SOME PHYSICOCHEMlCAL PROPERTIES OF STARCHES AS AFFECTED BY CHANGES IN ATMOSPHERIC PRESSURE

The effects of varying atmospheric pressures on the properties of starches were investigated. Four types of starches‐corn, rice, potato and wheat‐were studied for their water‐binding capacity and viscosity behavior. Photomicrographs of starch suspensions were taken at five altitudes and temperatures of 22 °, 60 °, 70 °, 80 ° and 90 °C respectively. Measurements of the photomicrographs showed corn, potato and rice starch granules to increase in size on changing elevation from sea level to 10,000 feet. Wheat starch was not affected. Water‐binding capacity increased for corn and potato starches as the altitude increased, but rice and wheat starches were not affected. The viscosity of corn, rice and wheat starch suspensions decreased initially with increasing altitudes but increased at the higher altitudes. The viscosity of potato starch suspensions did not change at increased elevations.