Citric acid and potassium contents were determined for Russet Burbank tubers collected from the major production areas in Alberta. An increase in the ratio of citric to chlorogenic acid content is known to be associated with a decrease in the tendency for potato tubers to darken after cooking. Tuber citric acid and potassium contents were higher in southerly locations than in central locations. The trend for citric acid is the reverse of that for chlorogenic acid established in a previous study. Thus, potatoes grown at southern Alberta locations have a higher citric to chlorogenic acid ratio than those grown in central locations, suggesting that they would be less subject to after-cooking darkening.Key words: Darkening (after-cooking), citric acid, chlorogenic acid, potassium content, Russet Burbank, potato
