Effects of pumpkin (Cucurbita moschata) flour addition on the antioxidant activity and nutritional quality of cookie

In this study; chemical compounds, dietary fiber amounts, phenolic contents, antioxidant activities, bioavailable phenolics, phenolic acid compositions and functional properties of pumpkin flours (PFs) obtained from pumpkin (Cucurbita moschata) with two different processes [with Na-metabisulfite (MS) pre-treatment and without pre-treatment] and two different drying methods [oven-drying (OD) and freeze-drying (FD)]. Pumpkin flours (PFs) were used to replace wheat flour in cookie formulation at the levels of 10, 20, 30 % (w/w). Control sample did not contain PFs. The effects of PFs on the quality and composition of cookie were determined.Dietary fiber contents of PFs were higher than that of the wheat flour. Freeze drying (FD) method protected redness and gave more lightness and deep-orange color to pumpkin flours. Water solubilities of oven dried pumpkin flours (ODPFs) were higher than those of freeze dried pumpkin flours (FDPFs.). Water and oil holding capacities of FDPFs were higher than those of ODPFs. MS pre-treatment decreased solubilities, water and oil holding capacities of PFs. ODPFs showed a much higher phenolic contents, bioavailable phenolics and stronger antioxidant activities than those of FDPFs. MS pre-treatment had a positive effect on antioxidant activities, phenolic contents and bioavailable phenolics. The most abundant phenolic acids were p-hydroxybenzoic, followed by caffeic and chlorogenic and syringic acids in all pumpkin flours. Oven-drying and MS pre-treatment caused higher phenolic acid levels than the others. Dietary fiber contents of cookies increased, carbohydrate amounts and energy values of them decreased as the PFs addition levels increased in cookie formulations. The colours of cookies supplemented with PFs were more deep-orange than that of control. Spread ratios and hardness values of the cookies with PFs were lower than control. PFs additions increased phenolic contents, bioavailable phenolics and antioxidant activities of cookies compared to control. The most abundant phenolic acids of the cookies with PFs were caffeic and p-hydroxybenzoic, followed by chlorogenic and syringic acids. The samples with added 10 and 20 % of ODPF and FDPF received acceptable scores from the taste panellists. Thus, PFs appears to be suitable as a functional additive providing increase in dietary fiber content, phenolics, antioxidant activity and bioavailable phenolics of several food products, especially bakery products