Enzymatic Extraction of Hydroxycinnamic Acids from Coffee Pulp
María Teresa Torres-Mancera1, Jesús Cordova-López2, Gabriela Rodríguez-Serrano1, Sevastianos Roussos3, Ma. Ascención Ramírez-Coronel1, Ernesto Favela-Torres1and Gerardo Saucedo-Castañeda1*
1Department of Biotechnology, Metropolitan Autonomous University (UAM-I), Av. San Rafael Atlixco 186, Vicentina 09340, D.F. Mexico
2University of Guadalajara (CUCEI), Blvd. Marcelino García Barragán 1421, Olímpica-44430 Guadalajara, Jalisco State, Mexico
3Department of Microbial Ecology and Biotechnology, Paul Cezanne University, FST Avenue Escadrille Normandie Niémen, FR-13397 Marseille Cedex 20, France
Article history:
Received September 18, 2010
Accepted January 25, 2011
Key words:
coffee pulp, olive oil, hydroxycinnamic acids, antioxidants, solid-state fermentation
Summary:
Ferulic, caffeic, p-coumaric and chlorogenic acids are classified as hydroxycinnamic acids, presenting anticarcinogenic, anti-inflammatory and antioxidant properties. In this work, enzymatic extraction has been studied in order to extract high value-added products like hydroxycinnamic acids from coffee pulp. A commercial pectinase and enzyme extract produced by Rhizomucor pusillus strain 23aIV in solid-state fermentation using olive oil or coffee pulp (CP) as an inducer of the feruloyl esterase activity were evaluated separately and mixed. The total content (covalently linked and free) of ferulic, caffeic, p-coumaric and chlorogenic acids was 5276 mg per kg of coffee pulp. Distribution was as follows (in %): chlorogenic acid 58.7, caffeic acid 37.6, ferulic acid 2.1 and p-coumaric acid 1.5. Most of the hydroxycinnamic acids were covalently bound to the cell wall (in %): p-coumaric acid 97.2, caffeic acid 94.4, chlorogenic acid 76.9 and ferulic acid 73.4. The content of covalently linked hydroxycinnamic acid was used to calculate the enzyme extraction yield. The maximum carbon dioxide rate for the solid-state fermentation using olive oil as an inducer was higher and it was reached in a short cultivation time. Nevertheless, the feruloyl esterase (FAE) activity (units per mg of protein) obtained in the fermentation using CP as an inducer was 31.8 % higher in comparison with that obtained in the fermentation using olive oil as the inducer. To our knowledge, this is the first report indicating the composition of both esterified and free ferulic, caffeic, p-coumaric and chlorogenic acids in coffee pulp. The highest yield of extraction of hydroxycinnamic acids was obtained by mixing the produced enzyme extract using coffee pulp as an inducer and a commercial pectinase. Extraction yields were as follows (in %): chlorogenic acid 54.4, ferulic acid 19.8, p-coumaric acid 7.2 and caffeic acid 2.3. An important increase in the added value of coffee pulp was mainly due to the extraction of chlorogenic acid.
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