Inactivation Kinetics Of Polyphenol Oxidase Research Articles

Inactivation kinetics of polyphenol oxidase and peroxidase enzymes in buffer solutions by ultraviolet light sources at multiple UV-C wavelengths

This study aimed to evaluate the effect of multiple wavelengths of UV-C light sources on the inactivation of polyphenol oxidase (PPO) and peroxidase (POD) in buffer solutions. Enzyme solutions were treated with a UV-C excimer lamp (EL) emitting at 222 nm, low-pressure mercury (LPM) lamp at 253.7 nm, four UV-LEDs sources emitting at 255, 265, 275 and 285 nm, and a novel pulsed UV-C lamp (PL) emitting at 232, 242, 261 and 272 nm. Three kinetic models were used to compare UV-C wavelengths enzymatic inactivation efficacy considering the volume average fluence for 90% reduction (HD). Validation of kinetic parameters was performed under continuous-flow treatment in a UV-C LED and EL system. EL treatment resulted in the highest inactivation efficacy of PPO and POD enzymes with HD of 52.8 and 74.8 mJ/cm2, respectively. PL inactivation efficacy for both enzymes was higher than with LPM lamp or UV-LEDs. The two-component first-order model best described the inactivation of PPO and POD in a buffer solution. The adjusted kinetic parameters for this model were validated under UV-C light continuous flow processing. This study contributes to the development of liquid food treatment by ultraviolet technology.

Modeling the inactivation kinetics of polyphenol oxidase and peroxidase during the cold plasma treatment of kiwifruit juice

AbstractCold Plasma (CP) is an emerging non‐thermal technology that preserves and decontaminates food. Kiwifruit juice spoilage enzymes polyphenol oxidase (PPO) and peroxidase (POD) were studied at 24‐36 kV, 2‐10 mm juice depth, and 2‐10 min treatment time using log‐linear, Weibull distribution, and logistic models. The Weibull and logistic model explained enzyme inactivation kinetics well based on goodness of fit (Coefficient of determination: 0.97‐0.99 & root mean square error: 0.11‐2.15) and validation indices (accuracy factor: 1‐1.06 and bias factor: 0.96‐1.04). The logistic model suited PPO and POD inactivation curves well, with the least Akaike weight in 71.29% and 61.45%, respectively. POD had a half‐maximal activity of 11.37, 5.22, and 3.60 min at 24 kV, 30 kV, and 36 kV at 6 mm juice depth, compared to 8.71, 4.41, and 2.51 min for PPO. This shows that POD is more CP‐resistant than PPO, making its inactivation in kiwifruit juice crucial.Practical ApplicationKinetic modeling helps to comprehend the fundamental process and is suitable for improving the inactivation process and enhancing its efficacy. As a relatively primary method, mathematical models facilitate a greater comprehension of the mechanism and factors influencing the inactivation processes. This study involves the inactivation of PPO and POD to produce a stable kiwifruit juice. The inactivation of PPO and POD enzymes will prevent the undesirable enzymatic browning of juice. The kinetic data related to enzyme inactivation will help in deciding the process parameters like plasma voltage, juice depth, and treatment time for producing enzymatically stable kiwifruit juice.

Purification, characterization and inactivation kinetics of polyphenol oxidase extracted from Cistanche deserticola.

PPO was purified from Cistanche deserticola, and its enzymatic characteristics were clarified. It was found that microwave treatment was an efficient way to inactivate PPO. Polyphenol oxidase (PPO) from Cistanche deserticola was obtained and purified through an acetone precipitation and anion exchange column, the enzymatic characteristics and inactivation kinetics of PPO were studied. The specific activity of PPO was 73135.15 ± 6625.7 U/mg after purification, the purification multiple was 48.91 ± 4.43 times, and the recovery was 30.96 ± 0.27%. The molecular weight of the PPO component is about 66kDa by SDS-PAGE analysis. The optimum substrate of PPO was catechol (Vmax = 0.048 U/mL, Km = 21.70mM) and the optimum temperature and pH were 30°C and 7, respectively. When the temperature is above 50°C, pH < 3 or pH > 10, the enzyme activity can be significantly inhibited. The first-order kinetic fitting shows that microwave inactivation has lesser k values, larger D values and shorter t1/2. It was found that microwave treatment is considered as an efficient and feasible way to inactive PPO by comparing the Z values and Ea values of the two thermal treatments.

