title: Degradation kinetics of passion fruit pectin in subcritical water.
abstract: The degradation of passion fruit pectin by subcritical water treatment in a continuous flow-type reactor was investigated in the temperature range of 80-160 °C at a constant pressure of 5 MPa. Changes in the degree of polymerization and reducing end formation were monitored and modeled by applying the Emsley equation and zeroth-order kinetics, respectively. The results showed that both the pectin degradation rate constant and the change in the amount of reducing end were enhanced by temperature, and that the temperature dependence of these parameters obeyed the Arrhenius relationship. The activation energies for pectin degradation and reducing end formation were 62.8 and 86.9 kJ/mol, respectively. The non-linear relationship between the ratio of broken galacturonic acid units to the total galacturonic acid units and the change in the amount of reducing end indicated that pectin cleavage became easier as hydrolysis progressed.
authors.affiliation: a Department of Food Technology, Faculty of Engineering and Industrial Technology , Silpakorn University , Nakhon Pathom , Thailand.
authors.forename: Khwanjai
authors.initials: K
authors.lastname: Klinchongkon
authors.affiliation: a Department of Food Technology, Faculty of Engineering and Industrial Technology , Silpakorn University , Nakhon Pathom , Thailand.
authors.forename: Pramote
authors.initials: P
authors.lastname: Khuwijitjaru
authors.affiliation: b Division of Food Science and Biotechnology , Graduate School of Agriculture, Kyoto University , Kyoto , Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Adachi
mesh_terms: D006603:Hexuronic Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D029598:Passiflora / Q000737:chemistry*; D010368:Pectins / Q000737:chemistry*; D011312:Pressure; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D006603:Hexuronic Acids; D014867:Water; C007819:galacturonic acid; D010368:Pectins
keywords: degradation; kinetics; molecular mass; pectin; subcritical water