In Situ Degradation of Cocoa (Theobroma cacao) Pod Husk Theobromine by Candida krusei

摘要

About 70% of the world's cocoa is produced in West Africa. As a consequence, massive amounts of cocoa pod husk (6.7 mmt) are generated in the sub-region annually. The elimination of theobromine and polyphenols, which negatively affect animal reproduction, digestion and feed intake, from cocoa pod husk is critical to the use of the pod husk as affordable animal feed by livestock formers in West Africa. We have investigated the effectiveness of C. krusei fermentation in reducing the theobromine and total phenolic content of cocoa pod husk. Milled cocoa pod husk samples were moistened and inoculated with C. krusei and incubated at ambient temperature for up to 4 weeks. Theobromine was determined using reversed-phase high performance liquid chromatography and total phenolic content was monitored spectrophotometrically. Quantitative extraction of C. krusei-treated pod husk followed by LC-MS analysis of dichloromethane extracts revealed C. krusei-mediated degradation of cocoa husk as well as biosynthesisof new molecules. Treatment of cocoa pod husk with C. krusei for 4 weeks resulted in a 62.5% and 41.5% reduction in theobromine and total phenolic content (p<0.05) respectively. A drastic reduction of 84.3% in condensed tannin content (p<0.05) was recorded after 7 days. Results revealed that the macronutrient profile of cocoa pod husk was altered after four weeks of treatment. Available carbohydrate and gross energy values decreased by 20.5% and 18.7% respectively. There was a significant increase in the crude fibre content ( 25.9%, p<0.05). The observations suggest that C. krusei fermentation might be a useful procedure for detoxifying cocoa pod husk and improving its digestibility.