The effect of storage on the amino acids composition in potato tubers

The aim of this study was to investigate the effect of storage duration on amino acids content in potato tubers. Tubers of six cultivars were stored for 16 weeks. Crude protein was determined by the Kjeldahl method. The amino acid content was identified after acid hydrolysis; sulphur amino acids were oxidized with the mixture of hydrogen peroxide,formic acid and phenol. The essential amino acids index and chemical score was calculated. The whole egg protein was used as reference protein. The effect of storage duration and cultivar on the total amino acids content was found to be significant in all potato varieties. The level of the total amino acids contents was determined within the range of 8087%. Similar downward trend was observed in crude protein. The essential amino acids index varied considerably among the potato cultivars,ranging from 42 to 57%. Sulfur amino acids and isoleucin were the limiting amino acids in all the investigated tubers.