De-esterification pattern of Valencia orange pectinmethylesterases and characterization of modified pectins

Hyoungill Lee, Josh Rivner, Jeffrey L. Urbauer, Nissim Garti, Louise Wicker*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

BACKGROUND: Pectinmethylesterase (PME, E.C. 1.1.11) isozymes from Valencia orange preparations with different specific activities were used to de-esterify citrus and sugar beet pectins. Enzymatic modification offers the opportunity to create pectins of tailored functionality and gelling ability. RESULTS: Based on nuclear magnetic resonance spectra, catalysis by all PME extracts produced block-wise de-esterification patterns in both citrus and sugar beet pectins. PME activity resulted in increased numbers of contiguous de-esterified groups and decreased numbers of contiguous esterified groups. De-esterification by PMEs increased the elastic property (G′) of citrus and sugar beet pectins in the presence of calcium from 10 to 571 and from 0.05 to 201 Pa, respectively. CONCLUSIONS: The results demonstrate the predilection of citrus PMEs toward block wise de-esterification of pectins and the relationship between calcium binding ability and de-esterification degree and patterning. Within a narrow range of de-esterification (37-48%) and with a narrow distribution of contiguous groups, PME modification did not markedly change gelling ability. At lower or higher de-esterification values, a 2-fold increase or 50-fold decrease, respectively in G′ values was observed.

Original languageEnglish
Pages (from-to)2102-2110
Number of pages9
JournalJournal of the Science of Food and Agriculture
Volume88
Issue number12
DOIs
StatePublished - Sep 2008

Keywords

  • Block wise
  • Calcium sensitivity
  • Functionality
  • Gel strength

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