Effect of Additives and Emulsifiers on the Stability of O/W Emulsion 
T. Deguchi1, S. Matsumoto1, H. Hondoh1, S. Arima2, A. Ogawa2, K. Sato1, S. Ueno 1
1. Hiroshima University, Higashi-Hiroshima, Japan
2.Mitsubishi-kagaku Foods Co., Yokohama, Japan

	Fat crystallization in O/W emulsion causes a partial coalescence phenomenon, and is one of the main factors of destabilization of the emulsion. We reported the sucrose palmitate ester (P-170, Mitsubishi Kagaku Foods Corporation) make the emulsion stabilize. The purpose of this study is to find out the stabilization mechanism of the O/W emulsion.
	Two types of the emulsifiers, decaglycerol palmitate (DGP) and polyoxyethylene soribitan mono-palmitate (Tween40) were employed. Palm oil was used for oil phase. P-170 was also added in oil phase as an additive. Gelation-resistant study was carried out to determine the stability emulsions, and synchrotron radiation micro beam X-ray diffraction measurement was used to determine the alignment of crystals in the emulsion. 
Main results were as follows: (i) The emulsion with DGP showed much higher stability than that with Tween40. (ii) Addition of P-170 elevated the stability of emulsion with DGP, while the stabilization effect of P-170 on the Tween40 emulsion was limited. (iii) All the lamellar planes of crystals in an oil droplet of the DGP emulsion trended in one direction with and without P-170. (iv) On the other hand, in the Tween40 emulsion, the lamellar planes of palm crystals were parallel to an interface near the outer edge of oil droplet without P-170. When P-170 was added to the Tween40 emulsion, crystals did not show any orientation. From these results, we conclude that the stabilization effect of P-170 will be regulated by the combination of emulsifiers.