Abstract
Curcumin, bioactive from turmeric Curcuma longa, has been known for its therapeutic properties. However, its lipophilic nature and poor bioavailability are the constraints to harnessing its properties. Encapsulation in nano-size helps to alleviate the constraints and enhance its biological properties due to its higher surface area. The study aims to encapsulate curcumin in a nanometer size range by solubilizing in lipid (milk fat) and using milk protein as a water-soluble carrier. The lipid:curcumin ratio (1:0.05, 1:0.1, 1:0.2, 1.5:0.1, 1.5:0.2, 2.0:0.1 and 2:0.2% (w/w)) produced nanoemulsion with droplets sizes 30-200 nm. The sample containing lipid: curcumin, as 1.0:0.05 resulted in an encapsulation efficiency of 92.6%, and its binding interaction with the carrier, was K(D) = 4.7 µM. A high solubility of curcumin in milk fat and digestion during in vitro lipolysis increased its bioaccessibility. A simulated gastro-intestinal in vitro studies showed that cumulative release percentage of nanoencapsulated curcumin was 60% at pH 7.4 compared to 0.8% of native curcumin. The anti-microbial property of nanoencapsulated curcumin was more potent than native curcumin against food pathogenic organisms such as S. aureus, B. cereus, E. coli, B. subtilis, P. aeruginosa, P. aeruginosa, C. violaceum. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-023-05684-5.