Abstract
During deesterification, the ester groups on the pectin can be removed in a random or block wise (sequential) manner. The removal of esters block wise is typically mediated by plant pectin esterases such as those found in papaya extracts. Pectins containing these blocks of unesterified groups on the chain are highly reactive to divalent cations such as calcium ion. In solution, in the presence of calcium ions, pectins deesterified by plant pectin esterases can exhibit unique rheological properties. One such property is that they can produce solutions that have pseudoplastic properties such as yield stress behavior. This yield stress behavior can be used for particle or pulp suspension. These pectins were used to suspend citrus pulp in the presence of calcium ions and the settling rate was 50 times slower than the control with no added pectin. Yield stress behavior can be important for pulp stabilization in fruit drinks, while providing low viscosity for acceptable mouth feel.
