Abstract

MICROENCAPSULATION OF SUPERCRITICAL CARBON DIOXIDE EXTRACT OF TUBEROSE FLOWERS (POLIANTHES TUBEROSA LINN.): PROCESS OPTIMIZATION AND STABILITY STUDIES

Probir Kumar Ghosh, Paramita Bhattacharjee* and Satadal Das

ABSTRACT

Supercritical carbon dioxide (SC-CO2) extraction parameters were optimized to obtain methyl eugenol-rich extracts from tuberose flowers possessing the best combination of antioxidant activity and in vitro antimicrobial potency (against Staphylococcus aureus). This extract is a ‘herbal preparation’ as per World Health Organization (WHO) guidelines. This extract was microencapsulated by spray drying and the encapsulate with highest methyl eugenol content along with highest antioxidant and antimicrobial activities was considered as the best encapsulate. Optimization of spray drying parameters for obtaining the best encapsulate was conducted by employing response surface methodology and the optimized conditions were an inlet air temperature of 160°C and wall material composition of maltodextrin (70%)-gum arabic (30%). The microencapsulation efficiency at these conditions was highest with respect to methyl eugenol content (72.82%), antioxidant (74.02%) and antimicrobial (73.48%) activities of the encapsulate. The in vitro release of methyl eugenol (90%) from the best encapsulate occurred within 60 min of dissolution by anomalous transport following Peppas model. The half-life of the best encapsulate was 4.44 times and 5 times higher than the SC-CO2 extract at ambient conditions and accelerated stability conditions respectively, over the SC-CO2 extract. This shelf stable encapsulate is a ‘finished herbal product’ in accordance with WHO guidelines.

Keywords: Tuberose, Supercritical carbon dioxide, Methyl eugenol, Spray drying, Stability.