Study of Radio Frequency Pasteurization and Drying of Poria cocos Solid-state Fermented Product

摘要

The soybean residue and rice bran were the media for Poria cocos solid-state fermentation to improve their antioxidant activities. Radio frequency (RF) can rapidly heat up water molecules or ions in food by rapid conversion of electric field; therefore, RF heating can overcome heat transfer resistance to accelerate pasteurization and drying processing of food product [1]. The drying time of 1.6 kg of in-shell walnuts reducing moisture content from 20% to 8% required 100 and 240 min by RF drying and only hot air drying, respectively [2]. After 90 s of RF treatment, the log reductions of Salmonella and Escherichia coli were 4.29, 4.55 and 4.39, 5.32 log CFU/g, respectively, in creamy and chunky peanut butter respectively, without affecting the quality [3]. Therefore, RF may applied in the downstream processing of Poria cocos solid-state fermentation.