Antioxidant activities of two sweet pepper Capsicum annuum L. varieties phenolic extracts and the effects of thermal treatment

Document Type: Original Research Article


Department of Biology, Faculty of Science, Urmia University, Urmia, I. R. Iran


Objectives: Sweet peppers Capsicum annuum L. (C. annuum) are an excellent source of vitamins A and C as well as phenolic compounds, which are important antioxidant components that may reduce the risk of diseases. The objective of this study was to evaluate their antioxidant activity under various temperatures.
Materials and Methods: To compare the antioxidant activity in various temperatures (20, 35, 50, and 65 °C), two different types of colored (red and green) sweet bell peppers C annuum were selected. The red peppers were selected from those cultivated in Shahreza, Esfahan and the green peppers with the local name of Gijlar were selected from those cultivated in Urmia, West Azarbayjan. The experiments were carried out to measure the total phenolic and flavonoid content, ferric reducing antioxidant power (FRAP), chain-breaking activity, scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH), and hydrogen peroxide radicals.
Results: Total phenol and flavonoid contents of pepper extracts were enhanced with increasing temperature to 65 °C. Scavenging capacity of DPPH radical of red pepper extract was enhanced because of putting at 50 °C for 30 min and for Gijlar pepper extract scavenging capacity was increased at 65 °C. Scavenging capacity of hydrogen peroxide radical of extracts was the highest at 35 °C. Chain-breaking activity of red pepper extract was increased for 60 min at 35 °C. FRAP (C) of red pepper extract was significantly different (p<0.05) in compare with Gijlar pepper.
Conclusion: An appropriate temperature maintained a high antioxidant activity of phenolic compound, which could be due to the combined effect of non enzymatic reaction and phenolic compound stability.


Akowuah GA, Mariam A, Chin JH. 2009. The effect of extraction temperature on total phenols and antioxidant activity of Gynura procumbens leaf. Pharmacogn Mag, 5: 81-85.

Aoyama S, Yamamoto Y. 2007. Antioxidant activity and flavonoid content of Welsh onion (Allium fistulosum) and the effect of thermal treatment. Food Sci Technol Res, 13: 67-72.

Benkeblia N. 2005. Free-Radical scavenging capacity and antioxidant properties of some selected onions (Allium cepa L.) and garlic (Allium sativum L.) extracts. Brazilian Arch Biol Technol, 48: 753-759.

Benzie IF, Strain JJ. 1996. The ferric reducing ability of plasma (FRAP) as a measure of ‘‘antioxidant power’’: the FRAP assay. J Anal Biochem, 239: 70-76.

Bonvehi JS, Torrento MS, Lorente EC. 2001. Evaluation of polyphenolic and flavonoid compounds in honeybee-collected pollen produced in spain. J Agricul Food Chem, 49: 1848-1853.

Brand-Williams W, Cuvelier ME, Berset C. 1995. Use of free radical method to evaluate the antioxidant activity. Lebensmittel Wissenshaft and Technologie-Food Sci Technol, 28: 25-30.

Burits M, Bucar F. 2000. Antioxidant activity of Nigella sativa essential oil. Phytother Res, 14: 323-328.

Cadenas E, Packer L. 1996. Hand book of antioxidants, Plenum, New York.

Chen ML, Yang DJ, Liu SC. 2011. Effects of drying temperature on the flavonoid, phenolic acid and antioxidative capacities of the methanol extract of citrus fruit (Citrus sinensis (L.) Osbeck) peels. Int J Food Sci Technol, 46: 1179-1185.


Chipurura B, Muchuweti M, Manditseraa F. 2010. Effects of thermal treatment on the phenolic content and antioxidant activity of some vegetables. Asian J Clin Nutr, 2: 93-100.

Deng OH, Yu AN, Cao XF. 2011. The effect of heating time on antioxidant activity of Maillard reaction products derived from a L-ascorbic acid and L-methionine model system. School of Chemistry and Environmental Engineering Hubei University for Nationalities Enshi, Hubei, China,445000.

Duan XW, Jiang YM, Su XG, Zhang ZQ, Shi J. 2007. Antioxidant property of anthocyanins extracted from Litchi (Litchi chinenesis Sonn.) fruit pericarp tissues in relation to their role in the pericarp browning. Food Chem, 101: 1382-1388.

Garau MC, Simal, S, Rosello C, Femenia A. 2007.  Effect of air-drying temperature on physico-chemical properties of dietary fibre and antioxidant capacity of orange (Citrus aurantium v. Canoneta) by-products. Food Chem, 104(3): 1014-1024.

Ho SC, Lin CC. 2008. Investigation of heat treating conditions for enhancing the anti-inflammatory activity of citrus fruit (Citrus reticulata) peels. J Agric Food Chem, 56: 7976-7982.

Horwitz W. 1984. Official methods of analysis of the association of official analytical chemists. Washington, D. C. 14 TH Ed. AOAC.

