Stability and structural changes of horseradish peroxidase: Microwave versus conventional heating treatment

Lopes, Lucas Costa; Barreto, Maria T.M.; Gonçalves, Karen M.; Álvarez, Heiddy M.; Heredia, Montserrat Fortuny; Souza, Rodrigo O. M. A. de; Cordeiro, Yraima; Dariva, Cláudio; Fricks, Alini Tinoco

doi:10.1016/j.enzmictec.2014.11.002

Cited by 65 publications

(47 citation statements)

References 37 publications

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“…Numerous reports agreed that thermal processing caused redisposition of secondary structure of PPO enzymes (Lopes et al, 2015 ) discovered that heat processing alters secondary configuration with a partial decrease of α-helix content of horseradish peroxidase. The α-helix contents 35.3 and 35.7% of PPO by CD analysis, respectively (Yi et al, 2012 ; Liu et al, 2013 ).…”

Section: Resultsmentioning

confidence: 98%

Aggregation and Conformational Changes in Native and Thermally Treated Polyphenol Oxidase From Apple Juice (Malus domestica)

et al. 2018

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This study investigated the effects of heat treatment after purification on dissociation, aggregation, and structural modification of polyphenol oxidase (PPO) activity from apple (Malus domestica) juice. PPO activity at the 70°C for 10 min was still activated and drastically decreased since 20–60 min with catechol and pyrogallol as substrate. Moreover, spectral results of fluorescence and circular dichroism (CD) indicated that increasing temperature for shorter and longer durations can cause reorganization of the secondary structure of PPO and demolished the native configuration of PPO respectively. Compared with native PPO, all thermally treated PPO showed reduced activity with gradually increasing particle size shift toward section III of some fully assembled proteins treated at 70°C for 10 min (2,670 nm). Polyacrylamide gel electrophoresis (PAGE) analysis also exhibited the increase in protein content at the 70°C for 10 min with molecular size 35 kDa (7.7 ± 0.016c). Hence, thermally treated juice subjected to purification at high temperature for a short time could induce the aggregation of protein and is not really effective for PPO inactivation. For PPO, higher degree of long duration can induce the inactivation of the enzyme after processing.

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Section: Resultsmentioning

confidence: 98%

Aggregation and Conformational Changes in Native and Thermally Treated Polyphenol Oxidase From Apple Juice (Malus domestica)

et al. 2018

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“…Lopes et al () also observed horseradish peroxidase (HRP) activation in buffer solution (0.1 M Na 2 HPO 4 .2H 2 O, pH 6.0) conventionally heated at 30–60°C for 48 hr. The results indicated that incubation of HRP between 30 and 45°C (maximal enzyme activation) may modify the HRP secondary structure, promoting better access of the substrate to the active site region, increasing the enzyme activation (Kelly & Price, ).…”

Section: Resultsmentioning

confidence: 99%

“…Analyzing point‐by‐point, the 10 Hz treatment differed from the others ( p < .05) in almost all time intervals, suggesting that POD activity is stimulated at low frequency. At low frequencies, electrochemical reactions, such as electrolysis of water and electrode corrosion (Mercali, Schwartz, Marczak, Tessaro, & Sastry, ), may happen, releasing in the medium compounds that could interact with some residues of the enzyme; this may change the conformational structure of its active site to more nonpolar regions, leading to a conformation in which the active site is more protected, thus promoting the activation of the enzyme (Lopes et al, ). Moreover, POD is a metal‐containing enzyme, and the electric field may affect the interaction between the metal in their prosthetic center and the protein structure.…”

Section: Resultsmentioning

confidence: 99%

“…The CIELAB parameters, L* (lightness or brightness/darkness), a* (redness), and b* (yellowness), were obtained with the light source D65 and an observation angle of 10°, using the reflectance specular included mode. happen, releasing in the medium compounds that could interact with some residues of the enzyme; this may change the conformational structure of its active site to more nonpolar regions, leading to a conformation in which the active site is more protected, thus promoting F I G U R E 2 Temperature profile of sugarcane juice during conventional and ohmic heating experiments with frequencies varying from 10 to 10 5 Hz F I G U R E 3 Experimental POD residual activity values for sugarcane juice during CH and OH at 60°C: different (a) electric field frequencies and (b) voltage gradients the activation of the enzyme (Lopes et al, 2015). Moreover, POD is a metal-containing enzyme, and the electric field may affect the interaction between the metal in their prosthetic center and the protein structure.…”

Section: Color Measurementmentioning

confidence: 99%

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Effect of moderate electric field on peroxidase activity, phenolic compounds and color during ohmic heating of sugarcane juice

