دکتر یدالله یمینی

Identification of volatile contaminants migrating from packaging materials that might affect the quality of packaged food and might cause problems to consumer health is great importance. Soft cheeses can undergo such migration and contamination during storage. This study aimed to exclusively identify abnormal volatile compounds in Iranian cheeses that likely originated from contamination and packaging rather than endogenous components using HS-SPME GC-MS. White brine and ultrafiltrated (UF) cheeses in packages were stored for 90 days at 4 degrees Celsius (°C). Headspace-solid phase microextraction (HS-SPME) using polysulfone and mesoporous carbon nitride (MCN/Polysulfone) fiber coupled to gas chromatography-mass spectrometry (GC-MS) was employed to extract and analyze volatile compounds. Migration-based contaminants exclusively present in stored versus fresh cheeses were identified through National Institute of Standards and Technology (NIST) library matching. In total 23 unwanted volatile contaminants originating from contamination/packaging were identified, including 19 compounds in white brine` cheese (phthalates, benzenecarboxylic acids, etc.) and 13 compounds in UF cheese (phthalates, benzenecarboxylic acids, triazenes, oximes, etc.). More migrants were observed in white brine cheese. Compounds also differed based on SPME extraction method. Prolonged storage induced migration of volatile contaminants from probable packaging sources into soft cheeses. Future research should focus on refining volatile organic compound (VOC)-based detection methods to enhance early identification of spoilage and pathogenic microorganisms in cheese production.

This paper reports application of cetyltrimethylammonium bromide (CTAB) coated magnetite nanoparticles (Fe3O4 NPs) as a novel adsorbent for removal of two types of disperse dyes, including disperse red 167, and disperse blue 183, from wastewater of textile companies. The effect of parameters including type of surfactant, pH of solution, surfactant concentration, and amount of salt, was investigated and optimized. The obtained results showed that the ratio of initial dye concentration to CTAB amounts has critical effect on removal processes so that removal efficiencies higher than 95% can be achieved even at high concentration of dyes as high as 500 mg l-1 when the ratio is optimum. Removal of dyes is very fast, and equilibrium is reached at times less than 10 min even for high concentration of the dyes. Very high adsorbent capacity (as high as 2000 mg g-1) was yielded for maximum tested concentration of the dyes (500 mg g-1). The obtained result was confirmed by thermogravimetric analysis data. This study showed that CTAB coated Fe3O4 NPs is a very efficient adsorbent for removal of dyes from wastewater of textile companies and has high capacity under optimum conditions.