phd ana carolina

Valorization of Brazilian native Capsicum peppers using supercritical technology: extraction and encapsulation

Author: Ana Carolina de Aguiar (2015)

Abstract: The characterization, extraction and encapsulation of extracts from Capsicum peppers with supercritical technology were studied. Initially, 20 varieties of peppers were characterized in terms of concentration of capsaicinoids. A large variation in the composition of capsaicinoids was observed, whereas capsaicin and dihydrocapsaicin were the major ones. Based on these results, two peppers were selected to obtain extracts with supercritical carbon dioxide (CO₂): malagueta for capsaicinoids extraction and biquinho to capsinoids extraction. Regarding the supercritical fluid extraction (SFE) of malagueta pepper, higher concentrations of capsaicinoids were obtained at lower pressures, indicating that there may be competition between capsaicinoids and other compounds soluble in supercritical CO₂ at higher pressures. The global yield was greater at higher pressures due to the increase of the solvent density. The extracts from biquinho pepper showed a considerable concentration of capsinoids. The SFE process with CO₂ resulted in global extractions yields lower than those obtained using low pressure extraction methods. Moreover, the extract obtained at lower CO₂ density had a high concentration of capsinoids, which suggests that supercritical CO₂ without cosolvents may be employed to obtain these compounds. Additionally, an estimate of the manufacturing cost of supercritical extracts of malagueta peppers at the optimized conditions (15 MPa and 40 °C) was performed and the result was compared with the commercial value of an extract with the same characteristics. It was found that the SFE process of malagueta pepper oleoresin may be economically viable. In a second stage, a unit of precipitation by Supercritical Antisolvent (SAS) and Supercritical Fluid Extraction of Emulsions (SFEE) methods was developed and evaluated in terms of the precipitation performance of pure PLLA and coprecipitation of poly(lactic acid) (PLLA) and β-carotene by SAS, and particle formation in suspensions of Hi-Cap 100® and malagueta pepper oleoresin by SFEE. The SAS experiments for precipitation of pure PLLA and coprecipitation of PLLA with β-carotene resulted in particles with different morphologies when comparing the operating conditions. Although it was not possible to evaluate the influence of operating parameters on the particles obtained by SAS, the experiments were important to demonstrate the operation of the assembled precipitation unit. The emulsions formed by ultrasound showed high stability, and from kinetic experiments it was determined that the appropriate injection time in the precipitation column was 10 min after emulsification. The SFEE experiments resulted in suspensions with low retention percentage of capsaicinoids, possibly due to the high rate of extraction of these compounds during the SFE and the loss of oleoresin verified in the collection flask. Regarding the residual solvent content in the suspensions, it was observed that the smaller the loss of oleoresin, the higher the solvent concentration in the suspension. The average mean diameter of the particles in suspension showed little variation from the average mean diameter of the injected emulsion, indicating that the particle size is more related to the size and nature of the emulsion droplets than to the mass transfer conditions of the process.