Losses in sweet potato quality at harvest and during the post-harvest handling in the Mwanza Region of Tanzania

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

The relationship between quality and economic value of fresh sweet potato and dried cassava products in Mwanza, Tanzania

This report outlines the relationship between quality and economic value for fresh sweet potato and dried cassava in the urban markets of Mwanza in north west Tanzania. These two crops form an increasingly important part of food security and, through the marketing of surpluses, of income generation for poor householders. The work reported in this report used a combination of participatory and more formal statistical methodologies in order to gauge relationships between quality and value of the marketed produce

The use of needs assessment methodologies to focus technical interventions in root and tuber crop post-harvest systems: a case study to improve incomes and reduce losses associated with marketing of fresh cassava from rural areas to Dar es Salaam

The Transfer of Needs Assessment Methodologies and Post-Harvest Technologies for Non-Grain Starch Staple Food Crops (NGSS) in sub-Saharan Africa project was initiated in Tanzania in July 1993 as a collaborative venture between the Natural Resources Institute (NRI) and the Tanzania Food and Nutrition Centre (TFNC). The project was funded by the UK Department For International Development (DFID). The main project involved activities in Ghana and Tanzania but this report deals exclusively with activities in Tanzania focusing on the transfer of needs assessment methodologies, the application of needs assessment in identifying post-harvest problems and technical interventions for NGSS and the identification, validation and dissemination of a technology to improve incomes and reduce post-harvest losses associated with marketing of fresh cassava roots from rural production areas to urban markets in Dar es Salaam. In the first stage of the project a range of needs assessment methodologies were successfully validated under field conditions through the mechanism of three case studies, which were carried out in Lake Zone, Tanga Region and Dar es Salaam of Tanzania. Following the case studies, two training in needs assessment workshops were conducted in Tanzania to disseminate needs assessment technologies to key personnel from research organisations and institutes in Tanzania, Mozambique, Uganda, Kenya, Ghana, Rwanda and Ethiopia. The needs assessment case study in Tanga Region highlighted post-harvest problems as a major constraint facing farmers and traders involved in the marketing of fresh cassava to urban areas, and formed the basis for a more detailed study of the marketing system for fresh cassava from rural production areas to urban markets in Dar es Salaam. Semi structured interviews with key stakeholders in the marketing system demonstrated that reductions in quality resulting from poor handling and delays in marketing lead to serious reductions in income throughout the market chain. Farmers and market personnel identified the criteria for a technical intervention to reduce income losses incurred when marketing fresh cassava. After considering various options a simple low cost storage technique for fresh cassava originally developed by the Centro Internacional de Agricultura Tropical (CIAT) and NRI and later modified with DFID RNRRS funds by the NRI and the Ministry of Food and Agriculture (MoFA) in Ghana was selected for validation in Tanzania. Validation exercises in Tanzania demonstrated that low cost fresh cassava root storage technology had the technical and economic potential to alleviate postharvest problems associated with marketing of fresh cassava and improve the incomes of those involved in the cassava market system. In the final stage of the project a flexible dissemination strategy was developed and used to carry out a limited technical dissemination campaign in the major cassava markets in Dares Salaam and selected villages ofKisarawe and Ruf~i Districts in Pwani (Coast) Region, and to promote wider awareness of the technology throughout Tanzania. Needs assessment techniques were used to develop practical approaches for dissemination and two impact assessments (November 1996 and December1997) were carried out to assess effectiveness of dissemination activities and allow for optimisation ofthe strategy. The first impact assessment (November 1996) was used to highlight the strengths and limitations of the initial dissemination strategy, so that a more effective strategy could be developed in collaboration with representatives of the Agricultural Extension Services and key stakeholders in the market system. In December 1997 a second impact assessment was made to assess the effectiveness of the revised dissemination strategy and to highlight any problems. The wider awareness campaign was found to have been effective and a number of expressions of interest had been received from organisations and individuals interested in fresh cassava within Tanzania. A high level of interest and awareness was found in markets and villages where training activities had taken place, but a number of problems were identified which were hampering uptake of the technology. The two main problems were: (a). to be effective the technology needs to be implemented at all points in the market system but individuals were unwilling to take the risk ofbeing the first to use the technology without proof of the economic benefits of the technology; (b). the market system is dominated by a large open type of package called a lumbesa which is not suitable for application of the technology or for transport of cassava but is used for other reasons related to transport charges. To overcome the first difficulty the project team developed a marketing demonstration to provide a practical demonstration of the financial benefits of low cost :fresh cassava root storage technology to potential beneficiaries within the marketing system. The second difficulty was addressed by representatives of various village governments and market co-operatives in collaboration with the TFNCINRI project team. In November of 1997 the village governments of Jaribu and Bungu villages in Rufiji District enacted bylaws to encourage adoption of close packaging for cassava and adoption of the new storage technology. To support this initiative the Agricultural Extension Service in Rufiji District have agreed to integrate the technology into their extension programmes, and in addition the village government in Jaribu has initiated its own training programme in the sub-villages around Jaribu. In December 1997 the village governments of Masaki, Sungwi and Gumba villages in Kisarawe District villages decided to follow the lead taken by villages in Rufiji District and develop bylaws and training programmes to promote uptake ofthe new technology. The Agricultural Extension Service for Kisarawe District have acknowledged the importance of cassava as a source of income generation in the District, and have agreed to integrate the technology into their extension programmes. If co-operation between the various stakeholders is maintained it seems likely that the technology will start to be adopted during 1998. This case study within the main regional Africa project has demonstrated not only that low cost :fresh cassava root storage technology has the technical and economic potential to reduce post-harvest losses and improve incomes, but has also shown that key stakeholders are genuinely interested in adoption of the technology and are willing to co-operate and spend their own funds to promote uptake of the technology. However, for successful uptake of the technology a wider dissemination at both local and national level is required. It is also clear that lack of funds in rural areas could constrain producers and country buyers from adopting this technology. To meet the needs ofthose involved in marketing of fresh cassava throughout Tanzania a sustained campaign of dissemination is required, involving close collaboration between the Agricultural Extension Services, selected NGOs and key stakeholders involved in marketing of fresh cassava from rural areas to various urban centres in Tanzania. A concept note for wider dissemination of low cost fresh cassava root storage technology in Tanzania is included in this report (Appendix 5). The fmdings of this case study have shown that successful adoption of this technology would improve the quality of cassava reaching urban consumers, and contribute to poverty alleviation by improving the income generating potential of marketing of fresh cassava

