Effect of supercritical CO2 impregnation of piperine and black pepper extract on properties of poly(l-lactic acid) films

The impregnation of piperine and black pepper extract into poly (L-lactic acid) (PLLA) films using supercritical CO₂ was investigated. Piperine was a model to determine the influence of operating conditions of pressure (10 and 12 MPa) and temperature (40 and 50 °C) on the impregnation yield. The most favorable conditions were obtained at 10 MPa and 50 °C and were used in the incorporation of piperine and black pepper extract into 200 µm films. The addition of 5 and 10 % ethanol as cosolvent was tested during the impregnation processes of black pepper extract and piperine. The impregnated films were characterized on their thermal, mechanical, structural and surface properties. The addition of 5 % cosolvent favored the increase in piperine yield (5.6 %). The impregnation of piperine and extract using co-solvent led to an increase in the crystallinity of the films and significant changes in the mechanical properties. Supercritical technology has shown promise for the impregnation of active agents into PLLA films for potential development in food packaging applications.