Mineral analysis
Calcium (Ca), iron (Fe), magnesium (Mg), sodium (Na), zinc
(Zn) and copper (Cu) were analyzed using Inductively
Coupled Plasma Optical Emission Spectrometry (ICP-OES)
(Perkin Elmer, USA). Finely ground sample (3 g) was digested
using a dry ashing method (AOAC, 2005). The resulting ash
was then dissolved in concentrated hydrochloric acid (7 ml)
before being diluted to 100 ml with deionized water. The solution
was filtered and the mineral content was determined using
ICP-OES.