Nutritional Properties of De-fatted Coconut (<em>Cocos nucifera</em> L.) Testa Flour Incorporated Sri Lankan Traditional Food: Roti

Abstract

Coconut testa (brown outer skin of coconut kernel) is a by-product of coconut industry and it does not have proper usage at present. The aim of this research was to evaluate the potential of coconut testa flour (TF) to substitute for wheat flour in preparation of unleavened bread or roti. TF is the ground defatted dehydrated coconut parings obtained from paring oil extraction. The dehydrated brown testa was subjected to oil extraction using cold press expeller followed by grinding into a fine flour. The quality of raw material (testa and TF) was evaluated. The samples of roti were prepared by incorporating 0%, 10%, 20% and 30% of TF instead of wheat flour and the sensory attributes of the roti were evaluated. Functional and proximate composition of flour blends and selected roti samples were compared with a control (100% wheat flour). Fat and moisture contents of dehydrated parings were 58.06% and 4.04% respectively, and the concentrations were reduced to 16.97% and 2.56% respectively while producing TF. All sensory attributes (taste, texture, appearance, smell, overall acceptability) of the TF incorporated roti were significantly different (P<0.05) compared to the roti made with 100% wheat flour (WF). According to the results, TF can be successfully substituted for wheat flour up to a level of 20% to enhance nutritional qualities of roti. No significant difference of swelling capacity, bulk density, tapped density and water absorption capacity (P>0.05) between the selected flour blend sample (20% TF: 80% WF) and 100% WF sample was observed. However, crude fiber and protein contents of the 20% TF and 80% WF blend were significantly (P<0.05) higher than the WF only samples. The TF incorporation (20%) contributed to increase the crude fiber content of roti from 1.81% to 7.04% and protein content from 12.43% to 16.06%.