Evaluation of combined methods to obtain dehydrated papaya and pumpkin

Abstract

In Brazil, an important agricultural producer, a significant amount of fruit and vegetables is lost. This could be minimized by processing these foods at source using simple techniques such as air drying. The purpose of his work is to combine pre-treatments and convective drying, investigate the effects of pre-treatments on drying kinetics, and evaluate the physic-chemical properties of dry products to improve their sensory and nutritional quality. Thermal blanching, osmotic dehydration (OD) or edible coatings addition, and combinations between them, will be optimized through response surfaces techniques taking into account color, ascorbic acid retention and, in the case of OD, process efficiency (water loss / solute gain). Samples obtained from the best feasible treatments will be hot-air-dried and its efficiency determined from drying rates. Color and volume will be determined before and after each drying experiment. Water activity in the intermediated moisture products will be measured. Parallel experiments with the same raw material samples, but under different conditions, will be conducted. The resulting best samples will be selected to evaluate the effects of the processes on sensory characteristics and on retention of specific nutrients, such as carotenes and ascorbic acid. Operational parameters useful for designing and for processing control are expected to be found. (AU)