The effects of rice bran oil, coconut oil and homogenisation pressure on the properties of oil-in-water emulsion loaded baicalein

Abstract Baicalein is a functional flavonoid that has been intensively studied for its health benefits. Loading baicalein in oil-in-water (O/W) emulsions could provide advantages for its application in foods. This work investigated the characteristics of O/W emulsions loaded with baicalein formulated by combination of vegetable oils and homogenisation pressures. Rice bran oil (RBO) and coconut oil (CCO), classified as long-chain triglycerides and medium-chain triglyceride, were used in the homogenisation process at 600–1200 bar. The rice bran oil-in-water emulsion loaded with baicalein (RBOb/W) produced at 1200 bar provided the emulsion with the smallest particle size of the surface-weighted mean diameter (d3,2) of 220 nm. The result showed that loading baicalein into RBO could reduce the particle size of O/W emulsion while it increased the particle size of coconut oil-in-water emulsion loaded with baicalein (CCOb/W). The RBOb/W and CCOb/W emulsions were physically stable in terms of droplet size during storage at 4 °C for 28 days. The change in viscosity of freshly prepared emulsion loaded with baicalein was dominant compared with the emulsion unloaded baicalein, however, the viscosity profiles of emulsions loaded with baicalein are like emulsions unloaded with baicalein after storage. The influence of baicalein on the viscoelastic properties of emulsion was observed in the storage modulus (G′) at low frequencies. These results suggest that baicalein could potentially interfere with the stabilising effect of Tween 20, contribute to droplet interactions, and migrate from the surface of RBO but not CCO. High baicalein retention of 91–98% was observed in the RBOb/W emulsions. This study recommends that RBO is preferable over CCO to produce O/W emulsion loaded with baicalein in terms of droplet size, stability and retention. It would be useful information to produce functional ingredients for the food industry.