Effects of osmotic treatment in corn syrup and modified atmosphere packaging on peeled white potatoes

The quality changes in terms of color, moisture, texture, and respiration of peeled potato cubes were studied. Potatoes were treated by holding in a control solution [1% (w/w) ascorbic acid and 1% (w/w) citric acid aqueous solution], a 10% (w/w) corn syrup in the control solution, and a 20% (w/w) corn syrup in the control solution for three osmotic times (0.5, 1.0, and 1.5h). The treated potatoes were packaging in barrier film under an air or a gas mixture (5% O₂: 10% CO₂: 85% N₂) atmosphere. The packaged potatoes were stored at 5°C and sampled after 1, 4, 7, 10, and 14 d. In addition, the effective inhibition of enzymatic browning on the surface of peeled potato cubes among the different treatments also was determined.

Osmotic treatment with com syrup did not reduce the moisture content of potato, but resulted in a softer potato. The gas mixture atmosphere in packages reduced the rate of respiration in treated potato cubes and enhanced the efficiency of inhibition of browning. There was no change in texture during the two week storage at 5°C.

The combination of corn syrup osmotic treatments and a gas mixture atmosphere packaging resulted in a synergistic effect and produced an average 54.1% inhibition of enzymatic browning which was more effective than the average 15.4% inhibition produced by the combination of osmotic treatments and air atmosphere treatment. Overall, 1.0-1.5h osmotic times produced the more effective inhibition of enzymatic browning. The combination treatment of 10% corn syrup and the gas mixture (5% O₂: 10% CO₂: 85% N₂) atmosphere packaging resulted in an average 59.2% inhibition of enzymatic browning during the 14 d of storage, maintained a nonperceptible color difference (δE < 3) in the potatoes for more than 14 days at 5°C, and produced less softening than the treatments utilizing 20% com syrup. Therefore, the treatment of 10% corn syrup for 1.0h osmotic time and packaged with gas mixture atmosphere is recommended to prevent enzymatic browning in peeled potatoes during a 14 d refrigerated (5°C) storage