Inactivation of apple pectin methylesterase induced by dense phase carbon dioxide.
The inactivation of apple pectin methylesterase (PME) with dense phase carbon dioxide (DPCD) combined with temperatures (35-55 degrees C) is investigated. DPCD increases the susceptibility of apple PME to the temperatures and the pressures have a noticeable effect on apple PME activity. A labile and stable fraction of apple PME is present and the inactivation kinetics of apple PME by DPCD is adequately described by a two-fraction model. The kinetic rate constants k L and k S of labile and stable fractions are 0.890 and 0.039 min (-1), and the decimal reduction times D L and D S are 2.59 and 58.70 min at 30 MPa and 55 degrees C. Z T representing temperature increase needed for a 90% reduction of the D value and the activation energy E a of the labile fraction at 30 MPa is 22.32 degrees C and 86.88 kJ /mol, its Z P representing pressure increase needed for a 90% reduction of the D value and the activation volume V a at 55 degrees C is 21.75 MPa and -288.38 cm (3)/mol. The residual activity of apple PME after DPCD exhibits no reduction or reactivation for 4 weeks at 4 degrees C.
Research center for fruit and vegetable processing Engineering of the Ministry of Education, China Agricultural University, Beijing 100083, China.
Xian
X
Zhi
Yan
Y
Zhang
Xiaosong
X
Hu
Jihong
J
Wu
Xiaojun
X
Liao
D001274:Atmospheric Pressure; D002245:Carbon Dioxide / Q000737:chemistry*; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D004795:Enzyme Stability; D007700:Kinetics; D027845:Malus / Q000737:chemistry / Q000201:enzymology*; D008954:Models, Biological; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D013696:Temperature
D010940:Plant Proteins; D002245:Carbon Dioxide; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase