Effect of storage management on free fatty acid content in dry cocoa beans

Though not a quality parameter, it is expected that the free fatty acids (FFA) content must be less than 1.0% to meet the acceptable level of 1.75% in cocoa butter extracted from the dry cocoa beans. This study therefore investigates the FFA content of stored dry cocoa beans from Ghana that was generally low compared to that of Côte d’Ivoire. The FFA content of dry cocoa beans increases with storage time and this was evident for both countries. The mean FFA of Ghana’s cocoa beans was 2.03% in 1999 and 0.90% in 2008 while that of Cote d’Ivoire’s cocoa beans was 2.57% in 2002 and 1.43% in 2008. The low mean moisture content of 6.5% of Ghana cocoa beans and the mean moisture content 8.0% of Côte d’Ivoire cocoa beans might have influenced the differences in mean FFA levels. To evaluate the effect of insect infestation on increase of FFA, dry cocoa beans were infested with ten young adults of Lasioderma serricorne (Fabricus), Tribolium castaneum (Herbst), Cryptolestes ferrugineus (Stephens) and stored for 9 mo under dry condition at 30±2°C. The mean FFA of the insect-infested dry cocoa beans increased from 0.76% at the time of storage to 1.81% after 9 mo of storage. However, the mean FFA of the control dry cocoa beans increased from 0.79% at the time of storage to 0.93% after 9 mo of storage. It could therefore be inferred conclusively that FFA content in dry cocoa beans increases with insect infestation.Keywords: Cocoa beans, Free fatty acids, Storage management, Quality preservation, Insect infestation

A novel approach to the protection of cocoa beans by preventing free fatty acid formation under hermetic storage

Hermetic storage has provided a successful storage method for the protection of dry cocoa beans by replacing fumigants for insect control and for quality preservation. Hermetic storage is achieved in specially constructed flexible plastic structures and is based on the principle of generation of an oxygen-depleted, carbon dioxide-enriched interstitial atmosphere caused by the respiration of the living organisms in the ecological system of a sealed storage. An increase in free fatty acids (FFA) content in dry cocoa beans is a significant factor that determines its quality preservation. After fermentation of the beans, moisture content (m.c.) is usually high that poses a risk for the rise of FFA in the beans. Tests were carried out to study the effects of hermetic storage of dry cocoa beans under aerobic and hermetically sealed conditions on the development of FFA's in the beans at 7.0%, 7.5%, and 8.0% m.c. for periods of 90 and 160 d at 30°C. The beans under hermetic conditions responded by creating progressive depleted oxygen conditions that were accompanied by the increased carbon dioxide due to the respiration of the beans. The lowest oxygen concentration took place at 7.0% m.c. after 35 d, at 7.5% m.c. after 29 d, at 8.0% m.c. after 26 d of storage and thereafter, no significant increase in oxygen concentration was observed. The FFA content of cocoa beans at 7.0%, 7.5%, and 8.0% m.c. under hermetic conditions of 30°C remained below or close to 1.0% after 90 and 160 d of storage. This was more comparable to the results obtained when the beans were stored at 4oC rather than the controls. In comparison, the aerated control stored at 30°C showed marked increase in FFA levels of up to 1.48%. Keywords: Hermetic storage, Modified Atmospheres, Cocoa beans, Quality preservation, Storage insect control, Flexible storage structures