Effects of Dielectric Barrier Discharge Cold Plasma on the Extraction of Bioactive Compounds from Colombian Arabica Coffee Powder

Abstract

This study investigates the application of dielectric barrier discharge plasma with argon gas to extract valuable bioactive compounds from Arabica coffee powder. The impact of different treatment durations (4, 8, 12, and 16 min) and applied voltages (12 and 18 kV) on the efficiency of extraction was assessed through spectrophotometric analysis. The total phenolic content (TPC) exhibited non-monotonic fluctuations at 12 kV. Initially, there was a fall of 15.59% after 4 min, followed by a large rise of 14.82% at 8 min, and then a decline over longer durations. At 18 kV, TPC rose by 29.34% after 4 min of treatment, but gradually decreased with prolonged exposure. The extraction of caffeine exhibited a complex pattern, with all samples treated at 12 kV showing reduced levels compared to the control. The highest concentration of caffeine was seen after 8 min under 18 kV, surpassing the control by 12% before declining. Antioxidant activity, assessed through DPPH inhibition, reached its maximum at 31.90% after 8 min at 12 kV and at 47.87% after just 4 min at 18 kV. Beyond these peak times, a marked decline in activity was observed with prolonged treatment durations. Furthermore, plasma treatment altered the fatty acid profile, increasing saturated and polyunsaturated fatty acids while decreasing monounsaturated ones. These results highlight the potential of cold plasma as a sustainable and effective method for enhancing the extraction of bioactive compounds from coffee powder, offering promising applications in the food industry for improving the nutritional and functional properties of coffee-based products.