Dielectric properties of salmon (Oncorhynchus keta) and sturgeon (Acipenser transmontanus) caviar at radio frequency (RF) and microwave (MW) pasteurization frequencies

Radio frequency (RF) and microwave (MW) heating provide an important advantage of more rapid heat penetration in pasteurization processes for heat labile high value foods, which to date, have only been pasteurized by conductive heating. The objectives of this work were to determine the dielectric constant, loss factor and power penetration depth for salmon (0.8% and 2.3% total salt) and sturgeon (0.20 and 3.3% salt) caviars at RF frequency of 27MHz and MW frequency of 915MHz (20–80 C). The dielectric constant (e 0) and dielectric loss factor (e00) for salmon and sturgeon caviar increased markedly with increasing temperature at 27MHz but not at 915MHz. Power penetration depth was higher at 27MHz compared to 915MHz, and in unsalted compared to salted roe. Power penetration depth tended to decrease as temperature increased. 2004 Elsevier Ltd. All rights reserved.