Wound Healing in Storage
Other pages about wound healing:
- The Process of Wound Healing
- Healing Factors
- Cutting Seed Tubers
- Handling Seed Pieces
- Wounding at Harvest
- Healing in Storage
After tubers are harvested, it is best to assume and would be expected that some bruising occurred during the harvest and piling operation. The initial storage period should be a 'curing period' which is used for healing the wounds of the harvested tubers. Curing is a short storage period after harvest and before tubers enter the 'holding period' which is the normal storage for the off-season.
Recommendations for curing are:
a. one to three weeks
b. temperatures between 50 and 60o F
If temperature is lower the wound healing process becomes too slow and take much too long and if the temperature is higher than pathogen populations increase and rots increase.
c. relative humidity between 90 and 95%
d. air movement at 10 to 30 cfm/20 cwt or per ton (US)
e. NO free water, that is condensate, wash etc. Free water blocks oxygen intake, stopping healing and promoting rots.
After the curing period, the storage temperature can be altered to the desired holding temperature. Temperature changes should be fairly rapid, about 0.5o F per day. The holding temperature depends on the market for the tubers. For seed tuber storage, the holding temperature is low, between 34 and 38o F unless they will leave storage early and dormancy needs to be overcome. Fresh market potatoes are stored nearly as cold, between 36 and 40o F; they may be stored slightly higher and longer if a sprout inhibitor is used. Tubers going for processing as french fries may be stored at 44 to 48o F and sprout inhibition practices are required. For most chip processing cultivars, holding temperature remains in the region of curing, 50 to 55o F. Sprout inhibition is required. Note that for chipping, growers may expose tubers to higher temperatures between 55 and 65o F for a short period called 'conditioning' or 'pre-conditioning' in order to lower reducing sugars in the tubers; this would replace the curing period. The higher temperatures for tubers to be processed by frying are needed to keep the sugar levels down and thereby minimize browning during frying, the Mallard Reaction.