VARIATION IN THE QUERCETIN CONTENT IN DIFFERENT COLORED ONIONS (ALLIUM-CEPA L)

The aglycone, or free quercetin, and total quercetin content of 75 cul tivars and selections was analyzed by reverse-phase high-performance l iquid chromatography. Quercetin glycosides were hydrolyzed into aglyco nes. Total quercetin content in yellow, pink, and red onions varied fr om 54 to 286 mg . kg(-1) fresh weight indifferent onion entries grown during 1992, White onions contained trace amounts of total quercetin, Free quercetin content in all the onions was low (< 0.4 mg . kg(-1)) e xcept in '20272-G' (12.5 mg . kg(-1) fresh weight), Bulbs stored at 5, 24, and 30C and controlled atmosphere (CA) for 0, 1, 2, 3, 4, and 5 m onths showed a most marked change in total quercetin content at 24C co mpared to other treatments, with a rise in mid-storage followed by a d rop, Storage at 5 and 30C also demonstrated a similar change, However, total quercetin content did not vary significantly in bulbs stored at CA for 5 months. We conclude that genetic and storage factors affect quercetin content on onions.