Storage studies in sweet potato roots: experiences with KSP20 cultivar

Abstract

Four sun-cured lots of sweet potato (cv KSP20) roots were stored under different conditions in the laboratory. One lot was stored in environmental cabinets operated at five temperature levels of 5, 10, 15, 20 and 29 °C. Two lots were stored in open wooden boxes, one filled with soil and the other saw-dust. A control sample was exposed to the ambient air in the laboratory. Objective physical and chemical indices were used to monitor quality changes in the stored roots. Although the storage time and temperature were important in influencing the quality of the roots, temperatures of 10 °C or lower and also higher than 15 °C were unsuitable for storage. At these temperatures sprouting rotting, pithiness, shrivelling or a combination of physiological factors became more important in quality deterioration. Subsequently, prolonged storage was possible only at 15 and 20 °C and also in saw-dust and soil cover.

Roots stored in soil or saw-dust were as wholesome as those at 15 °C, save for the sprouting which depleted the dry matter content, and had a superior appearance.

Exponential decay could predict both Vitamin C and beta-carotene loss. Reducing sugar developed in all samples but was highest in the saw-dust storage. Shrivelling through moisture loss was highest in the ambient air storage.

Using the back-extrusion test, it was shown that there were no significant differences between boiled roots after 4 weeks of storage under all conditions