The color, anthocyanin content per given surface area, and phenolics content of tuber periderm of four different varieties of red potatoes were compared. Three of the varieties, Norland, Red Norland, and Dark Red Norland, are members of a color sport family. Freshly harvested 'Norland' differed significantly in color, but not anthocyanin content per given surface area, from its sports. 'Red Norland' tubers were lighter in color than those of 'Dark Red Norland'. In general, storage resulted in darkening of tubers and, except for the fourth variety, MN17922, a decrease in anthocyanin content per given surface area. Tubers from green-killed 'Red Norland' plants were more purplish-red than those from vine-killed plants. Stored tubers had greater periderm total phenolics content than freshly harvested tubers. The increase in periderm phenolics and decrease in anthocyanin content per given surface area may lead to darkening of tubers with storage. Cell walls connecting periderm to cortex tissue of 'MN17922' tubers were thinner than those in 'Norland' tubers, which may explain why it is relatively easy to separate the periderm of 'MN17922' from its cortex.
Bibliographical noteFunding Information:
We thank Christian Thill for 'MN17922' tubers, Faye Prop-sore and Francis Zvomuya for statistical advice, and the McNair Program for financial support for A. Andersen. This research has been supported by the Minnesota Agricultural Experiment Station and NSF/BIR grant 9215615.