Table 1.

Advanced electrothermal treatment techniques used in the food industry

Advanced techniques	Technology involved	Application in food materials		References
		Sample(s) analyzed	Conclusions
Electroplasmolysis	Involves effective destruction of cell membrane matrix of different food materials with help of high electric current Helpful in increasing the efficiency of extraction	Apple, cucumber, pear, carrot, banana (Pear, banana: 900–1100 V/cm Apple, cucumber, carrot: 200–400 V/cm)	Electric field strength depends on the type of tissue (Disintegration index < 0.5) Electric field higher for cells having secondary cell wall	Bazhal et al. (2003)
		Tomato Range of field strength test: 36–108 V/cm Treatment time: 5– 30 s	Enzyme inactivation of pectin methyl esterase and Aspergillus niger decreased with increased in treatment time at 108 V/cm Highest amount of pectin obtained was 3.56% at 36 V/cm for 80 s	Yildiz and Baysal( 2006)
Microwave heating (post-pasteurization)	Involves absorption of electromagnetic energy leading to a temperature increase of the food (due to high dielectric capacity) thus improving the product quality Microwave heating is greatly influenced by shape, size, food matrix and equipment	Gurum (Citrulluslanatus var. Colocynthoide) Microwave power: 800 W Time: 6 min Frequency:2450 MHz	Increase in oil extraction yield from 27.6% to 35.4% Acid value increase from 0.68 mg to 0.95 mg KOH/g of oil Increase in polyphenol content from 22.6 to 25.3 mg Gallic acid equivalent (GAE)/kg oil Increase in antioxidant activity from 59.2–64.7%	Karrar et al. (2020)
		Saffron Temperature:45–125 °C Time:10–30 min Solvent concentration: Ethanol (0–100 v/v %)	Process conditions of 95.15 °C, 30 min and ethanol concentration of 59.5% was considered optimum for microwave heating	Sarfarazi et al. (2020)
		Apple juice Power: 270–900 W Frequency:2450 MHz Treatment time: 83 °C for 30 s	Reduction in microbes (E coli) post-microwave treatments Treatment between 720–900 W for 60–90 s showed 2 to 4 log population reduction in microbes	Cañumir et al. (2002)
Ohmic heating	Involves heating of the food by the passage of electric current. The food product acts as an electric resistance thus heating the whole matrix Higher the voltage applied, better the more the heat generated	Orange juice Temperature: 40–95 °C Time: 60 s	Comparison between conventional thermal heating and ohmic heating showed changes in the antioxidant activity (ascorbic acid) 7% decrease observed at 42 V/cm, 69 °C 11% decrease observed at 44 V/cm, 70 °C	Demirdöven and Baysal (2014); Salari and Jafari (2020)
		Tomato juice Conventional heating: 75–300 s Ohmic heating: 15–60 s	Lycopene presence observation and detection and comparison between conventional and ohmic heating Conventional: 20.5–23.3% increase observed Ohmic heating: 21.3–23.6%	Makroo et al. (2020); Salari and Jafari (2020)
		Orange juice Hot water treatment: 90 °C, 15–60 s Ohmic treatment: 90 °C, 15–60 s	Cartenoids detection Hot water: 2.3–3.9% decrease in carotenoids Ohmic heating: 1.6–4.27% decrease in cartenoids	Funcia et al. (2020); Makroo et al. (2020)