Growth Inhibition of Film-Forming Yeasts During Production of Ume-Zuke (Pickled Japanese Apricots) by an Antimicrobial Fraction Extracted from Paprika Seeds.

Paprika extract (50 to 100 μg/ml) obtained by suspending ground paprika seeds in water, adding ethanol (50%, v/v), and then filtering the suspension, inhibited the growth of film-forming yeasts (Kloeckera, Pichia, Debaryomyces, and Candida species) isolated during the production of ume-zuke, a processed food product made by salting Japanese apricots (Prunus mume). The antimicrobial activity of the extract towards Pichia anomala was influenced by the initial number of yeast cells, as well as the temperature, pH, and sodium chloride concentration of the culture medium (ume vinegar). The inhibitory effect was cumulatively enhanced, although not synergistically, when the paprika seed extract was used in combination with either SO2, sorbic acid, thiamine dilauryl sulfate, or acetic acid. The antimicrobial activity of the extract was not influenced by the vinegar components. The extract proved to be very effective as a preservative to prevent the contamination and spoilage of ume-zuke by film-forming yeasts.