Abstract
The contents and composition of free amino acids in potato tubers and their extraction by boiling water were examined. The free amino acid content of Danshakuimo was significantly higher than that of May Queen. As the day of harvest advanced, the free amino acid content of the tubers increased, and asparagine constituted half of this increased amount. Increased application of nitrogen fertilizer resulted in increasing free amino acid content of the tubers, with asparagine and glutamine constituting the major part of this increased amount. The percentage of free amino acids extracted by boiling water was about 60% of that in the tubers, the amount of extracted glutamic acid from Danshakuimo being higher than that from May Queen in proportion to the amounts present in the tubers. The water used for boiling potatoes in their normal cooking process is thought to contain an amount of glutamic acid exceeding the threshold value.
