Are consumers willing to pay more for 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 beta-carotene and adapted to local growing environments have the potential to significantly reduce the prevalence of vitamin A deficiency. One such example is the orange sweet potato (OSP). Because of its distinctive orange color, which is in contrast to the white varieties that are typically consumed in Africa, it is important to assess whether consumers will accept it. This paper attempts to address this question by using a choice experiment with the real product to quantify the magnitude of the premium or discount in consumers' willingness to pay that may be associated with it. It also considers the extent to which the provision of nutrition information affects valuations. Finally, the paper addresses whether the use of hypothetical scenarios is justified in a developing country context, and quantifies the magnitude of hypothetical bias that results as a consequence. We examine whether a “cheap talk” script, which as elaborated in the paper, reminds respondents that hypothetical scenarios are to be treated as if they are real, is effective in mitigating hypothetical bias. The experiment was conducted in Uganda, a key target country for the dissemination of orange sweet potato. Our results suggest that in the absence of nutrition information, there is no difference between white and orange varieties in consumers' willingness to pay, but there is a discount for yellow sweet potato (which does not have any beta-carotene). The provision of nutrition information does translate into substantial premia for the orange varieties, indicating that an information campaign may be key to driving market acceptance of the new product. Finally, there is a substantial hypothetical bias in both the willingness to pay (WTP), and the marginal WTP, for the new varieties; while “cheap talk” may mitigate this bias, it does not eliminate it.Cheap talk, Field experiments, Hypothetical bias, conjoint analysis, Universal logit,

Understanding carotenoid losses in orange-fleshed sweet potato in drying and storage

Biofortified orange-fleshed sweet potato (OFSP) is being promoted to tackle vitamin A deficiency, a serious public health problem affecting children and pregnant/lactating women in sub-Saharan Africa. The aim of the study was to quantify and understand the factors influencing provitamin A losses in OFSP dried chips. Losses were determined after drying and storage. A preliminary pilot-scale study demonstrated that carotenoid levels were not significantly different after either solar or sun drying. Field conditions using locally-promoted varieties in Uganda and Mozambique showed losses associated with drying were less than 40%. Flour made from OFSP could therefore be a significant source of provitamin A. In contrast, storage of chips at room temperature in Uganda for four months resulted in high losses of pro-vitamin A (ca. 70% loss from the initial dried product). Low-cost pretreatments, such as blanching, antioxidants and salting, did not improve carotenoid retention during storage. To understand the cause of the losses, dried sweet potato chips were stored under controlled conditions of temperature (10; 20; 30; or 40ºC), aw (0.1; 0.3; 0.5 or 0.7) and oxygen (0 [under nitrogen]; 2.5; 10 or 21% [air]). Losses in provitamin A were the least during storage at the lowest temperature and oxygen level and at the highest humidity level. Enzymatic catabolism of [bêta]-carotene in the flour was considered unlikely because of low peroxidase activities at low water activities and the loss of peroxidase activity during storage. (Résumé d'auteur

Using a Discrete Choice Experiment to Elicit the Demand for a Nutritious Food: Willingness-to-Pay for Orange Maize in Rural Zambia

Using a discrete choice experiment, this paper estimates the willingness to pay for biofortified orange maize in rural Zambia. The study design has five treatment arms, which enable an analysis of the impact of nutrition information, comparing the use of simulated radio versus community leaders in transmitting the nutrition message, on willingness to pay, and to account for possible novelty effects in the magnitude of premiums or discounts. The estimation strategy also takes into account lexicographic preferences of a subset of our respondents. The results suggest that (a) orange maize is well liked and can compete with white maize in the absence of a nutrition campaign, (b) there is a premium for orange maize with nutrition information, and (c) the mode of nutritional-message dissemination does not have a large impact on consumer acceptance, and (d) novelty effects do not translate into higher willingness to pay for orange maize.

‘Yellow is good for you’: Consumer perception and acceptability of fortified and biofortified cassava products

Vitamin A, an essential micronutrient for health, can be obtained from various food sources including cassava products made from either traditional white cassava varieties fortified with red palm oil containing provitamin A, or new high provitamin A biofortified yellow cassava varieties. Both products have a similar yellow appearance due to the coloured pigmentation of provitamin A. Using a range of methods to provide a comprehensive understanding of sensory acceptability (blind triangle test, sensory profiling, hedonic preference that included Check-all-that-applies and Just-about-right tests), we tested the acceptability and nutritional perception of traditional West-African food dough-like products (eba and fufu) made from biofortified, fortified, or control products made with non-fortified white cassava (n = 7) at three suburban locations near Ibadan, Nigeria on a total of 122 consumers. Biofortified, fortified, and control products could be differentiated blindly confirming that products clearly differed with respect to other sensory characteristics than appearance. Overall biofortified products were better accepted than control and fortified ones. Three classes of consumer preference were identified based on the dislike for control and fortified products, which indicated that acceptance of biofortified products was not a hindrance. On the contrary the traditional fortified product had poorer acceptance and this was due to its less desirable sensory characteristics as demonstrated by Just-about-right Penalty analysis. A majority of consumers (85%) had previous knowledge of biofortified cassava. Consumers associated ‘yellow colour’ with ‘good for eyesight’, ‘good for children’s health’ and ‘new’. More nutritional benefits were attributed to biofortified than fortified products although they had similar provitamin A contents and this demonstrates a bias. We suggest that nutrition promotion campaigns to improve the vitamin A status should also encompass all natural sources of provitamin A, including biofortified and traditional fortified products

