Factors affecting the curing process in root/tuber crops

1.Temperature- The optimum temperature for curing is higher than the temperature at which the crop is normally raised. For high land root crops (Potato and carrot) it is 15-250 c and for low land root crops (Gobi, radish, cassava, sweet potato, ginger, yam) it is 26-340c. Wound healing is faster at higher than at low temperature. However, it’s delayed at very low and very high temperature.

2.Relative humidity- The bulb and roots crops require different relative humidity for curing. A high RH is required for tuber/root crops. At very low RH (For ex.30%), no wound tissue appears to be formed. Outer layers of cells dry out to a crust resulting in the delay of the process. The optimum relative humidity (80-95%), wound healing occurs at a rapid rate. At 100% RH curing is delayed due to proliferation of cells on the surface of the wound. The bulb crops require low relative humidity for the drying of neck and better development of skin colour.

3.Gases – 10% or more CO2 and below 5% O2 inhibits wound healing of root/tuber crops due to the following reason-

• These conditions inhibit respiration, which is important in cell division and enlargement, which occurs in curing.
• Curing is a developmental process requiring synthesis of DNA and protein.
• Periderm formation does not occur at anaerobic conditions.

4.Type of damage- A generally smooth cut heals faster than other types of damage. If practical, a rugged cut should thus be trimmed so healing is faster.

5.Length of period after harvest- the rate of wound healing is faster immediately after harvesting and gradually decreases during storage. Therefore, cure produces as soon as possible and handle commodity as little as possible after curing.