Abstract
Kale (Brassica oleracea var. acephala) is known as a vegetable with good tolerance of environmental stress and numerous beneficial properties for human health, which are attributed to different phytochemicals. In the present study, investigation of how low temperatures affect proline, pigments and specialized metabolites content was performed using 8-weeks old kale plants subjected to chilling (at 8 °C, for 24 h) followed by short freezing (at −8 °C, for 1 h after previous acclimation at 8 °C, for 23 h). Plants growing at 21 °C served as a control. In both groups of plants (exposed to low temperatures and exposed to short freezing) a significant increase in proline content (14% and 49%, respectively) was recorded. Low temperatures (8 °C) induced an increase of pigments (total chlorophylls 7%) and phytochemicals (phenolic acids 3%; flavonoids 5%; carotenoids 15%; glucosinolates 21%) content, while exposure to freezing showed a different trend dependent upon observed parameter. After freezing, the content of chlorophylls, carotenoids, and total phenolic acids retained similar levels as in control plants and amounted to 14.65 ± 0.36 mg dw g−1, 2.58 ± 0.05 mg dw g−1 and 13.75 ± 0.07 mg dw CEA g−1, respectively. At the freezing temperature, total polyphenol content increased 13% and total flavonoids and glucosinolates content decreased 21% and 54%, respectively. Our results suggest that acclimatization (23 h at 8 °C) of kale plants can be beneficial for the accumulation of pigments and phytochemicals, while freezing temperatures affect differently specialized metabolite synthesis. The study suggests that growing temperature during kale cultivation must be considered as an important parameter for producers that are orientated towards production of crops with an increasing content of health-related compounds.
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Claims 14
Claim · model-written summary
Chilling increased proline content by 14%.
- Taxon
- Kale
Brassica oleracea var. viridist0 - Treatment
- low temperaturese0
- Outcome
- proline contente0
- Direction
- increasee0
- Value
- 14%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both groups of plants (exposed to low temperatures and exposed to short freezing) a significant increase in proline content (14% and 49%, respectively) was recorded.”
t0“Kale”
Claim · model-written summary
Short freezing increased proline content by 49%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- short freezinge0
- Outcome
- proline contente0
- Direction
- increasee0
- Value
- 49%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both groups of plants (exposed to low temperatures and exposed to short freezing) a significant increase in proline content (14% and 49%, respectively) was recorded.”
t0“Kale”
Claim · model-written summary
Chilling increased total chlorophylls by 7%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- Low temperatures (8 °C)e0
- Outcome
- total chlorophyllse0
- Direction
- increasee0
- Value
- 7%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low temperatures (8 °C) induced an increase of pigments (total chlorophylls 7%) and phytochemicals (phenolic acids 3%; flavonoids 5%; carotenoids 15%; glucosinolates 21%) content”
t0“Kale”
Claim · model-written summary
Chilling increased phenolic acids by 3%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- Low temperatures (8 °C)e0
- Outcome
- phenolic acidse0
- Direction
- increasee0
- Value
- 3%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low temperatures (8 °C) induced an increase of pigments (total chlorophylls 7%) and phytochemicals (phenolic acids 3%; flavonoids 5%; carotenoids 15%; glucosinolates 21%) content”
t0“Kale”
Claim · model-written summary
Chilling increased flavonoids by 5%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- Low temperatures (8 °C)e0
- Outcome
- flavonoidse0
- Direction
- increasee0
- Value
- 5%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low temperatures (8 °C) induced an increase of pigments (total chlorophylls 7%) and phytochemicals (phenolic acids 3%; flavonoids 5%; carotenoids 15%; glucosinolates 21%) content”
t0“Kale”
Claim · model-written summary
Chilling increased carotenoids by 15%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- Low temperatures (8 °C)e0
- Outcome
- carotenoidse0
- Direction
- increasee0
- Value
- 15%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low temperatures (8 °C) induced an increase of pigments (total chlorophylls 7%) and phytochemicals (phenolic acids 3%; flavonoids 5%; carotenoids 15%; glucosinolates 21%) content”
t0“Kale”
Claim · model-written summary
Chilling increased glucosinolates by 21%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- Low temperatures (8 °C)e0
- Outcome
- glucosinolatese0
- Direction
- increasee0
- Value
- 21%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low temperatures (8 °C) induced an increase of pigments (total chlorophylls 7%) and phytochemicals (phenolic acids 3%; flavonoids 5%; carotenoids 15%; glucosinolates 21%) content”
t0“Kale”
Claim · model-written summary
After freezing, chlorophylls remained at control level, 14.65 ± 0.36 mg dw g−1.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- freezinge0
- Outcome
- chlorophyllse0
- Direction
- retained similar levelse0
- Value
- 14.65 ± 0.36 mg dw g−1e0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After freezing, the content of chlorophylls, carotenoids, and total phenolic acids retained similar levels as in control plants and amounted to 14.65 ± 0.36 mg dw g−1, 2.58 ± 0.05 mg dw g−1 and 13.75 ± 0.07 mg dw CEA g−1, respectively.”
