Amino acid composition of flesh-coloured potatoes as affected by storage conditions.

The study determined nitrogen compounds and amino acid profile in dry matter of potatoes differing in flesh colour, stored at 2 °C and 5 °C for three and six months. With increased storage time, the total protein content and particularly amino acid content declined. The coagulable protein content increased at three months' storage by 25%. The majority of the amino acid content decreased from 19 to 6% and from 38 to 21% after three and six months' storage, respectively. Storage temperature did not influence the coagulable protein content or serine, glycine, cysteine, tyrosine and phenylalanine. However, potatoes stored at 2 °C contained slightly more amino acids than tubers stored at 5 °C. Independently of the storage conditions, potatoes of yellow-fleshed Fresco and red-fleshed Herbie 26 varieties were characterised by a relatively high nutritive value, limited by leucine (CS = 84), methionine plus cysteine (CS = 78) and leucine (CS = 72), respectively.