Márk Horváth

No Major Differences Found between the Effects of Microwave-Based and Conventional Heat Treatment Methods on Two Different Liquid Foods

Extension of shelf life and preservation of products are both very important for the food industry. However, just as with other processes, speed and higher manufacturing performance are also beneficial. Although microwave heating is utilized in a number of industrial processes, there are many unanswered questions about its effects on foods. Here we analyze whether the effects of microwave heating with continuous flow are equivalent to those of traditional heat transfer methods. In our study, the effects of heating of liquid foods by conventional and continuous flow microwave heating were studied. Among other properties, we compared the stability of the liquid foods between the two heat treatments. Our goal was to determine whether the continuous flow microwave heating and the conventional heating methods have the same effects on the liquid foods, and, therefore, whether microwave heat treatment can effectively replace conventional heat treatments. We have compared the colour, separation phenomena of the samples treated by different methods. For milk, we also monitored the total viable cell count, for orange juice, vitamin C contents in addition to the taste of the product by sensory analysis. The majority of the results indicate that the circulating coil microwave method used here is equivalent to the conventional heating method based on thermal conduction and convection. However, some results in the analysis of the milk samples show clear differences between heat transfer methods. According to our results, the colour parameters (lightness, red-green and blue-yellow values) of the microwave treated samples differed not only from the untreated control, but also from the traditional heat treated samples. The differences are visually undetectable, however, they become evident through analytical measurement with spectrophotometer. This finding suggests that besides thermal effects, microwave-based food treatment can alter product properties in other ways as well.

Preliminary results on the intensification of the BCR sequential extraction with sonication for sediments, soils, and gravitation dust sediment samples

This study deals with the problems of intensification of sequential extraction scheme, proposed by the European Community Bureau of Reference (BCR). The conventional extraction procedure has been modified by applying ultrasound energy from the titanium probe with the aim to shorten the long required extraction time. In this article we concentrated only on the first step of this extraction scheme, which has been applied for the fractionation of Ca, Mg, Fe (matrix elements) and Zn, Pb, Cu (trace elements) in sediment and soil samples collected in a typical agricultural region, and gravitation dust sample collected in a typical industrial region. The content of elements in extracts of conventional and ultrasound-assisted extraction was determined by FAAS. The results obtained from conventional extraction confirmed the differences among studied samples. In the soil sample adequate forms of only Ca and Mg (matrix elements) were detected, in the sediment samples was Ca, Mg, Fe, and Zn, and in the sample of gravitation dust sediment besides it these elements were found Pb and Cu, too. The effect of ultrasound on the acceleration of the extraction was different for all the studied samples and each element.

Study of application of BCR sequential extraction procedure for fractionation of heavy metal content of soils, sediments, and gravitation dusts

This article deals with the application of original and modified Community Bureau of Reference (BCR) sequential extraction scheme for fractionation of contaminant metallic elements (Zn, Cd, Pb, Ni, Cr, and Cu) in sediments, soils, and aerial gravitation dusts. Contamination level and extractability of contaminant element in our internal laboratory soil, sediment, and gravitation dust reference samples was studied by original BCR procedure proposed to certified reference material (CRM) 601 sediment reference material. A preliminary comparative study was performed to control the extraction ability of original and modified BCR procedure using CRM 601 and 701, respectively. It was established that original BCR scheme can be applied for different kinds of samples (sediment, soil, dust) when necessary sample amount is available; however, one has to calculate with analyte losses due to pH instability during the second and third leaching steps and readsorption may occur after third leaching step during the phase separation. This latter observation was verified by direct solid sample analysis of original samples and third-step solid residue.

