Determining grain seed micronutrient contents (iron and zinc) and cooking time for selected dry bean cultivars

Abstract

Micronutrient deficiencies caused by lack of Iron (Fe), Zinc (Zn) and Vitamin A in the human body have negative effect with regard to health issues worldwide. Imbalances of these nutrients in the human body create a significant risk of illness and mortality among children under five years of age, pregnant women and lactating mothers. Some of the food crops that thought to reduce micronutrients include rice, sweet potato, dry bean, sorghum, corn, barley, and finger millet have been biofortified through ways of agronomic practices, conventional breeding, or modern biotechnology. Despite the fact that dry beans address Fe and Zn deficiencies based on recommended dietary allowances (RDA), they often take a long time to cook. Many communities have limited cooking resources which make them rely on burning wood, charcoal or other biofuels that require more time and money. This study identified dry bean cultivars with enhanced Fe and Zn concentration levels and fast cooking time from 200 cultivars. Experiments were conducted under a complete randomized block design with two replications, 200 cultivars, and two different agro-ecologies. Iron and Zinc concentration levels were determined from the harvested seed grains of each bean cultivar using X-Ray Fluorescence while cooking time of similar cultivars were determined using the Mattson cooker. The variation of Fe and Zn concentration was significantly different at (p<0.001) among the treatments and environments. The range was between 46.76 mg/kg to 107.25 mg/kg for Fe and 21.70 mg/kg to 42.35 mg/kg for Zn concentration. From two testing sites, the concentration of Fe was higher at Lyamungo than SARI and Zn showed inversely proportional to these tested sites which means that the environment and soils were not homogenous in terms of soil health. The highest water uptake was 61.54% and the lowest was 3.70% and the higher the water uptake the lower the cooking time. Fast cooking time was ~15 min and the longest was ~76 min. Small seed-sized cultivars showed fast cooking time than large-seeded. These two traits in identified cultivars will enhance dry bean consumption, which will contribute to alleviating micronutrient deficiencies in this global growing population.

Phenotype based clustering, and diversity of common bean genotypes in seed iron concentration and cooking time

“…The availability of fast cooking beans in all market classes is an advantage for trait improvement within the preferred market class. While it took 36 mins for the fastest cooking genotype in this study to cook, other studies reported genotypes that were cooked in 14 to 29 minutes using the same method [ 38 , 41 , 42 ]. Variations could be due to genetics or conditions during seed production or storage.…”

“…The mean concentration of 64 ppm for FESEED was low compared to other populations described in literature. The mean FESEED has increased from 65 ppm in the first regional nutrition nursery for East African bush beans [ 37 ] to 75–78 ppm in some recently improved varieties [ 10 , 36 , 38 ]. The low mean FESEED in this study is attributed to the nature of the population that was assembled for multiple traits.…”