Nano-encapsulation of spice oleoresins using Hydroxypropyl β-cyclodextrin (HPBCD) and its bioavailability studies

Spices are mostly used in traditional medicine since ancient times and they are used in the food for its flavour. Oleoresins are the concentrated form of whole spices. There are many reports on the application of oleoresin, but its consumption is limited due to its high pungency and insolubility. Thus, nano-encapsulation by Hydroxypropyl beta-cyclodextrin (HPBCD) was attempted in this study to enhance the application of oleoresin into the food system. HPBCD can form an inclusion complex with the spice oleoresin and helps in applying oleoresin in food systems with improved solubility and bioavailability. In this study, the nano-encapsulation was done with pepper, turmeric and chilli oleoresin, characterised for its physicochemical properties, and studied its in-vitro drug release and in-vivo bioavailability. The particle size was found within 250 nm, and zeta potential was shown above -30 mV, indicating stability. The encapsulation efficiency was shown above 85 % in all the encapsulated oleoresin. The in-vitro drug release study showed that the highest percentage of the drug was released in the intestine phase than stomach and colon. The percentage of the active component released in the intestine was 92, 89 and 88 % by encapsulated pepper, turmeric and chilli oleoresin, respectively. The bioavailability of these oleoresins was also improved upto 40–50 %. Therefore, the nano-encapsulated spice oleoresin can be applicable in the food industry with its improvement in solubility and bioavailability.