Dielectric properties of green coconut water relevant to microwave processing: Effect of temperature and field frequency

Dielectric properties of zinc sulfide concentrate during the roasting at microwave frequencies

“…The dielectric loss factor at 915 MHz from Figure 3b is smaller than that at 2450 MHz from Figure 3d when the temperature under 400 °C, but reverse results when the temperature above 400 °C. It can be concluded that dipolar rotation is the main contribution to the loss factor when temperature under 400 °C, while ionic conduction contributes mainly to the loss factor when temperature above 400 °C because thermal agitation disturbs the alignment of the molecule dipole with the electric field and conduction increases as the temperature increases, similar results have also been reported by some literature [22,23]. In addition, the dielectric loss factor of apparent density of 1.63 g/cm 3 is mostly larger than that of 1.54 g/cm 3 for the same temperature.…”

“…Lastly drop sharply to an almost stable value, which means main reaction have finished by compared with the dielectric properties of zinc oxide we have measured. The dielectric loss factor is the function of frequency because of dipolar rotation and ionic conduction, and ionic conduction is the dominant mechanism at lower frequencies while dipolar rotation is the main source of dielectric loss at higher microwave frequencies [21,22], as shown in the following equation:…”

Dielectric Properties of Zinc Sulfide Concentrate during the Roasting at Microwave Frequencies

“…Later increases sharply from 400 to about 800 • C, it can be concluded that the oxidation reaction of zinc sulfide proceed gradually according to the temperature condition of zinc sulfide oxidation reaction [19,20], and there is a main phase transformation in this temperature range as well, Figure 2 also can prove that there are some reactions from 400 to about 800 • C. Lastly drop sharply to an almost stable value, which means main reaction have finished by compared with the dielectric properties of zinc oxide we have measured. The dielectric loss factor is the function of frequency because of dipolar rotation and ionic conduction, and ionic conduction is the dominant mechanism at lower frequencies while dipolar rotation is the main source of dielectric loss at higher microwave frequencies [21,22], as shown in the following equation: The dielectric loss factor at 915 MHz from Figure 3b is smaller than that at 2450 MHz from Figure 3d when the temperature under 400 °C, but reverse results when the temperature above 400 °C. It can be concluded that dipolar rotation is the main contribution to the loss factor when temperature under 400 °C, while ionic conduction contributes mainly to the loss factor when temperature above 400 °C because thermal agitation disturbs the alignment of the molecule dipole with the electric field and conduction increases as the temperature increases, similar results have also been reported by some literature [22,23].…”

“…The dielectric loss factor is the function of frequency because of dipolar rotation and ionic conduction, and ionic conduction is the dominant mechanism at lower frequencies while dipolar rotation is the main source of dielectric loss at higher microwave frequencies [21,22], as shown in the following equation: The dielectric loss factor at 915 MHz from Figure 3b is smaller than that at 2450 MHz from Figure 3d when the temperature under 400 °C, but reverse results when the temperature above 400 °C. It can be concluded that dipolar rotation is the main contribution to the loss factor when temperature under 400 °C, while ionic conduction contributes mainly to the loss factor when temperature above 400 °C because thermal agitation disturbs the alignment of the molecule dipole with the electric field and conduction increases as the temperature increases, similar results have also been reported by some literature [22,23]. In addition, the dielectric loss factor of apparent density of 1.63 g/cm 3 is mostly larger than that of 1.54 g/cm 3 for the same temperature.…”

Dielectric Properties of Beverages (Tamarind and Green) Relevant to Microwave‐Assisted Pasteurization

“…A continuous microwave system was proposed for apple cider by Gentry and Roberts (). Integrated studies of dielectric properties for microwave heating have been reported for grape juice (García, Torres, Prieto & De Blas, ), milk (Coronel, Simunovic, Sandeep, & Kumar, 2008), peanut beverages (Sabliov, Boldor, Coronel, & Sanders, ), apple, pear, orange, pineapple juices (Zhu, Guo, & Wu, ), and green coconut water (Franco, Yamamoto, Tadini, & Gut, ). In spite there are reports for different fruit juices, it is well known that reported data cannot be extended for other juices or beverages, because the composition and physicochemical properties are different.…”