Comparative studies on different methods of dehydration of the white potato

The effect of water removal during dehydration on quality retention of white potato cubes was studied. Treatment of frozen, thawed potato cubes were as follows: 1. thawed in air and in water and dried in dehydrator at 140°F; 2. pressed and dried in dehydrator; 3. soaked in ethyl alcohol and dried in dehydrator; 4. freeze-dried; and 5. freeze-dried, partially rehydrated, compressed, refrozen, and freeze-dried. Quality attributes measured were shape retention, volume, color, texture, and rehydration capability. Freeze-drying following by partial rehydration, compression, and subsequent refreezing and freeze-drying produced cubes of the highest overall quality. The cubes were compressed to 42 percent of their original volume. On rehydration in tap water, they regained full shape and volume in three minutes and complete rehydration in five minutes. They were softer in texture than cubes from any other treatment. Freeze-drying was the most efficient method of water removal. The freeze-dried cubes were significantly higher in shape retention, volume, and rehydration capability than all air dried cubes. Soaking cubes in ethyl alcohol prior to drying reduced overall drying time and resulted in better size, shape retention, and rehydration capability than all other air-dried cubes. Pressing the cubes prior to drying removed approximately 27 percent of the original water from the cubes but would not be economically feasible since it did not significantly affect overall drying time. Thawing in air or in water had no significant effect on any quality attribute evaluated in this study.