Differential quenching of free chlorine by organic compounds potentially exuded from injured plant tissues.

Toivonen, P.M.A. and Lu, C. (2013). "Differential quenching of free chlorine by organic compounds potentially exuded from injured plant tissues.", Postharvest Biology and Technology, 86, pp. 192-194. doi : 10.1016/j.postharvbio.2013.06.035  Access to full text

Abstract

Fresh-cut fruits and vegetables can release significant amounts of metabolites from damaged tissues on cut edges. These metabolites can potentially quench oxidative sanitizers and hence lead to loss of their antimicrobial effectiveness. In this study, the effects of organic acids, carbohydrates, phenolics, other metabolites and hydrogen peroxide on depletion of chlorine were evaluated by quantitative monitoring chlorine loss in simulated wash solutions. Gallic acid, caffeic acid and most amino acids had the greatest capacities for depleting chlorine, requiring concentrations in the range of 10 μmol L1 or less to deplete free chlorine by half. Pyruvic, ascorbic, chlorogenic, malonic and oxalic acids had slight lower capacities, with concentrations ranging from 17 to 100 μmol L1 leading to half depletion. All nitrogen containing metabolites had relatively high capacity in depleting chlorine at concentrations in the range of 10 μmol L1, whereas hydrogen peroxide had a half depletion concentration of 21.3 μmol L1. In contrast, all sugars and most carboxylic acids had lower free chlorine depletion capacities. These results demonstrate that not all organic molecules potentially exuded from cut fruit or vegetable tissue had equal or similar potential to quench free chlorine from wash water.

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