[Occurrence of chlorogenic acids in potatoes].

Ten varieties of potato cultivated under the same conditions were analyzed for the occurrence of chlorogenic acids by high performance liquid chromatography. 3-O-caffeoylquinic acid (n-chlorogenic acid) is the predominant compound with 22-71 ppm, (on average of 41 ppm) depending on variety. 4-O-caffeoylquinic acid (phi 11 ppm), 5-O-caffeoylquinic acid (phi 7 ppm), 3,4-dicaffeoylquine acid (phi 3 ppm), and at times 3,5-dicaffeoylquinic acid (in traces) were also demonstrated. Caffeic acid compounds are not distributed uniformly in the potato tuber. They occur in strongly decreasing concentration from the outer sections to the inner ones. About 50% of these compounds are located in the potato peel and the adjoining tissue.