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Involvement of pectolytic micro‐organisms in coffee fermentation

International Journal of Food Science & Technology (Impact Factor: 1.38). 01/2002; 37(2):191 - 198. DOI: 10.1046/j.1365-2621.2002.00556.x

ABSTRACT

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.

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    • "Oil yield and stability are improved after enzyme treatment and polyphenol and vitamin E content are increased, improving the oil's organoleptic quality (Kashyap et al. 2001; Hoondal et al. 2002; Iconomou et al. 2010). Pectolytic microorganisms are also used to ferment coffee beans, a process that removes the mucilage layer from the beans (Avallone et al. 2002). For example, a commercial enzyme product containing pectinase is applied to coffee beans to initiate fermentation (Pasha et al. 2013). "
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    • "(Avallone et al., 2001; Pereira et al., 2014). Over the years many studies have demonstrated that the coffee bean fermentation process needs to be well controlled to ensure the development of microorganisms that give a high-quality beverage with good coffee aroma (Agate & Bhat, 1966; Avallone et al., 2002; Evangelista et al., 2014; Silva et al., 2013). Failure in fermentation can result in the development of microorganisms that adversely affect coffee character and flavor (Frank, Lum, & Delacruz, 1965; Pereira et al., 2014). "
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