t0“Kale”
Claim · model-written summary
After freezing, carotenoids remained at control level, 2.58 ± 0.05 mg dw g−1.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- freezinge0
- Outcome
- carotenoidse0
- Direction
- retained similar levelse0
- Value
- 2.58 ± 0.05 mg dw g−1e0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After freezing, the content of chlorophylls, carotenoids, and total phenolic acids retained similar levels as in control plants and amounted to 14.65 ± 0.36 mg dw g−1, 2.58 ± 0.05 mg dw g−1 and 13.75 ± 0.07 mg dw CEA g−1, respectively.”
t0“Kale”
Claim · model-written summary
After freezing, phenolic acids remained at control level, 13.75 ± 0.07 mg dw CEA g−1.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- freezinge0
- Outcome
- total phenolic acidse0
- Direction
- retained similar levelse0
- Value
- 13.75 ± 0.07 mg dw CEA g−1e0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After freezing, the content of chlorophylls, carotenoids, and total phenolic acids retained similar levels as in control plants and amounted to 14.65 ± 0.36 mg dw g−1, 2.58 ± 0.05 mg dw g−1 and 13.75 ± 0.07 mg dw CEA g−1, respectively.”
t0“Kale”
Claim · model-written summary
Freezing increased total polyphenols by 13%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- freezing temperaturee0
- Outcome
- total polyphenol contente0
- Direction
- increasede0
- Value
- 13%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At the freezing temperature, total polyphenol content increased 13%”
t0“Kale”
Claim · model-written summary
Freezing decreased total flavonoids by 21%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- Low Temperaturest0
- Outcome
- total flavonoidse0
- Direction
- decreasede0
- Value
- 21%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total flavonoids and glucosinolates content decreased 21% and 54%, respectively.”
t0“Effects of Short-Term Exposure to Low Temperatures on Proline, Pigments, and Phytochemicals Level in Kale (Brassica oleracea var. acephala)”
Claim · model-written summary
Freezing decreased glucosinolates by 54%.
- Taxon
- KaleBrassica oleracea var. viridist0
- Treatment
- Low Temperaturest0
- Outcome
- glucosinolates contente0
- Direction
- decreasede0
- Value
- 54%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total flavonoids and glucosinolates content decreased 21% and 54%, respectively.”
t0“Effects of Short-Term Exposure to Low Temperatures on Proline, Pigments, and Phytochemicals Level in Kale (Brassica oleracea var. acephala)”
Claim · model-written summary
The authors suggest accounting for growing temperature when producing kale rich in health-related compounds.
- Taxon
- kaleBrassica oleracea var. viridise0
- Outcome
- growing temperature during kale cultivation must be considerede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“growing temperature during kale cultivation must be considered as an important parameter for producers that are orientated towards production of crops with an increasing content of health-related compounds.”
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