Effect of thermal blanching on the inactivation kinetics of polyphenol oxidase and peroxidase in lily bulb, and the functional properties of its flours

Effect of thermal blanching on the inactivation kinetics of polyphenol oxidase and peroxidase in lily bulb, and the functional properties of its flours

Ohmic heating blanching of Agaricus bisporus mushroom: Effects on polyphenoloxidase inactivation kinetics, color, and texture

The effect of ohmic heating blanching (OHB) on the inactivation kinetics of polyphenol oxidase (PPO), color, and texture from Agaricus bisporus mushroom treated at different temperatures (67–90 °C) for 1 to 5 min was investigated in the present work. OHB and conventional blanching (CB) treatments were able to inactivate mushroom PPO. However, the inactivation kinetics results showed a lower energy activation (Ea) value during OHB (16.03 ± 1.34 KJmol-1) compared to conventional blanching (20.07 ± 1.85 KJmol-1). Significant differences were observed in color (L*, h° and ΔE) and mushroom texture between the blanching treatments. Nevertheless, both treatments caused minimal physicochemical changes. Therefore, OHB is a promising technology for mushroom blanching because it promotes PPO inactivation in less time and reduces the impact on the color and texture of mushrooms compared to CB.

Inactivation kinetics of polyphenol oxidase and peroxidase in pineapple juice by dielectric barrier discharge plasma technology

The non-thermal plasma technique is an innovative non-thermal approach for food preservation and decontamination. Polyphenol oxidase (PPO) and peroxidase (POD), the principal food degrading enzymes in pineapple juice, were inactivated by the Dielectric Barrier Discharge (DBD) plasma. The inactivation kinetics of PPO and POD in pineapple juice were examined at three different voltages 25, 35, and 45 kV for up to 10 min of plasma treatment. The present study's findings revealed that plasma parameters such as voltage and treatment time substantially reduced enzyme activity of both enzymes, with the former parameter having a more pronounced influence on enzyme inactivity. To mathematically represent the model parameters, established kinetic models viz. log-linear, Weibull, and logistic were fitted to observe experimental data. The Weibull model was discovered to be the best fit for the enzyme inactivation kinetics. The scale factor for PPO was 15.95, 10.87, and 5.73 min at 25, 35, and 45 kV, respectively which was lower than POD with scale factor 40.74, 19.76, and 7.28, respectively. This shows that POD was more resistant to inactivation by DBD plasma than PPO.

Thermal inactivation kinetics parameters of browning enzymes in starfruit (Averrhoa carambola L.) juice

SummaryThis study aimed to evaluate the thermal inactivation kinetics of polyphenol oxidase (PPO) and peroxidase (POD) in starfruit juice. It followed the Malaysia Food Regulations 1985 and CODEX STAN 247‐2005. Glucose, fructose and sucrose were the main sugars in starfruit juice. The total soluble solids, pH, titratable acidity, and total phenolics content of the starfruit juice produced were 8.13 ± 0.25 °Brix, 3.80 ± 0.05, 0.43% ± 0.02% malic acid, and 93.67 ± 4.96 mg GAEL−1, respectively. Thermal inactivation kinetics of PPO and POD followed the first‐order kinetic model. The decimal reduction time at 83.6 °C (D83.6) of PPO and POD was 198.48 and 98.4 s, respectively, while the thermal resistance constant (z value) of PPO and POD was 12.8 and 5.4 °C, respectively. In conclusion, PPO might be a suitable signal for thermal processing on starfruit juice since it has higher heat resistance than POD.

