Comparative Analysis of Phenolic Composition and Antioxidant Effect of Seed Coat Extracts of Four Cowpea (Vigna unguiculata) Varieties on Broiler Meat

Document Type : Research Articles


Department of Animal Production, Faculty of Agriculture, University of Ilorin, Ilorin, Nigeria


Seed coat crude extracts of white-coloured ITA-256, white and brown-coloured TVS-716, deep brown-coloured IT-90K and light brown-coloured Ife brown cowpea varieties were analyzed for the presence and amount of total phenol, tannin and flavonoid content. Crude extracts of the cowpea varieties were analyzed for antioxidant activity using the Thiobarbituric Acid (TBA) assay. The seed coat extracts were added sepa-rately to 200 g of minced broiler meat sample at the rate of 0.05% of the weight of the meat and their effect compared to that of the synthetic antioxidant, butylated hydroxyl anisole (BHA) added to the meat at the rate of 0.05%. Each sample was divided into 16 parts of 12.5 g each. Eight of these were cooked while the other 8 parts were left raw. Antioxidant effect of the seed coat extracts was determined during refrigerated storage of raw and cooked minced broiler meat. All the cowpea varieties studied except TVS-716 contained phenol, tannin and flavonoids. TVS-716 contained only phenol and tannin. Seed coats extract from Ife brown contained higher levels of total phenol, tannin and flavonoids than the corresponding samples of IT-90K, ITA-256 and TVS-716. IT-90K had higher tannin content than ITA-256 and TVS-716 but its phenol and flavonoids content are not significantly different (P>0.05) from that of ITA-256. TBA assay shows that all the additives and BHA were able to reduce lipid oxidation in broiler meat. This was shown by lower TBARS values in broiler meat samples with added additives compared to the con-trol samples (meat without additives). Seed coat extracts of Ife brown, ITA-256 and IT-90k reduce lipid oxidation more than BHA in raw broiler meat samples but are less potent than BHA in cooked meat sam-ples. Seed coat extracts of Ife brown was more effective than other cowpea varieties in reducing lipid oxida-tion in both cooked and raw meat samples. The antioxidant potential of IT-90K was not significantly differ-ent (P>0.05) from that of ITA-256 while TVS-716 exhibited the least antioxidant potency.


