Effect of fermentation time and drying temperature on volatile compounds in cocoa

Area of Science:

• Food Science
• Agricultural Chemistry
• Sensory Analysis

Background:

• Cocoa bean quality is significantly influenced by post-harvest processing, specifically fermentation and drying.
• Understanding the impact of processing parameters on volatile compound profiles is crucial for developing desirable flavor attributes.
• Traditional sun-drying and mechanical drying methods yield different volatile profiles, affecting the final cocoa flavor.

Purpose of the Study:

• To determine the optimal fermentation time and drying temperature for enhancing desirable volatile compounds in cocoa beans.
• To investigate the effects of varying fermentation durations (2-8 days) and drying temperatures (60-80°C) on cocoa bean volatile profiles.
• To compare the volatile profiles resulting from optimized processing with those from traditional sun-drying and Samoa drier methods.

Main Methods:

• Cocoa beans were fermented for 2, 4, 6, and 8 days, followed by drying at 60, 70, and 80°C.
• Volatile compounds were extracted using Solid Phase Microextraction - Headspace Gas Chromatography-Mass Spectrometry (SPME-HS/GC-MS).
• Identified volatile compounds were classified into esters, alcohols, acids, aldehydes/ketones, pyrazines, and others, with 58 compounds identified in total.

Main Results:

• Six days of fermentation were sufficient to develop desirable flavor notes and avoid off-flavors.
• Drying at 70°C or 80°C after six days of fermentation resulted in volatile profiles comparable to sun-dried cocoa beans.
• Drying at 70°C offered a similar volatile profile to sun-drying but at a lower energy cost.

Conclusions:

• The optimal conditions for producing high-quality cocoa beans involve six days of fermentation followed by drying at 70°C.
• This processing strategy effectively balances the development of desirable flavor volatile compounds and minimizes undesirable ones.
• The 6-day fermentation and 70°C drying method presents a cost-effective and efficient approach to achieving superior cocoa bean flavor profiles.