Rheological Properties of Pastes and Gels made from Starch Separated from Different Potato Cultivars

Tests on potato cultivars in two years indicated a wide variation in dry matter (DM) content, boiled potato shear (BPS), and in the rheological properties of pastes and gels made from starch separated from the potatoes. These differences highlight the problems of potato processors trying to produce end-products of consistent quality. DM content was negatively correlated with BPS, with time to achieve peak viscosity (starch paste), with degree of retrogradation (starch paste), with gel compression values, and with amylose and phosphorus contents of the separated starch. DM was positively correlated with peak viscosity values (starch paste) and cooked paste stability. There was good agreement between the viscological properties of starch pastes and gels for the different potato cultivars. Freezing potato starch grains in situ had a reducing effect on peak viscosity values of starch pastes but an increasing effect on values for degree of retrogradation (starch paste), gel strength and cooked paste stability.