Study On Preparation,Stability And Antioxidant Activity Of Lycopene Microemulsion

Lycopene is a pigment extracted from various mature red fruits and vegetables such as tomatoes,strawberries and watermelon.It belongs to carotenoids.Its color is dark red.Lycopene can effectively eliminate free radicals,delay aging,enhance immunity to the body,prevent cancer,control swelling and other biological activities.The structure of lycopene includes aliphatic hydrocarbon and conjugated polyunsaturated structure,which will make the property of lycopene unstable and easy to degrade.Because lycopene itself is a fat soluble pigment,which is difficult to dissolve in water,the preparation of O/W micro lotion from lycopene is more conducive to the application of lycopene in food,medicine and other industries.The preparation of lycopene micro lotion by low-energy emulsification method is studied,and the stability and antioxidant effect of lycopene micro lotion are preliminarily discussed,which provides a reference for the application of lycopene micro lotion.The main research results are as follows:(1)The best formula of lycopene microemulsion prepared by low energy emulsification method is:the lycopene carrier oil is linseed oil,the emulsifier selects Twain-80,the emulsifier is anhydrous alcohol,and the ratio of emulsifier and assistant emulsifier is Twain-80:absolute alcohol=2:1.At this time,lycopene content in lycopene microemulsion was 382μg/m L,a red transparent microemulsion.The average particle size was 167.7±0.45 nm,the polydispersity coefficient was stable at 0.179±0.006,and the Zeta potential was-7.71±0.53 m V.(2)The stability of lycopene microemulsion prepared by low energy emulsification was studied under different conditions.The self stability of lycopene microemulsion was investigated by storage,centrifugation,dilution and freeze-thaw treatment.The stability of lycopene microemulsion under different p H,light source,temperature and gas conditions was studied through particle size and lycopene retention rate.The results showed that lycopene microemulsion had no stratification after storage for 12 weeks,and had centrifugal stability and dilution stability.The stability of lycopene microemulsion is better than that of p H 2.5～5.5 when p H 6.5～8.5.The particle size and lycopene retention rate of lycopene microemulsion in indoor dark storage for 60 h were 169.6 nm and 97.69%respectively.It was significantly higher than that of light and ultraviolet irradiation(P<0.05).The particle size and lycopene retention rate of lycopene microemulsion after 4 weeks storage were 172.9 nm and 75.30%,respectively,after 12 weeks of storage.Significantly higher than other control groups(P<0.05).The particle size and lycopene retention of lycopene microemulsion stored in vacuum for 12 weeks were 172.8 nm and 95.32%respectively.The stability of lycopene microemulsion under different gas conditions was vacuum>nitrogen>carbon dioxide>aerobic,and there was a significant difference(P<0.05).Under different treatment conditions,the retention rate of pigment in microemulsion was significantly higher than that in lycopene powder(P<0.05),indicating that the preparation of microemulsion from lycopene increased the stability of lycopene to some extent.(3)Adding different antioxidants to accelerate the oxidation of lycopene in lycopene microemulsion after accelerated oxidation at 6 d and 65 degrees,when the dosage of liposoluble antioxidant reaches 0.2g/kg,the pigment retention rate of lycopene microemulsion system is better.At this time,the retention rate of pigment is 75.23%～80.76%.By adding fat soluble antioxidants,the degradation of lycopene in microemulsion can be significantly slowed down;and the degradation rate of lycopene in the microemulsion is significantly reduced.The addition of V_Cto the lycopene microemulsion can accelerate the degradation of lycopene.When the concentration of metal ion chelator EDTA-2Na added 0.05 g/kg,the retention rate of lycopene microemulsion pigment slightly increased.The antioxidative effect of lycopene microemulsion in vitro was evaluated by chemical method.The results showed that lycopene microemulsion had a positive effect on the ability of scavenging hydrogen peroxide and the scavenging capacity of hydroxyl radical.The scavenging effect of lycopene microemulsion was higher than that of the control group.