This study aims to the evaluation of stability and antibacterial properties of the extracted chlorophyll from alfalfa. For this purpose, chlorophylls a and b from alfalfa were extracted by enzymatic and ultrasound methods. The results show that the content of chlorophyll a in alfalfa is higher than chlorophyll b and also the enzymatic method demonstrates higher yield in chlorophyll extraction. In the present study, the chlorophyll stability was evaluated in different conditions including temperature (-18, 4 and 25 °C), time (15, 30 and 45 days), pH (4.5 and 5.5) and NaCl concentration (50, 100 and 150 mM). Also, antibacterial effects were investigated at different concentrations of chlorophyll (20, 40, 60 and 100 μM) against some bactriaes by agar disk diffusion and microdilution (MIC and MBC) methods. The results demonstrate that 50 mM of NaCl, temperature -18 °C, pH = 4.5 and time 15 days are associated with the highest chlorophyll a and b contents. Furthermore, the resistance of bacterias in agar disk diffusion and microdilution methods observe Listeria < Staphylococcus < Salmonella < Escherichia < Pseudomonas and Listeria<(Staphylococcus = Escherichia = Salmonella)<Pseudomonas, respectively. Also, there are significant differences between different chlorophyll concentrations against Listeria and Staphylococcus in evaluation of inhibition effects of total extracted chlorophyll (p < 0.05).
Keywords: Alfalfa; Antibacterial properties; Chlorophyll; Enzymatic method; Stability; Ultrasonic.
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