Consumer preference and acceptability for sweet potato varieties in the lake zone of Tanzania

The study was carried out to evaluate consumer preference and acceptability for sweet potato in the Lake Zone. Genetic yield, farmers and consumers preference, sensory acceptability, effect of processing methods on nutritional qualities and marketing channels of sweet potato were evaluated using six sweet potato varieties; two white and four orange- fleshed local and new introduced cultivars. Results showed that there were several sweet potato varieties grown in the area mostly landraces and had yield differences. Sekondari variety had the highest yield of 4.8 t/ha and Polista the lowest 3.2 t/ha. Sekondari variety was mostly preferred in Missungwi (63.1%) while Polista variety was mostly preferred in both Meatu and Sengerema districts (60.3 and 58.9%) respectively. Reasons for preference were high dry matter content, good flavour and sweetness. Polista was highly preferred regardless of its low productivity. The results also show that the consumption of sweet potato in the Lake zone was very high, where 63.1 and 76.2% of farmers in Missungwi and Meatu respectively consumed sweet potato every day, while 63.7% in Sengerema consume sweet potato 3-5 times per week. It was observed that 69.2 and 63.7% of farmers in Missungwi and Sengerema respectively cook sweet potato by boiling whereas 51.5% of farmers in Meatu use both boiling and roasting methods. Nutrient content of fresh sweet potato varied significantly (P≤0.05) with varieties. Moisture content ranged from 55.00 to 72.44%, dry matter 27.56 to 45.00 %, total carbohydrate 23.55 to 41.09 g/100 g, total carotenoid 88.31 to 1620.07 μg/100 g and crude protein ranged from 1.39 to 2.77 g/100 g. Processing had no significant effect (P≤0.05) on ash, crude protein, total carbohydrate, calcium and zinc, while significant effect was observed in reducing sugars, iron, magnesium, phosphorous and total carotenoids. Losses in total carotenoids ranged from 37.72 to 69.13%. Traditional processing caused higher losses of more than 50% in alliii varieties. The main sweet potato varieties found in the market was white-fleshed (33.3%) and cream fleshed (66.7%). Market studies indicated that prices were low in the main season when the quality was good and higher in the low season when the quality was low. Problems experienced by traders were lack of capital, poor marketing, short shelf life, transportation and price fluctuations due to seasons. It is recommended that relevant stakeholders should give priority on post-harvest issues like more diversification of utilization methods, and marketing of sweet potato in the country in order to reduce losses and increase the value of the crop. In addition the breeding programme should put more emphasis on the culinary qualities as well as β-carotene content.

Assessment of genetic diversity, farmer participatory breeding and sustainable conservation of East African sweet potato germplasm project,” sponsored by the McNight Foundation of America