INTERACTION BETWEEN POTASSIUM SORBATE, OIL AND TWEEN 20: ITS EFFECT ON THE GROWTH AND INHIBITION OF Z BAILII IN MODEL SALAD DRESSINGS

Abstract

The effect of the interaction between potassium sorbate (KS), oil and Tween® 20 on the growth and inhibition of Z bailii in model salad dressings was studied. Z. bailii grew in emulsions containing 110 and 230 g/kg of oil and the addition of 0.5 g/kg of KS inhibited growth. When the oil content was raised to 460 g/kg, a steep death rate curve was observed and the effect of KS addition was hidden by the inhibitory action of the high oil level. Tween® 20 action depended on oil level: for emulsions containing 110 or 230 g/kg, a depression in the activity of KS was observed. This behavior was attributed to the decrease in the free form of the preservative due to the partition between surfactant micelles and the water. In contrast, when the oil content was 460 g/kg, KS activity was enhanced in spite of the decrease in the amount of its free form. These results highlight the importance of considering ingredient interactions when evaluating shelf‐life.

Identification of the best-performing novel microbial strains from naturally-aged graffiti for biocleaning research

“…This was expected because Tween® 20 is a non-ionic surfactant and emulsifier that is widely used as an additive in microbiological growth media, providing microorganisms with exogenous fatty acid, which can be used as an additional energy source and thus promoting and accelerating growth (Ando et al, 1959;Castro et al, 2003;Harterreiten-Souza et al, 2011). According to several authors (Castro et al, 2003;Partanen et al, 2001;Nielsen et al, 2016), Tween® 20 has a growth-promoting effect in bacterial and yeast strains due to i) the change in nutrient availability caused by the reduction in nutrient particle size and homogeneity, ii) the fact that microorganisms with lipase enzymes can use Tween® 20 as a nutrient, and iii) the fact that the surfactant helps nutrients enter cells by permeabilization of the cell membrane.…”

Effect of preservatives, tween 20, oil content and emulsion structure on the survival of Lactobacillus fructivorans in model salad dressings

“…It has to be pointed out that an increase of the oil content in an emulsion produced a decrease of sorbate concentration in the water phase (Castro, 2006;Castro et al, 2003;Wedzicha et al, 1990) which would affect the antimicrobial effectiveness of nisin depending on the oil level.…”

“…The latter procedure was done in order to mimic the acidic environment of the modeled food. Approximately after 36 h, the microbial suspension reached the early stationary phase of the microorganism (Castro et al, 2003). Inoculation, storage and sampling.…”

“…For this reason, the preservative effectiveness will be associated to its distribution in the different phases of the food emulsion, considering the interior of the micelles as a third phase. Castro, Garro, Gerschenson, and Campos (2003) found that potassium sorbate diminished its antimicrobial effectiveness when the surfactant Tween Ò 20 was added to the emulsion. This fact was attributed to the surfactant binding the preservative.…”