Pressure-temperature gelatinization phase diagram of starch: An in situ fourier transform infrared study

The gelatinization of rice starch is reported as a function of temperature and pressure from the changes in the ir spectrum. The diagram that is obser ved is reminiscent of those obtained for the denaturation of proteins and t he phase separation observed from the cloud point for several water soluble synthetic polymers. It is proposed that the reentrant shape of the diagram for starch is not only due to hydrogen bonding but also to the imperfect p acking of amylose and amylopectin chains in the starch granule. The influen ce of pressure and temperature on thermodynamic parameters leading to this diagram is discussed. (C) 2000 John Wiley & Sons, Inc.