Effect of roasting and mechanical depulping on the techno-functional properties of cocoa liquor

Abstract This study aimed to investigate the impact of mechanical pulp removal and roasting intensity on the lipid profile of Ghanaian cocoa liquor, a key intermediate in the chocolate production process. The research sought to determine how varying levels of pulp removal (0%, 50%, and 100%) and roasting conditions (110 °C for 60 min, 120 °C for 30 min, and 135 °C for 10 min) influence fat quality attributes, such as free fatty acid (FFA) content, peroxide value (PV), iodine value (IV), and saponification value. A 3 × 3 full factorial design was employed to evaluate the effects of pulp removal and roasting intensity on cocoa liquor. The study utilised Ghanaian cocoa beans subjected to mechanical depulping and three distinct roasting treatments. Lipid quality indices were analysed using standardised methods. Statistical analysis was performed using analysis of variance and Fisher's least significant difference test to assess significant differences among treatments. The results demonstrated that pulp removal significantly influenced FFA and IV. A key finding was that partial pulp removal (50%) generally minimised FFA content across several roasting conditions, indicating superior resistance to lipid hydrolysis; however, under the high-temperature short-time (HTST) roasting (135 °C/10 min), the lowest FFA was observed at 100% depulping (fully depulped beans), indicating an interaction between pulp removal and roasting intensity. Roasting intensity showed complex, parameter-specific effects: HTST roasting with 100% pulp removal yielded the lowest PV, while low-temperature long-time roasting with 50% pulp removal produced the highest IV. All parameters remained within established industrial standards. All measured parameters remained within industrial standards, confirming the resilience of cocoa lipids under varied processing conditions. While this research focused on Ghanaian beans, the findings offer insights that are likely applicable to other cocoa-producing regions. The study concludes that the optimal processing condition is not universal but depends on the target lipid attribute. For enhanced hydrolytic stability, 50% pulp removal is recommended, whereas, for oxidative stability, 100% pulp removal with HTST roasting is most effective. These findings provide practical, evidence-based strategies for cocoa processors to tailor postharvest operations for improved cocoa liquor quality and shelf-life.