Enhanced inactivation of pectin methyl esterase in orange juice using modified supercritical carbon dioxide treatment

Abstract

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‐CO2). Addition of ethanol to the SC‐CO2 at 2% (v/v) caused greater inactivation than SC‐CO2 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‐CO2 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.

Nonthermal Technologies for Fruit and Vegetable Juices and Beverages: Overview and Advances

“…With regard to inert gas processing, the addition of ethanol to orange juice processed by DPCD proved to be effective as 97% PME inactivation was achieved at the level of 2% (v/v; Iftikhar and others ).…”

Cloud stability of sour orange juice as affected by pectin methylesterase during come up time: Approached through fractal dimension

“…It was reported that the orange juice became more turbid by PME inactivation. [37] Also, during thermo-sonication treatment of grapefruit juice, the cloud value was promoted because the breaking up of the larger cloud particles into the smaller ones. [6] The smaller particles tend to being suspended in the juice and pass the light less through the juice; hence, the higher absorbance is recorded using spectrophotometer.…”

Effects of kiwi’s pectin methylesterase inhibitor, nanomilling and pasteurization on orange juice quality

“…Such PME residual activities are probably due to the presence of different PME isoforms some of which are extremely thermostable (Jolie et al, 2010;La Ratta et al, 1995). The PME-PMEI complex will not dissociate at high temperature but rather denature as a single entity (Jolie et al, 2010 (Iftikhar et al, 2014), while Kim, Tadini, and Singh (1999) described 100% inactivation at 80°C/70s. Also, SentandreuCarbonell, Carbonell, and Izquierdo (2005) found that PME residual activities in thermally treated juices from oranges, mandarins, and hybrids were 0, 1, 3, 15, and 20% at 95°C/20s, 90°C/10s, 85°C/10s, 80°C/5-20s, and 70°C /5-20s, respectively.…”

“…PME de‐esterifies pectin, and the produced low methyl esterified pectin will form insoluble pectates with the reaction with calcium ions. Such insoluble gel will coprecipitate with pulp particles causing cloud loss which is considered as one of the major problems in juices industry (Iftikhar, Wagner, & Rizvi, 2014; Krall & McFeeters, 1998; Krop & Pilnik, 1974). Therefore, to produce high‐quality OJ and due to the need for minimally processed orange juice of rich flavor, PME must be inactivated (Cameron, Niedz, & Grohmann, 1994).…”

“…Thermal inhibition of PME is the most common method used. However, thermal treatment negatively affects the sensory and nutritional quality of the juice (Iftikhar et al, 2014).…”