Preparation And Physicochemical Properties Of Eucommia Ulmoides Oliver Seed Oil-loaded Inverse Microemulsion

Eucommia ulmoides Oliver seed oil?E.ulmoides seed oil?is rich in polyunsaturated fatty acids,vitamin E?VE??190.96±1.15 mg/100g?and aucubin,among which especially?-linolenic acid?ALA?accounts for up to around 63%in the total fatty acid content.Thus,E.ulmoides seed oil is well-known for the functions of assisting in regulating blood lipid,lowering blood pressure,improving memory,promoting growth and development,antioxidation,anti-aging,anti-cancer,anti-tumor,anti osteoporosis and anti-inflammatory.It is a kind of natural functional oil with great application prospect.However,despite these excellent properties,there remain limitations in its use process.On the one hand,vegetable oil which is abundant in polyenoic acid is easier to oxidize and has low solubility.On the other hand,it is easily damaged by enviornmental changes during food processing and transportation,which has become the technical bottleneck of its application in the field of food and medicine.Therefore,in order to maximize its medical efficacy,it is advised that the E.ulmoides seed oil products should be stored in an appropriate form to solve the problem of low oxidation stability and solubility.Microemulsions are defined as homogeneous,thermodynamically stable,transparent or translucent nano dispersing systems with the particle size of about 1-100 nm consisting of blends of oil,water,surfactant,and co-surfactant.In recent years,the microemulsion system with vegetable oil as oil phase has been wildly applied in various fields of daily chemical products,food industry,drug carrier,biodiesel,bio lubricating oil and nanomaterial preparation,and is expected to become a hot and promising field.However,current research on oil microemulsions mainly focuses on the preparation of the carrier system of nutrients with short-chain and medium-chain oil and long-chain oil microemulsion while there are few reports which touch upon the long chain functional oil microemulsions containing polyunsaturated fatty acids,and their stability and physicochemical properties are not thorough enough.The main purpose of this article was to enhance the stability and solubility of E.ulmoides seed oil.E.ulmoides seed oil inverse microemulsion was formed based on pseudo-ternary phase diagrams after the screening of HLB value,co-surfactants,the water/co-surfactant ratio,and the effect of p H,ionic strength,and temperature on the mono-phase area of the microemulsion was analysed.Further researches were conducted on the morphology,viscosity,stability,conductivity,and antioxidant capacity of E.ulmoides seed oil microemulsion.Another objective was to apply E.ulmoides seed oil microemulsion as a delivery system in a water-soluble antioxidant,tea polyphenols.The effect before and after the addition of TPs on the phase behavior,particule size,polydisperity and microstructure of E.ulmoides seed oil microemulsion was investigated.Also,the antioxidant activities of TPs-E.ulmoides seed oil microemulsion were compared and the influence of different TPs concentrations and temperature on the oxidative stability of E.ulmoides seed oil microemulsion were studied.The shelf-life model for empty and TPs-E.ulmoides seed oil microemulsion was developed.Finally,based on E.ulmoides seed oil,nano-emulsion and microemulsion systems of different kinds were prepared and their in vitro digestion were studied.The conclusions of this paper are as follows:1?The microemulsion of Eucommia ulmoides seed oil was prepared by adding surfactants.The optimum formulation preparation conditions were as follows:Span 80:Tween 80?6:4?,PG serving as co-surfactant,and water:PG?1:1?.It is shown that the W/O microemulsion regions were significantly correlated with temperature,and had good acid and alkali resistance,salt tolerance and good storage stability.The E.ulmoides seed oil microemulsions not only had a various oil phase content,but also a good stability and tolerance to p H and salinity.In addition,E.ulmoides seed oil microemulsion has various features including narrow-sized distribution,nanoscale particle size?below 100 nm?transparent appearance and a wide range of oil phase content.The results of antioxidant assay in vitro showed that the E.ulmoides seed oil microemulsion had obvious reducing power and radical scavenging capacity for free radicals such as O₂^-·?DPPH·?ABTS⁺·?·OH with the corresponding IC₅₀ values of 7.208 mg/m L?55.951 mg/m L?37.895 mg/m L?11.563 mg/m L.2?The TPs-E.ulmoides seed oil microemulsion was prepared with stability performance.No obvious effects were observed on E.ulmoides seed oil microemulsion region phase behavior before and after TPs loaded.The particle size increases correspondingly with the increase of TPs concentration incorporated in microemulsion.After adding 1%TPs,the antioxidant activity of the system increased 36.1 times.The oxidation of Eucommia ulmoides seed oil can be slowed down before and after the addition of TPs.After adding TPs,the system showed stronger oxidation stability.TPs-E.ulmoides seed oil microemulsion was more effective than E.u oil microemulsion.0.02%TPs-E.ulmoides seed oil microemulsion extends the shelf-life of E.ulmoides seed oil at25 degree temperature from 90 to 156 days.3?Based on the microemulsion of Eucommia ulmoides seed oil,different dispersions were obtained.These nano-dispersion had smaller average particle size?23 nm and 320nm?and low polydispersity coefficient?0.213 and 0.381?.The empty and TPs-E.ulmoides seed oil microemulsion could both obviously alleviate the lipolysis effect of Eucommia ulmoides seed oil,and protect protect the active components from digestion and decomposition.E.ulmoides seed oil microemulsion has good characteristics as a water-soluble antioxidant delivery system.These systems enhance the solubility and stability of E.ulmoides seed oil and provide promising application possibility of water-soluble effective components,and E.ulmoides seed oil improve the nutritional value of system and the addition of TPs enhance the oxidation stability of E.ulmoides seed oil.This study provides theoretical basis and practical reference for the deep processing of E.ulmoides seed oil,and extends the integrated industry chain of Eucommia gum,oil and protein,so as to expand its application in the field of food,medicine and skin care products as a substitute of?-linolenic acid.