Abstract
The flavonol quercetin has been reported as having many health benefits, including a reduction in the risk of developing cardiovascular disease, stroke, and some types of cancer. The overall content of quercetin in onion was examined in four yellow varieties (`Rio Rita', `RNX 10968', `Predator', and `Tamara') and one red variety purchased at a local grocery store. Each bulb was quartered, with one quarter saved as a control and the other three quarters subjected to three cooking treatments that simulated common domestic processing methods of preparing onion. The treatments included sautéing in sunflower oil for 5 minutes at 93 °C, baking for 15 min. at 176 °C, and boiling for 5 minutes in distilled water. Samples were frozen in liquid nitrogen, ground to a fine powder, blended with 80% EtOH, and filtered for quercetin extraction. The filtrate was then analyzed with a spectrophotometer (uv 374 nm). Quercetin concentrations were obtained in mg quercetin/kg fresh weight of tissue by regressing spectrophotometer readings onto a standard curve. Significant differences between varieties were found when examining fresh samples alone with the red variety containing the highest content of quercetin. Results of cooking showed that sautéing produced an overall 27% gain in quercetin concentration (significantly higher than the fresh control), baking produced an overall 4% gain in concentration (insignificant from the fresh control), while boiling produced an overall 18% loss in quercetin concentration (significantly lower than the fresh control).
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Claims 4
Claim · model-written summary
Fresh red onion had the highest quercetin content among tested varieties.
- Taxon
- Onion
Allium cepat0 - Material
- red varietye0
- Outcome
- content of quercetine0
- Direction
- higheste0
- Comparator
- varietiese0
Not reportedOrgan / stage
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significant differences between varieties were found when examining fresh samples alone with the red variety containing the highest content of quercetin”
t0“Onion”
Claim · model-written summary
Sauteing raised quercetin concentration by 27% relative to fresh control.
- Taxon
- OnionAllium cepat0
- Treatment
- sautéinge0
- Outcome
- quercetin concentratione0
- Direction
- gaine0
- Value
- 27%e0
- Comparator
- fresh controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sautéing produced an overall 27% gain in quercetin concentration (significantly higher than the fresh control)”
t0“Onion”
Claim · model-written summary
Baking raised quercetin concentration by 4%, without a significant difference from fresh control.
- Taxon
- OnionAllium cepat0
- Treatment
- bakinge0
- Outcome
- concentratione0
- Direction
- gaine0
- Value
- 4%e0
- Comparator
- fresh controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“baking produced an overall 4% gain in concentration (insignificant from the fresh control)”
t0“Onion”
Claim · model-written summary
Boiling lowered quercetin concentration by 18% relative to fresh control.
- Taxon
- OnionAllium cepat0
- Treatment
- boilinge0
- Outcome
- quercetin concentratione0
- Direction
- losse0
- Value
- 18%e0
- Comparator
- fresh controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“boiling produced an overall 18% loss in quercetin concentration (significantly lower than the fresh control)”
t0“Onion”
The same questions in other papers
processing · molecular: metabolites · Allium cepa (onion)Positive and negative results
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See all 10 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.