Determination of Selected Metals and Nutritional Compositions of Pigeon Pea ( Cajanus cajan) Cultivated in Wolaita Zone, Ethiopia

Abstract

This study was aimed to determine the level of selected metals and nutritional composition of pigeon pea seed collected from seven districts of Wolaita zone. A wet digestion procedure involving the use of mixtures of (69%-72%) HNO 3 and (70%) HClO 4 at an optimum temperature and time duration was used to determine metals by using flame atomic absorption spectrometry. Kjeldahl digestion method, Soxhlet extraction and furnace were used to determine nutritional values of pigeon pea, and physicochemical properties of soils were assessed using standard methods. The results showed that the levels of concentration of metals in mg/kg dry weight were ranged 105.17 to 144.07 for K, 8.95 to 12.67 for Mg, 7.74 to 12.27 for Ca, 0.247 to 0.543 for Fe, 0.122 to 0.313 for Zn, 0.061 to 0.432 for Mn, 0.087 to 0.134 for Cu and 0.0011 to 0.00196 for Cr. The proximate composition of pigeon pea was in the range of 19.28% to 25.79% for crude protein, 0.993% to 1.75% for crude fat, 3.75% to 5.31% for ash, 10.65% to 13.73% for moisture, 2.28% to 3.06% for fiber, 54.36% to 60.1% for carbohydrate and 326.8 to 345.23 Kcal for energy.