Proximate, mineral and antioxidant activity of wonderful kola (Buchholzia coriacea) seed (fresh and freeze-dried)

Plants contain nutrient and phytochemicals, which serve as food and medicine to promote good nutritional and health wellbeing in human. Buchholzia coriacea is a perennial plant, and its seeds contain nutrient and medicinal properties. The present study, therefore, aimed at determining the proximate, mineral and antioxidant activity of fresh and freeze dried seed of Buchholzia coriacea. The Buchholzia coriacea seeds were processed as fresh and freeze dried using aqueous, ethanol and acetone extracts. The flour samples were analyzed for proximate, mineral and antioxidant activity using standard methods. From the results obtained in Mean ± SE, the moisture content (%) of fresh and freeze-dried seeds of Wonderful kola was 66.14±1.84 and 7.68±0.74, the Fat content (%) was 3.20±0.39 and 4.72±0.29, the Crude fiber content (%) was 7.09±0.08 and 5.63±0.28, the Crude Protein content (%) was 3.27±0.17 and 5.42±0.30, the Ash content (%) was 5.22±0.07 and 7.29±0.11, and the Carbohydrate content (%) was 15.08±0.90 and 69.26±1.15 respectively. The Sodium (Na) content of fresh seed and freeze dried seed was 10.46±6.01 and 14.80±0.50, Potassium (K) was 24.43±7.63 and 40.59±9.29, Calcium (Ca) was 7.56±0.98 and 12.33±0.60, Magnesium (Mg) was 2.68±1.41 and 8.24±0.58, Manganese (Mn) was 0.05±0.01 and 0.08±0.02, Iron (Fe) was 0.64±0.11 and 0.49±0.04, Copper (Cu) was 0.44±0.05 and 0.27±0.04, Zinc (Zn) was 0.44±0.04 and 0.50±0.13, Nickel (Ni) was 0.01±0.0 and 0.02±0.0, Cadmium (Cd) was 0.01±0.00 and 0.15±0.11, and Na/K was 0.43 and 0.36 respectively. Lead (Pb) was below detection limit in fresh seed, but was 0.02±0.01 in freeze dried seeds. All the extracts displayed high antioxidant activity and high value of free scavenging ability in all the solvents used. However, ethanolic extracts showed higher antioxidant activity compared to other solvents. The study concluded that the moisture content, fat, crude protein, ash and carbohydrate in freeze dried seed of Bulchholzia coriacea was higher compared to fresh seed. Comparatively, freeze dried seed had the highest values in Na, K, Ca, Mg, Mn, Zn, Ni and Cd than fresh seed samples. The proximate, mineral and antioxidant activity of wonderful kola seed was higher in freeze dried seed in comparison with the fresh seed.