Potatoes are often thought of as high GI. It is known that cooking and cooling affect GI and that these effects may be mediated through the physicochemical properties of their starch. As part of a Canadian initiative to develop low GI potatoes, novel potato varieties which differed in starch composition were tested in 2 separate studies. In study 1, we determined the GI of 8 varieties and found that cooling produced a wide range of effects (0-50% reduction in GI). In study 2, four previously tested varieties were re-examined. A significant variety-x-treatment interaction (p<0.01) was observed with cooling reducing GI in some potatoes. Examination of the starch properties and their role in determining GI showed that RDS was positively associated with GI (r2= 0.85, p= 0.001) and SDS (r2=-0.60, p= 0.02) and amylose (r2=-0.99, p=0.007) negatively associated with GI. No relationship between RS and phosphorous content and GI was observed.

No description available.

Thermal processing involves application of heat to destroy pathogenic microorganisms of public heath concern and to reduce the activity of microorganisms and enzymes that spoil the food. However, the technique is associated with considerable degradation of taste, color, texture, flavor and nutritional quality of processed foods. Data on kinetics of changes in quality factors and their temperature dependence, as well as the heat penetration behavior of the food during processing are necessary to predict and optimize the extent of quality retention. The objectives of this study were: (a) to evaluate the kinetics of thermal softening, color degradation and loss of ascorbic acid in potato (Solanum tuberosum) at selected temperatures (70--100°C) and to evaluate their temperature dependence; (b) to evaluate the effect of process variables (temperature, rotational speed, can size and nature of the covering fluid) on heating behavior of canned potatoes and (c) to determine the influence of the above process variables on process time and product quality.

No description available.

No description available.

The current study was conducted for evaluating the effects of two different strategies viz., phase control and cycle control, on the microwave/air drying process. A phase-controlled electrical power regulator was developed and connected in series with the original cycle-controlled power regulator of an existing domestic microwave oven. The microwave oven was further modified such that combined microwave and convectional drying can be accommodated. / The system performance was evaluated. It was observed that phase-controlled power regulator could be successfully used for quasi-continuous (fast-switching) power regulation with the maximization of power efficiency. The degradation of output microwave power was recorded and the nonuniform distribution of microwave field in the cavity was also verified. / The effects of phase control and cycle control were evaluated through combined microwave and convective drying of potato samples. Results showed that different power control methods had different impacts on drying kinetics and product quality. In both drying modes, the drying time increased with the decrease of microwave power density and the increase of air velocity. The drying rates of cycle-controlled drying are significantly higher than those of phase-controlled drying. In terms of rehydration capacity the phase-controlled drying mode produced better results. The product colour and sensory attributes were independent of the power control methods.

Graduation date: 1949

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Barry J. Jacobsen. Includes bibliographical references (leaves 115-128).

Thesis (Ph. D.)--University of Adelaide, Dept. of Crop Protection, 1996? / Three pages of addenda pasted inside back cover. Includes bibliographical references (leaves 166-189).

Thesis (Ph. D.)--University of Adelaide, Dept. of Crop Protection, 1999. / Includes bibliographical references (leaves 233-263).