Effect of bruising on the total glycoalkaloid and chlorogenic acid content of potato (Solanum tuberosum) tubers of five cultivars



Tubers from five potato cultivars were selected on the basis of their low, intermediate or high rates of glycoalkaloid synthesis in response to stresses such as light or cold storage temperatures. The tubers were subjected to a standard degree of damage sufficient to cause bruising but not severe damage such as cracking or splitting. Increases in glycoalkaloid levels in response to damage were observed in all cultivars. Importantly, the rates of glycoalkaloid synthesis in response to damage were in good agreement with cultivar response to light and cold temperature stress. The cultivars, Ailsa and Eden, exhibited a slower response than the higher synthesis rates observed in Pentland Dell or Brodick. The cultivar Torridon exhibited severe internal damage symptoms throughout the tuber as opposed to localised bruising observed in the other cultivars. The extensive cell death observed in the tubers of the cultivar Torridon severely curtailed glycoalkaloid and chlorogenic acid synthesis. The increased levels of glycoalkaloids in response to bruising damage ranged from approximately 27% (Ailsa, Torridon) to 130% for the cultivar Brodick. Chlorogenic acid levels increased in two cultivars (Brodick and Torridon) but not in the others, Ailsa, Eden and Pentland Dell. The α-chaconine/α-solanine ratios observed within the five cultivars were in good agreement with previous research. The consistency across years is notable, indicating a strong relationship in the synthesis of the two glycoalkaloids. The results are discussed in terms of implications for the potato industry, for the retail trade and also for selection within potato breeding programmes. © 1998 SCI.