Study On The Effects Of Tea Polyphenols On The Stability And Bioavailability Of ?-carotene In Oil-in-water Nanoemulsion

?/3-Carotene(BC)is an important lipophilic nutrient.But it is resulting in low oral bioavailability,which limiting its application in the field of functional foods.Oil-in-water nanoemulsion is a good nutrient transport carrier,which can protect fat-soluble nutrients and enhance their bioavailability.The ability to protect the embedded material of oil-in-water nanoemulsion has reduced during high temperature and longterm storage,so it's of great significance to choose a suitable antioxidant to improve its chemical stability.In this paper,tea polyphenols-?-carotene(TP-BC)nanoemulsion was prepared by using tea polyphenols as antioxidants to protect ?-carotene embedded in nanoemulsion,and ?-carotene nanoemulsion without tea polyphenol was prepared as control group.The physical properties and storage stability were further investigated by means of in vitro simulated digestion and oral gavage in rats to investigate the differences in stability and bioavailability between TP-BC and BC nanoemulsion.The main findings are as follows:1)Design the appropriate amount of ?-carotene and tea polyphenols,used corn oil as the oil phase and Tween 80 as the emulsifier,and prepare two emulsions under the pressure of 1000 bar for 5 cycle.Both nanoemulsions particle size lower than 100 nm zeta potential absolute value over 50 and had low polydispersity coefficient,indicating that both nanoemulsions with better stability.Physical and chemical indicators meet the quality requirements of nanoemulsion.2)TP-BC nanoemulsion and BC nanoemulsion were stored at 4?,25? and 35?for 30 days.The retention rates of ?-carotene in TP-BC nanoemulsion were 61.3%and 71.74%higher than that in BC nanoemulsion at 25 and 35? after 30 days' storage.3)In vitro simulated digestion experiments on two kinds of nanoemulsions showed that the recovery rate of ?-carotene in TP-BC nanoemulsion was significantly higher than that in BC nanoemulsion at simulated oral phase and gastric phase.It was indicated that the tea polyphenols have a good protective effect of ?-carotene in the oral and gastric stages of in vitro digestion.4)Rats were orally administered with two nanoemulsions for short-term metabolic experiments.From the results of in vivo absorption,compared with the BC nanoemulsion group rats,the TP-BC nanoemulsion group rats can convert more ?-carotene into vitamin A,and there is a significant difference after 12 hours in the liver(P<0.01).The ?-carotene nanoemulsion after the addition of tea polyphenols has a faster absorption rate and can increase the accumulation of vitamin A in the rat liver.At the same time,the total amount of ?-carotene excreted in feces by TP-BC nanoemulsion group rats was significantly lower than that of BC nanoemulsion group after 6 hours.