Effect of Saccharomyces cerevisiae Strain TIA2019A Concentration as Starter Culture on Volatile Aroma Fingerprint of Cocoa Beans and Sensory Perception of End-chocolate

Abstract

Cocoa from Côte d’Ivoire is currently characterized by low technological quality including the absence of desired fine flavors. Various yeasts are essential for cocoa fermentation and play a key role in the formation of cocoa volatile aroma precursors. This study investigated the improvement of aromatic quality of dry fermented cocoa beans through inoculation of yeats reported to be high potential aroma compounds producer to the cocoa fermentation. Starter culture based on Saccharomyces cerevisiae strain TIA2019A from wine fermentation were prepared at 2 concentrations about 0.5 and 1.0 g yeast per kg of fresh cocoa beans. Cocoa 6 days-fermentation with about 25 kg of fresh beans were carried out in plastic boxes (50×30×30 cm3) for 06 days with 2 turnings at 48 and 96 hours. Fermented cocoa beans was then sun-dried until a moisture content about 8%. Volatile organic compounds (VOCs) fingerprint of dry fermented cocoa beans were determined using SPME-GC/MS method. Main results showed that dry fermented cocoa beans fermented from inoculated 0.5 g of S. cerevisiae per kg of fresh cocoa recorded higher contents of relevant VOCs comprised between 100 and 600 µg.g-1 than cocoa beans inoculated at 1.0 g of yeast per kg.  Chocolate made from cocoa beans inoculated at 0.5 g of S. cerevisiae per kg of cocoa recorded better score for fresh fruit flavors and global organoleptic quality than those produced from cocoa beans inoculated at 1.0 g of S. cerevisiae per kg of cocoa.  Utilization of starter based on S. cerevisiae at low concentration promoted the organoleptic qualities of cocoa and derived chocolate. Selected yeast strains with VOCs producing performance can thus be used to improve aroma quality of dry cocoa beans and the organoleptic quality of chocolate produced thereof.