Preparation And Characterization Of Lycopene Nanoe Mulsion Using OSA Modified Starch As Emulsifier

Abstract:As a carotenoid hydrocarbon,lycopene is widely applied in food,pharmaceutical and cosmetic industries.It has the ability in disease prevention,strengthen the body's immunityandanti-aging and so on.However,due to the poly-unsaturated structure,lycopene is insoluble in water and sensitive to O²,light and heatand so on,which make them have great limitation in food industry.Nanoemulsions are colloid al systems that can further increase the aqueous phase solubility and bioavailability of lipophilic functional ingredients.In this study,biopolymer emulsifier-octenyl succinate anhydride modified starch?OSA starch?was chosen as emulsifier to prepare a nanoemulsion system to contain lycopene and the emulsifying characteristics of OSA starch were determined.The results showed that OSA starch showed an optimal emulsifying characteristics when dissolved at 70?with 30%?w/w?concentration.Nanoemulsion using OSA modified starch as emulsifier were homogenizedat 110 MPafor 3 times with the particle diameters about 138 nm,where the rate of oil to aqueous phase was 1:9?w/w?,lycopene?0.1%,w/w?in MCT and the relative lycopene containtionswere 72.32%.After 30 days storage at room temperature,theparticle size of emulsions have reached 166 nm and the increase less than 21%and lycopene retention was 41.41%,in comparison to the stability of lycopene dissolved in MCT?0?after14 days,which indicated thatnanoemulsions stabilized with modified starches can develop protection and delivery systems for lycopene.Thestructuralproperties changes due to the presence of lycopene in the interfacial film were examined by NMR,Raman spectroscopy,and ZetasizerNano ZS90 in order to illustrate the stability mechanism of lycopenenanoemulsions.The results showed that lycopene had a strong interaction with OSA molecules.In low concentration lycopene sample,the lycopene molecules are loaded in the hydrophobic core of the O/W nanoemulsions drops.With the addition of lycopene,they are diffusing in the interface between surfactant.Thatwould enhance the lateral packing of OSAmembrane,significantly decrease the particle size andincreased the stabilizationof nanoemulsions.By Turbiscan AGS measurement,we found that nanoemulsions with different loading of lycopene still exists the phenomenon of droplet coalescence and floation,indicating that Ostwald ripening is still the main reason for the instability of nanoemulsions.Finally,lycopene nanoemulsions were spray-dried to powders.And it showed that powders redissoluted in water after spray drying had s imilar mean particle diameters with the fresh nanoemulsions,which suggested that the spray drying process did not adversely affectthe size and the re-dissolving activity of nanoemulsions.The lycopeneantioxidant activities in suspension and in powderswere evaluated through chemicalmethods.The nanoencapsulation could enhance the reducing power and DPPH scavenging of lycopene.The FTIR-ATR and DSC analyses suggested that lycopene is amorphous in the nanopowders and hydrogen bonding was found between OSA molecules and lycopene.Additionally,the stability of redissoluted nanoemulsion in differentconcentration of pH?ionic strength and sugarwere measured.The results show that the redissoluted nanoemulsion show a widely tolerance to pH in the range of 3⁶,and high concentration of Na⁺,Mg²⁺strength and sugar could not decrease its stabilization.The results aboveindicated thatlycopene nanoemulsion and its spray-dried powder have the potential to be applied in food system.