Composition, physicochemical properties, and thermal inactivation kinetics of polyphenol oxidase from wax apple (Syzgium samarangense) juice

Thermal treatment can reduce the microbial load and enzymatic activity, which is important to produce a safe and good quality product in the fruit juice industry. Hence, it is crucial to determine suitable thermal processing condition parameters based on the composition and thermal properties of enzymes present in fruit juice to avoid over-processing. The aim of this work was to determine the enzymatic inactivation kinetics of wax apple to obtain useful information for production of ready-to-drink wax apple juice. The wax apple juice prepared in the present study complied with Malaysia Food Regulations 1985 Regulation 235. The main sugars present in the wax apple juice are fructose and glucose, and traces of sucrose. High content of potassium was detected in the wax apple juice. In addition, wax apple juice contains a considerable amount of phenolic compounds. The thermal inactivation kinetics of polyphenol oxidase (PPO) followed the first order kinetic model. The activation energy, enthalpy changes, D88.4 °C, and z value of PPO obtained were 75.93 kJ/mol, 62.14 kJ/mol, 5.89 min, and 36.9 °C, respectively. In conclusion, the results evidenced that PPO which is more heat resistant than peroxidase, is a better enzyme inactivation indicator for the thermal treatment of wax apple juice. Therefore, PPO could be used as a heat treatment index for thermal processing that would be useful in designing thermal process for manufacturing of ready-to-drink wax apple juice.

Mild‐thermal and high pressure processing inactivation kinetics of polyphenol oxidase from peach puree

AbstractThis study has investigated the inactivation of polyphenoloxidase (PPO) in peach puree during thermal (50–60 °C, 2–30 min) and combined high pressure‐mild thermal treatment (HPMT) (200–600 MPa, 25–45 °C, and 2–23 min). HPMT resulted immediately after treatment in an increase in PPO activity up to 66.50% at 200 MPa and 45 °C compared with the untreated samples. The reaction order (nth) of PPO thermal inactivation was 1.951 (0.1 MPa, 50–60 °C) and 0.953 for the HPMT treatment (200–600 MPa, 25–45 °C). Fractional kinetic models were applied in PPO thermal (~89% labile fraction, 11% stabile fraction) and HPMT inactivation (up to ~67% stabile fraction at 200 MPa, 25 °C). The activation energy estimated for the thermal inactivation in 50–60 °C range at 0.1 MPa was 148.26 kJ/mol, while for the HPMT inactivation varied from 82.31 kJ/mol at 300 MPa to 226.16 kJ/mol at 500 MPa. A third order polynomial model described the PPO inactivation by HPMT.Practical applicationInactivation of polyphenoloxidase (PPO), enzyme responsible for browning is a mandatory condition for maintaining quality of the processed fruits. As this enzyme is generally known to display variable thermal and/or barostability, depending on the type of food matrix, kinetic data are required to optimize the processing parameters. The data on peach puree PPO and the models provided in the current study could help producers to identify the optimum peach processing condition necessary for the inactivation of PPO by high pressure‐mild thermal treatment, leading to the extension of puree shelf life. However, methods for limitation of the oxygen presence in the peach puree mixtures should also be employed during processing and storage.

Inactivation of peroxidase and polyphenoloxidase in coconut water using pressure-assisted thermal processing

Abstract The effect of pressure assisted thermal processing (PATP) was evaluated on the inactivation kinetics of polyphenol oxidase (PPO) and peroxidase (POD) and selected quality attributes of coconut water. Coconut water from green young coconuts was treated at 200, 400 and 600 MPa, 40–90 °C, and 60–1800 s of holding time. The activities of PPO and POD were determined using spectrophotometric methods. No enzymatic activity was detected for both enzymes within 300 s at 90 °C/400–600 MPa. The combination of 400 MPa/90 °C/300 s yielded POD and PPO inactivation, and could be used in the industrial development of PATP treated-coconut water. The POD showed to be more pressure-temperature resistant than the PPO in coconut water. The pressure-temperature inactivation kinetics of PPO and POD in coconut water were well described by the Weibull model. The activation energy for the inactivation of POD and PPO were 107–192 and 41–191 kJ mol−1, respectively, while the activation volume varied from −13.2 to 10.2 and −37 to 9.2 cm3 mol−1, respectively. Total phenolic content extractability significantly increased after PATP treatments at all conditions evaluated compared to the control. Low ∆E values of PATP treated coconut water were obtained, indicating imperceptible change of color. Industrial relevance Pressure Assisted Thermal Processing (PATP) is an emerging technology that requires further research. The results of this study highlighted for the first time the potential of PATP on polyphenoloxidase and peroxidase inactivation of coconut water, maintaining color characteristics of coconut water. The pink color after PATP treatment was not observed. In addition, the use of kinetic models helped to determine the optimal conditions for enzyme inactivation. The outcomes of this study can be used for further industrial development of PATP treated-coconut water.

