Application of nanoencapsulation technology to improve the stability and bioactivity of tea polyphenols

Tea polyphenols (TP) become popular because of good bioactivity and ability to improve health, however easy degradation and low bioavailability affect its application in the food industry, our study aim to improve the stability and biological activity of TP by nanoemulsion encapsulation technology. Tea polyphenols nanoemulsions (TP-NM) were prepared by ultrasound-assisted method and the nanoparticles were observed to be uniformly spherical by transmission electron microscopy. The results showed that TP-NM had good thermal stability and were storage stable within 5 weeks. The quality of TP and TP-NM was assessed by DPPH, ABTS, α-glucosidase, α-amylase and antibacterial assays which showed that TP-NM had significantly enhanced antioxidant and hypoglycaemic abilities compared with free TP. In addition, TP-NM inhibited the growth of five bacterial species, with a better effect on Gram-positive bacteria, and scanning electron microscopy results confirmed the change in bacterial structure. Acute cytotoxicity and hemocompatibility tests showed that TP-NM was safe within concentration range. The research supported the use of nanoparticles to encapsulate TP and improve its stability and bioactivity to expand the application of tea polyphenols in the food industry.