Content of zinc, iron and their absorption inhibitors in Nicaraguan common beans (Phaseolus vulgaris L.)

Common bean (Phaseolus vulgaris L.), the staple crop of Nicaragua, provides protein and nonhaem iron, but inhibitors such as phytate may prevent absorption of iron and zinc by the consumer. Warehouses in Nicaragua do not have controlled atmospheres, so beans are exposed to high temperatures and humidities that may accelerate quality loss. To evaluate the impact of 6 months of storage on quality, four national accessions of common bean were submitted to two treatments, a conventional warehouse with uncontrolled temperature and humidity, and accelerated ageing at 40 °C and 75% RH. Iron content was 61–81 mg/kg of which 3–4% was bioavailable, and zinc content was 21–25 mg/kg, of which 10–12% was bioavailable. Bioavailability generally increased in storage, significantly so in year-old INTA Linea 628 in accelerated ageing. The concentration of phytate was 8.6–9.6 mg/g and it contained 54–63% of the total phosphorus. Improvement in bioavailability of divalent cations is needed.