Exploration of Lactiplantibacillus fabifermentans and Furfurilactobacillus rossiae as potential cocoa fermentation starters

Abstract

Aims:To investigate the characteristics of two minority autochthonous LAB species, with particular regard to those properties that could be exploited in an improved cocoa fermentation process from a quality and safety point of view.Methods and Results: Bacterial, yeast and mould strains characteristic of spontaneously fermented Dominican cocoa beans were isolated and identified by 16S or 26S rRNA gene sequencing. The potential of two autochthonous strains of LAB belonging to the species Lactiplantibacillus fabifermentans and Furfurilactibacillus rossiae were investigated. The two selected LAB strains were able to utilize glucose and fructose, produced mainly D-L lactic acid and had a good ability to resist to cocoarelated stress conditions such as low pH, high temperature and high osmotic pressure, as well as to grow in sterile cocoa pulp. The strains did not inhibit the growth of yeasts and acetic acid bacteria, that are essential to the cocoa fermentation process, and possessed a complex pool of peptidases especially active on hydrophobic amino acids. The strains also showed antifungal activity against mould species that can be found at the final stages of cocoa fermentation, as Aspergillus tamarii, A. nidulans, Lichtheimia ornata and Rhizomucor pusillus. Conclusions: The tested strains are good candidates for the design of starter cultures for a controlled cocoa fermentation process. Significance and Impact of the Study:This research showcases the potential of two alternative LAB species to the dominating Lactiplantibacillus plantarum and Limosilactibacillus fermentum as cocoa fermentation starters, with an interesting activity in improving the safety and quality of the process.

Evaluation of stress tolerance and design of alternative culture media for the production of fermentation starter cultures in cacao

“…As temperatures increased, both species experienced significant declines in growth, culminating in a complete absence of growth at 45 °C. This pattern of thermosensitivity mirrors the observations of Korcari [ 29 ], who also reported that these bacteria tolerate temperatures up to 37 °C but show markedly reduced growth at 42 °C. On the other hand, in examining thermotolerance ( Table 3 ), AAB displayed a lower growth rate than LAB.…”

“…The LAB species L. plantarum and L. fabifermentans were selected to assess their stress resistance. L. plantarum has been used as a starter culture to improve the production of volatile compounds [ 18 , 22 ]; while L. fabifermentans is known for its capacity to grow in low pH, elevated temperatures, and high osmotic pressure [ 29 ]. Similarly, the tolerance of the two AAB strains isolated was evaluated.…”

“…Following the guidelines from Pereira [ 28 ] and Visintin [ 12 ] for selecting starter microorganisms, tolerance to different stress conditions was assessed. Previously, the most relevant species in the application and development of starter cultures for cacao fermentation were chosen [ 10 , 18 , 22 , 29 , 30 ].…”

“…The fermentation experiments were conducted on a laboratory scale, as Pereira [ 24 ] suggested, with some modifications, using Nacional cacao obtained from the Agricultural Experimental Farm at ESPOL University. Cacao beans with pulp were pasteurized at 65 °C for 30 min [ 29 ], and 100 g were placed in 250 mL Erlenmeyer flasks. These flasks were inoculated with approximately 10 6 CFU mL −1 of each microorganism selected based on tolerance tests.…”

Fine Cocoa Fermentation with Selected Lactic Acid Bacteria: Fermentation Performance and Impact on Chocolate Composition and Sensory Properties

“…The aim of this work is to evaluate the impact of adjunct cultures of selected lactic acid bacteria (LAB) on fermentation parameters, flavour, and sensory profile of fine cocoa and chocolate. In a previous research [11], we characterised the microbial population of spontaneously fermented Dominican cocoa beans, with the aim of selecting autochthonous LAB species, which are used as adjunct cultures that could improve the quality and flavour of the final chocolate. For these reasons, we focalized the attention on two minority LAB species isolated together with the dominant Lactiplantibacillus plantarum and Limosilactibacillus fermentum.…”