Electrical Properties of Fish Mince During Multi‐frequency Ohmic Heating

Abstract

A multi-frequency ohmic heating system with 30 Hz~1 MHz range which could deliver 250 watts was developed for measuring electrical conductivity and absolute dielectric loss of food samples. Pacific whiting surimi paste and stabilized mince in the 20~70°C range were tested at frequencies from 55 Hz to 200 kHz. Sample impedance decreased slightly with frequency. The DC electrical conductivity ( dc ) and absolute dielectric loss (⑀Љ) of Pacific whiting surimi paste increased with temperature and salt concentration; dc and ⑀Љ of the stabilized mince increased with temperature. Empirical models of electrical properties for surimi paste (moisture content 79% and salt at 1, 2 or 3%) and stabilized mince (77% moisture and 0.74% salt) were derived. Electrolytic corrosion diminished with frequency.

Electrical Conductivity and Physical Properties of Surimi–Potato Starch under Ohmic Heating

“…No corrosion was reported when 5 or 20 KHz was used. The effect of applied frequency confirmed the results of Wu and others (1998) that conducting the experiment at 5 KHz or higher could eliminate product burning and electrode corrosion.…”

“…Two different (low and high) voltage (V) levels, 60 and 220 V, corresponding to a voltage gradient of 4.3 ± 0.2 and 15.5 ± 0.6 V/cm, respectively, were used for 5 and 20 KHz. However, to minimize electrode corrosion and to prevent heat explosion, which occurs from accumulated current density at the end of the corrosion electrode, only 60 V was used for 55 Hz (Wu and others 1998). …”

The temperature prediction of some botanical beverages, concentrated juices and purees of orange and pineapple during ohmic heating

“…It is predictable because the 50 Hz electrical frequency and stainless steel electrodes were applied in this study. Wu et al (1998) stated that if the electrical frequency lower than 5 kHz was used, the electrolytic corrosion would observably take place at the surface of electrodes made from common food-grade metals. As a consequence of electrode corrosion, some metal ions would migrate into the samples.…”

Electrical Conductivity of Multicomponent Systems During Ohmic Heating

“…Palaniappan and Sastry [2] reported that electrical conductivity is a linear function of temperature, and the relationship can be expressed as: Some research has been done on the electrical conductivity of selected solid and liquid foods, [2,[5][6][7][8] fruit based products, [9][10][11] and meat products. [12][13][14][15] However, relatively little attention has been focused on electrical conductivities of low acid particulate foods.…”