Pectin as a Rheology Modifier: Chemistry, Production, and Rheology

Abstract

Abstract Pectin is a diverse family of polysaccharides with an anionic backbone of α‐1,4‐linked d ‐galacturonic acid (GalA) units. It has been widely used as an emulsifier, gelling agent, glazing agent, stabilizer, and thickener in food, pharmaceutical, personal care, and polymer applications. Commercial pectin is obtained through acid extraction from food waste such as apple pomace, citrus peel, and to a lesser extent, sugar beet pulp. Commercial pectin is classified according to degree of methylation (DM): high methoxy pectin (HMP) with DM > 50% and low methoxy pectin (LMP) with DM < 50%. In general, pectin solution exhibits Newtonian behavior at low shear rate and pseudoplastic behavior when the shear rate is increased. The pseudoplastic behavior of pectin solution is more pronounced with higher pectin concentration. HMP gels in the presence of co‐solute in acidic medium through hydrogen bonding and hydrophobic interactions. Alternatively, LMP gels in the presence of cation over a wide range of pH through ionic linkages, famously known as the “egg‐box” model. This review provides an overview of the chemistry, production, and rheology of pectin. In addition, the effect of modification and processing on the physicochemical properties of pectin and the application of pectin as a rheology modifier are discussed.