Regeneration and carboxymethylation of cellulose and its derivatives: application assessment for brewery wastewater treatment

This research article published by Springer Nature Switzerland AG., 2021Coagulation–flocculation technique is usually employed in wastewater treatment by applying conventional inorganic materials such as alum and ferric chloride. Due cost to environmental challenges associated with the use of inorganic flocculants, biopolymers are gaining ground as alternative water treatment materials. In the present study, native cellulose and hemicelluloses isolated from sugarcane bagasse were used in the removal of turbidity and biological oxygen demand from industrial wastewater. Isolated native cellulose was modified to form regenerated cellulose (RC). Also, native cellulose, hemicellulose and RC were carboxymethylated using Na-chloroacetate. Thereafter, the functional groups on the carboxymethylated biopolymers were examined using Fourier transform infrared spectroscopy and the carbon–hydrogen–nitrogen–sulfur–oxygen elemental analysis. The degree of substitution (DS) for regenerated and carboxymethylated cellulosic materials was measured using recommended standard methods. Carboxymethyl cellulose (CMC) with 1.3 DS reduced turbidity and biological oxygen demand by 62.2 and 64%, respectively. Carboxymethyl regenerated cellulose (CMC-II) at 1.1 DS reduced turbidity and by 55.6 and 60%, respectively. Carboxymethyl hemicellulose (CMH) with 1.4 DS was capable of reducing turbidity and biological oxygen demand by 45.7 and 47%, respectively. Carboxymethyl cellulose and hemicellulose have rarely been used in the treatment of brewery wastewater. In the present study, these two novel materials showed a good prospect in removing biological oxygen demand and turbidity

Chronic Diseases in North-West Tanzania and Southern Uganda. Public Perceptions of Terminologies, Aetiologies, Symptoms and Preferred Management

Research outputs produced to support a quantitative population survey, quantitative health facility survey, focus groups and in-depth interviews performed by the projec

The agronomic performance and acceptability of orange fleshed sweetpotato varieties in the Lake zone of Tanzania

