Pyruvate scale
From Wikipedia, the free encyclopedia
The pyruvate scale measures pungency in onions and garlic with units of μmol/gfw (micromoles per gram fresh weight).[1] It is named after pyruvic acid, the alpha-keto acid co-product created in the biochemical pathway that forms syn-propanethial-S-oxide, the main lachrymatory agent in onions.
The standard onion[which?] has an eight rating, while "sweet onions" have a two or three rating on the scale. The lower the score or scale the more "sweet" the onions are rated. Anything less than five is considered a sweet onion. The Vidalia onion variety is considered sweet and must have a score of 5.0 μmol/gfw or less.[citation needed] The HoneySweet brand onion is claimed to consistently rate with a pungency level of 3.5 or less.[2]
The Supasweet onion (usually grown in Lincolnshire, England) registers 1.5 to 2 on the scale.[citation needed]
Influential factors
Soil type, rain, and sunlight affect the pungency in onions and garlic and, therefore, their score on the pyruvate scale.
