Revalorizing Apple Peel Flour as a Functional Component in Wheat-Based Cookies: Effects on Nutritional Profile and...

The physicochemical and bioactive characteristics, fatty acid profile, and sensory attributes (such as odor, taste, and overall acceptability) of cookies produced by mixing 5% and 15% apple peel powder into wheat flour were evaluated. While the L* and b* values of the cookies decreased with cooking, the a* values increased. The L* values of the cookie samples varied between 73.79 (15%) and 85.82 (Control), while the b values were measured between 25.57 (5%) and 28.68 (Control). In addition, the a values of cookies were determined between 0.28 (Control) and 5.21 (15%). While the total phenolic amount of the cookies prepared with the addition of 5% and 15% apple peel powder varied between 18.20 and 46.44 mg/100 g, the total flavonoid amount of the cookies was provided to be between 95.00 mg/100 g and 159.76 mg/100 g. The antioxidant capacities of the cookies varied between 0.15 and 2.35 mmol/kg. The major phenolic compounds in the dried apple peel were identified as catechin, rutin, gallic acid, and hesperidin. The predominant fatty acids of cookies were linolenic, linoleic, oleic, and palmitic acid. Palmitic and oleic acid quantities of cookie oils ranged from 25.07% (5%) and 26.38% (Control) to 4.71% (15%) and 4.89% (5%), respectively. Apple peel incorporation increased the Nutritive Value Index (NVI) of cookie oils from 0.183 (Control) to 0.200 at 5 min, followed by a slight decrease to 0.189 at 15 min. Despite this reduction, NVI values remained above the control, indicating a modest improvement in lipid nutritional quality. The macro element detected in the cookie samples was K in the highest amounts, followed by P, Ca, and Mg in decreasing order. In general, the sensory properties of cookies with 5% apple peel flour concentration had better values than those with 15%.