Cold Atmospheric Gas Plasma Processing of Apple Slices

Abstract

The food industry needs more effective drying procedures that would maintain the quality of the original fruit or vegetable. Infrared drying combined with advanced electrophysical technologies may be a perfect solution. The present research objective was to study the effect of low-temperature atmospheric gas plasma treatment on the drying efficiency of apple slices. The research featured apples of the Idared variety (Russia) sliced into pieces of 5, 7, and 10 mm. The experiment involved the parameters of drying kinetics and moisture diffusion. The quality of the apple slices was assessed by the total content of phenols and flavonoids, generalized antiradical activity, color characteristics, and the Fourier transform infrared (FT-IR) spectrum. The electropores induced by the cold atmospheric gas plasma processing had a tree-like structure. The pre-treatment reduced the drying time by 18.0, 13.0 and 10.5% for the samples with a thickness of 5, 7, and 10 mm, respectively. The specific energy consumption decreased by 15–18%, depending on the slice thickness. The pre-treatment also increased the total content of phenols, flavonoids, and antiradical activity by 2.5–14.3, 19.1–25.9, and 8.3–35.4%, respectively. Therefore, the pre-treatment with cold atmospheric gas plasma reduced the drying time and preserved the original biologically active compounds in dried apple slices.