Assessing rural consumers’ WTP for orange, biofortified maize in Ghana with experimental auctions and a simulated radio message

Deficiencies of micronutrients such as vitamin A are widespread, expecially in Africa. Biofortified crops such as maize, bred for high levels of provitamin A might offer a solution, but these crops are often bright orange, and African maize consumers prefer white. To estimate the consumers interest in orange biofortified maize, sensory evaluations were organized in rural Ghana with white, yellow and orange maize. The effect of information on willingness to pay for biofortification was estimated using a simulated radio message. Results indicate that color preferences are highly regional, wide variation exist within regions, and the provision of information is able to change these preferences. The color of biofortified maize should therefore not be seen as major impediment, but proper information messages should be targeted at the right channels such as rural radio.maize, biofortification, consumers, experimental auction, sensory evaluation, Crop Production/Industries, Demand and Price Analysis,

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

The retention of pro-vitamin A was determined on Orange Fleshed Sweetpotato after drying and storage. Preliminary trials were undertaken to compare various dryers in France (sun, solar and indoor-cross flow dryers) and to optimise and assess carotenoid extraction from fresh and dried samples. The approach was then tested with local varieties in Uganda and Mozambique. No significant difference was observed between chips dried under solar dryers or under direct sun; retention of pro-vitamin A was more dependent on the drying time and final moisture content than on the type of dryer. Drying gave high retention of pro-vitamin A (> 60%); On the other hand, storage of chips (4 months) resulted in low retention of pro-vitamin A (20-40%). Storing in transparent or opaque polythene-plastic packaging did not have a significant impact on the retention of pro-vitamin A. These findings can be used to recommend suitable drying and storage methods to African farmers in order to retain significant amounts of pro-vitamin A. Using varieties with a high provitamin A content (e.g., Resisto variety in Mozambique), sun dried chips with high content of pro-vitamin A (up to 2700 RE/100g* dry weight basis) could be produced and contribute to tackle vitamin A deficiency in Africa. Further studies on storage are required to determine the shelf life of samples and appropriate packaging

Consumer acceptance of provitamin A orange maize in rural Zambia:

This study analyzes consumer acceptance of biofortified orange maize in rural Zambia by eliciting consumers' willingness to pay. It attempts to examine the impact of nutrition information, comparing the use of simulated radio versus community leaders in transmitting the nutrition message, on consumer acceptance. Finally, it assesses whether product experience in a home-use setting influences the magnitude of premiums or discounts. The results suggest that (a) the negative perception of yellow maize does not affect orange maize which is well liked, (b) there is a premium for orange maize with nutrition information, (c) the mode of nutritional-message dissemination does not have a large impact on consumer acceptance, and (d) product experience does not translate into lower willingness to pay for orange maize.maize, willingness to pay, consumer acceptance,

Relationship among the carotenoid content, dry matter content and sensory attributes of sweet potato

The sensory characteristics of biofortified sweet potato in Africa were explored over a wide range of carotenoid (0.4–72.5 μg/g fresh weight) and dry matter contents (26.8–39.4%). The logarithm of the total carotenoid content was correlated with the dry matter content (declining by 1.2% with each doubling of the carotenoid content) and a wide range of sensory characteristics that involve visual, odour, taste and textural characteristics. Multiple linear regression models were developed. The logarithmic relationship of colour to the carotenoid concentration means that those varieties with a relatively low carotenoid content may appear to be of similar intensity to those with a much higher and hence nutritionally beneficial carotenoid content

On-farm evaluation of the impact of drying and storage on the carotenoid content of orange-fleshed sweet potato (Ipomea batata Lam.)

Drying of orange-fleshed sweet potato was evaluated under African rural conditions. Three locally built dryers (open- air sun, tunnel and shade) were tested using Resisto and MGCL01 varieties in Mozambique. Total carotenoid losses were low in all dryers being 9.2% on average. After drying, sweet potato chips were stored in a traditional way (jute bags inside a mud house). Chip size (thin, thick chip or slice) had a significant effect on drying (P < 0.05) but not on storage and variety had an effect on both. Total carotenoid losses during storage were much higher being 83.7% on average, after 4 months, with main individual carotenoids fitting a first-order kinetics degradation. Globally, carotenoid losses on-farm or on-research station were of similar level