Computational study on radio frequency thawing of irregularly shaped aquatic product: Using hairtail fish as an example

Radio frequency (RF) heating as one of the efficient thawing and tempering methods has attracted increasing attention, especially in its potential to thaw irregular products. In this study, a numerical model of hairtail fish with RF thawing was developed and validated based on its irregular structural characteristics, and the thawing performance under different conditions and arrangements was systematically evaluated. The results indicated that the model could accurately predict the internal temperature distribution of hairtail fish (smallest Root-Mean-Square-Error value: 0.44°C). The strongest geometric effect of the five upright hairtail fish significantly improved the electric field strength, resulting in a larger overall temperature difference, whereas five hairtail fish lying flat on the bottom electrode had the best heating uniformity (temperature uniformity index: 0.033) and moderate heating rate. In addition, the local RF thawing rate increased and the temperature uniformity decreased with increasing stacking layers for multilayer hairtail fish. This study provides a useful reference for broadening the application of RF thawing in irregularly-shaped products. •A numerical model was developed for RF thawing of hairtail in different arrangements.•The thawing effect of single-layer flat hairtail was in independent of the material gap.•Flat samples showed better temperature uniformity compared to upright samples.•The stacking layers significantly influenced the RF thawing performance.