Cross-linked chitosan polymers as generic adsorbents for simultaneous adsorption of multiple mycotoxins

The primary objective of this study was to synthesize three types of cross-linked chitosan polymers and further investigate their adsorption capability for multiple mycotoxins, including aflatoxin B₁ (AFB₁), ochratoxin A (OTA), zearalenone (ZEN), fumonisin B₁ (FB₁), deoxynivalenol (DON) and T-2 toxin (T2). Among these synthetic adsorbents, cross-linked chitosan-glutaraldehyde complex presented the highest adsorption capability for AFB₁ (73%), OTA (97%), ZEN (94%) and FB₁ (99%), but no obvious adsorption for DON and T2 (<30%). The effect of various incubation conditions (contact time, dosage and pH) was also studied. Subsequently, the experimental data were fitted to Langmuir, Freundlich and Hill models. The best fitting model to describe AFB₁ and FB₁ adsorption was Langmuir model (R² ≥ 0.99), with the theoretical maximum adsorption amounts of 5.67 mg/g for AFB₁ and 15.7 mg/g for FB₁. The Hill model was the best model for OTA and ZEN adsorption (R² > 0.98), with the predicted maximum adsorption amounts were 24.8 mg/g for OTA and 9.18 mg/g for ZEN. In addition, the adsorption capability of adsorbent for the simultaneous presence of multiple mycotoxins was also evaluated in buffer system and simulated gastrointestinal condition. The results indicated that the coexisted multiple mycotoxins didn't affected the adsorption capability of adsorbent, whereas the adsorption amounts of toxins were decreased by some gastrointestinal components. The findings of this research suggest that chitosan–glutaraldehyde complex has the potential to be applied as multitoxin adsorbent material for reducing the combined adverse effect of multiple mycotoxins on humans and animals.     

Addition of phytochemical-rich plant extracts mitigate the antimicrobial activity of essential oil/wine mixtures against Escherichia coli O157:H7 but not against Salmonella enterica

Marinades for preparing raw meats for cooking are frequently made of wine and herbs. We simulated several formulations of potential antimicrobial marinades with these components and other food compatible/food derived extracts. Red wine formulations containing essential oils from oregano or thyme, or their primary active components carvacrol and thymol, respectively, and a mixture of plant extract powders from phytochemical-rich apple skin, green tea, and olive, were evaluated for inhibitory activity against the foodborne pathogens Escherichia coli O157:H7 and Salmonella enterica. Red wine alone exhibited low activity, as did the plant extract suspended in the wine. Surprisingly, the high activity of oregano or thyme essential oils in red wine was reduced in E. coli, but not in Salmonella, by addition of the plant extract. This study shows that essential oils in red wine can be an effective antimicrobial in food, however the possibility exists that phytochemicals, added to the treatment solution or natively present in the food itself, could adversely impact the antimicrobial activity and should be addressed with future studies.     

Phase transition in potato starch–water system I. Starch gelatinization at high moisture level

Optical microscopy, micro-calorimetry (Calvet), FTIR spectroscopy and X-ray diffraction were used to study thermal phase transitions in potato starch–water systems at high moisture level (66–82%). Phase transition in potato starch–water systems depended on the moisture content of the system. At higher moisture contents (e.g. >66%), a first-order transition was observed at about 65 °C, which is associated with gelatinization of starch. The transition was cooperative, involving swelling of starch granules with loss of birefringence and crystallinity. Alteration in the secondary structure and conformation of starch is suggested by the changes around 1020 cm⁻¹ (mainly C–O–H bond vibration) in FTIR spectroscopy. The effect of cultivar, fertilization regime and genetic transformation and storage period on the phase transition behavior of potato starch–water system was also examined.     

Pectinesterase extraction from Mexican lime (Citrus aurantifolia Swingle) and prickly pear (Opuntia ficus indica L.) peels

Extracts from Mexican lime (Citrus aurantifolia Swingle) and prickly pear (Opuntia ficus indica L.) peels were tested for their pectinesterase activity. A factorial design was applied in this study as a method for enzyme extraction in which the variables were the source of enzyme (prickly pear and Mexican lime peels) and the NaCl solution concentration (0–3.0 M). In all cases, enzyme extracts obtained using the same NaCl concentration from lime peel showed higher activity than extracts from prickly pear peel. NaCl concentration influenced the pectinesterase extraction process in both cases. Maximum enzyme activities were obtained with NaCl 0.5 M and 1.0 M for Mexican lime and prickly pear peels, respectively.     

