PAPER TITLE :EFFECTS OF COOKING ON PHENOLIC CONTENT AND ANTIOXIDANT PROPERTIES OF AFRICAN WALNUT [TETRACARPIDIUM CONOPHORUM (MÜLL. ARG.) HUTCH. & DALZIEL.] SEEDS

FUTA JOURNAL OF RESEARCH IN SCIENCE | VOLUME 11 NUMBER 2 2015

Paper Details

  • Author(s) : A.O. Ademiluyi, G. Oboh, A.O. Ademosun, S.I. Oyeleye, I. I. Ejakpovi and O.B. Ogunsuyi
  • Abstract:

African walnut [Tetracarpidium conophorum (Müll. Arg.) Hutch. & Dalziel.] seeds are predominant African delicacy with ethnomedical relevance. The shelled seeds are processed by cooking (boiling) to obtain the edible cotyledons. This study investigated the effect of cooking on the phenolic and vitamin C constituents as well as antioxidant properties of aqueous extracts of African walnut seeds cooked with (shelled) and without (unshelled) the shell.  Walnut seeds were boiled with and without the shell for four hours and the edible cotyledon extracted into water. Results showed that shelled walnut extract had significantly (P<0.05) higher total phenol, total flavonoid and vitamin C contents than the unshelled walnut extract. Similarly, the shelled walnut extract possessed a significantly (P<0.05) higher reducing property, and there was also a significantly (P<0.05) higher 1, 1-diphenyl-2 picrylhydrazyl (DPPH) and hydroxyl (OH*) radicals scavenging abilities, as well as Fe2+ chelating ability than the unshelled walnut extract; there was however, no significant difference (P>0.05) in the 2, 2′-azino-bis (3-ethylbenzthiazoline-6sulphonic acid) (ABTS*+) radical scavenging abilities between the two extracts. The results of this study showed that cooking walnut with the shell could protect the antioxidant constituents from thermal decomposition and leaching thus culminating in the observed higher antioxidant activities over the unshelled walnut.  Keywords: African walnut, processed, cooking, antioxidants, phenolic acids, vitamin C