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Enhanced inactivation of pectin methyl esterase in orange juice using modified supercritical carbon dioxide treatment
Author(s) -
Iftikhar Tehreema,
Wagner Michael E.,
Rizvi Syed S. H.
Publication year - 2014
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12368
Subject(s) - chemistry , orange juice , ethanol , pectin , carbon dioxide , supercritical carbon dioxide , pectinase , alcohol , chromatography , supercritical fluid , esterase , orange (colour) , food science , nuclear chemistry , biochemistry , enzyme , organic chemistry
Summary The aim of the study is to quantify the effect of ethanol addition and exposure surface on the inactivation of pectin methyl esterase ( PME ), a juice clarifying enzyme, in orange juice using supercritical carbon dioxide ( SC ‐ CO 2 ). Addition of ethanol to the SC ‐ CO 2 at 2% (v/v) caused greater inactivation than SC ‐ CO 2 alone, with a maximum reduction of PME activity of 97% at 30 MPa and 40 °C for 60 min. As the surface area to volume ratio was increased, the rate of inactivation of PME increased. Analysis of first‐order reaction kinetic data revealed that D values were greatly influenced by ethanol addition and agitation. With the addition of 2% ethanol, the D value reduced by half, that is, 56 min from 109 min. With impeller agitation of the sample at 1100 ± 100 rpm, the D value for PME was further reduced to 43 and 30 min without and with ethanol, respectively. The activity of PME treated with SC ‐ CO 2 remained unchanged after 14 days of storage at 4 °C. Treatment did not significantly change pH or colour, but did significantly increase the cloud values of the juice, resulting in a cloud stabilised juice with similar qualities to fresh juice.