Efficacy of low pressure DBD plasma in the reduction of T-2 and HT-2 toxin in oat flour.

T-2 and its major metabolite HT-2 toxin are naturally occurring contaminants in cereals, with the highest concentrations determined in oats. Because of their toxicity and resistance to conventional methods used in mycotoxin degradation, development of new effective procedures for reduction of T-2/HT-2 toxin levels is needed. The aim of this study was to investigate the effect of different gas types within various timeframes on the efficiency of T-2 and HT-2 toxin degradation by low pressure dielectric barrier discharge (DBD) plasma in oat flour. Although humidity of the sample influences the intensity of the plasma, oxygen atoms efficiently oxidize the sample and produce CO and N2. Before and after treatment, T-2 and HT-2 toxin concentrations were analysed by the confirmatory liquid chromatography tandem-mass spectrometry (LC-MS/MS) method. The highest reduction of T-2 and HT-2 toxin of 43.25% and 38.54%, respectively, was achieved using nitrogen plasma and this proved to be time-dependent.

Proteomic analysis of Saccharomyces cerevisiae response to plasma treatment.

Food safety is one of the main issues for the food industry. Regarding the increased reports of food-associated infections new non-thermal technologies are rapidly developing and improving. The aim of this research was to define the inactivation, recovery and stress response of Saccharomyces cerevisiae ATCC 204508 cells after the treatment by high voltage gas phase plasma and liquid phase plasma discharges in bubbles. Variations of the plasma frequency (60, 90 and 120 Hz), input gas (air or argon) and processing time (5 and 10 min) have been used to define plasma effects on S. cerevisiae cells. Complete inactivation's by liquid plasma in bubbles were determined as well as recovery of treated samples. Transmission electron microscopy figures showed cells with the normal cell shape and intact inner and outer membrane after the plasma treatments. Proteomic analyses indicated overexpressed proteins which contributed in cell defense mechanisms to overcome stress conditions. S. cerevisiae ATCC 204508 cells were under the stress, but with the proven ability to recover its metabolic activity.

Green Procedure to Manufacture Nanoparticle-Decorated Paper Substrates.

For this study, a paper impregnated with silver nanoparticles (AgNPs) was prepared. To prepare the substrates, aqueous suspensions of pulp fines, a side product from the paper production, were mixed with AgNP suspensions. The nanoparticle (NP) synthesis was then carried out via laser ablation of pure Ag in water. After the sheet formation process, the leaching of the AgNPs was determined to be low while the sheets exhibited antimicrobial activity toward Escherichia coli (E. coli).

Modification of Physico-Chemical Properties of Acryl-Coated Polypropylene Foils for Food Packaging by Reactive Particles from Oxygen Plasma.

This investigation was focused on the influence of long-living neutral reactive oxygen species on the physico-chemical properties of acryl-coated polypropylene foils for food packaging. Reactive species were formed by passing molecular oxygen through a microwave discharge and leaking it to a processing chamber of a volume of 30 L, which was pumped by a rotary pump. The density of neutral O-atoms in the chamber was tuned by adjustment of both the effective pumping speed and the oxygen leak rate. The O-atom density was measured with a catalytic probe and was between 3 × 1018 and 5 × 1019 m-3. Commercial foils of biaxially oriented polypropylene (BOPP) coated with acrylic/ poly(vinylidene chloride) (AcPVDC) were mounted in the chamber and treated at room temperature by O atoms at various conditions, with the fluence between 1 × 1021 and 3 × 1024 m-2. The evolution of the surface wettability versus the fluence was determined by water contact angle (WCA) measurements, the formation of functional groups by X-ray photoelectron spectroscopy (XPS), and the morphology by atomic force microscopy (AFM). The WCA dropped from the initial 75° to approximately 40° after the fluence of a few 1022 m-2 and remained unchanged thereafter, except for fluences above 1024 m-2, where the WCA dropped to approximately 30°. XPS and AFM results allowed for drawing correlations between the wettability, surface composition, and morphology.

Stability of polyphenols in chokeberry juice treated with gas phase plasma.

Chokeberry juice was subjected to cold atmospheric gas phase plasma and changes in hydroxycinnamic acids, flavonols and anthocyanins were monitored. Plasma treatments were carried out under different treatment times and juice volumes under constant gas flow (0.75dm(3)min(-1)). The results were compared against control (untreated) and pasteurized chokeberry juice (80°C/2min). During pasteurization, the most unstable were hydroxycinnamic acids with losses of up to 59%, while flavonols and anthocyanins increased by 5% and 9%, respectively. On the contrary, plasma treated chokeberry juice showed higher concentrations of hydroxycinnamic acids and 23% loss of anthocyanins in comparison to untreated juice. In order to obtain the optimal cold plasma treatment parameters principal component and sensitivity analysis were used. Such parameters can be potentially used for pasteurization in terms of phenolic stability of chokeberry juice. Optimal treatment was at 4.1min and sample volume of 3cm(3).

Rheological properties of ultrasound treated apple, cranberry and blueberry juice and nectar.

Ultrasound is non-thermal food processing technique that has been used in food processing very extensively for the last 10 years. The objective of this study was to investigate the effect of high power ultrasound and pasteurization on rheological properties (n and k) of apple, cranberry and blueberry juice and nectar. Samples were treated according the experimental design, with high power sonicator at ultrasound frequency of 20 kHz under various conditions (treatment time, temperature of sample and amplitude). Thermosonication and sonicaton of juice and nectar samples have been performed. It was found that all samples of untreated, pasteurized and ultrasonically treated apple, cranberry and blueberry juices and nectars shows non-Newtonian dilatant fluid characteristics (n > 1). The interaction of treatment time and temperature of sample (BC) and temperature (C) of sample of apple juice had statistically significant effect on flow behavior index (n) for ultrasound treated apple juice. Interaction of treatment time and temperature of sample (BC) has statistically significant effect on the flow behavior index (n) for blueberry nectar. Also, there is statistically significant effect of temperature (C) of sample on consistency coefficient (k) for ultrasound treated apple juice.