Development of predictive models for optimization of phytate degradation in wheat and rye during hydrothermal processing

Whole kernels of wheat (Triticum aestivum 'Kosack'), rye (Secale cereale 'M otto') and rice (Oryza sativa) were hydrothermally treated to reduce the ph ytate content. The hydrothermal processes used in this study included alter nating wet and dry steeping periods. Two hydrothermal processes were used f or wheat and rye with two and three wet and dry steeping steps, respectivel y. The process using two wet and dry steeping steps (process 1) was optimiz ed for phytate reduction with respect to temperature during the process and lactic acid concentration used in the wet steeping steps. Optimal conditio ns for phytate breakdown in wheat and rye in process 1 were 55 degreesC dur ing the whole process and 1.3-1.5% lactic acid solution as the soaking agen t in the wet steeping periods for wheat and 1.3% for rye. The hydrothermal process with three wet and dry steeping periods for wheat and rye (process 2) showed that the temperature used in the third wet and dry steeps did not significantly influence (P > 0.05) the phytate reduction in wheat and rye during these steps. The maximal phytate reduction was 94.4-95.6% in wheat a nd 99.0-99.5% in rye during hydrothermal processing. In rice, hydrothermal processing resulted, at best, in a 99.8% phytate reduction.