Comparison of Cocoa Bean Quality Produced with Different Starter Cultures and Fermentation Methods

Abstract

<i>Saccharomyces cerevisiae</i>, <i>Lactobacillus plantarum</i> and <i>Acetobacter tropicalis</i> and <i>Shah</i> (maize-based fermented broth) was used as starter cultures in fermentations and the quality of cocoa bean produced assessed. This was a cross sectional study. Experiments were performed at JPJ Biotechnology Laboratory at IRAD Ekona, Cameroon from March – October, 2020. Fermentations of 10kg were performed in buckets and heaps. These were inoculated with 10^⁶CFU/mL per kg of cocoa bean for Composed Starter (CS) and 100 mL per kg of cocoa for <i>Shah</i>. Samples were collected every day for 5 days. Dried beans from Day 3 onwards of fermentation were assessed using cut-test and Equivalent per cent Fully Brown Score (EB_Score) while the Fermentative Index (FI) was carried out on dried beans of the 5 days. Means were compared using Analysis of Variance and a <i>p </i>-<i> </i>value < 0.05 was considered significant. Good cocoa bean quality (CBQ) with a cut-test of 66% and 62% was respectively obtained with CS and <i>Shah</i> after 3 days in bucket. Natural fermentation attained 62% fully brown beans after 4 days. The CBQ from heap fermentation with CS reached 64% after 4 days while all others remained moderate. Calculated EB_scores were not significantly different except for heap fermentations with values of Day 4 and 5 being higher. By Day 3, CS (FI=1.06) and <i>Shah</i> (FI=1.01) had FI values >1 suggesting that these bucket fermentations could be terminated. In the heap fermentation, good CBQ with CS (FI=1.02) was achieve on Day 4. <i>Shah</i> went on to D5 though the value of D4 (0.96) was not significantly different from that of D5 (1.03). An affordable method for cocoa fermentation was proposed using <i>Shah</i>. Good CBQ was attained faster with use of starter cultures and fermentation time was reduced to 3 days. This is the first study to demonstrate that <i>Shah</i> can be used as a starter culture with comparable results to CS for cocoa fermentation.