Influence of Cooking Methods on Phenolic and Antioxidant Activity of Yams <i>(Dioscorea Spp.) </i>and Cocoyam <i>(Xanthosoma Maffa [Scoth]) </i> Tuber Extracts


  • C. F. Ezeama
  • D. O. Ortiz
  • I. J. Aragon
  • P. C. Ojimelukwe


Phenolic, Antioxidant activity, Cooking methods, Yam (Dioscorea spp.), Cocoyam (X.maffa (Scoth).


The influence of cooking methods (boiling, roasting, deep-fat frying and oven-drying) on phenolic and antioxidant activity of  yams (Dioscorea cayenensis, Dioscorea dumetorum, and Dioscorea bulbifera) and cocoyam (Xanthosoma maffa (Scoth) were evaluated using Folin-Ciocalteu´s reagent, Aluminum chloride, ABTS(2,2´-azinobis-(3-ethylbenzothiazoline-6-sulponic acid)diammonium salt, DPPH(2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity).The correlation coefficient analysis was also determined. Almost all the cooking methods significantly increased (P<0.05) the polyphenols and flavonoids content of the yam (Dioscorea) tuber variety extracts, but with losses in X. maffa (Scoth) when compared to their fresh samples. High losses in ABTS radical scavenging activity was observed in X. maffa (Scoth) and D. dumetorum after all the cooking methods. Analysis of DPPH radical scavenging activity showed strong losses after different cooking methods in some of the tuber varieties. High ORAC value was observed in the boiled method in D. cayenensis and D. bulbifera while other methods showed significant (P<0.05) losses. A high correlation coefficient was observed between total flavonoids (TF) and ABTS (R2=0.839) in D. cayenensis, between total polyphenols (TP) and ORAC (R2= -0.917), TF and ORAC (R2= -0.862) in D. dumetorum, between TP and ORAC (R2= -0.852), TF and ORAC (R2= -0.930) in D. bulbifera, and between TF and ABTS (R2=0.957), TF and DPPH (R2=0.825) in X. maffa (Scoth). Significant correlation coefficient was also observed in the different cooking methods. Polyphenol and especially flavonoid were found to be major contributors to their antioxidant activities.



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How to Cite

Ukom, A. N., Ezeama, C. F., Ortiz, D. O., Aragon, I. J., & Ojimelukwe, P. C. (2014). Influence of Cooking Methods on Phenolic and Antioxidant Activity of Yams <i>(Dioscorea Spp.) </i>and Cocoyam <i>(Xanthosoma Maffa [Scoth]) </i> Tuber Extracts. Asian Journal of Agriculture and Food Sciences, 2(5). Retrieved from