Sensory quality of provitamin A biofortified maize-based foods and the effect of a provitamin A biofortified maize awareness campaign on their acceptance in KwaZulu-Natal, South Africa.
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Date
2018
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Abstract
Biofortification is a food-based intervention to combat nutrient deficiencies, including vitamin A deficiency (VAD), by increasing the levels of target nutrients in crops through traditional (conventional breeding) and modern genetic manipulation methods. Maize has been selected for biofortification with provitamin A to alleviate the prevalence of VAD in sub-Saharan Africa where white maize, which is devoid of vitamin A, is a leading staple. However, when compared to white maize, provitamin A biofortified (yellow) maize (PABM), consumers in several countries in sub-Saharan Africa found it less acceptable, largely due to their negative perceptions of yellow maize and its unfamiliar sensory properties. A combination of strategies such as food product development, consumer awareness campaigns, and nutrition education could improve consumer acceptance of yellow maize.
Two provitamin A biofortified (yellow) maize food products, phuthu (crumbled porridge) and jeqe (steamed bread), and their corresponding white maize products (controls), were evaluated for their acceptability. Consumer acceptability tests were conducted with a consumer sample of 68 untrained panellists of the age range 18-85 years. A 5-point smiley pictorial Hedonic scale was used to evaluate the sensory acceptability of samples of PABM phuthu and Jeqe. The two food products were selected mainly because of their popularity amongst the KZN community. The results showed low acceptability of yellow phuthu compared to white phuthu, whilst the acceptability of yellow jeqe was similar to that of white jeqe. It was not clear why the acceptability of yellow phuthu was lower than that of white phuthu. Therefore, a descriptive sensory analysis was performed to characterise the sensory attributes of yellow phuthu and thereby reduce the influence of its sensory attributes on its acceptability.
Eleven trained panellists analysed the sensory properties (attributes) of phuthu made from three varieties of provitamin A biofortified maize hybrids. Descriptive sensory analysis data were subjected to ANOVA, Fisher’s Least Significant Difference (LSD) tests, and Principle Component Analysis (PCA). The results showed that the yellow phuthu samples were characterised by lower intensity of chewiness, crumbliness, roughness, white specks, and had less malleability. The control phuthu had a lower intensity of stickiness and yellow colour compared to the yellow phuthu. The carotenoid pigments in the yellow phuthu were probably responsible for the yellow colour of the biofortified maize phuthu and its stickiness. It is necessary to reduce the intensity of the stickiness of yellow maize phuthu to enhance its acceptability.
To change the negative perceptions and lower acceptability of provitamin A biofortified maize compared to white maize, a provitamin A awareness campaign was conducted. A group of 21 community members who had negative perceptions about provitamin A biofortified maize attended a perception change workshop. This awareness campaign workshop ran over three days and attempted to change their negative perceptions of yellow (provitamin A biofortified) maize. Two learning approaches were integrated as persuasive communication, namely, Transformative learning and Indigenous learning. The two learning approaches contributed to finding a way to improve the willingness of the sample of target consumers to adopt provitamin A biofortified maize as a food-based intervention to alleviate vitamin A deficiency (VAD).
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Doctor of Philosophy in Food Security. University of KwaZulu-Natal, Pietermaritzburg, 2018.