Graphical representation regarding sources, extraction techniques and nutraceutical perspectives of eugenol.

It is shown how the various components of the overpotential due to an attached bubble on an electrode can be separated and estimated. By considering the resistance increments due to the presence on the electrode surface of a bubble, obtained from impedance measurements, it is possible to determine the predominant potential distribution which controls the gas evolution. A relationship between the measured overpotential and the diameter of the bubble is established. The time evolution of the overpotential due to a growing bubble is modelled in the case of the limitation of the bubble growth by dissolved gas diffusion in the solution. In agreement with previous experimental results a linear time variation is found.

The combined effect of ultrasound (US) and pulsed electric field (PEF) was investigated on microbial load and bioactive compounds of grapefruit juice. Grapefruit juice was PEF treated (flow rate: 80 ml/min, pulse frequency: 1 kHz, 20 kVcm−1 electric field strength, temperature: 40 °C, time: 600 μs) followed by US treatment in an ultrasonic bath cleaner radiating 600 W at frequency of 28 KHz and 20 °C for 30 min. PEF and US treatment resulted in a significant reduction in microbial load as compared to the control group. Using combined (PEF + US) treatment, carotenoids, lycopene, anthocyanin contents, and total antioxidant activity were increased from 0.84 μg/ml, 0.32 μg/ml, 1.37 mg/L, and 177.48 ascorbic acid equivalent µg/g (control) to 1.26 μg/ml, 0.92 μg/ml, 1.68 mg/L, and 262.32 ascorbic acid equivalent µg/g, respectively. The findings demonstrated that PEF + US could be successfully used for preserving bioactive compounds in grapefruit juice while improving the microbial quality for a better shelf‐life. Practical applications In recent years, nonthermal techniques, such as sonication and PEF or combination of these are used for the inactivation of microorganism and preserving the bioactive compounds of different juices. The results of the present study revealed that combined treatment (PEF + US) could improve the antioxidant activity, total phenolics, flavonols, flavonoids, lycopene, and total carotenoids. The findings of this study suggested that PEF + US has a potential to improve the quality of grapefruit juice and may be employed for the processing of grapefruit juice at industrial scale.