Abstract
Flavonoid changes in sliced and fried onions which were packed and stored at different atmospheric conditions (air, nitrogen and vacuum), temperatures (ambient, +5 and −18C) and light (dark or light) were investigated. Flavonoids were extracted using accelerated solvent extraction and analyzed using ultra performance liquid chromatography coupled with photodiode array detector. Total flavonoid content, quercetin-3,4′-O-diglucoside and quercetin-4′-O-monoglucoside contents in sliced reference onion samples were found as 1,570 ± 176, 926 ± 105 and 564 ± 64 μg q.e./g d.w., respectively. Frying did not result in significant losses of flavonoids. At room temperature, total flavonoid losses were significant, besides conversion of quercetin glycosides into aglycons. Dark conditions better retained flavonoids of sliced onions at all atmospheric conditions. For sliced onions; +5C, air or vacuum atmosphere, or −18C, vacuum or nitrogen atmosphere, under dark, preserved flavonoids for 21 days, whereas for fried onions, 7 days of storage at +5C, vacuum atmosphere under dark resulted in highest flavonoid content. Practical Applications Onion is one of the most widely consumed vegetable all over the world and also used in industrially processed forms for domestic and catering purposes. Onion includes high contents of flavonoids and has been attracting extra attention by consumers. Onion products are also preferred by consumers, but processing may be resulting in losses in those valuable flavonoids. Previous researches focused on the effect of domestic processing techniques such as chopping, shredding, peeling, roasting, cooking or boiling on flavonoid content and depending on the severity of heat treatment losses were evident. This study aims to investigate how the slicing and frying applications and storage of yellow onion products at different temperatures, light and modified atmosphere conditions, effect the flavonoid content and profile. By this means, the storage conditions retaining the flavonoids in packaged yellow onion products will be determined.
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Claims 10
Claim · model-written summary
Reference sliced onions contained 1,570 ± 176 μg q.e./g d.w. total flavonoids.
- Taxon
- onion
Allium cepae0 - Outcome
- Total flavonoid contente0
- Value
- 1,570 ± 176e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total flavonoid content, quercetin-3,4′-O-diglucoside and quercetin-4′-O-monoglucoside contents in sliced reference onion samples were found as 1,570 ± 176, 926 ± 105 and 564 ± 64 μg q.e./g d.w., respectively.”
Claim · model-written summary
Reference sliced onions contained 926 ± 105 μg q.e./g d.w. quercetin-3,4′-O-diglucoside.
- Taxon
- onionAllium cepae0
- Outcome
- quercetin-3,4′-O-diglucosidee0
- Value
- 926 ± 105e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total flavonoid content, quercetin-3,4′-O-diglucoside and quercetin-4′-O-monoglucoside contents in sliced reference onion samples were found as 1,570 ± 176, 926 ± 105 and 564 ± 64 μg q.e./g d.w., respectively.”
Claim · model-written summary
Reference sliced onions contained 564 ± 64 μg q.e./g d.w. quercetin-4′-O-monoglucoside.
- Taxon
- onionAllium cepae0
- Outcome
- quercetin-4′-O-monoglucosidee0
- Value
- 564 ± 64 μg q.e./g d.w.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total flavonoid content, quercetin-3,4′-O-diglucoside and quercetin-4′-O-monoglucoside contents in sliced reference onion samples were found as 1,570 ± 176, 926 ± 105 and 564 ± 64 μg q.e./g d.w., respectively.”
Claim · model-written summary
Frying produced no significant loss of onion flavonoids.
- Taxon
- onionAllium cepat0
- Treatment
- Fryinge0
- Outcome
- flavonoidse0
- Direction
- did not result in significant lossese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Frying did not result in significant losses of flavonoids.”
t0“Yellow Onions”
Claim · model-written summary
Room-temperature storage caused significant loss of total onion flavonoids.
- Taxon
- onionAllium cepat0
- Treatment
- room temperaturee0
- Outcome
- total flavonoid lossese0
- Direction
- lossese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At room temperature, total flavonoid losses were significant”
t0“Yellow Onions”
Claim · model-written summary
At room temperature onion quercetin glycosides converted into aglycons.
- Taxon
- onionAllium cepat0
- Outcome
- conversion of quercetin glycosides into aglyconse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“besides conversion of quercetin glycosides into aglycons.”
t0“Yellow Onions”
Claim · model-written summary
Dark storage better retained flavonoids in sliced onion under all atmospheres.
- Taxon
- onionsAllium cepae0
- Treatment
- Dark conditionse0
- Outcome
- flavonoidse0
- Direction
- better retainede0
- Qualifier
- at all atmospheric conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dark conditions better retained flavonoids of sliced onions at all atmospheric conditions.”
Claim · model-written summary
Dark storage at +5C with air or vacuum preserved sliced onion flavonoids for 21 days.
- Taxon
- onionsAllium cepae0
- Treatment
- +5C, air or vacuum atmospheree0
- Outcome
- flavonoidse0
- Direction
- preservede0
- Value
- 21 dayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For sliced onions; +5C, air or vacuum atmosphere, or −18C, vacuum or nitrogen atmosphere, under dark, preserved flavonoids for 21 days”
Claim · model-written summary
Dark storage at −18C with vacuum or nitrogen preserved sliced onion flavonoids for 21 days.
- Taxon
- onionsAllium cepae0
- Treatment
- −18C, vacuum or nitrogen atmospheree0
- Outcome
- flavonoidse0
- Direction
- preservede0
- Value
- 21 dayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For sliced onions; +5C, air or vacuum atmosphere, or −18C, vacuum or nitrogen atmosphere, under dark, preserved flavonoids for 21 days”
Claim · model-written summary
Fried onions had highest flavonoid content after seven days at +5C in dark vacuum storage.
- Taxon
- onionsAllium cepae0
- Treatment
- 7 days of storage at +5C, vacuum atmosphere under darke0
- Outcome
- flavonoid contente0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for fried onions, 7 days of storage at +5C, vacuum atmosphere under dark resulted in highest flavonoid content.”
The same questions in other papers
storage · quality: phytochemicals · Allium cepa (onion)Positive and negative results
1 paper in the same direction as this paper · 3 in the opposite direction
- negative
- no effect
- no effect
1 paper more in this group
See all 5 papers →light · quality: phytochemicals · Allium cepa (onion)Results agree
1 paper in the same direction as this paper
- positive
nitrogen · quality: phytochemicals · Allium cepa (onion)Results agree
5 papers in the same direction as this paper
- positive
- positive
- positive
2 papers more in this group
See all 6 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.