Hello dear, I think that your system is complex, because you want to obtain a emulsion with high  thermal stability, but you know that the temperature affect the colloidal stability mainly when you are using a no-ionic surfactant. You know that the Brownian movement of the particles increases with the temperature. I think that the thermal stability is better on miniemulsion than emulsion, because you can use a substances (hexadecane and cetyl alcohol) that can reduce the Oswald ripening and furthermore the miniemulsion is more stable.

Finally, I want to say that if you want to use another method that it does not include the evaporation because the colloidal stability may be affected. Furthermore you can use a volatile solvent for extracting after this solvent and increase the concentration and make it at low temperature. 

The starch also can affect your system, since this material is hydrophilic and it may reduce the micellar concentration of the no-ionic surfactant.

Hello dear, I think that your system is complex, because you want to obtain a emulsion with high  thermal stability, but you know that the temperature affect the colloidal stability mainly when you are using a no-ionic surfactant. You know that the Brownian movement of the particles increases with the temperature. I think that the thermal stability is better on miniemulsion than emulsion, because you can use a substances (hexadecane and cetyl alcohol) that can reduce the Oswald ripening and furthermore the miniemulsion is more stable.

Finally, I want to say that if you want to use another method that it does not include the evaporation because the colloidal stability may be affected. Furthermore you can use a volatile solvent for extracting after this solvent and increase the concentration and make it at low temperature. 

The starch also can affect your system, since this material is hydrophilic and it may reduce the micellar concentration of the no-ionic surfactant.

For a w/o emulsion nonionic surfactants with a low HLB are required. For this reason SPAN80 is more suitable for your emulsion, but it is seldom sufficient to add only one surfactant. Non-ionic surfactants are sensitive to high temperature. For this reason the addtion of an anionic surfactant to the SPAN80 is advisable, e.g. dioctylsulfosuccinate sodium salt (DOSS), which is proven for w/o emulsions. The link shows you the HLB values from the surfactants available from SIGMAALDRICH. Especially the tetramethyl-decyne-diol is often a magic bullet as co-surfactant. Also castoroil can be used as co-surfactant because is acts as an surfactant with a HBL value of about 2; Brij 93 is similar to castor oil. Another trick is to add an oligomeric surfactant like a Pluronic type as cosurfactant. At the end you will have a system of several surfactants with some DOSS, SPAN80, tetramethyl-decyne-diol and a PLURONIC-type.

http://www.sigmaaldrich.com/materials-science/material-science-products.html?TablePage=22686648

Your concept seems unclear - do you want to obtain starch particles well dispersed in oil phase? What is the size of particles envisaged?

Dear Titus,

Yes, the concept is to obtain starch particles dispersed in the aforementioned oils. Preferentially, need to get high solid content !!!

Particle size in my case in not that important. The only important issue is the stability of emulsion at high temperatures where water evaporates !

Dear Burkhard and Edwin, Thank you so much for your answers.

Starch soluble at 20 % level - seems to be chemically modified starch. Introduced functional groups certainly will have an effect on stabilization, especially if ionic.

Would not worry about higher temperature in case of nonionic surfactants, which will turn them more hydrophobic, i.e. make them more suitable as w/o emulsifier.

In case of ethoxylated nonionic surfactants there might be an additional effect of specific interaction of polyether group with dissolved carbohydrate as I observed in case of dextrin and ethoxylated surfactant. Dextrin solution precipitated out the surfactant. That is nonionic surfactant with higher degree of ethoxylation maybe suitable.

You should be aware that dispersion of starch solution in oil will be eased if continuous phase viscosity is higher. Therefore I would select oil phase accordingly.

Would be an interesting experiment to observe what would happen if for water removal emulsion is treated in a microwave oven.

Think a few first experiments would help to progress in understanding of your system.

Good luck

Thank you so much.

Regarding the microwave oven; what is going to happen by doing so? Why do you think it may help?

microwave oven will specifically heat up the water molecules. Maybe only the water evaporates or the starch particles will be disrupted too.

as far as I searched, microwave results in destabilization of W/O emulsions. However, it is worth it to try !

Thank you so much.

Other suggestions as well as referring to the related articles in this area are highly appreciated.

I did not mean for stabilization but for removal of water.

Yes, I know,

But, unanimously, it has been stated that microwave destabilize W/O emulsions.

Thanks

Regards