Promoting dye-sorghum for local and global markets
Dye sorghum (Sorghum bicolor) as a distinct crop was only recently “discovered” by scientists in Benin. It is specifically grown for the red pigments in its leaf sheaths, that are used to color foods (e.g. local cheese, porridge) and in traditional medicine. Apart from producing dye-containing leaf sheaths, dye sorghum also produces grain. Natural sorghum colorants are considered safe for consumption, and therefore they are of interest to the food industry to replace synthetic dyes. Sorghum is the only plant known to contain the specific 3-deoxyanthocyanins in significant quantities. The 3-deoxyanthocyanidins are recognized as health-promoting phytochemicals, as they are more cytotoxic to human cancer cells than their 3-hydroxylated anthocyanidin analogs. Recently, researchers from Benin and The Netherlands studied the diversity of dye sorghum, its chemical composition and extraction; and to develop methods for its cultivation and processing. The genetic diversity of dye sorghum proved to be limited. Interestingly, very high levels of 3-deoxyanthocyanidins (apigeninidin and luteolinidin) were found. The amount of apigeninidin was 30 times higher than in cereal bran and the total anthocyanin content 5 times higher than in fruits and vegetables. The concentration of 3-deoxyanthocyanidin is mostly linked to environmental conditions during crop growth. A fertilization trial showed clear differences in leaf sheath size between treatments. Cultivation practices were optimized and subsequently the yields of both bio-colorant and grain increased by a factor of 2 and 3, respectively. Farmers successfully cultivated the dye sorghum crop on a commercial basis. A Beninese company regularly purchases tons of fresh leaves for local and international trade thereby supporting livelihood of farmers. Improved practices for post-harvest handling of leaf sheaths were developed to facilitate the export of dry leaf sheaths abroad. Extraction methods for bio-colorants were also developed. Aqueous ethanol was the most efficient solvent, yielding an extract with the best coloring power. Innovative food processing of grain allowed to produce (un)fermented porridges and beer, which are highly appreciated by consumers. Efforts are still needed in the legislation domain in view to allow the introduction of the dye sorghum leaf sheath on the global market.
| Main Authors: | , , |
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| Format: | Article/Letter to editor biblioteca |
| Language: | English |
| Subjects: | antioxidants, apigeninidin, bio-colorants, dye sorghum, luteolinidin, |
| Online Access: | https://research.wur.nl/en/publications/promoting-dye-sorghum-for-local-and-global-markets |
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