Onion pungency testing and consumer calibration (VN04016)

This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

There was a considerable market in Australia for onions with a mild onion taste for their use in salads. However there was no way to ensure that consumers would consistently receive mild tasting onions, as there was no way to reliably measure onion pungency. Pungency was responsible for the hot onion taste when eating onions. This lack of a reliable cost-effective test for pungency was limiting the development of the Australian mild onion industry.

This project adapted and developed methods for extracting juice from the onion and to measure the chemical associated with the pungent taste in onions. This naturally occurring chemical in onions that was associated with pungency was called pyruvate. This was done at the NSW Department of Primary Industries, Wagga Wagga Agricultural Institute. The NSW DPI laboratory in Wagga began accepting commercial samples to measure onion pungency.

Having successfully developed a reliable and cost-effective test for onion pungency, the project assessed whether onions could be grouped into categories by consumers based on the pyruvate levels in the onion. The pungency levels in a range of onions were measured and assessed by both specialist tasters and regular consumers. This taste testing was undertaken by Food Science Australia in Sydney and showed that consumers preferred mild onions, and they could reliably distinguish between the different classes of onion pungency. The results provided industry with a tool to manage the establishment of the mild onion industry in Australia.