Multi-Elemental Inductively Coupled Plasma-Optical Emission Spectroscopic Calibration Problems of the Sequential Extraction Procedure for the Fractionation of the Heavy Metal Content from Aquatic Sediments

Abstract For the characterisation of the environmental mobility of heavy metal contamination in aquatic sediments, the EU Bureau of Reference has proposed a fractionation by sequential extraction procedure. For its validation, the CRM-701 sample is available containing Cd, Cr, Cu, Ni, Pb, and Zn. In this paper, the matrix-matched calibration problems are presented. A multi-elemental inductively coupled plasma-optical emission technique is employed for the detection of heavy metals in the extracts. It was established that the sensitivities are strongly influenced by the extractants, which causes significant matrix effects: the sensitivities are strongly influenced by the solvents applied in extraction steps; the summarised recoveries show an acceptable agreement with the certified values; however, in the individual extraction steps for certain elements significant differences may occur due to the neglected interferences. Therefore, further optimisation is required utilising the flexible line selection possibility offered by the HORIBA Jobin Yvon ACTIVA-M instrument.

HIGH CONCENTRATIONS OF RADON AND CARBON DIOXIDE IN ENERGY-EFFICIENT FAMILY HOUSES WITHOUT HEAT RECOVERY VENTILATION

The most significant factors of indoor air quality – besides temperature and humidity – are the concentrations of carbon-dioxide (CO2) and radon (222Rn). Radon seepage is caused by and affected by the materials used in walls and floors, the quality of insulation, cracks and even the amount of pipes running through the walls. The amount of CO2 is predominantly affected by the biological processes of the inhabitants, and possibly by potentially faulty HVAC systems. The energy efficiency related upgrades to family homes, which often only extend to window replacements and better insulation have a significant effect and could potentially increase concentrations of both radon and CO2 which has a significant effect on the well-being of the inhabitants. Our tests conducted in Hungary have proven that by using automated heat recovery ventilation (HRV) both energy efficient operation and low concentrations of radon and CO2 are achievable. Our results prove the significance and prevalence of the issue of higher concentrations of these pollutants, and offer a viable solution.

Improvement of the sequential extraction procedure based on supercritical CO2 and subcritical H2O solvents for the estimation of the environmentally mobile potentially toxic element fractions of sediments and soils

The estimation of environmental risk caused by pollution with potentially toxic elements (PTE) is usually carried out using the (3+1) step sequential extraction procedure suggested in 1993 by the Community Bureau of Reference (BCR). In the 1st step the water-soluble, exchangeable and carbonate-bound element content is extracted with acetic acid. In 2002 a fractionation procedure based on the application of supercritical CO 2 , subcritical H2O and of a mixture of subcritical H 2 O/CO 2 was proposed, which allowed the water-soluble and carbonatebound element contents to be extracted separately from sediment or soil samples weighed into the preparative column of a supercritical fluid extractor and diluted with quartz sand in a mass ratio of 1:20. The aim of the present study was to develop a new reduced-size column construction with which this dilution rate could be decreased to 1:2. A kinetic study was performed to determine the extraction time necessary for samples with different carbonate contents and the extracted element contents were compared to the results of the BCR sequential procedure on the same samples. It was established that fractionation using the reduced-size column may be a rapid way to obtain more reliable information on the easily mobilizable (watersoluble and carbonate-bound) PTE content of soils and sediments than was previously available to supplement BCR fractionation.

Heavy Metal Balance in a Communal Wastewater Treatment Plant

In early 2000, two contamination events at Baia Mare first and Baia Borsa second involving large amounts of toxic elements impacted the Hungarian section of the River Tisza with disastrous ecological and economical impacts. We evaluated the sort- and long-term effects of this pollution by determining the total and bioavailable concentrations of potentially toxic metals from soil samples collected along the Tisza (Tivadar, Vasarosnameny, Rakamaz, and Tiszacsege) in 2000 and between 2011 and 2013. The current and previous results were compared in respect of copper and lead contents.

Evaluation of the Heavy Metal Content of the Upper Tisza River Floodplain Soils over the last Decade

Abstract In early 2000, two contamination events at Baia Mare first and Baia Borsa second involving large amounts of toxic elements impacted the Hungarian section of the River Tisza with disastrous ecological and economical impacts. We evaluated the sort- and long-term effects of this pollution by determining the total and bioavailable concentrations of potentially toxic metals from soil samples collected along the Tisza (Tivadar, Vásárosnamény, Rakamaz, and Tiszacsege) in 2000 and between 2011 and 2013. The current and previous results were compared in respect of copper and lead contents.