Abdallah A.E. and Roozen J.P. (1999). Effect of plant extracts on the oxidative stability of sunflower oil and emulsion. J. Agric. Food Chem. 64, 323- 329.
Asghar A., Gray J.L., Buckley D.J., Pearson A.M. and Booren A.M. (1988). Perspectives in warmed-over flavor.Food Techno. 42(6), 102-108.
Awe I.S. and Shodipo O.A. (2001): Purification of Saponin of root of Bilighia sapida. Nig J. Biochem. Mol. Biol. (Proceeding supplement ). 16, 201-204.
Awika J.M., Rooney L.W., Wu X., Prior R.L. and Cisneros-Zevalos L. (2003). Screening methods to measure antioxidant activity of sorghum (sorghum bicolor) and sorghum products. J. Agric. Food Chem. 50, 6657-6662.
Branen A.L. (1975). Toxicology and biochemistry of butylated hydroxyl anisole and butylated hydroxyl toluene. J. Oil Chem. Sci. 52, 59-63.
Cai R., Hettiarachchy N.S. and Jalaludin M. (2003). High Performance liquid chromatography determination of phenolic constituents in 17 varieties of cowpeas. J. Agric. Food Chem. 51, 1623-1627.
Chang M.J., Collins J.L., Bailey J.W. and Coffey D.L. (1994). Cowpea tannin related to cultivar, maturity, dehulling and heating. J. Food Sci. 59, 1034-1036.
Egounlety M. and Aworh O.C. (2003). Effect of soaking, dehulling, cooking and fermentation with Rhizopus oligosporus on the oligosaccharide, trypsin inhibitor, phytic acid and tannins of soybean (Glycine max), cowpea (Vigna uguiculata L.Walp) and ground bean (Marcotyloma geocarpa Harms). J. Food Engin. 50, 249-254.
Giami S.Y. and OKwechime U.I. (1993). Physiochemical properties and cooking quality of four new cultivars of Nigerian cowpea (Vigna unguiculata L.Walp). J. Sci. Food. Agric. 63, 281-286.
Gray S.S., Gomnae E.A. and Buckley D.J. (1996). Oxidative quality and shelf life of meat. J. Meat Sci. 42, 127-132.
Kahl R. and Kappus H. (1993).Toxicology of synthetic antioxidants BHAand BHT in comparisonwith natural antioxidant Vitamin C. Zeitschrift-fuer Lebesmittel-Untersuchung and Forshung. 196, 329-338.
Krinsky N.I. (1994). Plant carotenoids and related molecules: important dietary antioxidants. Pp. 117-126 inProc. Biochemical Society Symposium. No 61. Ed., by C. Rice-Evans, B.B. Halliwell, and G.G. Lunt . Portland Press London, UK.
Larrauri J.A., Sanchez-Moreno C. and Saura-Calixto F. (1998). Effect of temperature on the free radical scavenging capacity of extracts from red and white grape pomace peels. J. Agric. Food Chem. 46, 2694-2697.
lattanzio V., Cardinali A., Linsalata V., Perrino P. and Ng N.Q. (1997). Flavonoid HPLC fingerprint of Wild Vigna species. Pp. 66-74 in Advances in Cowpea Research. B.B. Singh, D.R. Mohan Raj, K.E. Dashiella and L.E.N. Jackai, Eds.
Lethabo B.M. (2006). Cowpea seed coats and their extracts: Phenolic composition and use as antioxidant in sunflower oil. M S. Thesis. University of Pretoria.
Morrison I.M., Asiedu E.A., Stuchbury T. and Powel A.A. (1995). Determination of lignin and tannin contents of cowpea seed coats. Ann. Botany. 76, 287-290.
Oboh H.A., Muzquiz N., Burbano C., Cuadrado C., Pedrosa M.M., Ayet G. and Osagie A.U. (1998). Anti-nutritional constituents of six underutilized legumes grown in Nigeria. J. Chromatography. 823, 307-312.
Olorunsanya O.A., Olorunsanya E.O., Akanbi A.S. and Kayode R.M.O. (2009). Antioxidant properties of rice husk extract in raw and cooked pork patties. J. Appl. Agric. Res. 1, 143-147.
Olorunsanya O.A., Olorunsanya E.O., Bolu S.A.O., Adejumobi C.T. and Kayode R.M.O. (2010).Effect of graded levels of lemongrass (Cymbopogon citratus) on oxidative stability of raw and cooked pork patties. PakistanJ. Nutr. 9, 467-470.
Preet k. and Prunia D. (2000). Proximate composition, phytic acid, polyphenols and digestibility (in vitro) of four brown cowpea varieties. Int. J. Food Sci. Nutr. 50, 189-193.
Rice-EvansC.A., Miller N.J. and Paganga G. (1996). Structure-antioxidant activity relationships of flavonoids and phenolic acids. J. Free. Rad. Biol. Med. 20, 933-956.
Salih A.M., Price J.F., Smith D.M. and Dawson L.E. (1989). Lipid degradation in turkey breast meat during cooking and storage.J. Poult. Sci. 68, 754-761.
Smith G.C., Cross H.R., Carpenter Z.L., Murphy C.E., Savell J.W., Abraham H.C. and Davos G.W. (1982). Relationship of USDA maturity groups to palatability of cooked beef. J. Food Sci. 2, 47-50.
Sofowora A. (1980).Guidelines for research promotion and development in traditional medicine. Nigerian J. Pharmacy. 11, 117-118.
Sosulski F. and Dabrowski K. (1984). Composition of free and hydrosylable phenolic acids in the flours and hulls of ten legume species. J. Agric. Food Chem. 32, 131-133.
Sroka Z. and Cisowski W. (2003). Hydrogen peroxide scavenging antioxidant and antiradical activity of some phenolic acids. J. Food Sci. Chem. Toxicology. 41, 753-758.
Tarladgris B.G., Pearson A.M. and Dungan L.R. (1964). Chemistry of 2-TBA test for determination of oxidative Rancidity in foods and formation of TBA malonaldehyde complex without acid heat treatment. J. Sci. Food Agric. 15, 607-620.
Troszynska A., Estrella I., Lopez-Amores M.L. and Hermandez T. (2002). Antioxidant activity of pea (Pisum sativum L.) seed coat acetone extract. Lebensmittel-Wissenschaft und Technologie. 35, 158-164.
Veliogu Y.S., Mazza G., Gao L. and Oomah B.D. (1998). Antioxidant activity and total phenolics in selected fruits vegetables and grain products. J. Agric. Food Chem. 46, 4113-4117.