Abstract/Summary

Nutraceuticals face significant challenges in delivery due to poor solubility of some bioactives, and instability during processing. The major whey protein in bovine milk, ß-lactoglobulin (ß-Lg), has versatile properties and the potential for the development of novel delivery vehicles for bioactives. The aim of this study is to develop a solid and reproducible method to produce ß-Lg nanoparticles and investigate their application to the encapsulation of bioactives. Temperature and pH were found to be the key operating parameters to produce and control the size of nanoparticles. Monodisperse and spherical ß-Lg nanoparticles in the size range of 200-300 nm were produced at optimum conditions of pH (6.0) and heat load (heating incubation 75 °C for 45 mins). ß-Lg nanoparticles exhibited high colloidal stability (zeta potential: -37.42 mV) and high yield of aggregation (93%). The hydrogen bonding and hydrophobic interactions played a predominant role in the microstructure of these nanoparticles. Caffeine was bound to these nanoparticles with 13.54% as maximum encapsulation efficiency at 50:1 molecular ratio and the binding followed a Langmuir type isotherm. Only partial release of caffeine happened at gastric conditions (about 36%) whilst total release happened at intestinal conditions. Also, resveratrol-ß-Lg nanoparticles were produced at 181.8 nm using this method. Heat degradation and isomerisation of resveratrol occurred when heating at 75°C which led to reduced antioxidant activity. Resveratrol-beta-lactoglobulin nanoparticles exhibited an ability to improve antioxidant activity at this temperature and at pasteurisation condition. Lastly, whey protein nanoparticles could be produced following the same method with smaller size and lower yield of aggregation. Further studies should be carried out to explore other applications of ß-Lg/whey protein nanoparticles as a novel nanovehicle of bioactives in food products.