Myo-inositol phosphates profile of buckwheat and quinoa seeds: Effects of hydrothermal processing and solid-state fermentation with Rhizopus oligosporus

摘要

Phytate content, bioavailability and myo-inositol phosphates profile were analysed in pseudocereals (i.e., white and coloured quinoa, buckwheat) subjected to thermal processing and solid-state fermentation with Rhizopus oligosporus . Fair buckwheat groats were characterised by the highest level of phytate (18.3 μmol/g), with 54% share of InsP_(6) fraction. Processing (cooking, roasting, tempe-type fermentation) resulted in the significant decrease in phytate content, its bioavailability and the share of higher phosphorylated forms of myo-inositol (InsP_(6-5)) in the profile of all the samples. Fermentation of cereals resulted in generation of high amounts of inositol triphosphates, particularly in the case of buckwheat (32% share in the whole profile). The path of dephosphorylation, identified after fermentation of quinoa seeds including intermediate products – Ins(1,2,4,5,6)P_(5) and Ins(1,2,6)P_(3) – confirmed that the dominant phytase activity could be attributed to the presence of microbial 3-phytases from R. oligosporous .