Effect of Temperature on Production of Soybean Oil-in-Water Emulsions by Microchannel Emulsification Using Different Emulsifiers

Abstract

This paper reports the effect of temperature on the production characteristics of soybean oil-in-water (O/W) emulsions by microchannel (MC) emulsification using different emulsifiers. The temperature of an emulsification module including an MC array chip (MS104) was controlled between 10℃ and 70℃. Sodium oleate, pentaglycerol monolaurate (PGM), and polyoxyethylene sorbitan monolaurate (Tween 20) were used as emulsifiers. The contact angle of the dispersed phase on the channel wall exceeded 130° and decreased gradually as the temperature increased. Monodisperse O/W emulsions with coefficients of variation (CV) below 6% were produced, independent of the temperature applied and the type of emulsifier used. The resultant droplet diameters, which ranged between 30 μm and 36 μm, decreased gradually as the temperature increased. The resultant droplet diameter was also almost constant below a critical flow velocity of the dispersed phase in a channel. The critical flow velocity increased with increasing operating temperature. The sodium oleate-containing system had a critical flow velocity and a maximum droplet generation rate considerably higher than those for Tween 20-and PGM-containing systems at each temperature.

Protein-Stabilized Palm-Oil-in-Water Emulsification Using Microchannel Array Devices under Controlled Temperature

“…As indicated by photomicrographs, uniform and stable droplet generation was observed below the critical flow velocity ( Figure 7 b), whereas non-uniform droplet generation was observed above the critical flow velocity ( Figure 7 c). These results agree with those from previous studies [ 35 , 36 , 45 ]. As reported, critical flow velocity was analyzed in relation to the capillary number [ 45 ], which is defined as the relative magnitude of viscus force to interfacial force, although emulsification was affected by the physical properties of MCs [ 35 ] and the type of emulsifier [ 36 ].…”

“…These results agree with those from previous studies [ 35 , 36 , 45 ]. As reported, critical flow velocity was analyzed in relation to the capillary number [ 45 ], which is defined as the relative magnitude of viscus force to interfacial force, although emulsification was affected by the physical properties of MCs [ 35 ] and the type of emulsifier [ 36 ]. In our study, the critical capillary number above which emulsification became unstable was determined to be 0.006.…”

“…Especially for the solid lipid microsphere with a high melting temperature, temperature control during emulsification is essential for obtaining hot emulsions as the precursors of microspheres. However, only a few studies using high-temperature MC emulsification have been conducted [ 31 , 35 , 36 , 37 ], and only one study preparing hot emulsions using solid/semi-solid lipids has been reported [ 33 ]. Thus, in the present study, MC emulsification using palm oil was carried out above its crystallization temperature with food grade emulsifiers including nonionic and protein emulsifiers, with the intention of obtaining biocompatible lipid microspheres.…”

Formulation of Uniform-sized Agar Gel Microbeads from Water-in-oil Emulsion Prepared Using Microchannel Emulsification under Controlled Temperature

“…Therefore, emulsification temperatures between 10 and 55℃ [21]. In this study, equilibrium interfacial tension decreased with increased temperature, being similar to previous data for nonionic surfactants [19][20][21] [19,32,33]. Hence, the stability of the newly created interface should be dominated by the relative rate between the diffusion-adsorption process of emulsifier molecules and the creation of the droplet interface.…”

“…To prepare agar-containing W/O emulsions, the temperature must be kept above the gel point temperature of agar solutions to prevent gelation during emulsification. Details of the effects of temperature on MC emulsification have been reported only recently [19][20][21]. MC emulsification at temperatures above room temperature was reported in some cases when gelatin [22,23], alginate [13], and tripalmitin [24] were used as dispersed phase components.…”