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Papers by Tonbra Okunwaye

Research paper thumbnail of Purification and biochemical properties of lipase from raphia palm fruit mesocarp

African Journal of Biochemistry Research, 2015

Lipases hydrolyze lipids to yield fatty acids and glycerol which are used as raw materials in ind... more Lipases hydrolyze lipids to yield fatty acids and glycerol which are used as raw materials in industries. The lipase from raphia mesocarp was extracted, purified and characterized. Assay was carried out using p- nitrophenyl palmitate as substrate. The lipase was subjected to 80% ammonium sulphate precipitation, purified on ion exchange and gel filtration chromatography. Native and subunit molecular weights were determined on a gel filtration column and 10% sodium dodecyl sulphate polyacrylamide gel electrophoresis respectively. Kinetic parameters (Km and Vmax), effect of temperature, pH, sensitivity to metal ions and substrate specificities of the lipase enzyme were studied. Specific activity of 17.40µmol/min/mg and purification fold of 2.68% were obtained.Native and subunitmolecular weightwas 35 kDa. The Km and Vmax values were0.01mM and 20.5µmol/min/ml respectively. The lipase enzyme was inhibited by all metallic salts used and enhanced by CaCl2. Optimal pH was 7.0 and temperature...

Research paper thumbnail of Effect of processing germinated shea kernels on the quality parameters of shea (Vitellaria paradoxa) butter

Journal of Cereals and Oilseeds, May 31, 2013

The processing methods, kernel storage and phytosanitory conditions are some of the major challen... more The processing methods, kernel storage and phytosanitory conditions are some of the major challenges leading to production of low quality shea butter. The effect of processing germinated shea kernels on the overall quality of processed butter was examined. Shea fruits were picked under different shea trees, pooled, and divided into two portions: one portion was processed immediately; the other was germinated for 9 days. The butter expressed from the respective portions was analyzed using standard methods. The yield of the extracted butter from the germinated and ungerminated kernel was 52 and 49%, respectively. The physicochemical properties of butter from the ungerminated and germinated nuts were free fatty acid (FFA) (0.22 and 1.66%), saponification value (SV), (223 and 239 mg KOH/g), unsaponifiable matter (7.77 and 9.39%), iodine value (Wijs) (IV) (33 and 30), and peroxide value (PV) (0.10 and 8.14 meq/kg), respectively. Germination process depleted the lipid content of shea kernel, and elevated the FFA by 7-folds, the PV by 81, while IV decreased. Again, germination mobilized linoleic acid more than the other constituent fatty acids, and the elemental composition remained generally unaffected. Prompt sterilization and sorting out the germinated kernels are necessary steps to improving the quality of shea butter.

Research paper thumbnail of Purification and biochemical properties of lipase from raphia palm fruit mesocarp

African Journal of Biochemistry Research, 2015

Lipases hydrolyze lipids to yield fatty acids and glycerol which are used as raw materials in ind... more Lipases hydrolyze lipids to yield fatty acids and glycerol which are used as raw materials in industries. The lipase from raphia mesocarp was extracted, purified and characterized. Assay was carried out using p- nitrophenyl palmitate as substrate. The lipase was subjected to 80% ammonium sulphate precipitation, purified on ion exchange and gel filtration chromatography. Native and subunit molecular weights were determined on a gel filtration column and 10% sodium dodecyl sulphate polyacrylamide gel electrophoresis respectively. Kinetic parameters (Km and Vmax), effect of temperature, pH, sensitivity to metal ions and substrate specificities of the lipase enzyme were studied. Specific activity of 17.40µmol/min/mg and purification fold of 2.68% were obtained.Native and subunitmolecular weightwas 35 kDa. The Km and Vmax values were0.01mM and 20.5µmol/min/ml respectively. The lipase enzyme was inhibited by all metallic salts used and enhanced by CaCl2. Optimal pH was 7.0 and temperature...

Research paper thumbnail of Effect of processing germinated shea kernels on the quality parameters of shea (Vitellaria paradoxa) butter

Journal of Cereals and Oilseeds, May 31, 2013

The processing methods, kernel storage and phytosanitory conditions are some of the major challen... more The processing methods, kernel storage and phytosanitory conditions are some of the major challenges leading to production of low quality shea butter. The effect of processing germinated shea kernels on the overall quality of processed butter was examined. Shea fruits were picked under different shea trees, pooled, and divided into two portions: one portion was processed immediately; the other was germinated for 9 days. The butter expressed from the respective portions was analyzed using standard methods. The yield of the extracted butter from the germinated and ungerminated kernel was 52 and 49%, respectively. The physicochemical properties of butter from the ungerminated and germinated nuts were free fatty acid (FFA) (0.22 and 1.66%), saponification value (SV), (223 and 239 mg KOH/g), unsaponifiable matter (7.77 and 9.39%), iodine value (Wijs) (IV) (33 and 30), and peroxide value (PV) (0.10 and 8.14 meq/kg), respectively. Germination process depleted the lipid content of shea kernel, and elevated the FFA by 7-folds, the PV by 81, while IV decreased. Again, germination mobilized linoleic acid more than the other constituent fatty acids, and the elemental composition remained generally unaffected. Prompt sterilization and sorting out the germinated kernels are necessary steps to improving the quality of shea butter.