Acid preservation & OxygenFST104February 27, 2012Undissociated organic acids (unlike charged compounds and H+) pass freely into the cell.Food preservation with acidsonce inside the cell, they can dissociate: organic acids become more ionized as pH increasesRCOOH < pKa < RCOO-+ H+
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Organic acids for food preservativesAcetic acid (CH3COOH)Citric acid and Lactic acid not very effective (remain dissociated until low pHs)anions are not significantly inhibitoryanion has inhibitory effects (in addition to action of hydrogen ion)more effective than other organic acidscommon “pickling’ agentBenzoic acidwide usagesodium benzoate (E211), potassium benzoate (E212) and calcium benzoate (E213)Parabensnot very soluble. limited use in foodE214, E216, E218Organic acids for food preservativesPropionic acidwidely used to inhibit molds in bakery productslegal limit is too low to be effective against yeastsE280Sorbic acid (2,4-hexadienoic acid)commonly used to prevent yeasts and molds in fermented foodshydrophobic structure gives it very good membrane penetrationE200 – E204