Conductive hydro-drying of cayenne chili paste: Effects of intermittency, temperature and salt concentration on product quality and energy efficiency

Abstract

Cayenne chili paste, which has a high moisture content, can be preserved by drying and adding salt. A Box-Behnken design was used to investigate the effects of added salt (0, 7.5 and 15 g salt/100 g paste), intermittent heating (cycles of 15 min on and 0, 15 or 30 min off), and water temperature (70, 80, 90 °C) on the physicochemical properties, capsaicinoid content, total phenolic content (TPC), antioxidant capacity (AC) and energy efficiency. Salt content significantly affected drying time and product moisture, density, color, TPC and AC. The intermittency increased the concentrations of TPC and AC and decreased energy consumption by up to 31%. Drying at 90 °C significantly reduced the processing time compared to drying at 70 °C, preserving the color and capsaicinoid content (18.3–59.0 mg/100 g dry matter). Dried cayenne chili paste produced by intermittent conductive hydro-drying had higher quality than product from a continuous process, drying times were similar and the process was more energy efficient.