The introduction of improved orange-fleshed sweetpotato (Ipomea batatas) varieties from the International Potato Centre (CIP) was a result of recognising the negative health effects of vitamin A deficiency in Tanzania. Orange varieties, which are rich in β-carotene, were considered one of the sustainable strategies for addressing Vitamin A deficiency. Seven varieties from CIP, five of which were orange-fleshed, were tested on farm for two seasons (2001- 2002) in the Lake zone of Tanzania. Different sweetpotato recipes were prepared and tasted as alternative to boiled sweetpotato roots. Among the introduced orange varieties, Zapallo, NC 1560 and Tainung No 64 produced between 6.04 and 11.86 t ha-1 of fresh total root yield compared to 7.59 t ha-1 of the control variety. Mafutha and Japon tresimesino gave poor yields. Farmers ranked high Zapallo, Tainung No. 64 and NC 1560 for agronomic performance. However, Mafutha, Japon tresimesino and Tainung No. 64 were rated high for cooking quality. Zapallo and NC 1560 were rated high for dry texture. For children, internal root colour was the most important attribute for accepting a variety. Sweetpotato products prepared from orange fleshed varieties were preferred more by both adults and children than those prepared from white fleshed varieties. The over all acceptability of orange varieties and sweetpotato products was high. Key Words: β-carotine, CIP, Ipomea batatas RÉSUMÉ L'introduction des variétés améliorées de la patate (Ipomea batatas) douce orange graissée par le Centre International de la Patate (CIP) était le résultat de la reconnaissance d ‘effets négatifs de la carence en vitamine A en Tanzanie. Les variétés oranges qui sont riches en carotène-β, étaient considéré comme l'une des stratégies durables pour résoudre la carence en vitamine A. Sept variétés du CIP dont cinq oranges graissés, étaient testées sur fermes pour deux saisons (2001-2002) dans la région du lac Tanganyika. Différentes recettes de la patate douce étaient préparées et goûtée comme alternatives a la patate douce. Parmi les variétés oranges introduites, Zapallas, NC 1560 et Tainung No 64 ont produit entre 6.04 et 11.86 t ha-1 des racines fraîches comparé a 7.59 t ha-1 de la variété de contrôle. Mafutha et Japon tresimesino donnerent des rendements faibles. Les fermiers classèrent supérieure les performances agronomiques de Zapallo, Tainung No 64 et NC1560. Cependant, Mafutha, Japon tresimesino et Tainung No 64 étaient bien cotés pour la cuisson. Zapallo et NC1560 étaient bien cotés pour la texture à sec. Pour les enfants, la couleur interne était l'attribut le plus important pour accepter la variété. Les produits de la patate douce préparés des variétés orange graissées étaient préférés par les enfants et les adultes que les ceux préparés des variétés graissées de couleur blanche. L'acceptabilité des variétés oranges et les produits associés étaient élevés. Mots clés: Carotène-β, CIP, Ipomea batatas African Crop Science Journal Vol.12(3) 2004: 229-24

Effect of leaf harvesting frequency on growth and yield of sweetpotato in the Lake Zone of Tanzania

The objectives of this study were to assess the effects of leaf harvesting frequency on growth and yield of sweetpotato (Ipomoea batatus L.); to determine the suitable varietal types for use as source of leaf vegetable and to determine the suitable leaf harvesting frequency(ies) for reduced detrimental effects on growth and yield of sweetpotato. Two narrow leafed varieties Budagala and Mwananjemu and two broad leafed varieties SPN/O and Biganana were used in a randomised complete block design with 3 replications. Plot size was 8.4 m2 . Tip cuttings of 20 cm long were used as planting materials. The fully expanded top and tender leaves were plucked, counted and weighed. Tender leaves were harvested once, twice and three times during the growing period. Results showed that there were small differences between varieties and harvesting frequencies, however, harvesting at one month intervals for three times gave the highest leaf vegetable production although the yield was affected tremendously. Harvesting twice in a growing period proved the best in leaf production as well as root yields. Overall, there were significant differences between varieties and harvesting frequencies. Key Words: Ipomoea batatus, leaf harvesting, Tanzania, tuber and vine yields (African Crop Science Journal 2001 9(1): 97-103

Damage reduces shelf-life of sweetpotato during marketing

Although sweetpotato is primarily grown for home consumption, marketing is becoming increasingly important, and in this case, short shelf-life of the roots is a major constraint. An assessment of the levels of damage of sweetpotatoes when they arrive at urban markets indicated that between 49% and 93% roots exhibited some form of damage. The major types of damage noted were breakages, cuts, infestation by weevils (Cylas spp.), rotting and superficial scuffing. All forms of damage, except superficial scuffing, lead to a shortened shelf-life due to both increased fresh weight loss and rotting. Superficial scuffing increased the rate of rotting but not of weight loss. It was estimated, based on the six cases considered, that the damage resulted in a reduction of shelf-life of between 23% and 47%. Key Words: Ipomoea batatus, post-harvest losses, Tanzania (African Crop Science Journal 2001 9(1): 301-308