PHYTOCHEMICAL COMPONENTS, PROXIMATE ANALYSIS, AND ANTIMICROBIAL PROPERTIES OF FERMENTED AND NON-FERMENTED SAMPLES OF Zingiber officinale

Abstract

The desirability of fermented foods may be attributed to their benefits. This study investigated the pH, in vitro antimicrobial assays including Minimum Inhibition Concentration (MIC), Minimum Fungicidal Concentration (MFC), and disc diffusion assay of fermented and non-fermented samples of Zingiber officinale against Candida albicans, Staphylococcus aureus, and Escherichia coli. But phytochemical screening, proximate compositions, and High-Performance Liquid Chromatography (HPLC) were carried out only on the non-fermented sample.  The pH decreased steadily throughout while the MIC ranged between 12.5 – 50.0 mg/mL. The MIC of the non-fermented sample ranged between 25-50.0 mg/Ml. The highest zones of inhibition obtained were between 8.0 mm- 16.0 mm at 100 mg/mL, 8.0 mm- 14.00 mm at 50.0 mg/mL, and 2.00-8.4 mm at 25 mg/mL. Comparatively, the zones were higher (6.8-8.4 mm) for the fermented than for the non-fermented sample (1.8-4.0 mm) and higher against S. aureus (4-16.0 mm) than E. coli (2.0 -12.0 mm) and C. albicans (2.0-6.0 mm). The fermented sample contained alkaloids, anthraquinones, flavonoids, phlobatannins, saponins, tannins, and terpenoids, while alkaloids, flavonoids, glycosides, saponins, steroids, tannins, and terpenoids were in the non-fermented sample. The fermented sample contained 87.31% moisture, 1.24% ash, 0.29% fat, 9.73% carbohydrate, 0.24% fiber, and 1.48% protein, while the non-fermented sample contained 83.10% moisture, 1.02% ash, 0.21% fat, 14.46% carbohydrate, 0.18% fiber, and 1.24% protein. HPLC revealed Alpha farnesene (51.77), zingiberene (11.30), zingerone (14.53), 6-gingerol (12.44), and quercetin (35.21) in the fermented sample. Thus, the fermented sample of Zingiber officinale is a suitable candidate for the promotion of human health.