Influence of heating time and pressure treatment of potato starch on the generation of radicals: EPR studies.

The influence of heating time and pressurizing time under pressure of 1 GPa on radicals generation in potato starch polymer was investigated by EPR. Potato starch was heated at two temperatures: 413 ± 2 K (140 °C) and 473 ± 2 K (200 °C) for 15, 30, 60, 120, 180, 240, 270 and 300 min and subdued to pressurizing under pressure of 1 ± 0.002 GPa for 6, 60, 300 and 1440 min.

Acid excreting mutants of yeast Saccharomyces cerevisiae.

Saccharomyces cerevisiae mutants acidifying glucose medium containing bromocresol purple were shown to excrete protons when placed in unbuffered water in the absence of any external carbon source. The mutants belong to 16 different complementation groups. Most of them do not grow on glycerol and the excreted protons are associated to particular sets of organic anions such as citrate, aconitate, succinate, fumarate or malate.