Occurrence of Storage Fungi in Dried Ginger (Zingiber officinale) and Their Impact on Its Nutritional Composition

Abstract

Ginger (Zingiber officinale) is a crop well known for its spicy and medicinal rhizome Fungi rots can cause spoilage and subsequent reduction in quality of dried ginger during storage. Rot fungi identification and management are crucial for sustainable cultivation of ginger and storage. This study was carried out to identify various fungi causing dry ginger rot and their effects on its proximate and phytochemical composition. Dried ginger samples (n=10) were purchased from two main markets in Umuahia from which fungi were isolated and identified. Proximate and phytochemical content of fungi-inoculated ginger were also determined. Experiment design was CRD in triplicates. ANOVA at α0.05 was performed for data. Rhizopus sp. had highest incidence (38%), followed by Fusarium oxysporum (19%), Trichoderma sp (17%). Rhizopus sp. and F. oxysporum caused highest rot percentage (50%), while Aspergillus niger and A. flavus caused moderate rot (20-40%). Fungi significantly altered phytochemical and proximate contents of inoculated ginger samples. Fusarium Solani and Rhizopus sp reduced saponin content, while Rhizopus sp, A. flavus, F.  Solani significantly reduced flavonoid and tannin content. Phenol was reduced in F. oxysporum, A. ochraceous and Rhizopus inoculated samples. Crude fiber and ash were significantly lower in fungi-inoculated samples than control. Fungal contamination significantly alters composition of dried ginger and affect its quality.