Sorbitol impregnation reduces freeze–thaw damage in potato slices subjected to different freezing methods

Summary This study investigated the effect of sorbitol impregnation on freeze–thaw damage in potato slices subjected to four freezing methods: −40 °C contact plate freezing (−40 °C-CPF), −80 °C contact plate freezing (−80 °C-CPF), liquid nitrogen freezing (LNF), and vacuum freezing (VF) to compare their freezing characteristics, water status, cell activity, and microstructure. Results indicate that sorbitol impregnation significantly reduced the drip loss (DL), the freezing time and the relative electrical conductivity (REC) (except for LNF) of freeze–thawed potato slices, presenting a higher reduction in REC index under the freezing method of −80 °C-CPF. Low-frequency nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) analysis showed that the change in the peak area proportion of sorbitol-impregnated sample at −80 °C-CPF was found to be minimal, which was beneficial for the retention of water. Compared with LNF and VF freezing methods, it retained relatively more intact cell structures and exhibited less cell death. Overall, sorbitol impregnation derived more alleviation of freeze–thaw damage in potato slices under the −80 °C-CPF freezing method.