Effects of titanium dioxide nanoparticles on intestinal commensal bacteria

Nanomaterials and nanotechnology have great potential in the biological and biomedical field. Recent studies reveal that many nanomaterials possess antibacterial activities. While most of these studies focus on the ability of nanomaterials to inhibit the growth of pathogenic bacteria in vitro, few of them test the effects of nanomaterials on intestinal commensal bacteria. Here, we report that Ti O_2nanoparticles(10, 50 and 100 nm in size) can inhibit the growth of Drosophila intestinal commensal bacteria in vitro. This activity depends on the dosage or size, but is independent of the photocatalytic activity of Ti O_2 nanoparticles. Surprisingly, dietary Ti O_2 nanoparticles of the same dosage fail to display similar effects in Drosophila larvae or adults. These flies show a normal amount of intestinal commensal bacteria, as well as a normal developmental cycle, energy store, and locomotor activity. These results imply that the antibacterial effect of Ti O_2 nanoparticles differs in vitro and in vivo.     

Development of a rapid magnetic bead-based immunoassay for sensitive detection of zearalenone

Here we demonstrate a novel magnetic bead-based enzyme-linked immunosorbent assay (MB-ELISA) for zearalenone (ZEN) detection. Firstly, an anti-ZEN monoclonal antibody (mAb) was prepared by hybridoma technique, and immobilized on carboxyl modified MBs to obtain mAb-MBs. In addition, the biotinylated ZEN-BSA was labelled by streptavidin-HRP for use as competitor. Based on the mAb-MBs and streptavidin-HRP labelled ZEN-BSA, a MB-ELISA which contains only one 20 min antigen-antibody reaction step and takes no more than 45 min for dozens of samples analysis was developed. The half maximal inhibitory concentration (IC₅₀) and limit of detection (LOD) of the MB-ELISA are 1.78 ng/mL and 0.13 ng/mL, respectively. And the MB-ELISA working range for corn samples analysis is from 5.0 μg/kg to 255.2 μg/kg. The recoveries for ZEN spiked corn samples ranged from 82.3 to 110.5% with coefficient of variation (CV) under 8.9%. For natural corn samples analysis, the results of MB-ELISA showed good agreement with the results of conventional direct competitive ELISA (R² = 0.9742).     

Long‐Term Effects of Nanoparticles on Nutrition and Metabolism

Nanoparticles have shown great potential in biological and biomedical applications due to their distinct physical and chemical properties. In the meanwhile, the biosafety of nanoparticles has also raised intense concerns worldwide. To address such concerns, great efforts have been made to examine short‐term effects of nanoparticles on cell survival and proliferation. More recently, exploration of long‐term effects of nanomaterials, particularly those with promising biomedical applications in vivo, has aroused significant interest. For example, gold nanoparticles (AuNPs) are generally considered non‐toxic to cell growth, whereas recent studies suggest that AuNPs might have long‐term effects on cellular metabolism and energy homeostasis. In this Review, recent advances in this direction are summarized. Further, possible mechanisms under which nanoparticles regulate metabolic signaling pathways, potential long‐term effects on cellular anabolic or catabolic processes, and their implications in human health and metabolic disorders are discussed.     

A novel linear-chain material showing sandwiched stacking via alternative Pt(II)⋯Pt(II) or Pt(II)⋯S and π⋯π interactions

A novel linear-chain material, [Pt(8-QNS)₂][Pt(terpy)Cl]₂(ClO₄)₂ (8-QNS=8-quinolinethiolate; terpy=2,2^′:6^′,2″-terpyridine), has been serendipitously isolated and characterized by a crystallographic study. The title compound composed of alternative cationic [Pt(terpy)Cl]⁺ pairs and [Pt(8-QNS)₂] moieties is formed by an interesting rearrangement process, and it shows sandwiched stacking via alternative Pt(II)⋯Pt(II) or Pt(II)⋯S and π⋯π interactions.     

EMD-based online Filtering of Process Data

In chemical industries, measurements corrupted by noise or outliers may affect operators’ recognition of the current situation and lead them to make inappropriate control decisions. Data quality is a critical factor for process monitoring and fault diagnosis. A robust online filtering method (OLREMD¹) is proposed to implement online process data rectification with Empirical Mode Decomposition (EMD) as the basic algorithm. Tests with synthetic data show that OLREMD performs robustly with a lower sensitivity to parameters and improved performance on elimination of both noise and outliers. When applied to an industrial de-ethanizing column, OLREMD is shown to enhance the process monitoring performance.