Removal of Aflatoxin B1 from solid and liquid matrices using cold atmospheric plasma reactors: Insights into reactor configurations and food quality testing

Abstract

The study describes the distinct performance of surface dielectric barrier discharge (SDBD) and corona discharge (CD) in removing aflatoxin B1 (AF B1) from solid surfaces and liquid. Reactive chemical species (RCS) generated within these reactors were thoroughly characterized using chemical probe methods, optical emission spectroscopy (OES), and optical imaging. Optical imaging of the CD reactor confirmed higher emission intensities for key RCS transitions, including the OH rotational band $(A^2{\Sigma }^{+}\to X^2\Pi )$at 308.4 nm, N₂ second positive system $(C^3{\Pi }_u\to B^3{\Pi }_g)$ between 330 and 380 nm, and O $(2s^{2}2p^3\left({}^4{S}^0\right)3s^5{S}_2-2s^{2}2p^3\left({}^4{S}^0\right)3p^5{P}_{1,2,3})$ at 777 nm. Water sample analysis indicated greater RCS production in the CD reactor (0.21 mM H₂O₂ and 0.05 mM •OH) compared to the SDBD reactor (0.12 mM H₂O₂ and 0.02 mM •OH). The optical imaging showed that CD generated more intense but spatially localized RCS, while SDBD exhibited a low-intensity but more uniform RCS distribution over a larger plasma area. Despite these differences, both reactors achieved comparable AF B1 degradation in liquid. Notably, SDBD outperformed in removing AF B1 from solid surfaces, delivering an order of magnitude higher energy yield. The reactors generate reactive species like •OH, H₂O₂, O₃, ¹O₂, and other oxygen- and nitrogen-containing compounds, which facilitate AF B1 degradation. Among these, •OH radicals are especially important due to their high oxidation potential and non-selective reactivity. The study also assessed the impact of plasma exposure on peanuts. Exposure to SDBD caused negligible changes in the appearance of peanuts, whereas CD treatment resulted in noticeable alterations in color and texture. The findings suggest that reactors like SDBD, which produce a uniform RCS distribution over a broader area, are safer and more effective for decontaminating AF B1 on solid food samples such as peanuts.