Experimental study on a novel vacuum sublimation–rehydration thawing of frozen potatoes

To realize a quick thawing of frozen potatoes, the experimental investigation of thawing performance was conducted by using a novel vacuum sublimation-rehydration thawing (VSRT) in this study. Frozen diced potatoes (20 mm × 20 mm × 20 mm) with a total mass of 1.5 kg were selected as the thawing object. The center temperature of the frozen diced potato was raised from -18°C to 5°C to assess the beginning and end of thawing. The effects of sublimation time, heating plate temperature, and rehydration temperature on thawing time of frozen potatoes were experimentally studied. The VSRT and vacuum steam thawing (VST) were compared in terms of thawing time, hardness, and specific energy consumption. The results showed that the conditions of sublimation time of 25 min, heating plate temperature of 30°C, and rehydration temperature of 100°C could effectively shorten the thawing time of VSRT for thawing frozen potatoes. The thawing time of VSRT was only 49% of that of VST. Compared to the hardness of frozen potatoes thawed by VST, the hardness of frozen potatoes thawed by VSRT was closer to that of blanched (unfrozen) potatoes. The specific energy consumption of VSRT was lower than that of VST. PRACTICAL APPLICATION: The quality of frozen potatoes is directly affected by the thawing method used. A novel vacuum sublimation-rehydration thawing was conducted in this study, which can provide a new idea for a reasonable, effective, and quick thawing method for frozen potatoes.