![]() | Only 14 pages are availabe for public view |
Abstract Phenolics and flavonoids at moderate levels promote peroxidase (POX) activity and inhibit catalase (CAT) activity; but the reverse was true at high levels. The tested fungi, particularly the basidiomycetes have limited ability to produce phenolics but can consume exogenous phenolics through the action of peroxidase. POX was expressed only in the basidiomycetes while CAT was expressed in both basidiomycetes and ascomycetes but in favor of the ascomycetes. High POX activity is associated with low CAT activity. Fungi, particularly the ascomycetes, can release free flavonoids from flavonoid precursors. The reducing power and DPPH scavenging activity were the least sensitive measures of non-enzymatic antioxidant activity, with limited variability among the solid state fermentation system (SSFS) components (fungi versus orange peel), among the two fungal groups (ascomycetes versus basidiomycetes) and among individual fungal species within each group. The segregation pattern of the investigated fungal species based on DNA sequencing does not match that based on the differential antioxidant activity of the SSFS. Orange peel is appropriate for production of fungal CAT and POX, banana peel is more suitable for CAT and pomegranate peel is suitable for the production of phenolics and flavonoids. The optimum moisture content, pH, temperature, nitrogen form and incubation period for antioxidant activity of solid state fermentation, vary between ascomycetes and basidiomycetes. |