10:00 am - 11:00 am
318-J Agriculture/Forestry Centre, Agriculture/Forestry Centre, Edmonton
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES PhD Final Exam Seminar by Ehsan Feizollahi. This seminar is open to the general public to attend.
Meeting ID: 936 1095 3980 | Passcode: 348956
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Find your local number: https://ualberta-ca.zoom.us/u/akvA9ZdJu
Thesis Topic: Mycotoxin degradation in food and feed grains by atmospheric cold plasma technology
PhD with Dr. Roopesh Syamaladevi.
Contamination of grains with mycotoxins causes quality loss and hence considerable financial loss to the grain industry. Also, mycotoxins negatively affect human and animals’ health. Several mycotoxins are resistant to high temperatures and the elimination of them from grains is a challenging task. Atmospheric cold plasma (ACP) is an emerging non-thermal technology, that has attracted attention due to its mycotoxin degradation potential. The overall objective of this research was to assess the efficacy of different types of ACP systems to degrade selected mycotoxins. The influence of important process and product factors on the mycotoxin degradation efficacy of ACP as well as the degradation mechanism of deoxynivalenol (DON) mycotoxin during ACP treatment were studied. Furthermore, the efficacy of ACP treatment on Fusarium graminearum inactivation was determined in order to assess the potential use of this technology in the barley malting industry.
In the first study, the degradation of DON by dielectric barrier discharge ACP and sequential treatment with heat and ultraviolet (UV, 395 nm) light was tested. There was no synergistic DON degradation effect when ACP was used in sequential combination with thermal or UV treatment. The ACP treatment was more effective when DON was in solution form compared to dry state. There were major changes in DON functional groups after ACP treatment. In the second study, DON was spiked on barley grains and the efficacy of ACP on the degradation of DON and selected barley quality parameters was investigated. The results from optical emission spectroscopy proved the presence of reactive oxygen and nitrogen species (RONS) and N2 spectra were dominant. The ACP was able to significantly reduce DON content in a short period of time. Elevating the relative humidity of the surrounding air and increasing the moisture content of barley did not impact the DON degradation efficacy of ACP. Steeping of barley grains prior to ACP treatment significantly increased the DON degradation rate by ACP treatment. No significant differences were observed for the tested quality parameters of barley in comparison with control samples.
The third study focused on the impact of selected product and process factors on zearalenone (ZEA) degradation using two technologies i.e., jet ACP and dielectric barrier discharge ACP. Type of product (barley grains, canola grains, and canola meal) affected the ACP efficacy and the presence of oxygen in the carrier gas to produce ACP significantly increased the ZEA degradation by ACP treatment. Type of gas mixtures (air and selected combinations of N2 and O2) did not influence ZEA degradation by 3 min ACP treatment. Direct jet-ACP with higher UV intensity had better ZEA degradation efficacy compared to indirect jet-ACP with zero UV intensity. The results also suggested the contribution of factors other than the assessed RONS, such as high energy electrons and free radicals in ZEA degradation.
Degradation mechanisms of DON by plasma activated water (PAW) treatment of naturally contaminated barley grains during steeping was investigated in the fourth study. High-performance liquid chromatography ultraviolet mass spectrometry results indicated twelve major degradation products of DON after ACP treatment and their chemical formulae were determined. Oxidation was probably the main degradation mechanism of DON by ACP treatment. PAW treatment significantly reduced DON content and using PAW in indirect mode increased β-amylase activity and germinated acrospire’s percentage compared to control. The significant reduction in DON in naturally contaminated barley without influencing the germination and quality parameters of barley malt indicates the potential application of PAW for barley steeping. In the last study, the potential of using PAW bubbles produced from selected ACP generation methods on DON degradation and F. graminearum inactivation during barley steeping was investigated. Bubble spark discharge ACP produced more potent PAW with high concentrations of RONS compared to a continuous jet-ACP, resulting in greater degradation of DON. The results from plating and qPCR technique showed that the PAW bubble treatment did not have a significant impact on natural pathogens and F. graminearum inactivation on naturally contaminated barley grains.
This research demonstrated the efficacy of ACP treatment on DON and ZEA degradation. The fundamental information gained from this research has set the stage for further research and development and implementation of the ACP systems in commercial applications, specifically in the barley malting industry for mycotoxin degradation and germination improvement.