Jahanban Sfahlan A, Mahmoodzadeh A, Hasanzadeh A, Heidari R, Jamei R. 2009. Antioxidants and antiradicals in almond hull and shell (Amygdalus communis L.) as a function of genotype. Food Chem, 115: 529-533.

Jeong SM, Kim SY, Kim DR, Jo SC, Nam KC, Ahn DU, Lee SC. 2004. Effect of heat treatment on the antioxidant activity of extracts from citrus peels. J Agric Food Chem, 52: 3389-3393.

Lima GPP, Lopes TDVC, Rossetto MRM, Vianello F. 2009. Nutritional composition, phenolic compounds, nitrate content in eatable vegetables obtained by conventional and certified organic grown culture subject to thermal treatment. International J Food Sci Technol, 44: 1118-1124.

Lopez J, Uribe E, Vega-Galvez A, Miranda M, Vergara J, Gonzalez E, Di Scala K. 2010. Effect of air temperature on drying kinetics, vitamin C, antioxidant activity, total phenolic content, non-enzymatic browning and firmness of blueberries variety O Neil. Food Bioprocess Technol, 3: 772-777.

Madrau MA, Piscopo A, Sanguinetti AM, Del Caro A, Poiana M, Romeo FV, Piga A. 2009. Effect of drying temperature on polyphenolic content and antioxidant activity of apricots. Eur Food Res Technol, 228: 441-448.

Meir S, Kanner J, Akiri B, Hadas SP. 1995. Determination and involvement of aqueous reducing compounds in oxidative defense systems of various senescing leaves. J Agric Food Chem, 43: 1813-1817.

Miglio C, Chiavaro E, Visconti A, Fogliano V, Pellegrini N. 2008. Effects of different cooking methods on nutritional and physicochemical characteristics of selected vegetables. J Agric Food Chem, 56: 139-147.

Miranda M, Maureira H, Rodriguez K, Vega-Galvez A. 2009. Influence of temperature on the drying kinetics, physicochemical properties, and antioxidant capacity of Aloe Vera (Aloe Barbadensis Miller) gel. J Food Eng, 91: 297-304.

Oboh, G, Rocha JB. 2008. Hot Pepper (Capsicum spp.) protects brain from sodium nitroprusside- and quinolinic acid-induced oxidative stress in vitro. J Med Food, 11: 349-355.

Que F, Mao L, Fang X, Wu T. 2008. Comparison of hot air drying and freeze-drying on the physicochemical properties and antioxidant activities of pumpkin (Cucurbita moschata Duch.) flours.  Int J Food Sci Technol, 43: 1195-1201.

Reyes LF, Cisneros-Zevallos L. 2007. Degradation kinetics and colour of anthocyanins in aqueous extracts of purple and red flesh potatoes (Solanum tuberosum L.). Food Chem, 100: 885-894.

Roginsky V. Lissi EA. 2005. Review of methods to determine chain-breaking antioxidant activity in food. Food Chem, 92: 235-254.

Roy MK, Takenaka M, Isobe S, Tsushida T.  2007. Antioxidant potential, anti proliferative activities and phenolic content in water-soluble fractions of some commonly consumed vegetables: effect of thermal treatment. Food Chem, 103:106-114.

Ruch RJ, Cheng SJ, Klauring JE. 1989. Prevention of cytotoxicity and inhibition of intracellular communication by antioxidant catechins isolated from Chinese green tea. Carcinogenesis, 10: 1003-1008.

Sies H. 1996. (Ed., (Antioxidants in disease, mechanisms and therapy, Academic Press, New York.

Siriwardhana SSKW, Shahidi F. 2002. Antiradical activity of extracts of almond and its by-products. Am J Oil Chem Soc, 79: 903-908.

Sun T, Xu Z, Wu CT, Janes M, Prinyawiwatkul W, No HK. 2007. Antioxidant activities of different colored sweet bell peppers (Capsicum annuum L.). J Food Sci, 72: S98-102.

Vanderslice JT, Higgs DJ, Hayes JM, Block G. 1990. Ascorbic acid and dehydroascorbic acid content of food-as-eaten.  J Food Compos Anal, 3: 105-118.

Vega-Galvez A, Di Scala K, Rodriguez K, Lemus-Mondaca R, Miranda M, Lopez J, Perez-Won M. 2009. Effect of air-drying temperature on physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper (Capsicum annuum L. var. Hungarian). Food Chem. 117: 647-653.

Xu G, Ye X, Chen J, Liu D. 2007. Effect of heat treatment on the phenolic compounds and antioxidant capacity of citrus peel extract. J Agric Food Chem, 55: 330-335.

Zhang DL, Grigor JM, Quantick PC. 2000. Changes in Phenolic compounds in Litchi (Litchi chinensis Sonn.) fruit during postharvest storage. Postharv Biol Technol, 19: 165-172.

Zhang ZQ, Pang XQ, Yang C, Ji ZL, Jiang YM. 2001. Role of Anthocyanins degradation in Litchi pericarp browning. Food Chem, 75: 217-221.