Abstract

WORLOCK, J  and  URFALINO, D. P. Estimación del contenido de sorbato de potasio residual en ciruela tiernizada. RIA. Rev. investig. agropecu. [online]. 2018, vol.44, n.2, pp.65-73. ISSN 1669-2314.

The purpose of this study was to generate a table for high moisture prune makers to be able to estimate the residual potassium sorbate content depending on the concentration of preservative used and the type of application made (immersion or spraying). Medium size plums (35 to 48 fresh units per kg) were harvested with an average maturity over 20°Brix and dehydrated in oven until they reached an average humidity of 21 ± 1% and an average water activity (aw) of 0,682 ± 0,013. Subsequently, the softening process was done in an autoclave reaching a humidity of 30 ± 2% and a aw of 0,782 ± 0,020, prunes were drained and pitted. The average performance of medium size prunes was 1,08 ± 0,01 kg of prunes to obtain 1,00 kg of pitted high moisture prunes. The average residue of pits was 14 ± 1%. 8 treatments were carried out with 4 repetitions of 20 units of high moisture prunes, in which potassium sorbate was applied using the following concentrations; 1,25; 1,50; 1,75; 2,00; 2,25; 2,50; 2,75 and 3,00% through immersion and spraying. Samples were stabilized in hermetic containers for twenty-four hours. Residual potassium sorbate was determined using ISO 5519:2008 analytical technique and a table was made with the data obtained. In both methods, immersion and spray, the residual potassium sorbate obtained, depending on the concentrations used, adjusted to linear models and were grouped by ranges. Both methods showed significant differences in residual potassium sorbate. The Argentinean Alimentary Code establishes a residual maximum content of 100 ppm, which is not enough to preserve the final product, since it was found that the antimicrobial action of sorbates occurs between 200 and 600 ppm (0,02 and 0,06%) depending on the moisture content. This was corroborated in the Codex Alimentarius International Food Standards, which allows the use of sorbates with a maximum level of 500 ppm in dried fruit.

Keywords : D’agen plum; Prunus domestica; (2E, 4E)-hexa-2, potassium 4-dienoate.

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