Nutritional characterization of traditional and improved dihé, alimentary blue-green algae from the lake Chad region in Africa

- Samples of traditional and improved dihé were nutritionally characterized.
- Both traditional and improved dihé possess a high nutritional quality.
- Nutritional characteristics vary with site and season.
- The traditional technique is more protective of photosensitive and thermolabile nutrients.
- Heavy metals and other elements of toxicological interest are also present in dihé.

Samples of dihé, a natural food product traditionally consumed in the lake Chad region in Africa, made of dried algae of the Arthrospira genus, were analysed to evaluate their nutritional quality and some aspects of safety of use. Traditional dihé resulted to be a food of high nutritional quality, with an elevated content of high biological quality proteins, rich in mineral elements, with an interesting quantity of lipids containing essential unsaturated fatty acids, a generally sufficient and often very high content of folates, a good content of phenols and of vitamin E and an elevated content of carotenoid pigments, especially beta carotene. The dihé characteristics varied with the site and the season. Samples of dihé produced with a new experimental technique that allows to obtain a sand-free, microbiologically safer product, were also analysed. The comparison between traditional and improved dihé revealed that the improved technique is less protective of photosensitive and thermolabile nutrients, like folates, phenols, vitamin E and carotenoids. This study also revealed the presence, in both the traditional and the improved product, of heavy metals and other elements of toxicological interest. However, the potential danger represented by these elements is dependant on the level of consumption of dihé.