Kinetic Analysis of Partial Decomposition of Starch in Hot-Compressed Water

Shigeaki Ueno, Mayumi Anzai, Toru Shigematsu, Tomoyuki Fujii

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The partial decomposition reaction of starch in hot-compressed water was studied using a tubular reactor at 160-210°C and 25-45 MPa. The increase rate of r ducing sugar concentrations at short residence times was considered as initial reaction rate of partial decomposition. The kinetic analysis of the initial reaction rate indicated that the reaction mechanism over 190°C was different from that below 180°C. The reaction mechanism over 190°C could be expressed by bimolecular reaction between starch and ionized water. The activation energies for starch partial decomposition were about 120 kJ/mol, which was almost the same as the activation energies of maltose and isomaltose hydrolysis. The activation volumes were equivalent to the volume of a few water molecules, suggesting that the reaction proceeded like the gas phase reactions. In contrast, the reaction mechanism below 180°C could be expressed by multimolecular reaction. The activation volumes were significantly larger than those over 190°C. The large activation volume below 180°C suggested that the reaction proceeded, like the liquid phase reactions, with solvent effect between starch and multiple water molecules.

Original languageEnglish
Pages (from-to)143-150
Number of pages8
Journaljapan journal of food engineering
Volume9
Issue number3
DOIs
Publication statusPublished - 2008 Jan 1
Externally publishedYes

Keywords

  • activation energy
  • activation volume
  • hot compressed water
  • partial decomposition
  • starch

ASJC Scopus subject areas

  • Food Science
  • Industrial and Manufacturing Engineering

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