A number of countries are setting legislations on mycotoxins. In order to reduce dispute between importing and exporting countries, the analytical data should be as comparable as possible, especially when levels are close to the regulatory limits. The present trend in the analysis of mycotoxins is to use immunoaffinity column (IAC) as a clean-up and enrichment technique, and Association of Official Analytical Chemists and European Union have validated methods which address a few food commodities. This study describes our experience using both conventional and IAC approaches in the analysis of three mycotoxins. Aflatoxins (AFs): Aflatoxin G1 has been detected by liquid-liquid partitioning methods with HPLC detection as false-positive in some maize. On IACs, this compound behaves as an AF, lowering the amount of the AFs trapped. The problem was solved using either TLC or HPLC with detection in the Kobra cell. Depending on the additives to food during the processing and cooking, the AFs might appear as an opened ring not recognised by the antibody. Fumonisins (FB): Compounds interfering with the FB's antibodies were also observed while analysing breakfast cereals leading to underestimation of FB. Ochratoxin A (OTA): Depending on the food composition and extraction techniques, OTA is underestimated with IAC in some breakfast cereals and coffee. These data strengthen the necessity to validate methods using IAC for each complex matrix. 相似文献
The effect of nanosilica addition on the morphology and mechanical properties of blends of isotactic PP and an ethylene/octene copolymer (EOC) is studied. TEM reveals that the well‐dispersed nanoparticles are localized exclusively in the PP phase. In the presence of a maleated PP compatibilizer addition of nanosilica leads to more finely dispersed EOC domains and a finer co‐continuous morphology. The nanoparticles reduce the rate of coalescence of the dispersed phase domains. The mechanical properties depend on the EOC and PP‐g‐MA content. Tensile and flexural properties are significantly enhanced in the presence of the silica nanoparticles, whereas impact properties are not affected. These enhancements are attributed to the favorable microstructure of the blends.
Grain dietary fiber content is an important health-promoting trait of bread wheat. A dominant dietary fiber component of wheat is the cell wall polysaccharide arabinoxylan and the goatgrass Aegilops biuncialis has high β-glucan content, which makes it an attractive gene source to develop wheat lines with modified fiber composition. In order to support introgression breeding, this work examined genetic variability in grain β-glucan, pentosan, and protein content in a collection of Ae. biuncialis. A large variation in grain protein and edible fiber content was revealed, reflecting the origin of Ae. biuncialis accessions from different eco-geographical habitats. Association analysis using DArTseq-derived SNPs identified 34 QTLs associated with β-glucan, pentosan, water-extractable pentosan, and protein content. Mapping the markers to draft chromosome assemblies of diploid progenitors of Ae. biuncialis underlined the role of genes on chromosomes 1Mb, 4Mb, and 5Mb in the formation of grain β-glucan content, while other QTLs on chromosome groups 3, 6, and 1 identified genes responsible for total- and water-extractable pentosan content. Functional annotation of the associated marker sequences identified fourteen genes, nine of which were identified in other monocots. The QTLs and genes identified in the present work are attractive targets for chromosome-mediated gene transfer to improve the health-promoting properties of wheat-derived foods. 相似文献
We propose a generic sound δ-rule, based on a quite general method for the construction of Skolem terms, which can be used
as a common framework for proving the soundness of known variants of the δ-rule, and we compare their relative effectiveness.
Attempts to instantiate some of the δ-rules present in the literature within our framework allowed us to pinpoint unsoundness
problems for two of them. In both cases, we propose revised versions that are proved sound by reducing them within our framework.
This paper is based on results preliminarily presented in [5]. 相似文献
The prevalence of Listeria monocytogenes in retail roe, as well as the microbiological and sensory qualities of the roe, were studied for three fish species under three different storage conditions. A total of 147 Finnish rainbow trout (Oncorhynchus mykiss), whitefish (Coregonus lavaretus), vendace (Coregonus albula), and burbot (Lota lota) roe samples were bought fresh, frozen, or frozen-thawed from Finnish retail markets. The overall prevalence of L. monocytogenes was 5%; however, the prevalence of the pathogen in fresh roe was 18%. Fresh-bought roe tested positive for Listeria spp. and for L. monocytogenes, respectively, 5 and 20 times as often as did frozen and frozen-thawed roe products combined. The microbiological quality (analyzed as total aerobic heterotrophic bacteria and coliform bacteria) of 78% of the roe samples was unacceptable. Frozen roe samples were found to have the best microbiological quality. According to the results of a sensory evaluation, at least one sensory attribute (appearance, odor freshness, texture, and freshness of taste) was unacceptable for 29% of the roe samples studied. The sensory quality of roe samples bought fresh was better than that of roe samples bought frozen or frozen-thawed. From the results of this study, it is concluded that both the microbiological and the sensory qualities of roe at the retail level need to be improved. 相似文献