Phytochemical Screening and Effect of Temperature on Proximate Analysis and Mineral Composition of Zingiber officinale Rosc.

Abstract

Aims: To investigate the phytochemical composition and effect of temperature on the proximate and mineral composition of Zingiber officinale. Study Design: Activity directed phytochemical screening, proximate analysis and mineral composition investigation of Z. officinale rhizomes using in vitro methods. Place and Duration of Study: Medicinal Plants Section, Bioresources Development Centre, Ogbomoso, Nigeria between May and November, 2016. Methodology: Fresh rhizome of Z. officinale was milled, extracted with absolute ethanol and screened for phytochemicals. Proximate and mineral analyses were carried out at various temperatures; room temperature (28°C; control), 40, 50 and 60°C. Results: Phytochemicals including; alkaloid, tannins, saponins and cardiacglycosides were present in the rhizomes. The results showed significant (P< 0.05) decrease in the percentage of crude protein (9.53±0.04) at 60°C when compared with room temperature; control (9.62±0.04), increase in crude fiber and ash at 40°C (8.31±0.02 and 6.76±0.02 respectively) and 60°C (8.34±0.03 and 6.77±0.02 respectively) when compared with the control (8.28±0.15 and 6.74±0.01 respectively). The results also showed a significant (P< 0.05) decrease in the percentage of sodium (0.057±0.001 and 0.061±0.001) at 40 and 60°C respectively when compared with the control (0.064±0.002); potassium (1.65±0.01) at 40°C when compared with the control (1.73±0.02); magnesium and calcium at 40°C (0.197±0.002 and 0.083±0.001 respectively) when compared with the control (0.203±0.005 and 0.087±0.001 respectively). Conclusion: The current study showed that drying at above room temperature does not affect the proximate and mineral composition of Z. officinale rhizomes. The presence of nutrients and phytochemicals in Z. officinale could be exploited for the overall well-being of man.