Encapsulation of passion fruit seed oil by means of supercritical antisolvent process

Abstract

Large quantities of passion fruit seeds are wasted after juice production. Heat and light can cause loss or reduction of seed oil biological activities including antioxidant and antimicrobial. Thus, co-precipitation with polymers by Supercritical AntiSolvent (SAS) process could be used to preserve seed oil compounds. This work aimed to apply SAS process to produce passion fruit seed oil particles encapsulated with a biopolymer, PLGA (poly(lactic-co-glycolic) acid). The phase behavior of the seed oil in dichloromethane with and without PLGA in CO2 was studied to support to determine the best SAS processing conditions. The static synthetic method was applied for the phase equilibrium assays with different CO2 compositions (60–98.8wt%) and different temperatures (35–55°C). Liquid-vapor, liquid-liquid and liquid-liquid-vapor phase transitions were observed. Based on phase behavior, the selected SAS encapsulation conditions were: 35 and 45°C, CO2 mass fraction of 92.5 and 95.0%, and pressures of 90 and 110bar. Microscopy images showed that pressure affected PLGA+passion fruit seed oil particles morphology and size, which varied from spherical shape at low pressure (90bar) to irregular shape at high pressure (110bar). The particle size ranged from 721 to 1498nm and the oil encapsulation efficiency varied from 67.8 to 91%. According to differential scanning calorimetry results, all SAS conditions produced particles with encapsulated oil. The oil release consisted of an initial burst, raising gradually (until 24h), followed by a uniform release up to 72h. The amount of oil released reached 88% of total entrapped material. This study shows the potential of using green methods to aggregate value to agroindustrial waste materials.