Scientific Study

This study investigated the effect of roasting (150°C for 30 min) and storage (12 months at 4°C, 25°C and 25°C in vacuum package), conditions of which are generally applied in the industry and markets, on the formation of Maillard reaction and sugar degradation products, namely dicarbonyl compounds, 5-hydroxymethylfurfural, N-e-fructosyllysine, and N-e-carboxymethyllysine in Tombul and Levant hazelnuts. Roasting increased all dicarbonyl compounds significantly (p<0.05). The concentration of methylglyoxal was highest while 1-deoxyglucosone was lowest in roasted hazelnuts. 5-hydroxymethylfurfural and N-e-carboxymethyllysine also increased significantly (p<0.05) with roasting while furosine decreased. Roasting changed the progress of Maillard reaction from the early stage to the advanced stage. On the other hand, there were no significant changes (p>0.5) in the concentration of Maillard reaction and sugar degradation products independent of the storage conditions or time and hazelnut variety, except for glyoxal, diacetyl, and 1-deoxyglucosone. Therefore, neither 5-hydroxymethylfurfural nor furosine could be suggested as the storage marker of Maillard reaction and sugar degradation.