The quality of protein of coloured fleshed potatoes.

Potatoes of purple varieties and red flesh colour were estimated as the important food product containing valuable protein. Amino acids concentration and protein nutritive value of coloured potatoes were analysed and compared with traditional yellow-fleshed varieties. Studies comprised potatoes of 13 varieties: 7 of purple-fleshed, four of red-fleshed and two of yellow-fleshed. There were observed differences between studied potatoes with respect to dry matter, starch and protein content as well as to amino acids concentration and protein quality independently on flesh colour. Potatoes of low as well of high content of total protein, independently on flesh colour, characterised similar protein quality, like for example varieties of Blaue Anneliese and Highland B. Red or Blue Congo and Salad Blue. Leucine limited the quality of majority of coloured fleshed potato varieties used for the experiment. The best amino acid profiles and protein quality confirmed by chemical scores and EAA index values characterised purple fleshed Vitelotte and Blaue Anneliese, yellow fleshed Verdi as well as red fleshed Herbie 26, Highland B. Red and Rosemarie.