Comparison of the inactivation kinetics of pectin methylesterases from carrot and peach by high-pressure carbon dioxide

Comparative study on cloudy apple juice qualities from apple slices treated by high pressure carbon dioxide and mild heat

“…Similarly, PME matrix, sources, fruit maturity and HPCD treatment conditions may also account for different inactivation level in these literatures. Zhou, Zhang, et al (2009) found the RA of PME in peach juice was significantly greater than that in 20 mM Trischloride buffer (pH 7.5) under HPCD treatment conditions of 8 MPa for 200 min, 15 MPa for 210 min and 22 MPa for 180 min, which indicated the original PME in the juice was less inactivated by HPCD. Sampedro, Rodrigo and Hendrickx (2008) also reported higher stability of PME in an orange juice-milk beverage than purified PME under treatment of 5 min in a temperature range from 45 to 90°C.…”

Inactivation of polyphenol oxidase from Pacific white shrimp by dense phase carbon dioxide

“…However, many reactions catalyzed by enzyme had been performed in supercritical CO 2 (Habulin & Knez, 2001;Wimmer & Zarevúcka, 2010). The stability and the activity of enzymes exposed to DPCD treatment are affected by the type and source of the enzyme, DPCD treatment conditions such as pressure, temperature, time, and properties of the suspending medium (Chen et al, 1992;Liu et al, 2008;Zhou, Zhang, Hu, Liao, & He, 2009). Enzyme inactivation by DPCD could be due to the three-dimensional structure changes of enzymes and inhibitory effect of molecular CO 2 on enzyme activity (Damar & Balaban, 2006;Wimmer & Zarevúcka, 2010).…”

Effects of high pressure CO2 treatments on microflora, enzymes and some quality attributes of apple juice

“…Zhi et al (2008) reported that better inactivation of apple PME with an increase of temperature from 35 to 55°C at 30 MPa and the maximal reduction of apple PME activity (in Tris-chloride buffer, pH 7.5) was 94.57% at 30 MPa and 55°C for 60 min. Zhou et al (2009a) also showed that the activity of carrot and peach PME was reduced as the treatment time extended. Several other studies also studied the inactivation of PME in juices by HPCD treatment.…”

“…Similarly, it could be reasoned that the greater sensitivity of PPO to HPCD treatment than PME is caused by the difference in its structure. Furthermore, the inactivation of PPO and PME induced by HPCD could also result from the alterations in secondary and tertiary structures (Park et al, 2002;Zhou et al, 2009a). Table 2 shows the colour change of cloudy apple juice after continuous HPCD treatment.…”

“…Its efficacy on at least 12 gram-positive bacteria, 10 gram-negative bacteria, 8 bacterial spores, and 8 fungi as filament or spores, has been studied over the last few years . HPCD has also been proven effective to inactivate many indigenous fruit enzymes, including PPO (Pozo-Insfran et al, 2007;Gui et al, 2007;Chen et al, 1992;Liu et al, 2008), Peroxidase (Liu et al, 2008), Lypoxygenase (Liao et al, 2009) and PME (Arreola et al, 1991;Park et al, 2002;Kincal et al, 2006;Zhi et al, 2008;Zhou et al, 2009a). However, there is only a limited number of published studies on the effects of HPCD on the quality of foods (Damar and Balaban, 2006), or the change of particle size distribution (PSD) of cloudy juice.…”