Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 77: 6489 - 6499 Published May 31, 2014.
Biochemical and functional properties of lactic acid bacteria isolated from Ivorian cocoa fermenting beans
Djéneba H. OUATTARA, *Honoré G. OUATTARA, Bernadette G. GOUALIE, Liliane M. KOUAME and Sébastien L. NIAMKE1. Laboratoire de Biotechnologies, UFR Biosciences, Université Félix HOUPHOUËT-BOIGNY, 22 BP 582 Abidjan (Côte d’Ivoire)
* Corresponding author: kidou12@yahoo.fr Phone/Fax: 00 (225) 22 44 44 73
Original submitted in on 19th February 2014. Published online at www.m.elewa.org on 31st May 2014. http://dx.doi.org/10.4314/jab.v77i1.9
ABSTRACT
Objective:
Fermentation is an important step in the post-harvest processing of
cocoa beans. The quality of beans and chocolate depends strongly on the
type and characteristics of microbial strains involved in the
fermentation. This study investigates some functional properties of
lactic acid bacteria (LAB), involved in Côte d’Ivoire cocoa
fermentation.
Methodology and results: Bacterial growth was monitored during spontaneous heap fermentation using plate count and decimal dilution methods. LAB was present throughout the fermentative process with a load comprised between 6.0 log (UFC/g of bean) at the beginning to 6.60 log (UFC/g of bean) at the end. The maximum load of LAB corresponding to 7.22 log (UFC/g of bean) was reached after 24 h of fermentation in the condition of 42 °C of temperature and pH round 3.55. Among the 150 strains isolated, 99 were lactobacilli and 51 lactococci. Almost all these LAB showed ability to ferment glucose, fructose and sucrose with an important acidification capacity while only 8 strains belonging to lactococci proved to be able to assimilate citrate. Moreover, a weak proportion (7.33 %) of LAB strains isolated was heterofermentative type. These heterofermentative LAB strains were particularly characterized by a great fermentative capacity especially with glucose and sucrose with a gas production up to 5 mL.
Conclusion and application of results: The citrate metabolism and the strong fermentative capacity of certain LAB strains, indicate interesting technological traits potentially useful for their utilization as starters in cocoa fermentation.
Key words: lactic acid bacteria, fermentative power, cacao fermentation, acidification, citrate metabolism.Methodology and results: Bacterial growth was monitored during spontaneous heap fermentation using plate count and decimal dilution methods. LAB was present throughout the fermentative process with a load comprised between 6.0 log (UFC/g of bean) at the beginning to 6.60 log (UFC/g of bean) at the end. The maximum load of LAB corresponding to 7.22 log (UFC/g of bean) was reached after 24 h of fermentation in the condition of 42 °C of temperature and pH round 3.55. Among the 150 strains isolated, 99 were lactobacilli and 51 lactococci. Almost all these LAB showed ability to ferment glucose, fructose and sucrose with an important acidification capacity while only 8 strains belonging to lactococci proved to be able to assimilate citrate. Moreover, a weak proportion (7.33 %) of LAB strains isolated was heterofermentative type. These heterofermentative LAB strains were particularly characterized by a great fermentative capacity especially with glucose and sucrose with a gas production up to 5 mL.
Conclusion and application of results: The citrate metabolism and the strong fermentative capacity of certain LAB strains, indicate interesting technological traits potentially useful for their utilization as starters in cocoa fermentation.
FULL PAPER [PDF AVAILABLE HERE]
