THE THERMAL-PROPERTIES OF POTATOES AND CARROTS AS AFFECTED BY THERMAL-PROCESSING

The effects of processing on the thermal properties of white potatoes and carrots were studied. The test samples were blanched, boiled, cook ed and canned. Whole potato tubers were baked to study the effects of starch gelatinization. The thermal conductivity (k) and density (rho) were measured and the specific heat (c(p)) and thermal diffusivity (al pha) were calculated. Results showed that in general, alpha initially decreased and then increased during processing. Test samples were foun d to have a gain in a! when their moisture content increased by more t han 9%. The ct of potatoes decreased after canning and increased after boiling. In carrots, a similar trend was also observed but to a lesse r degree. The alpha of potatoes was unaffected after blanching or cook ing. In all the processing treatments of carrots, the k and the c(p) i ncreased and the rho was unaffected. The baking study showed that gela tinization significantly decreased the k of potatoes.