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.

Biofortification is an effective method to improve the nutritional content of crops and nutritional intake. Breeding for higher micronutrient mineral content in beans is correlated with an increase in phytic acid, a main inhibitor of mineral absorption in humans. Low phytic acid (lpa) beans have a 90% lower phytic acid content compared to conventional beans. This is the first study to investigate mineral and total phytic acid retention after preparing common household recipes from conventional, biofortified and lpa beans. Mineral retention was determined for two conventional, three biofortified and two lpa bean genotypes. Treatments included soaking, boiling (boiled beans) and refrying (bean paste). The average true retention of iron after boiling was 77.2–91.3%; for zinc 41.2–84.0%; and for phytic acid 49.9–85.9%. Soaking led to a significant decrease in zinc and total phytic acid after boiling and refrying, whereas for iron no significant differences were found. lpa beans did not exhibit a consistent pattern of difference in iron and phytic acid retention compared to the other groups of beans. However, lpa beans had a significantly lower retention of zinc compared to conventional and biofortified varieties (p < 0.05). More research is needed to understand the underlying factors responsible for the differences in retention between the groups of beans, especially the low retention of zinc. Combining the lpa and biofortification traits could further improve the nutritional benefits of biofortified beans, by decreasing the phytic acid:iron and zinc ratio in beans.

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For biofortification to be successful, biofortified crops must demonstrate sufficient levels of retention of micronutrients after typical processing, storage, and cooking practices. Expected levels of retention at the breeding stage were verified experimentally. It was proven that the variety of biofortified crop, processing method, and micronutrient influence the level of retention. Provitamin A is best retained when the crops are boiled/steamed in water. Processing methods that are harsher on the food matrix (i.e. drying, frying, roasting) result in higher losses of provitamin A carotenoids. Degradation also occurs during the storage of dried products (e.g. from sweet potato, maize, cassava) at ambient temperature, and a short shelf life is a constraint that should be considered when foods are biofortified for provitamin A. Iron and zinc retention were high for common beans (Phaseolus vulgaris) and cowpeas (Vigna unguiculata), indicating that iron and zinc were mostly preserved during cooking (with/without soaking in water).

Highlights Zinc in rice endosperm moved to the outer layers during parboiling. Zinc retention in parboiled rice was lower than non-parboiled rice after milling. Biofortified rice had higher zinc retention than non-biofortified. Biofortified rice could provide more than half of the zinc EAR% for children.