Long-term storage of sweetpotato by small-scale farmers through improved post harvest technologies

Sweetpotato (SP) small-scale farmers of Luweero and Mpigi districts were introduced to improved long-term storage methods (pit and clamp) as a way of improving their livelihood. Based on a participatory approach, farmers were involved in a storage study where dry matter, beta-carotene and sugar content parameters were monitored over a 60 day period in Mpigi and 75 days in Luweero district. Pit and clamp stores were constructed by farmers in selected sites of each district. Improved SP varieties (Ejumula, Naspot 1, Naspot 2, New Kawogo, Semanda and SPK004) were used for the storage study. Dry matter contents of SP were exceptionally high, particularly for roots from Mpigi district, with Semanda variety having the highest dry matter (41%). High beta-carotene concentrations were recorded for the orange-fleshed varieties, SPK004 and Ejumula, 68 and 125 mg/100 g, respectively. Total sugar contents of the roots were generally low (1.6-3.7 g/100 g), with exception of Naspot 2 (5.7 g/100 g). Changes in dry matter, beta-carotene and sugar contents of SP depended on location, and differed for both districts. No consistent trends in dry matter, reducing and sucrose contents were noted for SP in Luweero district. The decrease in sugar contents noted for Mpigi SP was due to a general decrease in dry matter for these SP. Although betacarotene generally decreased with storage period for SP in both districts, the residual beta-carotene (2.6-3.4 mg/100 g) in the orange-fleshed SP varieties could be sufficient as the recommended daily allowance intake of vitamin A. Monitoring temperature, relative humidity and atmospheric compositions of the long-terms stores is needed to assess the performance of individual SP varieties.