S.K. Pankaj

In-package nonthermal plasma degradation of pesticides on fresh produce.

In-package nonthermal plasma (NTP) technology is a novel technology for the decontamination of foods and biological materials. This study presents the first report on the potential of the technology for the degradation of pesticide residues on fresh produce. A cocktail of pesticides, namely azoxystrobin, cyprodinil, fludioxonil and pyriproxyfen was tested on strawberries. The concentrations of these pesticides were monitored in priori and post-plasma treatment using GC-MS/MS. An applied voltage and time dependent degradation of the pesticides was observed for treatment voltages of 60, 70 and 80 kV and treatment durations ranging from 1 to 5 min, followed by 24h in-pack storage. The electrical characterisation revealed the operation of the discharge in a stable filamentary regime. The discharge was found to generate reactive oxygen and excited nitrogen species as observed by optical emission spectroscopy.

Surface, Thermal and Antimicrobial Release Properties of Plasma-Treated Zein Films

The effects of dielectric barrier discharge plasma treatment on zein film containing thymol as an active ingredient were evaluated. The plasma discharge was optically characterized to identify the reactive species. A significant increase in the film roughness (p 0.05) was observed for the thermal properties of the antimicrobial films after DBD plasma treatment.

Effect of high voltage atmospheric cold plasma on white grape juice quality

BACKGROUND This study focuses on the effects of novel, non-thermal high voltage atmospheric cold plasma (HVACP) processing on the quality of grape juice. A quality-based comparison of cold plasma treatment with thermal pasteurization treatment of white grape juice was done. RESULTS HVACP treatment of grape juice at 80 kV for 4 min resulted in a 7.4 log10 CFU mL-1 reduction in Saccharomyces cerevisiae without any significant (P > 0.05) change in pH, acidity and electrical conductivity of the juice. An increase in non-enzymatic browning was observed, but total color difference was very low and within acceptable limits. Spectrophotometric measurements showed a decrease in total phenolics, total flavonoids, DPPH free radical scavenging and antioxidant capacity, but they were found to be comparable to those resulting from thermal pasteurization. An increase in total flavonols was observed after HVACP treatments. CONCLUSION HVACP treatment of white grape juice at 80 kV for 2 min was found to be comparable to thermal pasteurization in all analyzed quality attributes. HVACP has shown the potential to be used as an alternative to thermal treatment of white grape juice.

Effects of Cold Plasma on Food Quality: A Review

Cold plasma (CP) technology has proven very effective as an alternative tool for food decontamination and shelf-life extension. The impact of CP on food quality is very crucial for its acceptance as an alternative food processing technology. Due to the non-thermal nature, CP treatments have shown no or minimal impacts on the physical, chemical, nutritional and sensory attributes of various products. This review also discusses the negative impacts and limitations posed by CP technology for food products. The limited studies on interactions of CP species with food components at the molecular level offers future research opportunities. It also highlights the need for optimization studies to mitigate the negative impacts on visual, chemical, nutritional and functional properties of food products. The design versatility, non-thermal, economical and environmentally friendly nature of CP offers unique advantages over traditional processing technologies. However, CP processing is still in its nascent form and needs further research to reach its potential.

Effects of Cold Plasma on Surface, Thermal and Antimicrobial Release Properties of Chitosan Film

This work aims to analyze the effects of cold atmospheric air plasma treatment of antimicrobial chitosan film with different levels of thymol. Optical characterization of the dielectric barrier discharge showed the generation of reactive nitrogen and oxygen species by the system. A significant increase (p < 0.05) in the surface roughness was observed after cold plasma treatment of the films. No significant difference (p > 0.05) was observed in the thermal profile of the plasma-treated films. A significant increase (p < 0.05) in the thymol diffusion coefficient was observed after the plasma treatment for all the active films.

Cold Plasma Applications in Food Packaging

Cold plasma is a non-thermal technology which has been used, in the packaging industry for decades. The advances in plasma science have created a multitude of applications for cold plasma, apart from surface modifications. The adverse effects of plasma reactive species on microorganisms have facilitated its use for sterilization of air, water, food products, equipment and packaging materials. Cold plasma is also beneficial in altering the polymerization of packaging materials for development of novel polymers with unique properties. The in-package processing has shown potential to be used as an alternative to conventional thermal food processing technologies.

Degradation kinetics of organic dyes in water by high voltage atmospheric air and modified air cold plasma

High voltage atmospheric cold plasma (HVACP) is a novel, non-thermal technology which has shown potential for degradation of various toxic components in wastewater. In this study, HVACP was used to examine the degradation kinetics of methyl red, crystal violet and fast green FCF dyes. HVACP discharge was found to be a source of reactive nitrogen and oxygen species. High voltage application completely degraded all dyes tested in less than 5 min treatment time. Plasma from modified gas (∼65% O2) further reduced the treatment time by 50% vs. plasma from dry air. First order and Weibull models were fitted to the degradation data. The Weibull model was found better in explaining the degradation kinetics of all the treated dyes.