Abstract
In this study, we investigated the effects of two types of polyglycerol fatty acid esters, both of which were made from the same polar group of polymerized 10 glycerols, on the crystallization of n-hexadecane (n-HD). One of the emulsifiers, known as THL-17, consists of three different saturated fatty acid chains with different carbon numbers between 8 and 18. Another emulsifier, known as 10G10S, contains a stearic acid chain only. The two emulsifiers were added to retard the crystallization rate of n-HD, which has melting point of 18.0°C, and was chosen as a model fat material. Visual and optical microscopic observations showed that the growth of n-HD seed crystals in bulk liquid was significantly retarded by the addition of 1.0 wt.% THL-17 at 17.0°C. The DSC cooling peaks of n-HD with and without the addition of THL-17 showed that the crystallization temperature (Tc) of n-HD decreased with increasing concentrations of THL-17 from 15.9°C (in the pure form) to 14.0°C (in the solution containing 1.0 wt.% THL-17). In contrast, 10G10S did not affect the Tc value, even at a concentration of 1.0 wt.%. The results of this study suggest that the inhibition of n-HD crystal formation in the presence of THL-17 results from effects on both crystal nucleation and post-nucleation crystal growth processes.
