Effects of Different Drying Techniques on the Post-Harvest Quality of Fermented Cocoa Beans in Ghana

Drying plays a pivotal role in post-harvest processing, influencing the quality, storability, and commercial value of cocoa beans. This study compared the impact of three drying techniques-open sun drying (OSD), convective oven drying (COD), and a modified convective oven drying method (MCOD), which emulates sun drying by controlling temperature and humidity-on the quality characteristics of fermented cocoa beans from Ghana. Key attributes assessed included pH, fermentation index (FI), fermentation quality (FQ), fat and polyphenol content, levels of free fatty acids (FFA), sugars, organic and amino acids, and the profile of volatile compounds. Beans dried using MCOD achieved the highest FI (1.16) and a higher FQ of 96.23%, closely mirroring results from OSD (FI = 1.14, FQ = 98.23%). COD produced the lowest values (FI = 0.90, FQ = 89.23%). Fat content was preserved in OSD and MCOD (52.82% and 52.03%, respectively), whereas COD resulted in a lower fat yield (40.29%). Total polyphenol content (TPC) peaked in COD samples (40.55 mg GAE/g), while MCOD had the lowest FFA content (0.77%). OSD and MCOD retained higher levels of sugars and free amino acids and showed richer volatile profiles. Principal component analysis revealed similar chemical profiles between OSD and MCOD, particularly in sugars, amino acids, and volatiles, while COD samples were more associated with organic acids. These findings suggest MCOD is a practical and scalable substitute for traditional sun drying, especially under unfavorable weather conditions. Further studies should examine its potential in retaining bioactives, minimizing mycotoxins, and preserving sensory attributes.