The inactivation kinetics of polyphenol oxidase and peroxidase in bayberry juice during thermal and ultrasound treatments

Abstract Ultrasound is recognized as a non-conventional processing technology for food preservation and quality improvement. Effects of thermal and ultrasound treatment on the inactivation kinetics of polyphenol oxidase (PPO) and peroxidase (POD) in bayberry juice were studied. Whether cooling with ice bath during ultrasound treatment was conducted to separate effects of heat and cavitation effects. In all processes, the inactivation kinetics of PPO and POD followed a first-order model (R2 = 0.864–0.997).The DT value during thermal inactivation varied from 151.99 to 6.23 min for PPO and the corresponding ZT values and activation energy (Ea) were 13.16 °C and 166.77 kJ/mol, while those parameters of POD were 298.26–7.08 min, 14.25 °C and 153.49 kJ/mol, respectively. The ultrasound (US) inactivation rate constants (k) for PPO ranged from 0.0556 min− 1 to 0.8878 min− 1 with the corresponding D values of 41.44–2.59 min and ZUI values of 312.50 W/cm2. However, the k value of PPO during ultrasound with cooling (USC) decreased to 0.0412–0.3268 min− 1, while the D and ZUI values increased to 55.92–7.05 min and 432.90 W/cm2, indicating that the heat brought out during ultrasound treatment significantly enhanced the inactivation kinetics of PPO. The inactivation rates of POD by US treatment were also higher than those by USC at the same ultrasound intensity and time. In addition, the kinetic parameters for POD by US and USC treatment were lower than those of PPO, inferring its more sonication resistant. Industrial relevance Ultrasound is a non-thermal food processing method for microorganism and enzyme inactivation, as well as quality maintenance. Attractive color is one of the most important quality attribute of bayberry products and strongly affects the consumer acceptance and preference. A key role in color degradation in berry fruit products is attributed to enzymatic browning of phenolic compounds which mainly related to PPO and POD. Therefore, the inactivation of PPO and POD is necessary for better color retention and shelf life increasing. This study would provide technical support for PPO and POD inactivation of ultrasound technique in bayberry juices processing.

Kinetic modeling of polyphenoloxidase inactivation during thermal-assisted high pressure processing in black tiger shrimp (Penaeus monodon)

High pressure inactivation kinetics of polyphenol oxidase (PPO) was studied in black tiger shrimp (Penaeus monodon), with the applied processing parameters ranging from 300 to 600 MPa, 30–60 °C and 0–15 min for pressure, temperature and holding time, respectively. The inactivation kinetics was demonstrated with pressure pulse effect followed by static pressure-hold period. A synergistic effect of pressure and temperature was noted on inactivation rate of PPO. Enzyme inactivation kinetics followed a 0.97 order reaction within the range of experimental domain. The activation energy (Ea) and the activation volume (Va) values computed to describe the temperature and pressure dependence of inactivation rate constant (k, min−1), decreased with increase in pressure and temperature, respectively. An empirical model was proposed taking into account the pressure and temperature dependence of Ea and Va, to describe the inactivation rate of PPO as a function of pressure and temperature. A good correlation was established between experimental and predicted values of k.

Kinetic modelling of polyphenol oxidase, peroxidase, pectin esterase, polygalacturonase, degradation of the main pigments and polyphenols in beetroot juice during high pressure carbon dioxide treatment

Supercritical carbon dioxide (SCCD) was applied for the inactivation of tissue enzymes in beetroot juice. The SCCD process parameters had a significant effect on the inactivation kinetics of polyphenol oxidase (PPO), peroxidase (POD), pectin esterase (PE) and polygalacturonase (PG). The use of traditional pasteurization (TP) resulted in a higher level of inactivation of the tested enzymes than SCCD. The lowest decimal reduction time was noted for PG and the highest for POD. The PG, PE, PPO and POD inactivation kinetic constants were calculated as 0.90, 0.85, 0.82 and 0.6 × 10−2 min−1 for k-values and 256, 271, 281 and 384 min for D-values, respectively, based on the first order kinetic model. The highest degradation of bethacyanins, bethaxanthins and polyphenols occurred at 60 MPa at 55 °C, for 30 min: 58, 32 and 30%, respectively. Overall, SCCD treatment is a promising technique to obtain high quality non-acidified beetroot juice but further studies should concentrate on additional factors affecting the inactivation of tissue enzymes.

