Tomlins, K.I., Ndunguru, G.T. and Rwiza, E. (1998) Losses in sweet potato quality at harvest and during the post-harvest handling in the Mwanza Region of Tanzania. [Working Paper]

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Abstract

A preliminary survey of the sweet potato marketing chain, from the farm to the market, indicated that substantial loses in quality can occur at all stages. Sacks, containing between 107 and 114 kg of sweet potatoes took between 16 and 23 hours to reach the market. After leaving the farm, they were transported by bicycle, trolley, canoe, ship and light commercial vehicle. Assessment of the sweet potatoes, immediately after harvesting, indicated that approximately 20% to 35% of the sweet potatoes had minor cuts, 14% to 28% had breaks, 19% to 60% had signs of minor skinning, 13% to 59% had skin weevil and 1% to 4% burrowing weevil damage. After transport from the farm to the market, the level of damage in freshly harvested sweet potatoes increased such that 100% of the sweet potatoes had skinning damage, most severely, and 38% to 56% had breaks. Transport had little impact on the proportion of sweet potatoes with cuts or weevil damage. Shrivelled sweet potatoes were less susceptible to damage. The presence of rots, however, led to the sweet potatoes receiving a nominal market value. Handling of the sacks was monitored by visual observations and by shock, temperature and humidity measurements recorded by an 'electronic sweet potato', designed and assembled at NRI, which was inserted into the centre of the sacks. The most severe handling (shocks above 20g) occurred during loading and unloading from the ship, at the customs station of the port and at the markets and appeared to be associated with the occurrence of major breaks. The temperature (220C to 340C) in the sacks was optimum for curing although the very high humidity (greater than 95%) might lead to the occurrence of rots. Further studies will investigate seasonal variations along with other methods of transport to suggest practical and economic recommendations on improved transport and handling practices and direct future research.

Item Type:	Working Paper
Uncontrolled Keywords:	sweet potato, postharvest loss, damage, skinning damage, skin weevil, burrowing weevil, supply, handling, quality, electronic sweet potato, artificial sweet potato
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science > Natural Resources Institute Faculty of Engineering & Science > Natural Resources Institute > Food & Markets Department
Related URLs:	Publisher
Last Modified:	26 Nov 2019 12:06
URI:	http://gala.gre.ac.uk/id/eprint/11495

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