Extraction of chilli pepper (var. Byedige) with supercritical CO2: Effect of pressure and temperature on capsaicinoid and colour extraction efficiency

The influence of operating parameters (pressure from 100 to 400 bar and temperature of 40, 60 and 80 °C) on the extraction efficiency of capsaicinoids and colour components from chilli pepper (variety Byedige) was studied. Capsaicinoid content and colour value were determined in raw material and residue material after extraction. The colour intensities of residue material and obtained extracts were given by ASTA (American Spice Trade Association) and CU (Colour Unit) value, respectively. Total extraction yield and extraction efficiency of capsaicinoids increased with increasing pressure at constant temperature as well as with increasing temperature at constant pressure. The highest extraction yield for total solids of 12.8% was obtained at 400 bar and 40 °C, where almost 96% of capsaicinoids and 80% of colour components were removed from the raw material. The highest CU value of chilli pepper extract, obtained by a single step extraction at 40 °C and 400 bar, was approximately 15,000 CU. Calculated mass transfer coefficients of chilli pepper extract from solid material varied from 2 × 10−7 to 11 × 10−7 m s−1in the pressure range of 100–400 bar and temperature range 40–80 °C. It was observed that the mass transfer coefficient is a linear function of the density of carbon dioxide in the range of applied operating conditions.