Quantitative analysis of patulin in apple juice by thin-layer chromatography using a charge coupled device detector

A method was developed and validated in-house for the detection and quantification of patulin in apple juice concentrate using a charge coupled device (CCD) on thin-layer chromatography (TLC) plates. Samples were extracted with ethyl acetate and then cleaned-up by extraction with a sodium carbonate solution. The method showed a mean recovery of 95%. The quantification and detection limit were 14 µg l^?1 and 0.005 µg per spot, respectively. The CCD camera is sufficiently sensitive to detect changes in spot fluorescence intensity caused by small differences in mycotoxin concentration under homogeneous illumination from a UV light source. The results of validation confirmed the efficiency of the method, which is sensitive enough to be used to quantify patulin in apple juice by producers or for government monitoring/survey programs. The method was applied to the analysis of 16 apple juice concentrate samples and patulin levels ranged from 15 to 46 µg l^?1. This study demonstrated the applicability of the TLC–CCD technique as a tool for monitoring patulin in apple juice.     

Differentiation of wines according to grape variety using multivariate analysis of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection data

Headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) was used to analyse the volatiles in five types of wines elaborated with grapes of Cabernet Sauvignon, Merlot, Chardonnay, Sauvignon Blanc and Pinot Noir varieties. Fisher ratio, principal component analysis (PCA) and stepwise linear discriminant analysis (SLDA) were used to develop a discriminant model and, as a result, 12 volatile compounds enabled differentiation and classification of wines according to grape cultivars. A detailed examination of GC×GC/TOFMS data showed that the use of one-dimensional gas chromatography with a mass spectrometric detector (1D-GC/MS) would probably result in misidentification of some of these 12 compounds, as they showed partial coelution with other components in the first chromatographic dimension.     

Reducing salt level in food: Part 1. Factors affecting the manufacture of model cheese systems and their structure–texture relationships

A model lipoproteic matrix able to mimic hard-type cheese was produced with controlled structural and textural properties. Changes in the microstructural and rheological properties of these model cheeses made from different milk concentrate powder, anhydrous milk fat, salt contents and pH values at renneting were characterised. Rheological properties were measured by texture profile analysis, fat globule and protein aggregate size distributions by laser light scattering. Microstructural properties of the model matrices were studied by confocal laser scanning and scanning electron microscopy.Significant differences between the matrices were found for the structural, physico-chemical and rheological parameters measured. Cheeses with higher dry matter content were significantly harder and contained more insoluble proteins than cheeses with lower dry matter content. The salt concentration and the pH at renneting had significant influence on cheese hardness and adhesiveness of rheological parameters. The model lipoproteic matrix presented air bubbles and powder aggregates which could not be avoided during the manufacture of products. However, compared with classic cheese making with rennet or acid coagulation, the technology used here allows model cheeses to be produced rapidly with a good reproducibility of texture.     

Expansion of rice flour treated with lactic acid and sodium bisulphite

This study aimed to develop the expansion property of rice flour using a 2² complete factorial experimental design, investigating the effects of sodium bisulphite concentration and pH on the expansion capacity, carbonyl and carboxyl contents and viscoamylographic behaviour. The sodium bisulphite concentration and pH influenced the development of the expansion property of the lactic acid treated rice flour, presenting the best volumes at pH 4 with 2.18 and 7.82 g/100 g sodium bisulphite. In order to express the highest specific volume, the proportion between the carbonyl and carboxyl groups was more important than the sum of the two, the best proportion being between 0.3 and 0.4 carbonyl and between 0.6 and 0.7 carboxyl. The chemical modification using lactic acid and sodium bisulphite affected the maximum viscosity of the rice flour, but did not influence the minimum or final viscosities.     

