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In this study, film packaged fresh-cut pear samples were supercooled at −5 ℃ for 3 days and then tissue characteristics and physicochemical properties were compared with samples stored at 1 ℃(control). The tissue characteristics of the samples were then evaluated by electrical impedance, microscopic observation, and a triphenyl tetrazolium chloride (TTC) assay. The results showed that the supercooled samples had Cole-Cole plots with welldefined circular arcs, intact cell structure, and cell viabilities that were comparable to those of fresh samples, indicating that supercooled samples were not adversely affected by freezing. Physicochemical evaluations of supercooled samples showed that changes in mass, coloration, and softness were all less apparent than they were in the control samples. Additionally, the ethylene concentration in the supercooled sample packages was significantly lower than that of the control samples, indicating that supercooling reduced ethylene production from fresh-cut pears. The results showed that supercooling could potentially extend the shelf life of fresh-cut pear.

We conducted atmospheric freeze drying (AFD) of fresh-cut Japanese radish (daikon) at different temperatures (0, −5, −10, −18 ℃) with an air speed of 0.43 m･s −1 , and evaluated moisture content changes. We assessed samples dried by AFD for surface color, soluble solids content ( °Brix), rehydration ratio, and texture (breaking stress and initial elasticity) after rehydration. In the rehydration and texture tests, we compared AFD using −5 ℃ samples and samples dried by hot air at 60 ℃. An exponential model was used to describe the sample moisture content during AFD, which decreased exponentially with drying constant with an Arrhenius-type temperature dependency. Compared to the sample dried at 60 ℃, the rehydration ratio was 1.29 times higher for AFD at −5 ℃, and the sample showed a large number of voids. There were no significant differences between the −5 ℃ and 60 ℃ samples in terms of breaking stress or initial elasticity. These results indicate that AFD is an effective drying method for preserving the quality of products.