In this study, the effect of hot air drying and vacuum freeze-drying on the drying characteristics and quality of ‘Meihong' and ‘Fuji' apple slices was investigated. Water status, texture characteristics, nutritional quality, and sensory evaluation of ‘Meihong' apple slices during drying were evaluated. Results showed that both the hot-air drying and vacuum freeze-drying were reduced-speed drying, and the drying rate of hot-air drying was faster. As to the water status, it could be seen that free water disappeared primarily in the early drying stage. The water binding ability of ‘Meihong' apple slices was weaker than that of ‘Fuji' apple. The brightness (L*) value of ‘Meihong' apple slices reduced after hot-air drying and increased after vacuum freeze-drying. When the moisture content was higher than 40%, the total color difference (△E) of apple slices significantly increased (P＜0.05). The content of dry-based total phenols and flavonoids in ‘Meihong' apple slices significantly decreased after hot-air drying(P＜0.05), while vacuum freeze-drying had no significant changes (P＞0.05). Hot-air drying led to compact structure, higher hardness, and obvious surface shrinkage. Vacuum freeze-drying slices showed a uniform appearance, porous structure, and higher rehydration. In conclusion, vacuum freeze-drying is suitable for the drying of high-flavonoid red-fleshed apple slices.
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