Taste Evaluation of Potato Glycoalkaloids by the Aymara: A Case Study in Human Chemical Ecology

A chemical ecological model can be the basis for defining testable hypotheses concerning human interactions with plants. Selection by A ymara subsistence cultivators against toxic glycoalkaloids in the ongoing domestication o f the Bolivian potato cultigen Solanum x ajanhuiri was used as a specific case study of human interactions with phytochemicals. In taste perception tests, A ymara subjects were able to discriminate between concentrations o f pure glycoalkaloids in solution only above 20 mg/lO0 ml. Taste panel tests of potato clones indicated that glycoalkaloid levels are important to the A ymara in determining quality only as part o f a decision-making process involving two character states: too high or acceptable. Glycoalkaloids in potatoes are regarded as toxic to humans above 20 mg/lO0 g fresh weight. Among the Aymara, a breakpoint in the curve for glycoalkaloid preference appears to occur between 20-38 mg/lO0 g. This distinction is evident in the Aymara potato taxonomy which distinguishes bitter (luq'i ch'oke) from nonbitter (ch'oke) potatoes.