Heat-treatment of Tartary Buckwheat (Fagopyrum tataricum Gaertn.) Provides Dehulled and Gelatinized Product with Denatured Rutinosidase

Abstract

Despite the increasing attention garnered by Tartary buckwheat (Fagopyrum tataricum Gaertn.) for its health benefits, its use has been limited by the difficulty in dehulling and a rutin hydrolysis-induced bitter taste caused by endogenous rutinosidase activity. Using circulating fluidized bed at 200 °C, the buckwheat was observed to produce a popcorn-like gelatinized product. Gelatinization was confirmed by differential scanning calorimetry, and rutinosidase activities were examined using activity staining on native-PAGE, and the substrate (rutin) and product (quercetin) were quantified by LC-MS. Owing to denaturation of rutinosidase in the heat-treated products, the rutin content was retained without the formation of the bitter product quercetin. Nutritional analysis of pre- and post-treated products showed retention of the macro and micro nutrients even after heat-treatment. The popped Tartary buckwheat could, therefore, be obtained by simple treatment, and might reveal new opportunities to utilize pre-gelatinized and rutin-rich properties by rutinosidase denaturation.