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

ABSTRACT

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 InsP₆ 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)P₅ and Ins(1,2,6)P₃ – confirmed that the dominant phytase activity could be attributed to the presence of microbial 3-phytases from R. oligosporous.

KEYWORDS:

• Seeds
• Functional properties
• Enzyme
• Enzymatic reaction
• Food property

Acknowledgements

The authors would like to thank the Ministry of Science and Higher Education of Poland for financing the national grant number DS 3700/WTŻ/2015. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.