# Ohmic Heating in the Food Industry: Developments in Concepts and Applications during 2013-2020
## 10 Effect of Ohmic Heating on Inactivation of Enzymes in Food
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**Foods** & **Condition** & **Effects On Bioactive Compounds Content, Phenolic Content, and Antioxidant Activity** & **References** \\ \hline Chinese Chives & 11.5 V/cm,100 \({}^{\circ}\)C and followed by 5.3 V/cm, 45 min & Reduced extraction time from 3 h to 45 min (75\% reduction) compared to Hydrodistillation method. In addition, there was no significant difference in antioxidant activities of the extracts compared to Hydrodistillation method. & [91] \\ \hline Blue-berry flavored dairy deserts & (1.82, 3.64, 5.45, 7.30, 9.1)V/cm, 90 \({}^{\circ}\)C, 3 min & 1.82 V/cm of electrical field intensity contributed to better preservation of bioactive compounds (phenolic compounds, anthocyanins) and increased antioxidant ability. & [92] \\ \hline Black rice bran & 50, 100, 150, and 200 V/cm,105 \({}^{\circ}\)C, 3 min & A higher yield of bioactive and anthocyanin contents using ohmic heating compared to the steam-assisted solvent extraction methods. & [93] \\ \hline Banana pulp & 13.33, 20 and 26.66 V/cm, 100 \({}^{\circ}\)C, 210 s & A decrease in ascorbic acid content was observed with an increase in voltage gradient. & [94] \\ \hline Aloe vera gel juice & 30, 35, 45 and 55 V/cm at 60 Hz, 20 to 85 \({}^{\circ}\)C & Vitamin C was decreased during ohmic heating more compared to conventional heating, while total phenolic content was increased more significantly compared to conventional pasteurization. & [95] \\ \hline Tomato by-products & 4, 6 and 11 V/cm, 0–100 \({}^{\circ}\)C for 30 min & An improvement in the process of extracting polyphenols using ohmic heating by 77\% compared to the control sample treated by the conventional method, extracting lycopene by 4.93 g/g FWfrom the byproducts of tomato without using organic solvents & [33] \\ \hline Acerola pulp & 30 V, 60 Hz; 80, 85, 90, and 95 \({}^{\circ}\)C for 60 min, under oxygen atmosphere & The electric field did not affect the degradation rates of both ascorbic acid and carotenoid during ohmic heating. The results also reported high rate of both ascorbic acid and carotenoid degradation when the initial oxygen concentration is & [96] \\ \hline Apple juice & 30, 35 and 40 V/cm, 60 Hz frequency; 60, 70 and 80 \({}^{\circ}\)C & The total extracted phenolic content was increased by 5.4\% with ohmic heating and 2.5\% with conventional method compared to fresh apple juice. The loss of ascorbic acid and carotenoids contents of ohmic treated sample was less than the conventional treated sample. & [97] \\ \hline \hline \end{tabular}
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Table 4: The effects of ohmic heating on bioactive compounds content, phenolic content, and antioxidant activity. [PERSON] et al. [107] found that the treatment of tomato juice using ohmic heating for 1 min at 90 \({}^{\circ}\)C was sufficient to inhibit the pectin enzyme methyl esterase and polygalactur-onase, while conventional treatment at the same temperature required 5 min to obtain the same inhibition of enzymes. [PERSON] et al. [108] studied the effect of ohmic heating on the activity of the urease in soymilk at an electrical field of 160-220 V and a frequency of 10-10 kHz. The study showed that the electric field was able to inhibit the enzyme activity. [PERSON] et al. [35] inhibited the enzymes polyphenoxidase, galactosidase-ox, lipoxygenase, pectinase, and alkaline phosphatase by using ohmic heating and conventional method under the same conditions. Polyphenoloxidase and lipoxygenase significantly decreased the electric field, reducing the time required for inhibition. The results showed that the electric field was able to inhibit phosphatase, alkaline phosphatase, and galactosidase-\(\beta\). While both polyphenoxidase and lipoxygenase were affected significantly by using ohmic heating compared to the conventional method regarding the required time for inactivation [35]. [PERSON] et al.