Effect Of Sesame Meal Utilization On Its Emulsifying Properties And Preliminary Study On Mechanism

Sesame is one of the main oil crops in China,about 80% of sesame were used to prepare sesame oil each year and produced a lot of by-products—sesame meal.Sesame protein is an oilseed protein which is extracted from sesame meal,it is speculated that sesame meal should have good emulsifying properties.However,there are few studies and applications on its emulsifying properties,and the effect of different utilization methods on emulsifying properties has not been clearly understood.Based on this,this research compared the effect of peeling and roasting treatment on the emulsifying properties of defatted sesame meal,and provided guidance for the utilization of sesame meal.At the same time,the possible reasons for the difference of emulsifying properties were preliminarily explored by particle size,ζ-potential,three-phase contact angle,interfacial tension and series physical image observation.On this basis,the possible application of high internal phase emulsion prepared by defatted sesame meal was investigated.The research results can directly provide the basis and guidance for the processing of sesame meal in sesame processing enterprises,the scientific procurement of sesame meal application enterprises,and the analogous promotion ideas for the by-product utilization research of oil processing enterprises.The main research contents and results are as follows:1.The effect of peeling on the emulsifying properties of defatted sesame meal was studied.The study found that the physical stability and properties of DSM(defatted sesame meal)-stabilized emulsion were better than that of the PDSM(peeled defatted sesame meal)at the same solid content of defatted sesame meal;three-phase contact angle and interfacial tension analysis showed that the three-phase contact angle of DSM was closer to 90°,indicating the hydrophilicity and lipophilicity of DSM were better.The time for DSM to reach the adsorption equilibrium at the oil-water interface was shorter,and the interfacial tension value was smaller;image analysis showed that the amount of protein adsorption on the interface of DSM-stabilized emulsion was more,and thecellulose was distributed more at the interface of DSM-stabilized emulsion and presented a spherical distribution on the surface of the droplet,and the surface of DSM-stabilized emulsion was rougher.The increased amount of defatted sesame meal contributed to the adsorption at the interface and the formation of smaller droplets.The emulsion with solid content of 1.5% had the best droplet distribution characteristics and superior stability.2.The effect of high temperature roasting treatment on the emulsifying properties of PDSM and DSM were further studied.Whether peeling or not,high temperature roasting could significantly improve the water holding capacity,oil holding capacity,emulsifying activity and emulsifying stability of defatted sesame meal.The results of interfacial tension measurement showed that defatted sesame meal after 140℃ roasting could obviously reduce adsorption equilibrium time and interfacial tension value at oil-water interface.Combined with the results of image analysis,it was speculated that the reason might be the interaction between the molecules in the defatted sesame meal,or more hydrophobic groups were exposed or formation protein aggregations owing to sesame protein denaturation after high temperature roasting treatment.3.The application of high internal phase emulsions(HIPEs)stabilized by PDSM and DSM was discussed.The effects of solid content of defatted sesame meal,oil phase volume fraction,p H and ion concentration on the microstructure,oil droplet size and rheological properties of HIPEs were examined.The results indicated that at the 5.0%solid content of defatted sesame meal,the highest oil phase volume fraction of PDSM and DSM stabilized HIPEs was 0.75 and 0.85,respectively.At an oil phase volume fraction of 0.75,the minimum solid content of PDSM and DSM was 5.0% and 3.0%,respectively.PDSM and DSM stabilized HIPEs had the best stability under the condition of neutral p H as well as the addition of 30 mM NaCl.Rheological analysis showed that there was an elasticity-dominated gel network structure inside HIPEs.With the increase of solid content of defatted sesame meal,the droplet size decreased and distributed uniformly,and the viscoelasticity of HIPEs increased.