In situ observation of pressure-induced gelation of starches studied with FTIR in the diamond anvil cell

Pressure-induced gelation of six different starch types has been followed b y Fourier-transform infrared (FTIR) spectroscopy. The diamond anvil cell al lowed us to follow changes in situ at high pressure. Changes in the infrare d spectrum due to conformational modifications and solvation changes in the starch granule were analysed. The spectra of these starches showed a simil ar behaviour at increasing pressure. Bands in the region 900-1300 cm(-1) in creased in intensity and changed position at high pressure. A correlation w as found between the stability and the structure of the different starch ty pes. B-type starches tend to be more pressure resistant than A- and C-type starches. In situ observation of the gelation was also performed with a mic roscope. At the pressure at which gelation occurred, a swelling of the star ch granules was observed. (C) 1999 Elsevier Science Ltd. All rights reserve d.