Novel Deconvolution Approach for the Analysis of Complex Electron Paramagnetic Resonance Spectra of Irradiated Sweet Potatoes

Abstract

Electron paramagnetic resonance (EPR) spectroscopy is an unambiguous technique to analyze free radicals. Dehydrated sweet potatoes (SPs) can provide crystalline cellulose environments to stabilize irradiation-derived free radicals and allow their analysis using EPR spectroscopy. This study demonstrated a peak enhancement method to deconvolute complex EPR spectra for the quantitative assessment of irradiation. The SPs were prepared with two moisture contents (48.3 and 9.7%) and irradiated at 0, 5, 10, 20, 30, and 50 kGy. The slow-tumbling EPR spectra of nonirradiated SPs showed a singlet peak located at 334.5 mT, while irradiated SPs were characterized by cellulose satellite peaks located 3 mT apart from the central peak, and a glucose shoulder 0.9 mT away from the center. The free radical formation was quantified by using total peak areas, cellulose satellite peak areas (SPAs), and glucose peak areas with and without artificial intelligence-assisted peak enhancement, which allowed analysis of glucose peaks and improved dosage sensitivity and reduced variability of SPA analysis (coefficient of variation less than 25%), especially for high-moisture samples. The high-field SPA was more sensitive to the irradiation dose as compared to the low-field signal. Overall, this study demonstrates the applicability of the peak enhancement procedure to improve the EPR analysis of irradiated fruits and vegetables.