Inoculum of the starter consortia and interactive metabolic process in enhancing quality of cocoa bean (Theobroma cacao) fermentation

- A starter consortium with an inoculum of 10-60% was used in Solid state fermentation (SSF) of the cocoa bean.
- 10% inoculum accelerated microbial activity associated and thereby fermentation.
- The starter consortia inoculum (10%) reduced fermentation duration from 7 to 3 days.
- Quality profile of the processed cocoa beans were confirmed to be good and consistent.
- Starters with precise inoculum demonstrate significance in cocoa fermentation.

Fermentation of cocoa (Theobroma cacao) is the pivotal in the post-harvest process. Solid state fermentation of the cocoa with inoculum of 10-60% of defined starter consortia of Saccharomyces cerevisiae, Lactobacillus plantarum and Acetobacter aceti in cocoa fermentation boxes was carried out. The microbial ecology, metabolism, bean chemistry and chocolate quality along with natural (control) fermentation were evaluated. An inoculum of 10% resulted to temperature of 42 °C and pH 5.5. The variation in microbial metabolites was indicative with reference to alcohol (2.3 ± 0.2 mg/g), lactic acid (0.1 ± 0.3 mg/g), acetic acid (1.6 mg/g), anthocyanin (8.5 ± 0.5 mg/kg) and total polyphenols (34 ± 0.2 mg ECE/g). The HPLC profiles revealed key alkaloids such as theobromine (2.2 ± 0.08 mg/g), caffeine (1.92 ± 0.06 mg/g), theophylline (0.42 ± 0.03 mg/g). The sensory profile with 10% inoculum scored 8.5 on hedonic scale and was significant (p < 0.05). High density cell culture (30-60%) resulted in undesirable fermentation leading to low-quality cocoa beans. Use of 10% inoculum of starter consortia regulated microbial succession, consistent fermentation and development of desirable characteristics of the cocoa beans and potentially reduced the fermentation time to 3 days, as against that of 5-7 days in case of natural fermentation.