Elucidating the contribution of microorganisms to the spontaneous fermentation and the quality of Ivorian cacao (Theobroma cacao) beans

Cacao (Theobroma cacao) beans are among the most important ingredients in food and beverage industries. They are mainly produced in tropical and subtropical forests. Africa is the biggest producer of cacao bean providers in the world and the Ivory Coast remains the world leader with an estimated yearly production of 3 million tonnes. Cacao beans are used in many food items such as chocolate products, cocoa butter, confectionary products, iced drinks, cocoa powder, etc. The quality and organoleptic characteristics of these food products are strongly related to those of the cocoa beans obtained from different processing treatments. The pulps surrounding the cacao beans are rich in water, sugars, pectins, proteins, minerals, vitamins, citric acid, and phenolic compounds. Many different processing methods are utilized and fermentation is a crucial postharvest treatment having a great influence on the quality of cacao beans and their related products. Spontaneous fermentation is a common practice carried out by the cacao farmers in Ivory Coast. The microorganisms involved in this process are primarily the yeasts (anaerobic phase), which convert the pulps containing sugars into alcohol with a sporicidal temperature increase and then the lactic and acetic acid bacteria (aerobic phase) that produce lactic and acetic acids, respectively. The degradation of the substrates inside the cacao pulps results in the generation of aroma precursors and compounds. The goal of this review was to elucidate the factors affecting the spontaneous fermentation of Ivorian cacao beans and clarify the transformation of the raw material during fermentation.