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Involvement of pectolytic micro‐organisms in coffee fermentation
Author(s) -
Avallone Sylvie,
Brillouet Jean M.,
Guyot Bernard,
Olguin Eugenia,
Guiraud Joseph P.
Publication year - 2002
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1046/j.1365-2621.2002.00556.x
Subject(s) - fermentation , pectinase , leuconostoc mesenteroides , mucilage , lactic acid , bacteria , food science , lactobacillus brevis , chemistry , leuconostoc , erwinia , lactobacillus , biology , lactobacillus plantarum , enzyme , biochemistry , botany , genetics
During the fermentation of Coffea arabica L., the most frequently found pectolytic bacteria were Erwinia herbicola and Klebsiella pneumoniae . These micro‐organisms produce pectatelyase which is unable to depolymerize esterified pectins of mucilage without previous de‐esterification. Furthermore, the optimal activities are observed at pH 8.5 whereas fermentation conditions are acidic (5.3–3.5). The major lactic acid bacteria, Leuconostoc mesenteroides , do not produce pectolytic enzymes. Only a Lactobacillus brevis strain, rarely isolated with a low frequency, shows a polygalacturonase activity compatible with fermentation conditions. Mucilage decomposition seems to be correlated to acidification and not to enzymatic pectolysis. Inoculation with pectolytic micro‐organisms allows microbiological control of the fermentation but does not speed up the process. It would be preferable to use lactic acid bacteria so that the pH remained as close as possible to natural fermentation, where acidification is important. This practice would standardize the coffee fermentation microflora and therefore control the end product quality.