Formation of capsaicin loaded nanoemulsions with high pressure homogenization and ultrasonication

Nanoemulsions could increase the bioavailability of lipophilic compounds. In this study, nanoemulsions were obtained by high pressure homogenization and ultrasonication using capsaicin (oleoresin capsicum) (2 g/100g) in the oil phase and Tween 80 (2 g/100g), glycerol (0-50 g/100g) in the aqueous phase at pH 7.4 and 3.8. Mean droplet sizes below 65 nm were obtained with ultrasonication. Translucent nanoemulsions with minimum 79% efficiencies were obtained with high pressure homogenization. Pressurized nanoemulsions reduced Staphylococcus aureus and Escherichia coli population up to 5.89 and 2.79 log respectively at pH 7.4. The addition of glycerol resulted in almost transparent, bright red colored nanoemulsions. Therefore, capsaicin nanoemulsions showing good antimicrobial activity could be obtained by high pressure homogenization, whereas ultrasonication mostly helped to improve physical properties such as particle size and color.