Amino acid composition and nutritional value of four cultivated South American potato species

Protein content, amino acid composition, nutritional quality and patatin characteristics were determined in tubers of four South American cultivated potato species (Solanum andigenum, Solanum goniocalyx, Solanum phureja, Solanum stenotomum) and a cultivar of the commonly cultivated cultivar Desirée of Solanum tuberosum. Protein content (on dry matter basis) of S. andigenum and S. stenotomum was highest at 7.9% and 8.0%, respectively, and the relative quantities of patatin for both species were 41.7% and 34.0%, respectively. The nutritional value of patatin, in terms of essential amino acid index with respect to a reference protein of FAO/WHO (EAAIadult) ranged from 93.0% (S. phureja) to 112.5% (S. goniocalyx). In case S. goniocalyx, the patatin fraction was a nutritionally better protein fraction than a protein concentrate or tuber dry matter, which had EAAIadult values of 97.6% and 82.9%, respectively. This suggests that this species may have potential in potato breeding programmes and in human nutrition.