Curcumin microencapsulation into yeast cells (Saccharomyces cerevisiae) via osmoporation: process parameters, thermal stability and antioxidant capacity
curcumin; osmoporation; S. cerevisiae; antioxidant activity; stability; microencapsulation.
This study investigated the encapsulation of curcumin into Saccharomyces cerevisiae cells through osmoporation as an efficient way of increasing curcumin stability. The influence of three process parameters (cell, ethanol and curcumin concentrations) on the encapsulation process were evaluated and the obtained bio-capsules were characterised with regard to physical and photochemical stabilisation. Results showed that the encapsulation efficiency was favoured by the increase of cells/curcumin ratio and ethanol concentration up to 60%. Differential scanning calorimetry (DSC) curves revealed that yeast-encapsulation increased curcumin melting point up to 207 °C. Encapsulated curcumin retained over 80% of antioxidant activity after thermal treatment (150 °C) and over 70% after a 50-day exposure to artificial light. Photochemical stability of yeast-encapsulated curcumin was increased by 5.7-fold and the half-life time reached 181 days when bio-capsules were exposed to light. Overall, osmoporation-produced yeast bio-capsules confirmed the versatility and efficiency of osmoporation as an encapsulation technique that could successfully improve curcumin stability.