The Emulsifying and Emulsion-Stabilizing Properties of Pectin: A Review

Pectin, a plant cell wall polysaccharide, is a natural multifunctional ingredient which imparts textural and rheological properties to a wide range of food systems. Up to the last decade, most pectin blank applications stemmed from its gel-forming ability. Nowadays, pectin is gradually gaining acceptance as an effective emulsifier in numerous food applications. Accordingly, the emulsifying and emulsion-stabilizing properties of this hydrocolloid are increasingly being assessed. These pectin functionalities are controlled by both the properties of the carbohydrate moieties and of the often attached protein groups. Generally, the protein moiety, feruloyl, and acetyl groups, play a major role in pectin emulsifying activities, while the emulsion-stabilizing properties of the polymer are controlled by the homogalacturonan (HG) domain and the neutral sugar side chains of the rhamnogalacturonan-I (RGI) structural element. However, the neutral sugar side chains might obstruct the accessibility of pectin hydrophobic species to the oil/water interface, thereby hampering emulsification. In addition, the contribution of HG to emulsion stabilization might be dependent on the polymer HG: RGI ratio. Hence, the influence of pectin structural features on the polymer emulsifying potentials is yet to be fully unraveled, as identified in this review. Furthermore, the emulsifying and emulsion-stabilizing properties of pectin are influenced by the composition of emulsions.