Investigation of effect of cold plasma on microbial load and physicochemical properties of ready-to-eat sliced chicken sausage.

Sausage may be contaminated with spoilage microorganisms during the processing after cooking and during the chilling process. Non-thermal decontamination such as cold plasma (CP) can be used to prevent the growth of spoilage microorganisms in sausage after packaging. The objective of this study was to investigate the effects of CP on sliced chicken sausage during 60 days of storage. The sausages were divided into three groups: negative control, ultraviolet (UV)-radiated (positive control for 200 and 400 s), plasma (power of 30 and 70 w for 200 and 400 s). The microbial load, pH, color, peroxide value (PV), and textural parameters of the sausages were compared with those of the negative and positive controls. According to the results, total count decreased significantly (p < 0.05) about 1.87 log CFU/g after 400 s of the CP treatment and at the end of storage at 70 w. CP reduced the lightness (L*) and increased redness (a*) more than the UV rays. The PV more increased by UV rather than by plasma. There were no significant changes in pH value and textural parameters after the CP and UV treatments. Although CP more affected some of the physicochemical properties, compared with UV, CP was shown to efficiently inhibit the rapid growth of microorganisms, resulting in a longer shelf-life.

Preparation of magnetic molecularly imprinted polymer for dispersive solid-phase extraction of valsartan and its determination by high-performance liquid chromatography: Box-Behnken design.

In this work, core/shell magnetic molecularly imprinted polymer nanoparticles were synthesized for extraction and pre-concentration of valsartan from different samples and then it was measured with high-performance liquid chromatography. For preparation of molecularly imprinted polymer nanoparticles, Fe3 O4 nanoparticles were coated with tetraethyl orthosilicate and then functionalized with 3-(trimethoxysilyl) propyl methacrylate. In the next step, molecularly imprinted polymer nanoparticles were synthesized under reflux and distillation conditions via polymerization of methacrylic acid, valsartan (as a template), azobisisobutyronitrile and ethylene glycol dimethacrylate as cross linking. The properties of molecularly imprinted polymer nanoparticle were investigated by FTIR spectroscopy, field emission scanning electron microscopy, and X-ray diffraction. Box-Behnken design with the aid of desirability function was used for optimizing the effect of variables such as the amounts of molecularly imprinted polymer nanoparticles, time of sonication, pH, and volume of methanol on the extraction percentage of valsartan. According to the obtained results, the affecting variables extraction condition were set as 10 mg of adsorbent, 16 min for sonication, pH = 5.5 and 0.6 mL methanol. The obtained linear response (r2  > 0.995) was in the range of 0.005-10 µg/mL with detection limit 0.0012 µg/mLand extraction recovery was in the range of 92-95% with standard deviation less than 6% (n = 3).

Synthesis of mesoporous silica for adsorption of chlordiazepoxide and its determination by HPLC: Experimental design.

In this work, mesoporous silica (SBA-15-NH2 ) was used as an efficient adsorbent for extraction of chlordiazepoxide from different samples based on dispersive nanomaterial-ultrasound assisted microextraction followed by high-performance liquid chromatography. The prepared sorbent was characterized by fourier transform infrared spectroscopy, scanning electron microscopy, low-angle X-ray diffraction, thermal analysis, and N2 adsorption-desorption surface area measurement. Several variables affecting the extraction efficiency of the chlordiazepoxide, including the amounts of adsorbent, time of adsorption, pH and volume of desorption solvent were optimized by central composite design combined with desirability function. The values of variables were set as 10 mg of SBA-15-NH2 , 15 min adsorption time, pH = 7.3 and 1 mL methanol. The linear response (0.998) was obtained in the range of 0.006-10 µgmL-1 with detection limit 0.0014 µg/mL and extraction recovery was in the range of 91-96% with relative standard deviation < 6%.