Functional role of yeasts, lactic acid bacteria and acetic acid bacteria in cocoa fermentation processes

Abstract

Cured cocoa beans are obtained through a post-harvest, batchwise process of fermentation and drying carried out on farms in the equatorial zone. Fermentation of cocoa pulp-bean mass is performed mainly in heaps or boxes. It is made possible by a succession of yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) activities. Yeasts ferment the glucose of the cocoa pulp into ethanol, perform pectinolysis and produce flavour compounds, such as (higher) alcohols, aldehydes, organic acids and esters. LAB ferment the glucose, fructose and citric acid of the cocoa pulp into lactic acid, acetic acid, mannitol and pyruvate, generate a microbiologically stable fermentation environment, provide lactate as carbon source for the indispensable growth of AAB, and contribute to the cocoa and chocolate flavours by the production of sugar alcohols, organic acids, (higher) alcohols and aldehydes. AAB oxidize the ethanol into acetic acid, which penetrates into the bean cotyledons to prevent seed germination. Destruction of the subcellular seed structure in turn initiates enzymatic and non-enzymatic conversions inside the cocoa beans, which provides the necessary colour and flavour precursor molecules (hydrophilic peptides, hydrophobic amino acids and reducing sugars) for later roasting of the cured cocoa beans, the first step of the chocolate-making.

Curing of Cocoa Beans: Fine-Scale Monitoring of the Starter Cultures Applied and Metabolomics of the Fermentation and Drying Steps

“…Cocoa fermentation and drying are key steps in the curing of cocoa beans to make them ready for the production of chocolate ( Schwan and Wheals, 2004 ; Saltini et al, 2013 ; De Vuyst and Weckx, 2016 ; Pereira et al, 2016 ; Ozturk and Young, 2017 ; Castro-Alayo et al, 2019 ; Figueroa-Hernández et al, 2019 ; De Vuyst and Leroy, 2020 ; Santander Muñoz et al, 2020 ). The microbial communities involved in cocoa fermentation processes are mainly composed of yeasts (in particular Candida , Hanseniaspora , Saccharomyces , and Pichia species), lactic acid bacteria (LAB; in particular Lactiplantibacillus and Limosilactobacillus species), and acetic acid bacteria (AAB; in particular Acetobacter species).…”

“…Traditionally, cocoa fermentation processes are spontaneous, uncontrolled, on-farm processes ( Schwan and Wheals, 2004 ; De Vuyst and Weckx, 2016 ; Pereira et al, 2016 ; Ozturk and Young, 2017 ; Figueroa-Hernández et al, 2019 ; De Vuyst and Leroy, 2020 ; Santander Muñoz et al, 2020 ). They usually consist of two phases.…”

A Microbial Ecosystem: Agricultural Jiaosu Achieves Effective and Lasting Antifungal Activity against Botrytis Cinerea

“…Previous studies have shown that AJ contains acid-based substances (AS), such as lactic acid (LA) and acetic acid (AA), and bene cial microorganisms (BM), such as lactic acid bacteria (LAB) and acetic acid bacteria (AAB); (Selvakumar and Sivashanmugam 2017;Arun and Sivashanmugam 2015;Rahman et al 2020;Di et al 2020), which are veri ed to show the inhibitory ability against B. cinerea (Trias et al 2008;Drysdale and Fleet 1989;Golnaz Hesami 2013;Lagopodi et al 2009;De Corato et al 2014;De Vuyst and Leroy 2020). As an ecosystem of AS and BM, AJ has displayed a strong antifungal activity in rural regions of China.…”

Potential of Bacteria from Alternative Fermented Foods as Starter Cultures for the Production of Wheat Sourdoughs

“…Finally, strains of AAB species isolated from fermenting cocoa pulp-bean mass were tested. Acetobacter pasteurianus prevails during the aerobic phase of cocoa pulp-bean mass fermentations, oxidizing the ethanol produced by the yeasts during the preceding anaerobic phase to acetic acid [ 35 , 40 , 46 , 47 ]. In the presence of carbohydrate excesses during the aerobic phase, G. oxydans oxidizes glucose to gluconic acid [ 65 , 81 ].…”

“…The alternative fermented food ecosystems mentioned above are of particular interest. Strains of Limosilactobacillus fermentum prevail during the LAB phase of the three-step cocoa fermentation process, consuming carbohydrates and citrate and producing lactic acid, acetic acid, mannitol, and buttery-flavor compounds [ 35 , 46 , 47 , 48 ]. Meat fermentations for fermented sausage production are mainly carried out by Latilactobacillus sakei acidifying the meat batter and, in some cases, producing bacteriocins against spoiling and pathogenic bacteria [ 42 , 49 ].…”