Coloured potatoes (Solanum Tuberosum L.) – Anthocyanin Content and Tuber Quality

Anthocyanins gain more and more importance as natural colourants. Besides many other plant species, coloured potatoes could serve as a potential source. Therefore, 27 potato cultivars and four breeding clones of different origin were analysed for their anthocyanin contents in fresh weight (fw). On average the highest amounts of anthocyanins were found in the skin (0.65 g kg−1 fw) of potatoes. The corresponding values of samples taken from whole tubers (0.31 kg−1 fw) and flesh (0.22 kg−1 fw) were significantly lower (p<0.03). The analysis revealed considerable differences in the amounts of anthocyanins between the 31 cultivars/breeding clones. Among them ȁ8Peru Purpleȁ9 revealed the highest anthocyanin content in the skin with 2.96 g kg−1 fw. A similar high value was reached by ȁ8Violettfleischigeȁ9 and clone 1.81.202–92 N. Also for the other two types of samples, flesh and whole tubers, these three genotypes exhibited the highest level of anthocyanins. Interestingly, different rates of nitrogen fertilization at 100 and 200 kg ha−1 had no significant effect on the pigment content of potatoes. The same was observed with respect to the year or the location of plant growth. There were also no significant changes in the anthocyanin contents of tubers during storage for 135 days. In dry matter, starch and protein contents the coloured potato cultivars/breeding clones were comparable with traditional cultivars. Further tests have shown that the glycoalkaloids were mainly localized in the skin of coloured potatoes.