Effect of Solid‐State Fermentation Tempe Type on Antioxidant and Nutritional Parameters of Buckwheat Groats as Compared with Hydrothermal Processing

The effect of fermentation with R hizopus oligosporus , roasting and cooking on functional parameters and nutritional composition of unroasted buckwheat groats was studied. Tempe showed 57 and 124% higher activity against 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cation ( ABTS ●+ ) than cooked unroasted and roasted groats, respectively. Efficient doses of mg material necessary to scavenge ● OH ( IC 50 ) and exert reducing power ( RP 0.5 ) were decreased in tempe (by 61% and about 30%, respectively, as compared with roasted groats). All the parameters were strongly correlated with the soluble phenol level. Tempe contained more thiamine (2.5‐fold) and riboflavin (7.5‐fold) than cooked buckwheat. It had 143 g/kg protein of the highest C ys +  M et and Tyr + Phe levels. In vitro bioavailability of tempe protein (56%) was higher than cooked unroasted groats (41%) and similar to cooked roasted ones. Sensory analysis of buckwheat tempe was concluded with a good overall assessment. Tempe‐type fermentation may be recommended as a favorable technique of unroasted buckwheat groats processing. Practical Applications Conventional cooking and/or roasting of buckwheat seeds influences the nutritional composition and partially diminishes the functional parameters of groats. Tempe‐type product obtained from unroasted groats is a convenient food of improved parameters that may broaden the gluten‐free product spectrum on the market. Fermented buckwheat groats are also a potential source of flour of advantageous antioxidant parameters for application as a food additive.