Production and stability of pediocin N5p in grape juice medium

The production and stability of pediocin N5p from Pediococcus pentosaceus, isolated from wine, were examined in grape juice medium. Maximum growth and higher titre (4000 U ml-1) were observed at a initial pH of 7.5 and 30 degrees C. The activity of the inhibitory substance was stable between pH values from 2.0 to 5.0 at 4 degrees and 30 degrees C. At pH 10.0 it was completely inactivated. When submitted to 30 min at 80 degrees, 100 degrees and 115 degrees C, maximal stability was observed at pH 2.0. Ethanol up to 10% did not affect pediocin activity at acid pH, nor did 40-80 mg 1-1 SO2, independently or combined with different ethanol concentrations, affect inhibitory activity.