title: Investigation of CO2precursors in roasted coffee.
abstract: Two CO2formation pathways (chlorogenic acid (CGA) degradation and Maillard reaction) during coffee roasting were investigated. CGA is shown not a major contributor to CO2formation, as heating of this compound under typical roasting conditions did not release a large quantity of CO2. However, heating of a CGA moiety, caffeic acid, resulted in high yield of CO2(>98%), suggesting that CGA hydrolysis could be the rate limiting step for CO2formation from CGA. A large amount of CO2was detected from glycine-sucrose model system under coffee roasting conditions, implying the importance of Maillard reactions in CO2formation. Further studies on the heating of various components isolated from green coffee beans showed that CO2was generated from various green coffee components, including water insoluble proteins and polysaccharides. Around 50% of CO2was formed from thermal reactions of lower molecular weight compounds that represent ∼25% by weight in green coffee.
authors.affiliation: Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Xiuju
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada. Electronic address: llim@uoguelph.ca.
authors.forename: Loong-Tak
authors.initials: LT
authors.lastname: Lim
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D002726:Chlorogenic Acid / Q000737:chemistry*; D040503:Coffea / Q000737:chemistry*; D003069:Coffee / Q000737:chemistry*; D003296:Cooking; D006358:Hot Temperature; D015416:Maillard Reaction
chemical_list: D003069:Coffee; D002245:Carbon Dioxide; D002726:Chlorogenic Acid
keywords: CO(2) precursor; Chlorogenic acid; Coffee roasting; Thermal degradation