Impact of cooking on nutritional contents of kenger in terms of antioxidants

Abstract Kenger (Gundelia tournefortii) grown in Sanliurfa and neighbouring provinces in Turkiye, is known for its health promoting potential due to the presence of bioactive compounds as phenolics and antioxidant vitamins. However, such compounds in food may be affected by thermal treatment as cook...

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Main Authors: Indrani Kalkan, Ozan Emre Eyupoglu, Sukru Karatas, Zakia El Miri Aissaoui, Rusen Anık
Format: Article
Language:English
Published: BMC 2025-01-01
Series:Food Production, Processing and Nutrition
Subjects:
Online Access:https://doi.org/10.1186/s43014-024-00274-0
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author Indrani Kalkan
Ozan Emre Eyupoglu
Sukru Karatas
Zakia El Miri Aissaoui
Rusen Anık
author_facet Indrani Kalkan
Ozan Emre Eyupoglu
Sukru Karatas
Zakia El Miri Aissaoui
Rusen Anık
author_sort Indrani Kalkan
collection DOAJ
description Abstract Kenger (Gundelia tournefortii) grown in Sanliurfa and neighbouring provinces in Turkiye, is known for its health promoting potential due to the presence of bioactive compounds as phenolics and antioxidant vitamins. However, such compounds in food may be affected by thermal treatment as cooking. This study investigated the impact of common cooking techniques (boiling and stir-frying in oil) on phenolics, vitamin C content and antioxidant activity of kenger. Phenolic compounds were analysed using LC–MS/MS and DPPH inhibition. Vitamin C was quantified using HPLC and antioxidant activities were assessed by DPPH inhibition, ABTS and FRAP methods. Major phenolic compounds in raw samples were vanillic (18.755 ± 0.606 µg/g) and fumaric (16.211 ± 0.524 µg/g) acids. In boiled kenger, significant loss of fumaric (5.789 ± 0.187 µg/g), in stir-fried kenger, loss of vanillic (15.604 ± 0.504 µg/g) and fumaric (8.113 ± 0.262 µg/g) acids were noted (p < 0.05). Vitamin C content of raw kenger was 7.104 ± 0.074 µg/g but decreased to 6.812 ± 0.22 µg/g in boiled and 6.898 ± 0.072 µg/g in stir-fried samples. The radical scavenging potentials of sample extracts at different concentrations (25 mg/mL, 50 mg/mL, 75 mg/mL, 100 mg/mL,150 mg/mL and 300 mg/mL) were tested by DPPH, FRAP and ABTS methods. At 300 mg/mL, antioxidant activity in raw kenger was calculated as 1.350 ± 0.0007 μmoles/mg/mL (FRAP), 0.731 ± 0.0008 μg (EC50 DPPH) and 52 ± 3.45% TEAC (ABTS). In general, antioxidant activities for all methods increased with rising concentration of the sample extract. Antioxidant activity of boiled samples decreased significantly as per FRAP and increased for stir-fried kenger at higher sample concentrations as per FRAP and ABTS, possibly due to chemical changes during high thermal treatment in oil. Correlation between cooking methods was not significant (p > 0.05) in terms of phenolic compounds and vitamin C. Correlation between antioxidant activity assessing methods were only significant for 75 and 100 mg/mL sample concentration (rho = -0.90 p < 0.05). In conclusion, boiled and stir-fried kenger is suggested as optional consumption methods. Inclusion of condiments, herbs, olive oil, yoghurt during service would not only increase palatibility but also add to the health benefits. Graphical Abstract
