1,721,001 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Influence of the heat treatment on the degradation of the minor Fusarium mycotoxin beauvericin

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    Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains and known to have various biological activities. This study investigated the degradation of the minor Fusarium mycotoxin BEA present in the concentration of 5 mg/kg in a model solution and in different crispy breads produced with different flours typologies (corn, hole, wheat, durum wheat, soy and rice) during the heat treatment carried out in an oven at three different temperatures of 160, 180 and 200 C and at 3, 6, 10, 15 and 20 min incubation. The concentration of the bioactive compound studied, analyzed with the technique of the liquid chromatography tandem mass spectrometry (LCeMS/MS), decreased in the experiment carried out in the model solution from 2.89 0.13 mg/kg of the assay at 160 C for 3 min until the complete degradation at 200 C during 20 min incubation. In the experiments carried out using the crispy breads prepared with different kind of flours, as system to simulate a food preparation, the percentage of BEA degradation, resulted variable from 20 to 90%, with no a significative differences showed in the use of the different flour matrices. Also a metabolite of the thermical degradation of the mycotoxins BEA was identified using the LCeMS in the full scan mode

    Antifungal and antimycotoxigenic activity of hydrolyzed goat whey on Penicillium spp: An application as biopreservation agent in pita bread

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    Whey is a by-product of the cheese industry, yet it contains proteins that have a high nutritional value and are an important source of antifungal peptides. Food deterioration caused by toxigenic fungi is one of the challenges of food safety. In this context, trypsin was used to hydrolyse goat milk whey at 37. The resultant peptides were characterised by LC–ESI–TOF-MS. Antifungal activity of the goat milk whey hydrolysate (HGW) was determined against 10 toxigenic fungi from the genus Penicillium, in solid and liquid media. Furthermore, HGW was used as an ingredient for bread elaboration. Bread elaborated with HGW and inoculated with toxigenic fungi was included in a shelf-life study of the reduction of fungal growth, mycotoxin production and the use of the additive calcium propionate in bread. A total of 27 peptides from α-lactalbumin, β-lactoglobulin, κ-casein and lactoferrin were identified. HGW evidenced fungal growth inhibition and presented minimum inhibitory concentration and minimum fungicidal concentration ranges of 3.9–62.5 and 15.8–250 g HGW/L, respectively. Bread with HGW displayed a 1-log reduction of fungal growth, 85–100% mycotoxin production, and extended the shelf-life by 2 days

    Reduction in vitro of the minor Fusarium mycotoxin beauvericin employing different strains of probiotic bacteria

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    The interaction between the minor Fusarium mycotoxins BEA and 13 bacterial strains characteristic of the gastrointestinal tract as Bifidobacterium longum, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium adolescentes, Lactobacillus rhamnosus, Lactobacillus casei-casei, Lactobacillus plantarum, Eubacterium crispatus, Salmonella fecalis, Salmonella termofilus, Lactobacillus ruminis, Lactobacillus casei and Lactobacillus animalis was studied. The fermentations were carried out in the liquid medium of MRS during 4, 12, 16, 24 and 48 h at 37 C, under anaerobic conditions. Levels of BEA in the fermentation liquid, on the cell walls and on the internal part of the cells were determined using liquid chromatography coupled to the mass spectrometry detector (LC-MS/MS). Results showed that the bacteria reduced the concentration of the BEA present in the medium, part of the mycotoxin was adsorbed by cell wall and part internalized by the bacteria. All the bacteria analyzed in this study showed a significant BEA reduction during the fermentation process, in particular the mean diminution resulted variable from 66 to the 83%

    Influence of different soluble dietary fibers on the bioaccessibility of the minor Fusarium mycotoxin beauvericin

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    Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains and is known to have various biological activities. This study investigated the bioaccessibility of the BEA tested in concentrations of 5 and 25 mg/L, in a model solution and in wheat crispy breads elaborated with different natural binding compounds as the soluble alimentary dietary fibers b-1,3 glucan, chitosan low molecular weight (L.M.W.), chitosan medium molecular weight (M.M.W.), fructooligosaccharides (FOS), galattomannan, inulin and pectin, added at concentrations of 1% and 5%. The bioaccessibility was determinated by employing a simulated gastrointestinal digestion that simulates the physiologic conditions of the digestive tract until the colonic compartment. The determination of BEA in the intestinal fluids was carried out by liquid chromatography– mass spectrometry detection (LC–MS). The mean BEA bioaccessibility data in the model solutions ranged from 31.8% of the samples treated with only the duodenal digestion until 54.0% of the samples processed including the colonic fermentation, whereas in the alimentary system composed by the wheat crispy breads produced with different fiber concentration the duodenal and the duodenal + colonic BEA bioaccessibility resulted in 1.9% and 27.0% respectively
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