Effect of malt pretreatment and/or cooking on phytate and essential amino acids contents and in vitro protein digestibility of corn flour

Corn grains of cultivar Mugtama 45 (phytate: 526 mg/100 g and 2 h pepsin digestion: 13.8%) were germinated for 6 days to obtain 2, 4 and 6 day-old corn malts. Corn malt was added at concentrations of 4%, 8% or 12% to corn flour. The mixtures were incubated with shaking for 2 h. Phytic acid and in vitro protein digestibility (IVPD) were assayed for all treatments, while amino acid composition was assayed for the 12% mixture. The results revealed that phytate content was significantly reduced in both cooked and uncooked mixtures. The 12%, 6 day-old malt reduced the phytate content by 71% and 42% for uncooked and cooked mixture, respectively. The IVPD was significantly (P⩽0.05) improved as a result of malt pretreatment, while cooking significantly reduced IVPD. Amino acid content of cooked and uncooked mixture depended on the malt age. The rate of reduction of phytate content and the rate of increment in IVPD increased with age and concentration of the malt.