Coffee pulp as a flour substitute in biscuits: The effects on physicochemical properties, sensory quality, and flavor characteristics

Coffee pulp (CP), a byproduct of coffee processing, is rich in bioactive compounds and dietary fibers but remains underutilized. This study developed biscuits incorporating CP and comprehensively investigated the effects of different CP concentrations (2.5 %, 5 %, 7.5 %, 10 %) and pretreatment methods (sun-drying or roasting) on their physicochemical properties, sensory quality, and flavor profiles for the first time. The results showed that total phenolic content increased 3.7-fold (0.54–2.56 mg gallic acid equivalent (GAE)/g), and ABTS radical scavenging capacity rose 4.83-fold (2.56–12.46 μmol Trolox/g) at 10 % CP. However, 5-hydroxymethylfurfural (5-HMF) spiked 13.7-fold (0.53–7.27 μg/g) at 7.5 % CP, though still below safety thresholds. Biscuits with 5 % CP exhibited optimal consumer acceptance. Roasted CP resulted in darker biscuits with higher 5-HMF content compared to those supplemented with sun-dried CP. Headspace solid-phase microextraction-gas chromatography-mass spectrometry and odor activity value analyses revealed enhanced caramel and sour aromas, with phenylacetaldehyde (key aroma compound) increasing 1.82-fold in sun-dried CP biscuits and 1.79-fold in roasted CP biscuits. Our study validates sun-dried CP as a promising flour substitute in baking products, prioritizing nutrient retention and consumer preferences. • Addition of coffee plup (CP) to biscuits increased their antioxidant activity. • Biscuits with 5 % of CP exhibited optimal consumer acceptance. • CP enhanced cohesiveness and decreased the hardness and chewiness of biscuits. • CP processing methods did not significantly change the quality of biscuits. • CP imparted caramel, green, fatty, and sour flavour to the biscuits.