High-intensity ultrasonication impact on the chlorothalonil fungicide and its reduction pathway in spinach juice

Among different novel technologies, sonochemistry is a sustainable emerging technology for food processing, preservation, and pesticide removal. The study aimed to probe the impact of high-intensity ultrasonication on chlorothalonil fungicide degradation, reduction pathway, and bioactive availability of spinach juice. The chlorothalonil fungicide-immersed spinach juice was treated with sonication at 360 W, 480 W, and 600 W, 40 kHz, for 30 and 40 min at 30 ± 1 °C. The highest reduction of chlorothalonil fungicide residues was observed at 40 min sonication at 600 W. HPLC-MS (high-performance liquid chromatography-mass spectroscopy) analysis revealed the degradation pathway of chlorothalonil and the formation of m-phthalonitrile, 3-cyno-2,4,5,6-tetrachlorobenamide, 4-dichloroisophthalonitrile, trichloroisophtalonitrile, 4-hydoxychlorothalonil, and 2,3,4,6-tetrachlorochlorobenzonitrile as degradation products. High-intensity sonication treatments also significantly increased the bioavailability of phenolic, chlorophyll, and anthocyanins and the antioxidant activity of spinach juice. Our results proposed that sonication technology has excellent potential in degrading pesticides through free radical reactions formation and pyrolysis. Considering future perspectives, ultrasonication could be employed industrially to reduce pesticide residues from agricultural products and enhance the quality of spinach juice.