-like protease activities cleaving N-Benzoyl-L-Phe-L-Val-L-Arg-p-nitroanilide, N-Succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroanilide,and N-Succinyl-L- Ala-L-Ala-L-Pro-L-Leu-p-nitroanilide, respectively, was common among the strains examined. Separation of trypsin- and chymotrypsin-like activities by column chromatography revealed, that both systems are complex consisting of several isoenzymes. The pH-dependence of these two protease systems was also studied. Based on the results, the different isoenzymes seem to have different optimal pH values. Extracellular proteolytic enzymes may be involved in the pathogenecity of Trichoderma strains as facultative human pathogens.