Impact of solid state fermentation by Trichoderma spp. on phenolic content, antioxidant and antibacterial activities of curry leaf powder

摘要

The aim of the present study is to evaluate the influence of solid state fermentation (SSF) by Trichoderma spp. on phenolic content, antioxidant and antibacterial activities of curry leaf powder. The phenolic contents of curry approximately increased5–6 folds after SSF by T. verins, T. viride, T. reesei and T. harzianum. The major identified flavonoids analysis by HPLC increased several folds ranged from 2.5 to 8.1 in fermented curry than unfermented curry. The phenolic compounds of fermented curryhad higher antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS) and phosphomolybdenum complex (PMC) assays compared with unfermented curry. The minimum inhibitory concentrations (MICs) of fermented curry by Trichoderma spp. against Bacillus cereus (B.C.), Bacillus subtils (B.S.), Staphylococcus aureus (S.A.), Escherichia coli (E.C.), Pseudomonas aeruginosa (P.A.) and Klebsiella pneumonia (K.P.) were lower than those of unfermented curry. The time-killing curves of E.C., P.A., B.C., B.S. and K.P. in presence of phenolic compounds of curry fermented by T. harzianum were similar to Ampicillin as control. The results showed the strong correlation between the concentration of phenolic content of curry and antioxidant and antibacterial activities. In conclusion, the SSF upgraded the nutrient value of curry as spices which used widely in human foods.