Brochier

Mercali

Marczak

2019

J Food Process Preserv

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The influence of moderate electric field was evaluated during thermal treatment of sugarcane juice. Conventional and ohmic heating (OH) experiments at temperatures of 60 and 80°C were conducted to investigate the effect of frequency (0–105 Hz), waveform (sine, square, and triangle) and voltage gradient (0–16.7 V/cm) on inactivation of peroxidase (POD), phenolic compounds stability and color changes. Enzyme activity was significantly (p < .05) affected by OH; the nonthermal effects promoted POD activation at 60°C (mainly at 10 Hz) and inactivation at 80°C (mainly at 100 kHz). It was not found variation of phenolic compounds with the different operational conditions applied. Moreover, the color of the juice was modified using low frequency (possibly due to electrochemical reactions) and different waveforms. Overall, OH is suitable for POD inactivation at 80°C with the usual process parameters (sine wave and 60 Hz) or higher frequencies. Practical applications Sugarcane juice is a popular energy drink, nonalcoholic, with sweet and pleasant taste. It is commercialized predominantly in the informal marketplace because its processing and marketing are limited due to its rapid deterioration. The objective of this work is to provide an alternative technology for sugarcane juice processing, ensuring safety, and lower impact on nutritional compounds, allowing its commercialization in formal markets. Ohmic heating (OH) is a faster heating technology, appropriate for pasteurization of heat‐sensitive products. The study of the effect of the process variables (temperatures, electric field frequency, waveform, and electric field strength) on enzyme inactivation, degradation of total phenolic compounds, and color stability is important to support modeling and optimization, making OH a viable technology for sugarcane juice pasteurization.

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“…Microwave heating can result in localized high-temperature regions, even though the bulk temperature is maintained low by convective airflow. There are many reports indicating that the heat generated by microwave can inactivate both PPO and POD (Chávez-Reyes, Dorantes-Alvarez, Arrieta-Baez, Osorio-Esquivel, & Ortiz-Moreno, 2013;Latorre, Bonelli, Rojas, & Gerschenson, 2012;Lopes et al, 2015;Matsui, Gut, de Oliveira, & Tadini, 2008;Siguemoto, Pereira, & Gut, 2018). Chávez-Reyes et al (2013) found that PPO in the mesocarp of the loquat fruit was inactivated after 210 s of 478 W microwave exposure.…”

Section: Degradation Kinetics Of Phenolic Compoundsmentioning

confidence: 99%

Kinetics of nutrient change and color retention during low‐temperature microwave‐assisted drying of bitter melon ( Momordica charantia L.)

Nguyen

Luu

et al. 2019

J Food Process Preserv

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The changes in nutrient (phenolics and vitamin C) and color of bitter melon slices, during microwave‐assisted drying (MWAD) at different microwave power values (1.5, 3.0, and 4.5 W/g) and air temperatures (20, 25, and 30°C) are reported. Fits of the experimental data to a semi‐empirical mathematical model were used to determine the half‐lives of the nutrients. Color change during drying was similarly characterized using CIELAB color space parameters. The rates of nutrient degradation and color change increased with an increase in microwave power, and drying temperature, but the drying times decreased significantly. The total electrical energy consumed under various drying conditions was measured. Although a microwave power of 1.5 W/g and an air temperature of 25°C resulted in the highest levels of nutrient retention, the drying time and process energy consumption were relatively high. In comparison, the drying conditions of 4.5 W/g and 30°C provided an acceptable compromise. Practical applications Low‐temperature MWAD is a promising alternative to conventional drying for food that contains temperature‐sensitive nutrients. This article provides a methodology for analyzing the kinetics of nutrient and color change during a MWAD process. A 32 factorial design was used to derive predictive correlations for drying time, nutrient half‐life, time constants characterizing color change, and electrical energy consumed during the drying process. The relative influences of microwave power and drying temperature could be readily discerned using these correlations. The reported study will help in developing and optimizing microwave drying processes for a variety of food products.

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Stability and structural changes of horseradish peroxidase: Microwave versus conventional heating treatment

Cited by 65 publications

References 37 publications

Aggregation and Conformational Changes in Native and Thermally Treated Polyphenol Oxidase From Apple Juice (Malus domestica)

Aggregation and Conformational Changes in Native and Thermally Treated Polyphenol Oxidase From Apple Juice (Malus domestica)

Effect of moderate electric field on peroxidase activity, phenolic compounds and color during ohmic heating of sugarcane juice

Kinetics of nutrient change and color retention during low‐temperature microwave‐assisted drying of bitter melon ( Momordica charantia L.)

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