Construction And Microencapsulation Of Sesame Meal Emulsion Systems

Sesame is one of the most important oil crops in China,around 70 % of sesame produced all over the world is utilized for oil extraction,the by products from sesame oil extraction is known as the sesame meal.At present,the main processing and application of sesame meal mainly centralized on feed industry or extracting and isolating bioactive constituents.However,there was few researches on the emulsifying properties and applications of sesame meal.Sesame is high oil content above 50%,the residue after pressing sesame oil was defatting,milling and sieving to prepare defatted sesame meal(DSM),the DSM could wrap the oil forming a stable system as the original sesame seed?Therefore,the paper employed the DSM and soybean oil(SO)as raw material,first explored the behavior of DSM in oil-water interface.Then prepared the O/W emulsion stabilized by DSM with high pressure homogenization and studied the influence of DSM concentration,oil fraction,the external environments(Na Cl,p H)on the emulsion stability;Besides,the study also investigated the common process of seame like roasting treatment impacting on DSM of emulsifying properties.Finally,curcumin(Cur)microcapsules powders were produced by the DSM or combining with maltodextrin(MD)as wall materials with spray drying technology in order to explore the embedding characteristics of DSM.This research could improve the the added value of DSM and potentially apply to the low cost,economic wall materials suitable for oil-soluble active substances,which had great significance for providing a new angle for the comprehensive utilization of the DSM and reference for the sustainable development of sesame industry.The main study results of this paper were indicated as follows:1.The main constituents of DSM were proteins,its contents were as much as 63%,which was close to the protein content of sesame protein concentrate.The behavior of different DSM concentrations in oil-water interface by tensionmeter,the results indicated that the equilibrium interfacial tension value was smaller and the adsorption equilibrium time was shorter as the increse of DSM concentration in aqoeous solution.The O/W emulsions were prepared using DSM as emulsifier,SO as the oil phase by high pressure homogenization.Upon the increase of DSM concentration,the size of emulsion droplets and creaming index(CI%)both decreased,emulsifying stability increased significantly.Rheology and microstructure showed that the gel network was formed in emulsions and its structures became more compact with the increase of oil fraction(?).The characteristics of emulisons were generally consistent with those of the conventional Pickering emulsions.So DSM could act as a potential Pickering emulsion stabilizer.Furthermore,there had no significant effect on the stability of emulsion under the condition of low salt concentration(0-400 m M),but the emulsions was markly dependent on the p H,and the most stable emulsion was obtained at neutral condition of p H 7.0.2.The functional properties and ability to formation stable emulsions of sesame meal were observably influenced by the process of roasting treatment.As the results displayed that the emulsifying activity,emulsion stability and gel performance of sesame meal all remarkably enhanced,but its water or oil holding capacity changed less obviously.DSC results showed that the enthalpy value of RDSM enhanced 2.6 times compared with DSM,meaning that protein of sesame meal denaturation degree increased or the interaction between sesame meal compositions strengthened,which promoted the increase of interfacial activity,shortened its oil-water interfacial adsorption equilibrium time and decreased the interfacial tension.Moreover,the viscoelasticity of RDSM were improved by the increase of interfacial film thickness.Second,the size and emulsion stability of emulsions stabilized by RDSM had no obvious change after storage for 40 d under ambient temperature,the roasting treatment greatly boosted the stability of the emulsion.The probable reasons might be the interaction of components of sesame meal heightened or exposure much more hydrophobic groups or formation protein aggregations owing to sesame protein denaturation after roasting treatment.At the same time,the gel network of emulsion droplets were intensified and the appearance of emulsion was similar with gel emulsion.3.Cur microcapsules powders were prepared using DSM or combining with MD by spray drying.As the results,first,the loading capacity of Cur was less than 50%,the encapsulation efficiency of microcapsule powders all exceeded 85% and moisture content was inferior to 5%.There was no notable impact after redissolving.Second,the encapsulation efficiency of microcapsule products had no distinct change after storage in high temperature and humidity environment by accelerated storage test.Moreover,SEM demonstrated that the appearance of microcapsules were relatively complete without any break on the surface after storage for 180 d at room temperature.Finally,the microcapsule powders could be digested in gastrointestinal tract and release the nutrients in vitro digestion experiment.Products with MD could enhance the bioavailability in the gastrointestinal tract.