Studies on Antibacterial Activity of Gardenia Yellow Pigment

To investigate the antibacterial activity of gardenia yellow pigment extracts from fruit of Gardenia jasminoides Ellis. The antibacterial activity was determined by disc diffusion and minimum inhibitory concentration (MIC) determination method against human food spoilage microorganism.We evaluated the purity of gardenia yellow pigment by HPLC and we also analyzed the influence of gardenia yellow pigment on gram negative bacteria and gram positive bacteria by Oxford cup method. Meanwhile, we measured the minimum inhibitory concentration (MIC).We found that gardenia yellow pigment has antibacterial activity against gram negative bacteria and gram positive bacteria, the minimum inhibitory concentrations of gardenia yellow pigment on Proteus species and Bacillus subtilis were 5ug mL-1 and 10ug mL-1 respectively. But the antimicrobial mechanism of Proteus species and Bacillus subtilis was different. When adding gardenia yellow pigment, the cell membrane of the Proteus species was ruptured. After adding gardenia yellow pigment, the growth of Bacillus subtilis was inhibited, and the formation of spores was too early to enter the stabilizer.

Significance and Impact of the Study: Gardenia yellow pigment can be widely used in food preservatives due to its bacteriostatic action and it plays a significant role in accelerating the natural pigment replaced chemical addition agent or preservative. The application of gardenia yellow pigment in the food industry will promote the development of food industry, which means natural pigment replacement preservative has become an inevitable trend in the development of industry.