Sensory Perception of Cookies Enriched with Grapefruit Peel Powder: Bitterness as a Challenge and an Opportunity

This study investigated the incorporation of grapefruit peel powder (GFPP) into wheat cookies to improve their nutritional and bioactive profile by evaluating physical, sensory, and functional attributes. Wheat flour was rich in protein, whereas GFPP contained high crude fiber (10.39%), ash (2.63%), TPC (10.36 mg GAE/g), and exhibited significantly higher antioxidant activity (64.90% DPPH inhibition). Nutritionally, GFPP-enriched cookies showed modest increases in crude fiber, slight reductions in protein, and a significant increase in TPC and antioxidant activity, ranging from 0.47 to 1.21 mg GAE/g and 4.95 to 9.80% respectively, confirming the functional potential of GFPP polyphenols. Sensory evaluation with 110 panelists suggested that bitterness increased with GFPP inclusion; however, 1–2% substitution was acceptable, while higher levels intensified bitterness. Interestingly, 37% of panelists appreciated the 5% GFPP cookies, indicating that niche consumer segments valued bitterness for its perceived health benefits. Overall, GFPP use valorizes citrus by-products while creating nutrient and bioactive-rich cookies with market potential.