Table of Contents
Journal of Food Processing
Volume 2014, Article ID 418380, 4 pages
Research Article

Effect of Thermal Processing on the Nutritional, Antinutritional, and Antioxidant Properties of Tetracarpidium conophorum (African Walnut)

Department of Food Technology, Federal Polytechnic Ado Ekiti, Ado Ekiti 360231, Ekiti State, Nigeria

Received 29 May 2014; Revised 11 October 2014; Accepted 11 October 2014; Published 9 November 2014

Academic Editor: Franco P. Pedreschi

Copyright © 2014 S. Olanrewaju Arinola and Kunle Adesina. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The effect of thermal processing (roasting and boiling) on the nutritional, antinutritional, and antioxidant properties of African walnut was studied. Tetracarpidium conophorum (African walnut) was subjected to thermal treatment of roasting (RWIS), boiling with shell (BWIS), and boiling without shell (BWOS). The resulting samples with raw nut (RAAW) which served as control were analysed for proximate composition, antinutritional components, and antioxidant activity. The protein, fat, and ash contents of the samples on dry basis were 29.14%, 54.14%, and 3.32% (RAAW); 24.13%, 61.75%, and 2.77% (BWIS); 22.47%, 62.65%, and 2.16% (BWOS); and 24.25%, 60.52%, and 2.48% (RWIS), respectively. Thermal processing had significant effect on all the proximate principles; boiling and roasting generally reduced the protein and ash contents of the nut. Boiling with or without shell reduced the phytate and tannin contents of the nut while roasting increased the level of these two antinutritional components; walnut boiled without shell however, had the lowest phytate and tannin contents of 0.815 mg/100 g and 0.239 mg/100 g, respectively. The antioxidant activities of the samples were 8.47% (RAAW), 13.82% (BWIS), 14.96% (BWOS), and 7.29% (RWIS). This study reveals that thermal processing has a significant effect on the proximate principles, bioavailability, and antioxidant activity of African walnut.