Subject area	Biology
More specific subject area	Plant sciences, food chemistry
Type of data	Figure, graph
How data was acquired	High Performance Liquid Chromatography (HPLC)
Data format	Processed, analyzed
Experimental factors	Aqueous onion extracts were directly analyzed by HPLC. For quercetin and kaempferol, chemical hydrolysis was performed prior to the analysis.
Experimental features	Pure standards of seven phenolic compounds commonly found in onion [quercetin, myricetin, kaempferol, rutin, catechin, epicatechin gallate (ECG), and epigallocatechin gallate (ECGC)] were analyzed by HPLC. Absorption spectra in the range 400–540 nm and bulb contents for these seven phenolic compounds were determined in onions with different bulb color.
Data source location	INTA La Consulta, San Carlos, Mendoza, Argentina
Data accessibility	Data are within this article