In-vitro assay and inactivation kinetics of polyphenol oxidase of some Nigerian banana and plantain cultivars

Activity of polyphenol oxidase (PPO) from the pulp of three banana cultivars grown in Nigeria, namely: plantain, light green-skinned banana and red-skinned banana at unripe and ripe states were investigated. The efficiency of extraction of crude PPO enzyme and in-vitro assay of its activity were determined. Polyethylene glycol detergent gave the highest extraction efficiency. Enzyme activity and rate of browning were found to be highest in plantain and least in light green-skinned banana. Enzymes from all the cultivars were specific towards O-diphenolic compounds and not to monophenolics. The optima pH of PPO of the cultivars tends towards neutrality (6.6-7.0). Enzyme activity was destroyed between 2 and 4 min at 80°C. Thermal inactivation kinetic parameters revealed plantain's PPO to be the most thermal stable. Sodium metabisulphite was the most effective chemical inhibitor of the PPO. The electrophoretic patterns of banana PPO showed heterogeneity with greater number of bands in ripe.

In-vitro assay and inactivation kinetics of polyphenol oxidase of some Nigerian banana and plantain cultivars

Activity of polyphenol oxidase (PPO) from the pulp of three banana cultivars grown in Nigeria, namely: plantain, light green-skinned banana and red-skinned banana at unripe and ripe states were investigated. The efficiency of extraction of crude PPO enzyme and in-vitro assay of its activity were determined. Polyethylene glycol detergent gave the highest extraction efficiency. Enzyme activity and rate of browning were found to be highest in plantain and least in light green-skinned banana. Enzymes from all the cultivars were specific towards O-diphenolic compounds and not to monophenolics. The optima pH of PPO of the cultivars tends towards neutrality (6.6-7.0). Enzyme activity was destroyed between 2 and 4 min at 80°C. Thermal inactivation kinetic parameters revealed plantain's PPO to be the most thermal stable. Sodium metabisulphite was the most effective chemical inhibitor of the PPO. The electrophoretic patterns of banana PPO showed heterogeneity with greater number of bands in ripe.

Inactivation Kinetics of Polyphenol Oxidase in an Aqueous Model System under Stand-Alone and Combined Ultrasound and Ultraviolet Treatments

The objectives of this work were to study the ultrasound- and ultraviolet light-induced inactivation kinetics of polyphenol oxidase extracted from different sources in a model system. The polyphenol oxidase crude extract was obtained from bananas, apples, quince, eggplants, plums, dill, and cultured mushrooms, which exhibited high enzyme activity. The polyphenol oxidase crude extract was treated with ultrasound and ultraviolet light at 40°C temperature for 40 min. The study showed that the polyphenol oxidase enzyme was inactivated between 12 and 100% during ultrasound only treatment; between 4 and 29% during ultraviolet light only treatment; and between 80 and 100% during simultaneous ultrasound and ultraviolet light treatment. Based on the measurements, an exponential decay model for determining polyphenol oxidase inactivation kinetics was developed. The model provides high determination coefficients (R2): 0.968–0.999 with ultrasound only treatment, 0.881–0.990 with ultraviolet only treatment, and 0.975–1.000 with simultaneous ultrasound and ultraviolet treatment. The polyphenol oxidase kinetics evaluation showed that different treatments provided different inactivation times, or D-values. The D-values were 7.0–656.1 min for ultrasound only treatment (DUS), 251–1887 min for ultraviolet only treatment (DUV), and 3.3–59.4 min for combined ultrasound and ultraviolet treatment (DUS+UV).

Composition, physicochemical properties and thermal inactivation kinetics of polyphenol oxidase and peroxidase from coconut (Cocos nucifera) water obtained from immature, mature and overly-mature coconut

Composition, physicochemical properties and enzyme inactivation kinetics of coconut water were compared between immature (IMC), mature (MC) and overly-mature coconuts (OMC). Among the samples studied, pH, turbidity and mineral contents for OMC water was the highest, whereas water volume, titratable acidity, total soluble solids and total phenolics content for OMC water were the lowest. Maturity was found to affect sugar contents. Sucrose content was found to increase with maturity, and the reverse trend was observed for fructose and glucose. Enzyme activity assessment showed that polyphenol oxidase (PPO) in all samples was more heat resistant than peroxidase (POD). Compared to IMC and MC, PPO and POD from OMC water showed the lowest thermal resistance, with D83.3°C=243.9s (z=27.9°C), and D83.3°C=129.9s (z=19.5°C), respectively.

