Post harvest discoloration of chips from early summer potatoes

Summary

Three plots (a high fertility, a low fertility, and a low fertility plus 120 lb of nitrogen) were planted using the variety Cobbler. These plots were located in the Gilcrest, Colorado summer potato producing area. Potatoes were harvested July 7, 11, 18, 25, August 1 and 8, a sample was chipped, and other tubers were placed into 50, 70, and 90 F storage. An injury treatment was included with the July 25 harvest. At three-day intervals over a period of 21 days, respiration, chip color and reducing sugars were determined.

Results showed that early harvested (immature) potatoes can be held for less than 3 days before going out of condition for chipping purposes. Delaying the harvest of potatoes lengthened the period during which potatoes could be stored and still make acceptable chips.

Storage at near the soil temperature from which the potatoes were harvested seemed best. Storage at 50 F was detrimental for summer chipping potatoes.

Potatoes from fields with low fertility and low yields usually produced the lightest colored chips. However, this may have been due to early dying of vines and greater maturity at any given harvest date.

Mechanical injury to tubers increased reducing sugar accumulation and resulted in darker chips.