Abstract:

By means of filter paper method, the antimicrobial activities of the alkaloid extracted from eggplant fruits against common spoilage microorganisms in food were studied. The results showed that the alkaloid extract from eggplant fruits has the stronger antibacterial activities against the tested bacteria, yeast and mold than 3% Sodium benzoate, especially against Staphylococcus aureus, Bacillus subtilis, Saccharomyces cerevisiae, Candida sp. and Aspergillus niger. With Staphylococcus aureus, Saccharomyces cerevisiae and Aspergillus niger as the indicators for the stability study, the alkaloid extract plays the best antibacterial activities to Staphylococcus aureus and Aspergillus niger in neutral condition and to Saccharomyces cerevisiae in weak base condition, respectively, but its antibacterial activities are inhibited in strong acid or alkali condition. Moreover, the antibacterial activities of alkaloid extract have good thermal stability when temperature is not over 100 ℃. However, when temperature is up to 121 ℃,the antimicrobial activities decrease following with the increase of heating time.

Key words: eggplant fruit, alkaloid, antimicrobial activities, stability