Pungency determination of argentine onion cultivars

SANCE, M; GALMARINI, C.R.; BAUZÁ, M.M.

ACTA HORTICULTURAE

Año: 2005 p. 313 - 316

0567-7572

Argentina is the first exporting onion country in South America. The demand for mild onions is increasing in the world and represents an opportunity for Argentine exports and also for the domestic market. Around 20,000 ha are yearly cropped with onions in Argentina; 90% of which is seeded with local cultivars. Up to now the pungency of these materials has not been tested. The aim of this work was to assess the variability of the local germplasm for their pungency. In order to do that, first it was necessary to adapt the Schwimmer and Weston technique to measure pungency to the local laboratory conditions. Trials to choose the adequate dilution of the sample, bench time to allow enzymatic hydrolysis of the flavour precursors, time of centrifugation and the effect of freezing the samples were performed. The cultivars ‘Valcatorce INTA’, ‘Valuno INTA’, ‘Cobriza INTA’, ‘Navideña INTA’, ‘Antártica INTA’, ‘Refinta 20’, ‘Grano de Oro’, and 4 experimental hybrids were evaluated. The bulbs were grown in a replicated trial at E.E.A. INTA La Consulta. The modified Schwimmer and Weston technique was used to evaluated pyruvate, 30 days after harvesting. The freezing of the samples did not change the ranking of the evaluated cultivars although changed the absolute value of pyruvate. ‘Valuno INTA’ was significantly less pungent than Cobriza INTA and Refinta 20. In general all cultivars showed an intermediate pungency (4.3 to 6.1 μmoles/g). ‘Valcatorce INTA’, which is the main exported cultivar, is a mild onion.