Provitamin A biofortified maize hybrids were developed to target vitamin A deficient populations in Africa. The purpose of this study was to evaluate the degradation of carotenoids after milling, cooking, and storage among biofortified varieties released in Zambia. The biofortified maize hybrids contained 7.5 to 10.3 μg/g dry weight (DW) of provitamin A as measured by β-carotene equivalents (BCE). There was virtually no degradation due to milling. The BCE retention was also high (>100%) for most genotypes when the maize was cooked into thick (nshima) and thin porridge, but showed a lower BCE retention (53-98%) when cooked into samp (dehulled kernels). Most of the degradation occurred in the first 15 days of storage of the maize as kernels and ears (BCE retention 52-56%) which then stabilized, remaining between 30% and 33% of BCE after six months of storage. In conclusion, most of the provitamin A degradation in biofortified maize hybrids occurred during storage compared with cooking and the magnitude of this effect varied among genotypes.

HighlightsDegradation rate of βCX was 51% lower than βC during storage of orange maize grain.Grain storage methods with 16% oxygen level reduced carotenoid degradation by 9.1%.Orange maize is an alternative to improve vitamin A status of deficient populations.

In sorghum brewing, obtaining sufficient Free Amino Nitrogen (FAN) for rapid and complete fermentation remains a problem due to the high proportions of unmalted sorghum used and the poor digestibility of wet-heat treated sorghum protein. Sorghum mutant lines with high protein digestibility have been developed through breeding. These high protein digestibility sorghums (HPDS) have protein bodies with villi-like borders that apparently facilitate protease access. This work investigated FAN production from HPDS when malted and mashed, to assess their potential for use in sorghum brewing to improve wort FAN levels. When malted, HPDS contained substantially higher levels of FAN than normal protein digestibility sorghums (NPDS), 32 mg/100 g malt more. However, when the HPDS were mashed either as malt, or as grain or malt plus exogenous proteases, FAN production during mashing was not substantially higher than with NPDS subjected to the same treatments, only 6, 6-18 and 9-13 mg/100 g grain or malt, respectively. This is probably due to wet-heat induced cross-linking of the kafirin proteins reducing their susceptibility to proteolysis. Notwithstanding this, HPDS could be very useful for improving FAN levels in sorghum brewing if they are malted.

Biofortified maize hybrids with higher content of provitamin A (proA) were developed to target vitamin A deficient populations in Africa. The purpose of this study was to evaluate the degradation of proA after processing, cooking and storage among the first wave of biofortified varieties released in Zambia. The biofortified maize hybrids according to the harvesting period contained 4–11 (green maize) and 5–8 (dry maize) ìg/g of proA on a dry weight basis, respectively. The effect on the degradation of proA varied among the different genotypes. One maize genotype showed 60% retention of proA after the maize was roasted for about 20 minutes, while no degradation was observed among the other genotypes. The retention of proA ranged from 61–85% after boiling for 35 minutes at 95oC. During storage of maize grains, most of the degradation occurred in the first 15 days of storage (52–56% retention) which then stabilized retaining 30–33% of proA after 6 months of storage. In conclusion, most of the proA degradation in biofortified maize hybrids occurred during storage compared with cooking processes and the magnitude of the effect varied among the different genotypes.