The inactivation kinetics of polyphenol oxidase in mushroom (Agaricus bisporus) during thermal and thermosonic treatments

The effect of thermal and thermosonic treatments on the inactivation kinetics of polyphenol oxidase (PPO) in mushroom (Agaricus bisporus) was studied in 55–75°C temperature range. In both the processes, the inactivation kinetics of PPO followed a first-order kinetics (R2=0.941–0.989). The D values during thermal inactivation varied from 112±8.4min to 1.2±0.07min while they varied from 57.8±6.1min to 0.88±0.05min during thermosonic inactivation at the same temperature range. The activation energy during thermal inactivation was found to be 214±17kJ/mol, while it was 183±32kJ/mol during thermosonic inactivation. The inactivating effect of combined ultrasound and heat was found to synergistically enhance the inactivation kinetics of PPO. The D values of PPO decreased by 1.3–3 times during thermosonic inactivation compared to the D values of PPO during thermal inactivation at the temperature range. Therefore, thermosonication can be further developed as an alternative to “hot break” process of mushroom.

Inactivation kinetics of polyphenol oxidase using a two-stage method with low pressurized carbon dioxide microbubbles

Inactivation kinetics of polyphenol oxidase (PPO) by a two-stage method which was additionally pressurized at ambient temperature after carbon dioxide microbubbles (MB-CO2) was mixed with a solution at low temperature and pressure (two-stage MB-CO2) was analyzed. The PPO inactivation efficiency of the two-stage MB-CO2 treatment was higher than that of heat treatment. A decrease in the decimal reduction time (D value) and activation energy during PPO inactivation using the two-stage MB-CO2 treatment was observed as the temperature of the heating coil and the pressure in the mixing vessel increased. The temperature rise required for a 90% reduction in the D value was increased. Furthermore, the pressure rise required for a 90% reduction in the D value and activation volume increased with the temperature of the heating coil. These results showed that PPO inactivation using the two-stage MB-CO2 treatment could be achieved with less energy than heat treatment.

High pressure and thermal inactivation kinetics of polyphenol oxidase and peroxidase in strawberry puree

The objective of this work was to study the thermal and high pressure inactivation kinetics of polyphenol oxidase (PPO) and peroxidase (POD) in strawberry puree. PPO from two strawberry cultivars (‘Festival’ and ‘Aroma’) was found to be highly thermostable in strawberry puree with no significant inactivation even after 30 min treatment at 100 °C. In contrast, POD from the two cultivars displayed very high thermosensitivity with complete inactivation in less than 5 min at 70 °C. The thermal inactivation kinetics of strawberry POD was described by a biphasic model. The activation energies for the inactivation of the stable and the labile fractions were estimated to be 254.9 and 221.6 kJ/mol respectively. Combined high pressure–thermal treatment at pressures ranging from 100 to 690 MPa, temperatures ranging from 24 to 90 °C and treatment times between 5 and 15 min did not have significant effect on PPO while substantial inactivation of POD was observed. The inactivation kinetics of POD during combined high pressure–thermal processing was well described by first-order kinetics probably due to the inactivation of the labile fraction during the pre-heating and the compression phase. The oxidative enzymes polyphenol oxidase and peroxidase cause the degradation of anthocyanins and other polyphenols in strawberry products, leading to discoloration and loss of antioxidant activity. In this work the thermal and high pressure inactivation of strawberry polyphenol oxidase and peroxidase was investigated so as to assess the suitability of high pressure processing as an alternative to thermal processing. Strawberry polyphenol oxidase was found to be highly resistant to both thermal and high pressure inactivation. Thus in order to maintain the quality of processed strawberry products, high pressure processing should be accompanied by additional measures such as exclusion of oxygen, refrigerated storage and the use of natural enzyme inhibitors.