Influence of roasting on chemical profile, antioxidant and antibacterial activities of dried chili

Roasted dried chili, used to improve texture and taste, is important for various cuisines. The effect of roasting at 90 °C for 25 min on the chemical profile and bioactivities of dried chili extracted by petroleum ether was investigated. Based on GC–MS analysis, the crude extracts of roasted dried chili exhibited different chemical profile compared to the control. Roasting of dried chili significantly increased total phenolic compounds. Consequently, the antioxidant activity indicated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP) significantly improved. Conversely, a reduction in the antibacterial agents, capsaicin (32.36%) and dihydrocapsaicin (9.11%), in the roasted sample resulted to a decline in antibacterial activity. The extracts showed a strong activity against Bacillus cereus followed by B. subtilis, and Staphylococcus aureus compared to Escherichia coli based on the results of agar disk diffusion, minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and electron scanning microscopy observation.