Effect of pH on potassium metabisulfite biocidic activity against yeast cell cultures

摘要

Potassium metabisulfite (PMB - E224) is largely used as antimicrobial additive in food industry (Romano et al., 1999), mainly in wines to prevent spoilage and oxidation (Mendoza et al, 2009), dried fruits, dried potato products, biscuits and chocolate, jam, sausage and salami. PMB in an aqueous solution is converted to sulfite, dihydrogen sulfite and sulfur dioxide in different proportions according to the pH. In winemaking PMB is normally used at low pH, suggesting that the biocidic activity is exerted by the sulfur dioxide. As a matter of fact a long experience in enology suggests that the best results are obtained with grape musts at pH values below 3.0.