Utilization of atmospheric pressure plasma for decontamination and detoxification of foods | Atmosferik basınç plazma uygulamasının gıdaların dekontaminasyonu ve detoksifikasyonu amacıyla kullanımı

This study focuses on the utilization of plasma technique for the reduction of fungal spores,inoculated on model foods (hazelnut, flaked red pepper), to determine whether non-thermal atmospheric and low-pressure plasmas could provide an effective alternative method to current decontamination and detoxification methods. Both plasma systems were tested for the inactivation of Aspergillus flavus and parasiticus. Different plasma parameters and different gas types were tested for low-pressure plasma (discharge power 0–100 W, exposure time 0–30 min, application gases:nitrogen, oxygen, air) and atmospheric pressure plasma(plasma frequency:16-20-25 kHz, reference voltage:40-100, plasma jet velocity:50-100 m/min, gas flow rate:3000-5000 L/h, raster offset:3-5 mm, cycle time:5, application gases:nitrogen, air).After each plasma treatment, remained spores were counted and optimum plasma parameters were determined. The optimum parameters for decontamination of spores were determined as air plasma 100 W-30 min (discharge power-time) for low pressure plasma and air plasma with frequency of 25 kHz, reference voltage at 100 W, plasma jet rate of 60 m/min, gas flow rate of 3000 L/h, scanning range at 3mm, recycle time of 5 min for atmopheric pressure plasma. After that, physicochemical and aflatoxin analysis, and toxicological experiments were carried out to determine the effects of non-thermal plasma treatment on basic components and bioactive compounds of model foods, i.e. hazeltnut and red pepper. Results were also compared with 10kGy gamma irradiated test samples. After the plasma and irradiation treatments of both food samples, moisture, water activity (aw) and color; free fatty acids (FFA), peroxide value (PV), total phenolic content (TPC), and aflatoxin analysis were perfomed. Cytotoxicity of different concentrations of aflatoxins(1-1000 ppb) on L929 mouse fibroblast cells was investigated with MTT tests. Results of cytotoxicity tests were confirmed by HPLC results quantitatively. The effectiveness of plasma decontamination was also supported by SEM images to see how plasma can affect the outer surface of spores. In this study, both plasma systems were determined to be adequate and efficient for decontamination/detoxification of model foods. Since effects of atmospheric pressure plasma on physico-chemical properties of food were close to that of gamma radiation, atmospheric pressure plasma could be an alternative to gamma radiation compared to low-pressure plasma system.