Interactions between polyglycerol polyricinoleate (PGPR) and pectins at the oil–water interface and their influence on the stability of water-in-oil emulsions

Abstract

The interactions between a hydrophobic emulsifier (polyglycerol polyricinoleate) and pectin at the oil–water interface were studied using drop shape tensiometry, and the results were related to the emulsifying behavior of these ingredients in water-in-oil emulsions. High methoxyl pectin (HMP) and sugar beet pectin (SBP) were used as model polysaccharides, because of their differences in interfacial activity. Pectins were added to the aqueous phase in the absence and presence of PGPR in the oil phase. SBP was shown to further decrease the interfacial tension when added simultaneously with PGPR. In the presence of PGPR, SBP or HMP caused the formation of a weakly elastic interfacial film. Water-in-oil emulsions containing PGPR (2–6%) showed improved stability when containing SBP or HMP (0.1%), compared to water alone. This work highlights the potential for reducing the amount of PGPR added to water-in-oil emulsions by creating interacting films with polysaccharides at the oil–water interface.