Effect of manual depulping and roasting on functional, rheological and sensory characteristics of cocoa liquor

Cocoa liquor serves as a fundamental intermediate in chocolate production, with its quality attributes largely determined by post-harvest processing parameters. This study investigated the effects of varying mechanical depulping levels (0 %, 50 % and 100 % pulp removal) and roasting conditions (110 °C for 60 min, 120 °C for 30 min and 135 °C for 10 min) on the physical and sensory characteristics of cocoa liquor produced from Ghanaian cocoa beans (Theobroma cacao L.). A 3 × 3 full factorial design was implemented under a Completely Randomised Design framework. Following standardised fermentation (6 days) and drying (55 °C to 7–8 % moisture content), beans were roasted, milled and evaluated for textural properties (firmness: 175.93–584.80 g; consistency: 963.66–1847.96 g·s; cohesiveness: 165.02–360.64 g) and viscosity index (728.5–1364.9 g·s) using back-extrusion analysis. Quantitative Descriptive Analysis by 10 trained panellists (2 males, 8 females; age range 25–45 years) assessed nine sensory attributes. Results demonstrated that depulping significantly reduced cohesiveness (F (1,23) =4.58, p = 0.043) and modified consistency (F(3,23) =5.87, p = 0.0066), with 100 % depulping decreasing cohesiveness by 54 % compared to undepulped controls. Complete depulping intensified bitterness (p ' 0.05) and astringency, attributable to elevated polyphenol retention (Asiedu et al., 2025). Moderate roasting at 120 °C for 30 min produced optimal nutty and cocoa notes, particularly in non-depulped samples which exhibited significantly higher cocoa liquor aroma and flavour intensities (p ' 0.05). Strong correlations emerged between cohesiveness and viscosity index (r = 0.95, R² = 0.91, p ' 0.05). The combination of 50 % depulping with moderate roasting (120 °C/30 min) yielded cocoa liquor with improved texture, stable rheology (consistency: 1245.32 g·s) and enhanced sensory quality, providing practical guidance for optimising cocoa processing operations.