Effect of drying and storage on the content of provitamin A of orange fleshed sweet potato (Ipomoa batatas): direct sun radiations do not have significant impact

[Introduction] Sweetpotato is an important crop that is widely consumed in sub-Saharan Africa. Sun drying of sweetpotatoes is a traditional practice: after drying on rocks crushed or sliced dried sweetpotato are stored in granaries; re-hydrated and boiled to be eaten like fresh roots, or milled into flour to make porridge. Orange fleshed sweetpotato is being promoted in Africa to tackle vitamin A deficiency. There are inconsistent reports on the effect of sun-drying on pro-vitamin A retention. High losses have been reported which may be associated with the unsaturated instable provitamin A carotenoids easily degraded by light, oxygen and heat (Rodriguez Amaya 1997). This poster describes work to understand the effects of sun/solar drying and storage on pro-vitamin A retention

Quality attributes of sweet potato flour as influenced by variety, pretreatment and drying method

The effect of pretreatment methods (soaking in water, potassium metabisulphite solution, and blanching) and drying methods (sun and oven) on some quality attributes of flour from ten varieties of sweet potato roots were investigated. The quality attributes determined were chemical composition and functional properties. Data obtained were subjected to descriptive statistics, multivariate analysis of variance, and Pearson's correlation. The range of values for properties of sweet potato flour were: moisture (8.06–12.86 ± 1.13%), starch (55.76–83.65 ± 6.82%), amylose (10.06–21.26 ± 3.92%), total sugar (22.39–125.46 ± 24.68 μg/mg), water absorption capacity (140–280 ± 26), water solubility (6.89–26.18 ± 3.80), swelling power (1.66–5.00 ± 0.50), peak viscosity (24.50–260.92 ± 52.61 RVU), trough (7.08–145.83 ± 34.48 RVU), breakdown viscosity (11.00–125.33 RVU), final viscosity (10.21–225.50 ± 60.55 RVU), setback viscosity (3.04–92.21 RVU), peak time (6.07–9.06 min) and pasting temperature (69.8–81.3°C). Variety had a significant (P 0.05) affect moisture, fat and lightness (L*). Drying method did not significantly (P > 0.05) affect fiber and L*. The interactive effect of variety, pretreatment and drying method had a significant (P < 0.001) effect on all the attributes except fat and fiber. Total sugar correlated significantly (P < 0.01) with water solubility (r = 0.88) of the flour samples. Variety was a dominant factor influencing attributes of sweet potato flour and so should be targeted at specific end uses

Effect of drying and storage on the degradation of carotenoids in orange-fleshed sweetpotato cultivars

BACKGROUND: Orange-fleshed sweetpotato (OFSP) can be used to tackle vitamin A deficiency, a major public health problem in most developing countries. In East Africa, common ways of using sweetpotato include drying and subsequent storage. The aim of the study was to investigate the impact of drying and storage on the total carotenoid retention (as an estimate of provitamin A retention) from OFSP. RESULTS: Losses of total carotenoid during drying were generally low (15% or less). Total carotenoid retention in OFSP was not dependent on the type of dryer (solar or sun). Sweetpotato cultivar (Ejumula, Kakamega, SPK004/1, SPK004/1/1, SPK004/6 or SPK004/6/6) had a significant effect on retention in drying (P < 0.05). High percentage losses of total carotenoids were, however, correlated with high moisture content and high carotenoid content in fresh sweetpotato roots. After 4 months' storage at room temperature in Uganda, losses of total carotenoid in dried sweetpotato chips were high (about 70%) and this was not dependent on the use of opaque or transparent packaging. CONCLUSION: Losses of carotenoids during storage were considered to be more of a nutritional constraint to the utilisation of dried sweetpotato than losses occurring during drying. The relationship between characteristics of the cultivars and losses of carotenoids during drying should be taken into account in selection of cultivars for processing

Population attributable fraction of Esophageal squamous cell carcinoma due to smoking and alcohol in Uganda

Background: Despite the high rates and regional variation of esophageal squamous cell carcinoma (ESCC) in East Africa, the contributions of smoking and alcohol to the ESCC burden in the general population are unknown. Methods: We conducted a case-control study of patients presenting for upper gastrointestinal endoscopic examination at Mbarara Regional Referral Hospital, Uganda. Sociodemographic data including smoking and alcohol intake were collected prior to endoscopy. Cases were those with histological diagnosis of ESCC and controls were participants with normal endoscopic examination and gastritis/duodentitis or normal histology. We used odds ratios associated with ESCC risk to determine the population attributable fractions for smoking, alcohol use, and a combination of smoking and alcohol use among adults aged 30 years or greater who underwent upper gastrointestinal endoscopy. Results: Our study consisted of 67 cases and 142 controls. Median age was 51 years (IQR 40–64); and participants were predominantly male (59 %). Dysphagia and/or odynophagia as indications for endoscopy were significantly more in cases compared to controls (72 % vs 6 %, p < 0.0001). Male gender and increasing age were statistically associated with ESCC. In the unadjusted models, the population attributable fraction of ESCC due to male gender was 55 %, female gender - 49 %, smoking 20 %, alcohol 9 % and a combination of alcohol & smoking 15 %. After adjusting for gender and age, the population attributable fraction of ESCC due to smoking, alcohol intake and a combination of alcohol & smoking were 16, 10, and 13 % respectively. Conclusion: In this population, 13 % of esophageal squamous cell carcinoma cases would be avoided if smoking and alcohol use were discontinued. These results suggest that other important risk factors for ESCC in southwestern Uganda remain unknown

Are consumers in developing countries willing to pay more for micronutrient-dense biofortified foods? Evidence from a field experiment in Uganda

Vitamin A deficiency is a major health problem in Africa and in many other developing countries. Biofortified staple crops that are high in pro-vitamin A have the potential to reduce the prevalence of vitamin A deficiency. Using a choice experiment with the real product in Uganda, we quantify the magnitude of the premium or discount in consumers’ willingness-to-pay (WTP) that may be associated with it. Results suggest that taste plays an important role in consumer acceptance, and the provision of nutrition information does translate into substantial premiums for the biofortified variety. There is a substantial hypothetical bias in the WTP for the new varieties, and while cheap talk mitigates this bias, it does not eliminate it