Effect of addition of plant extracts on the durability and sensory properties of oat flake cookies

Fragile cookies are one of the most popular high-fat cereal products. Products of this type with added oat flakes may be labeled with a nutrition claim and may be included in functional foods. Fat from oat flakes and which is a recipe ingredient of cookies undergoes degradation during storage which leads to the formation of harmful oxidation products and sensory changes in products. The aim of this study was to determine the effect of green tea extracts (GT), blackcurrant (BC) seeds and nettles (N) on the rate of fat degradation in cookies with oat flakes and their sensory properties. In this work, the antioxidant effect of natural extracts antioxidant on oxidative stability of fat extracted from cookies was evaluated by differential scanning calorimetry (DSC) and by peroxide value, anisidine value and specific UV extinctions (K value). Moreover, cookies were subjected to sensory analysis and to instrumental measurements of color changes. The extracts used in the study had an influence on the rate of fat oxidation changes in cookies after baking and also during 3months of storage. The most effective fat degradation inhibitor was the extract with GT in 1% addition, while the most unfavorable change was observed in fat with the lowest addition of N extract (0.5%). It was observed that the applied plant extracts did not significantly reduce the sensory properties of the products. The most desirable products were the cookies with 1% GT extract and those with the highest proportion of blackcurrant seed extract (1.5%).