Thermotropic polymorphism of a nonphospholipid mixture: Lactylated fatty acid esters of glycerol and propylene glycol

Lactylated FA esters of glycerol and propylene glycol (LFEGPG) are a lipid blend that is commercially available and used in the food industry as an emulsifying agent. Because the mutual impact of the two different backbones on the lipid phase behavior was of particular interest, we fractionated the commercial lipid blend by column LC. Fractions with varying ratios of glycerol and propylene glycol esters were collected and characterized by MS. DSC and X‐ray diffraction were applied to study the thermotropic phase behavior of the dry emulsifier and the derived lipid fractions. LFEGPG exhibited rich polymorphic behavior, adopting a sub‐α‐crystalline phase that converted to an α‐crystalline phase. Concomitantly, a β‐crystalline phase was formed by some components of this lipid mixture. We found that the fractions with the highest amounts of lipids bearing the less‐polar propylene glycol as their backbone tended to form a β‐crystalline phase. Also, a higher number of self‐polymerized lactic acid molecules in the head group of the propylene glycol esters favored the formation of a β‐crystalline phase.