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 Randomized Design framework. Following standardized 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, R 2 = 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 optimizing cocoa processing operations.