Abstract: The antibacterial activities of flavonoids extracted from banana peels alone and their blends with propionic acid or tea polyphenols against common pollutant and pathogenic bacteria in foods were tested based on inhibition circle size and minimum inhibitory concentration (MIC). Meanwhile, the preservative effect of synergistic blends on selected foods was explored. The results showed that the inhibition circle diameter of the 1:0.25 (V/V, similarly hereinafter) banana peel flavonoids-propionic acid blend against Candida albicans, presenting a 41.7 mg/mL MIC, was 7.2-fold higher than that of banana peel flavonoids alone, and also superior to sodium benzoate, suggesting a marked synergistic effect between banana peel flavonoids and propionic acid. The 1:1 banana peel flavonoids-propionic acid blend also demonstrated a synergistic inhibitory effect on Aspergillus flavus with a 10.4 mg/mL MIC. The 1:1 banana peel flavonoids-tea polyphenols blend had a better anti-Bacillus subtilis effect with a 7.8 mg/mL MIC than tea polyphenols alone and sodium benzoate. Therefore, banana peel flavonoids also have a synergistic effect with tea polyphenols. All the above blends revealed a better preservative effect on pineapple juice beverage, bread and fresh pork meat than sodium benzoate and calcium propionate at the same concentrations.

Key words: banana peel flavonoids, blends, antibacterial activity, preservation