Encapsulation Of Tea Polyphenols In W/O/W Emulsion Stabilized With Binary Gum Mixtures

Owing to special three-phase structures,water-in-oil-in-water(W/O/W)emulsions play important roles in encapsulation and controlled release of water-soluble active ingredients.This concept is widely used in food,medicine,cosmetics,and other fields.However,due to the fact that multiple emulsions have a more complex structure compared to simple oil-inwater emulsions,they are sensitive to the effects of various factors.One of the main challenges is the instability of multiple emulsions caused by the osmotic pressure difference between the internal and external water phases which has a certain impact on the coating effect of the active material.To this end,we evaluated stability of multiple emulsions and the preservation rate of active components in the aqueous phase by adding a mixed polysaccharide system in the internal water phase.During the course of the investigation,we discovered the following results:1.The synergistic interaction of two mixed polysaccharide systems was studied:xanthan gum and guar gum(XG/GG),xanthan gum and locust bean gum(XG/LBG).It was found that the XG/LBG mixture exhibited higher viscosity,stronger viscoelastic strength,and its synergistic interaction was stronger compared to XG/GG mixture.Furthermore,tea polyphenols(TPPs)were embedded in both binary gum mixtures.TPPs were slowly released from these mixtures,and it is concentration-dependent.Interestingly,the slowest release rate was obtained with XG/LBG mixture at a ratio of 6:4.2.The optimal preparation process of water-in-oil(W/O)emulsion was explored.The W/O emulsion prepared with polyglycerol polyricinoleate(PGPR)as the lipophilic emulsifier(2% concentration),coconut oil as the oil phase,and the oil-water ratio of 80:20demonstrated the best stability.Furthermore,in order to investigate the influence of emulsifier concentration and XG/LBG mixture on the stability of W/O emulsion TPPs were encapsulated in W/O emulsion containing XG/LBG mixture(6:4).We discovered that the stability of the emulsion increases with the increase in the emulsifier concentration.Moreover,it was observed that the XG/LBG mixture reduced the interfacial tension between oil and water and improved the stability of the emulsion.After 30 days of storage at 25 ° C,the retention rate of TPPs was more than 70%.3.Next step was to design the preparation process of W/O/W emulsion.We used PGPR as lipophilic emulsifier,soybean lecithin as the hydrophilic emulsifier,and 0.2% of xanthan gum as the external phase stabilizer.The novel W/O/W emulsion displayed uniform droplet distribution and good stability.The addition of XG/LBG to the internal water phase allowed to reduce the particle size of the W/O/W emulsion,improve the anti-coalescing stability of the emulsion droplets,strengthen the interface film between oil and water,and improve the stability of multiple emulsions.4.Lastly,we studied the stability and protective effect of multiple emulsions,by adding TPPs to the internal water phase of W/O/W multiple emulsions.It was found that XG/LBG can enhance the steadiness of the W/O/W system and improve the thermal stability of the system.The XG/LBG mixture effectively protects the tea polyphenols encapsulated in the internal water phase,enhances the preservation rate of tea polyphenols,and plays a vital role in slowing down the oxidation process of tea polyphenols.Experiments show that the multiple emulsion system with XG/LBG mixture added to the internal water phase has a improved encapsulation effect and encapsulation stability on tea polyphenols.