Biofortification to enhance nutrition: the potential of rice, common beans, and pak choi

Abstract

Biofortification is a promising strategy to improve the nutrient content in staple foods, aiming to tackle micronutrient deficiencies - hidden hunger - in the population. This document presents a compilation of studies aimed at investigating zinc (Zn), iron (Fe), and selenium (Se) biofortification in three important food crops: rice, common beans, and pak choi. Through agronomic and genetic biofortification approaches, such as the application of fertilizers and the study of promising genotypes, experiments were conducted to increase the content of these micronutrients in the selected crops. Four studies were conducted, involving different genotypes and/or application strategies to optimize the absorption and accumulation of Zn, Fe, and Se in the edible parts. The results demonstrated that biofortification was effective in increasing the content of these nutrients in rice, common beans, and pak choi crops using the selected strategies. Furthermore, it was observed that biofortification had an impact on the nutritional quality of the foods, as it affected the protein content in beans and rice, as well as amino acids in rice and phenolic compounds in pak choi. In pak choi, the accumulation capacity of Se was inversely related to the total content of phenolic compounds, which could be identified by the purple color of the genotypes. The San fan genotype was the most sensitive to Se application and also had the highest accumulation in the shoots. For common bean grains, the application of Se-enriched urea resulted in a higher Se content compared with ammonium sulfate, with the latter being also not recommended as it reduced the protein content in the grains. The Madrepérola genotype had the best response to biofortification with the use of Se fertilizers. Among the common bean genotypes studied for Fe, Zn, and protein, none reached levels above the average reported in the literature without supplementation. However, there was genetic variation in the content and accumulation of these elements, with Madrepérola, OV, and Supremo showing the best performance. In rice, a higher accumulation of Zn and Se was observed in whole grains compared with polished grains, indicating that the consumption of whole grains is the most efficient way to obtain the benefits of biofortification in this crop. Additionally, it was found that Zn was able to increase the accumulation of Se in whole grains. The genotypes CMG ERF 221-19 and CMG ERF 85- 15 were the best genotypes for Zn and Se biofortification.