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

Abstract

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) 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

Keywords

• Antioxidant activity
• Kenger
• Boiling
• Stir-frying
• Phenolic compounds
• Vitamin C