Chemical stability of Curcuma longa extract stored in hydrophobic deep eutectic solvent and polymers emulsion

Curcuma longa is a plant that, despite its present great bioactive potential, is composed of bioactive compounds that show low water stability and solubility. Therefore, this work aimed to verify the stabilization of Curcuma longa extract in emulsions gel using hydrophobic deep eutectic solvents (HDES), alginate, and carboxymethylcellulose (CMC). The Curcuma longa encapsulation efficiency and stability were evaluated to determine the optimum emulsion composition and homogenization time. The DPPH• and ABTS + methods were used to analyze the in vitro antioxidant capacity stability during storage. Besides, emulsions were characterized by zeta potential and scanning electron microscopy (SEM). Results showed an encapsulation efficiency varying from 1.9% to 36.3%. The Curcuma longa extract obtained with HDES helped stabilize the antioxidant capacity in vitro during 30 days of storage. In the emulsion gel produced with the extracts, there was a decrease in vitro antioxidant capacity, possibly due to the interactions between the system components. This work describes a new methodology to produce emulsion gels with Curcuma longa extract that may help its application in food and drug formulation.