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spelling doaj-art-abdd95f6c99a4a71902305998b0f697e2025-01-05T12:41:51ZengBMCFood Production, Processing and Nutrition2661-89742025-01-017111210.1186/s43014-024-00274-0Impact of cooking on nutritional contents of kenger in terms of antioxidantsIndrani Kalkan0Ozan Emre Eyupoglu1Sukru Karatas2Zakia El Miri Aissaoui3Rusen Anık4Faculty of Health Sciences, Nutrition and Dietetics Department, Istanbul Medipol UniversitySchool of Pharmacy, Biochemistry Department, Istanbul Medipol UniversityFaculty of Health Sciences, Nutrition and Dietetics Department, Istanbul Arel UniversityScience Faculty, University of GranadaDietician M.ScAbstract Kenger (Gundelia tournefortii) grown in Sanliurfa and neighbouring provinces in Turkiye, is known for its health promoting potential due to the presence of bioactive compounds as phenolics and antioxidant vitamins. However, such compounds in food may be affected by thermal treatment as cooking. This study investigated the impact of common cooking techniques (boiling and stir-frying in oil) on phenolics, vitamin C content and antioxidant activity of kenger. Phenolic compounds were analysed using LC–MS/MS and DPPH inhibition. Vitamin C was quantified using HPLC and antioxidant activities were assessed by DPPH inhibition, ABTS and FRAP methods. Major phenolic compounds in raw samples were vanillic (18.755 ± 0.606 µg/g) and fumaric (16.211 ± 0.524 µg/g) acids. In boiled kenger, significant loss of fumaric (5.789 ± 0.187 µg/g), in stir-fried kenger, loss of vanillic (15.604 ± 0.504 µg/g) and fumaric (8.113 ± 0.262 µg/g) acids were noted (p < 0.05). Vitamin C content of raw kenger was 7.104 ± 0.074 µg/g but decreased to 6.812 ± 0.22 µg/g in boiled and 6.898 ± 0.072 µg/g in stir-fried samples. The radical scavenging potentials of sample extracts at different concentrations (25 mg/mL, 50 mg/mL, 75 mg/mL, 100 mg/mL,150 mg/mL and 300 mg/mL) were tested by DPPH, FRAP and ABTS methods. At 300 mg/mL, antioxidant activity in raw kenger was calculated as 1.350 ± 0.0007 μmoles/mg/mL (FRAP), 0.731 ± 0.0008 μg (EC50 DPPH) and 52 ± 3.45% TEAC (ABTS). In general, antioxidant activities for all methods increased with rising concentration of the sample extract. Antioxidant activity of boiled samples decreased significantly as per FRAP and increased for stir-fried kenger at higher sample concentrations as per FRAP and ABTS, possibly due to chemical changes during high thermal treatment in oil. Correlation between cooking methods was not significant (p > 0.05) in terms of phenolic compounds and vitamin C. Correlation between antioxidant activity assessing methods were only significant for 75 and 100 mg/mL sample concentration (rho = -0.90 p < 0.05). In conclusion, boiled and stir-fried kenger is suggested as optional consumption methods. Inclusion of condiments, herbs, olive oil, yoghurt during service would not only increase palatibility but also add to the health benefits. Graphical Abstracthttps://doi.org/10.1186/s43014-024-00274-0Antioxidant activityKengerBoilingStir-fryingPhenolic compoundsVitamin C
spellingShingle Indrani Kalkan
Ozan Emre Eyupoglu
Sukru Karatas
Zakia El Miri Aissaoui
Rusen Anık
Impact of cooking on nutritional contents of kenger in terms of antioxidants
Food Production, Processing and Nutrition
Antioxidant activity
Kenger
Boiling
Stir-frying
Phenolic compounds
Vitamin C
title Impact of cooking on nutritional contents of kenger in terms of antioxidants
title_full Impact of cooking on nutritional contents of kenger in terms of antioxidants
title_fullStr Impact of cooking on nutritional contents of kenger in terms of antioxidants
title_full_unstemmed Impact of cooking on nutritional contents of kenger in terms of antioxidants
title_short Impact of cooking on nutritional contents of kenger in terms of antioxidants
title_sort impact of cooking on nutritional contents of kenger in terms of antioxidants
topic Antioxidant activity
Kenger
Boiling
Stir-frying
Phenolic compounds
Vitamin C
url https://doi.org/10.1186/s43014-024-00274-0
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AT ozanemreeyupoglu impactofcookingonnutritionalcontentsofkengerintermsofantioxidants
AT sukrukaratas impactofcookingonnutritionalcontentsofkengerintermsofantioxidants
AT zakiaelmiriaissaoui impactofcookingonnutritionalcontentsofkengerintermsofantioxidants
AT rusenanık impactofcookingonnutritionalcontentsofkengerintermsofantioxidants