Impact of gelatinization on common (Fagopyrum esculentum) and Tartary (Fagopyrum tataricum) buckwheat : effect on taste and flavor assessed by e-senses in relation to phenolic compounds

This work investigated the effect of gelatinization on the sensory traits of common (Fagopyrum esculentum) and Tartary (Fagopyrum tataricum) buckwheat flours in relation to their phenolic composition. Flours from two samples of common and Tartary buckwheat were heat-treated in the laboratory under controlled conditions to promote starch gelatinization; in addition, a common buckwheat sample heat-treated industrially was considered. The aromatic profiles of buckwheat samples were evaluated by electronic nose, while the electronic tongue was applied to assess taste. Rutin and quercetin concentrations were evaluated by HPLC; total phenolic compounds and antioxidant activity were also determined before and after thermal treatment. The heat treatment carried out in laboratory decreased both the total phenolic content and antioxidant activity and promoted the almost total hydrolysis of rutin into quercetin. The same effect was not detected in the sample treated industrially. Concerning sensory traits, a decrease in bitterness and astringency and a less intense aromatic profile were observed after gelatinization at lab scale; on the contrary, the industrially gelatinized sample was less affected by the thermal treatment, showing a sensory profile similar to the raw sample.