Submitted to: Subtropical Technology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 11, 2006
Publication Date: October 18, 2006
Citation: Luzio, G.A., Cameron, R.G. 2006. Functional properties of pectin after treatment qith an orange pectin methylesterase. Subtropical Technology Conference Proceedings. 57:16. Technical Abstract: Degree of esterification (DE) is a primary determinate for applications involving pectin. More recently it has been demonstrated that the yield stress behavior of pectin in the presence of calcium ions is dependent on the type of deesterification (ordered vs. random) as well as the overall DE, but these pectin structures were not characterized. Recent work indicates that pectin structural information can be obtained and these structural changes can be matched with the functional properties. This will be important for new high-volume applications involving suspension such as using citrus peel for drilling muds or for paper additive products. In this work the rheological data resulting from the stepwise decrease in DE of non-calcium sensitive pectin after demethylation at pH 4.5 and 7.5 with the salt-independent PME from citrus fruit peel was correlated with pectin structural properties. Yield stress measurements using an AR2000 rheometer together with calcium sensitivity values were matched with block size and number as determined by HPAEC analysis of pectin methylesterase (PME) block deesterified pectins. Starting with high DE pectin, DE had to be reduced to a value of 70 or less before yield stress behavior was observed in the presence of calcium ion. Both block size and block number appears to be important for suspension properties. It may now be feasible to structurally characterize de-esterification patterns produced by PME and relate this to its functional properties. The goal now is to impart greater chemical stability into this citrus peel product for these new applications.