The impact of two insecticides on the pollutant cycle and quality of surface and groundwater resources in the irrigated lands of Yasuj, Iran.

The increase in the need for food and agricultural development has led to an increase in the use of insecticides. The use of insecticides leads to air, soil and water pollution. This study investigated the pollutant concentration cycle in the environment by analyzing diazinon and deltamethrin in a river and groundwater sources affected by an agricultural area. The samples were analyzed based on the standard method for insecticides in water using a GC-MS. The results showed that the quality of the surface water affected by the agricultural effluents decreased so that the changes of dissolved oxygen, nitrate, turbidity, TOC, BOD, and COD were 15.2%, 189.6%, 00%, 53%, 176%, and 57.5%, respectively. The concentration of diazinon and deltamethrin in agricultural wastewater was 86 µg/L and 11.62 µg/L. The self-treatment capacity of the river reduced the concentration of diazinon in the distance of 2 km and 15 km by 80.8% and 90.3%, respectively. These conditions were observed for deltamethrin in 74.8% and 96.2%, respectively. Also, the concentration of the two insecticides in water resources has temporal and spatial variation. The difference between the maximum and minimum concentration of diazinon and deltamethrin at different times was 183.5 and 1.73, respectively. The concentration of diazinon and deltamethrin in the downstream groundwater of the studied irrigated area was 0.3-0.7 µg/L, respectively. Although the soil structure and the self-purification capacity of the river caused a significant reduction of insecticides, the remained concentration of these pollutants in underground and surface water resources can still be a health and environmental concern.

Effect of eliminating hdcA gene of Staphylococcus epidermidis TYH1 on Histamine production.

Background and Objectives: The possible adverse effect of histamine on human health has made it a detrimental aspect to the quality and safety of many fermented food products especially fish sauce. Materials and Methods: In the present study, hdcA gene in Staphylococcus epidermidis TYH1 was knocked out and its effect on histamine production was evaluated. HdcA encodes histidine decarboxylase, an enzyme that produces histamine from histidine. Both strains of TYH1, the wild type (WT) and mutant (ΔhdcA) were then incubated in tryptic soy broth (TSB) supplemented with histidine (0.5 mM). The histamine content determined by capillary zone electrophoretic (CZE) analysis. Safety assessment of this mutant of food origin was conferred by virulence genes. Results: It was found that S. epidermidis TYH1 exhibited production of histamine (50.09 ± 0.06 µg/mL), while ΔhdcA strain of TYH1 exhibited no histamine forming activity. Safety assessment of ΔhdcA revealed the presence of nuc gene, while superantigenic toxins and coa genes were not observed. Therefore, it has the ability to be used as a starter culture to decrease the histamine content in any fermented food products. Conclusion: Our study findings may contribute to provide a novel approach of promoting the food safety of fish sauce and other fermented food products regarding the regulation of histamine content.

Qualitative analysis of the structural, thermal and rheological properties of a plant ice cream based on soy and sesame milks.

The aim of this study was to investigate the structural, physicochemical, and rheological properties of soy and sesame milk-based ice cream in order to optimize its formula. The overrun percentage of the optimized ice cream was acceptable compared to the conventional ice cream (produced with cow milk). The hardness and consistency of the optimized ice cream were significantly (p < .05) higher than those of the conventional one, while its cohesiveness was lower. All the samples showed the pseudoplastic behavior and the power-law model had a high efficiency (R 2 ≥ .99) in describing their rheological behavior. The lowest span value, the lowest mean particle diameter, and the highest mean particle surface area, and thus, the most stable and homogenous samples were associated with the conventional ice cream followed by the optimized plant one. The number of air bubbles in the structure of the conventional and optimized ice creams was significantly (p < .05) higher than in the other samples. The soy ice cream had the lowest Tg (-58.04°C), whereas the conventional one had the highest Tg (-55.05°C). Unlike the plant-based samples, especially the soy ice cream, the conventional ice cream had the lowest ice content (IC), the highest unfreezable water (UFW), and the lowest frozen water (FW). Overall, this ice cream was more acceptable in terms of sensory attributes in comparison with the control sample and could be supplied to consumers as a novel, high-quality, and marketable ice cream.

The dependency of rheological properties of Plantago lanceolata seed mucilage as a novel source of hydrocolloid on mono- and di-valent salts.

The effects of NaCl and CaCl2 (0-200 mM) on the rheological properties of Plantago lanceolata seed mucilage (PLSM) as a novel potential source of polysaccharide gum were investigated in this study. Furthermore, FTIR analysis was measured to supply more structural information. The FTIR spectra revealed that PLSM with the presence of glycoside bonds and carboxyl and hydroxyl groups behave like a typical polyelectrolyte. It was observed that the gum solutions exhibited viscoelastic properties under the given conditions and the addition of salts had significant affection on the rheological parameters of gum solutions. The weak gel-like behavior (0.1 < tan Î´ < 1) observed for all solutions at different ion types and ionic strengths. The limiting values of strain mostly increased with enhance cation concentration due to the intermolecular interaction and therefore increase the stiffness of gum solutions in the concentrated domain. The frequency sweep results showed that developing ion concentration had a positive effect on the viscoelasticity of gum solutions which Ca2+ was more effective than Na+. Tanglertpaibul&Rao model showed the highest efficiency to evaluate the intrinsic viscosity of PLSM for all co-solutes. The results of this study could be useful when considering the effects of salts on food systems.

Effects of high hydrostatic pressure on the rheological properties and foams/emulsions stability of Alyssum homolocarpum seed gum.

The ability to modify food and increase the shelf life by enhanced stability using nonthermal process is of interest to many food companies. Here, we investigate the effects of high hydrostatic pressure (HHP), as a nonthermal process, at various pressure levels (200, 400, and 600 MPa for 30 min) on the functional properties of aqueous dispersions of Alyssum homolocarpum seed gum (AHSG). In this regard, the rheological properties, foam stability, and emulsion stability of the HHP-treated gums were analyzed and compared. Dynamic oscillatory test indicated that the HHP-treated gums had more gel-like behavior than viscous-like behavior (storage modulus > loss modulus) at designated pressures. When AHSG was treated by HHP, both elastic (G') and viscous (G″) moduli were increased compared to the native AHSG. The native- and HHP-treated gums exhibited a shear-thinning (pseudoplastic) behavior. Furthermore, the pressure levels have a significant effect on consistency coefficient, flow behavior index, and yield stress (p < .05) of AHSG. The results showed that the HHP-treated gums lead to improve the foam and emulsion stability of AHSG. Finally, we assume that HHP-treated AHSG improves texture in the food materials.