Authors: Seung-Min Lee, Ashwini Wagh, Guneev Sandhu, Marie K. Walsh
Sugar fatty acid esters (SFAE) are a class of synthetic emulsifiers used in the food, pharmaceutical, and personal care industries. The influence of the fatty acid chain length on the emulsification properties of lactose fatty acid esters (LFAE) including lactose monooctanoate (LMO), lactose monodecanoate (LMD), lactose monolaurate (LML) and lactose monomyristate (LMM) was investigated in this study. The stability of the emulsions as well as the oil droplet size distribution in 20% soybean oil-in-water emulsions was measured at 0.1%, 0.25% and 0.5% of LFAE concentrations. In order of LFAE with the strongest emulsion stabilization characteristics were LML, LMD, LMO and LMM. Oil droplet distributions resulted in the same trend, with LML and LMD maintaining the smallest droplet sizes and thus the most stable emulsion. The hydrophilic-lipophilic balance (HLB) and critical micelle concentrations were determined for each LFAE. An increase in HLB value was seen with an increased CMC value for each LFAE, showing the strength of the linear relationship between these two measured values. Additionally, there was a decrease in HLB and CMC values with a decrease in the fatty acid chain length of each LFAE. This research showed that LML and LMD formed more stable emulsions, even with HLB and CMC values higher than those of LMM suggesting HLB and CMC values alone do not predict emulsifier effectiveness.
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