Crystallization at Interfaces in Food Emulsions – A General Phenomenon

Monoglycerides based on saturated acyl chains, which are a dominating emulsifier type in foods, have been studied by interfacial tension measurements and crystallization behaviour. It was found that the requirement for formation of an interfacial film is that the concentration and temperature limits for crystallization in the corresponding oil has been reached. Thus, association of the emulsifier molecules into a layer with crystalline chains between oil and water cannot take place unless the limit of association of the emulsifier in oil has been reached. Crystals at the interface will expose a hydrophobic surface towards the oil and a hydrophilic surface towards water, and might therefore be termed surface‐active crystals. This interfacial crystallization explains the mechanisms behind numerous presently applied emulsification processes, derived empirically, as well as other food emulsion phenomena, such as interfacial desorption of proteins by monoglycerides in the preparation of ice‐cream.