Colloidal Active Matter Mimics the Behavior of Biological Microorganisms—An Overview

This article provides a review of the recent development of biomimicking behaviors in active colloids. While the behavior of biological microswimmers is undoubtedly influenced by physics, it is frequently guided and manipulated by active sensing processes. Understanding the respective influences of the surrounding environment can help to engineering the desired response also in artificial swimmers. More often than not, the achievement of biomimicking behavior requires the understanding of both biological and artificial microswimmers swimming mechanisms and the parameters inducing mechanosensory responses. The comparison of both classes of microswimmers provides with analogies in their dependence on fuels, interaction with boundaries and stimuli induced motion, or taxis.     

Continuation and further development of sustainability criteria in the assessment system for sustainable house building

There is currently an assessment system for sustainable house building in Germany for the assessment of sustainability of buildings with up to five residential units. In order to ensure practicality and update the assessment of houses to the state of the technology, selected fact sheets from the BNK criteria catalogue developed in 2015 were updated and further developed with specialist support from experts known all over Germany.     

Cytocompatibility,physical properties,and antibiofilm activity of endodontic sealers with amoxicillin

The aim was to evaluate the cytocompatibility of the AH Plus and Sealapex associated with amoxicillin (AA) in a quantity of 10% by total weight of the sealers, the flow and setting time of these sealers with 10%‐0.25% AA and antibiofilm activity of these sealers associated with AA in a concentration that does not alter their physical properties (1%). Cytocompatibility was assessed by MTT, neutral red and cytoskeletal fluorescence assays. Setting time and flow was evaluated using the specifications of ISO 6876/2012. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentin blocks. The incorporation of AA into the sealers did not diminish the viability of the fibroblasts and did not cause structural changes in the cytoskeletal. The flow of AH Plus + AA at 1.0; 0.5 and 0.25%, and of Sealapex + AA at 5.5; 2.5; 1.0; 0.5 and 0.25% were within the specifications of the ISO 6876. AH Plus, and AH Plus + AA at 1.0; 0.50 and 0.25% presented a setting time of 730, 439, 455, and 474 min., respectively. Sealapex ‐ pure or associated with AA did not set completely. The addition of 1% AA to the sealers did not increase their antibiofilm activity. It was concluded that the incorporation of 10% AA caused no toxic effects on fibroblasts, but harmed the physical properties. The addition of AA in concentration that does not affect the physical properties of the sealers did not increase their antibiofilm activity.     

Toxicokinetic model describing bioconcentration and biotransformation of diazinon in Daphnia magna

A toxicokinetic model for Daphnia magna , which simulates the internal concentration of the insecticide diazinon, its detoxification product 2-isopropyl-6-methyl-4-pyrimidinol, and its active metabolite diazoxon, is presented. During in vivo exposure to diazinon with and without inhibition of cytochrome P450 by piperonyl butoxide, the parent compound as well as its metabolites were quantified with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) in extracts of D. magna . Rate constants of all relevant toxicokinetic steps were obtained by modeling the time course of the internal concentrations with a multicomponent first-order kinetics model. When cytochrome P450 was inhibited, the kinetic bioconcentration factor (BCF) of diazinon increased from 17.8 to 51.0 mL·g(ww)(-1). This clearly indicates that diazinon is biotransformed to a high degree by cytochrome P450 in D. magna . The dominant elimination step of diazinon was shown to be its oxidative dearylation to pyrimidinol (62% of total elimination) with a corresponding rate constant of 0.16 h(-1). In contrast, oxidative activation to diazoxon with a rate constant of 0.02 h(-1) amounted to only 8% of the total elimination. During exposure to diazinon, the active metabolite diazoxon could be detected only in very low concentrations (approximately 0.5% of the parent compound), presumably due to a very fast reaction with the target site acetylcholinesterase. During the exposure experiments (no feeding of daphnids), an exponential decline of the lipid content in D. magna with a first-order rate constant of 0.013 h(-1) was observed. For short exposure times (≤ 24 h), this had only a minor influence on the determined TK parameters. Such a TK model containing detailed biotransformation processes is an important tool for estimation of the toxic potential of chemicals, particularly, when active metabolites are formed inside an organism.