Impact of soaking and phytase treatments on phytic acid, calcium, iron and zinc in faba bean fractions

Abstract

SummaryWith the aim to maximise phytic acid removal and minimise losses of dry matter and minerals (Ca, Fe, Zn) in faba bean, fractions of faba beans (whole faba beans, dehulled faba beans, hulls) and flours, were soaked in demineralised water at 10 °C (SDW), NaAc buffer of pH 3.5 at 10 °C (SAB), and 500 U L−1 phytase of pH 5.5 at 50 °C (SPS). In whole seeds and flour, SAB removed 20–51% phytic acid from seeds, and SPS 100% from flour depending upon different preheating treatments; dry matter, Ca, Fe, and Zn losses were 1.8–18%, 20–61%, 33–61% and 8–51%. In dehulled seeds flour, phytic acid could be removed 100% by SPS treatments. In dehulled seeds and flour, losses of dry matter, Ca, Fe were 2.4–18.6%, 12–63%, 11–43%, and Zn apparent gain was 12–73% respectively. In hulls flour, SPS removed 80–82% phytic acid, and SAB 48–50% depending upon different preheating treatments; dry matter, Ca, Zn losses were 6.4–28.7%, 16–46%, 60–72%, and Fe apparent gain was 2–73%, respectively. Phytase application is an effective method to rapidly remove phytic acid while preserving relatively more dry matter and minerals than other soaking approaches in faba bean fractions.