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Keywords:

  • air drying;
  • lactic bacteria;
  • osmotic response;
  • trehalose;
  • water permeability;
  • zeta potential

Abstract

Aim: This work determines the efficiency of trehalose on the preservation by heat or osmotic drying of a strain of Lactobacillus delbrueckii ssp. bulgaricus. Cell recovery at different trehalose concentrations during drying correlated with the surface properties and osmotic response of cells after rehydration.

Methods and Results: Bacteria were dried in the presence of glycerol, trehalose, sucrose at 70°C and at 20°C. Trehalose attenuates the loss of viability at 0·25 m. At this concentration, the osmotic response and zeta potential of the bacteria were comparable with the nondried ones.

Conclusions: Trehalose diminishes significantly the damage produced by dehydration both when the bacteria are dried by heating or subjected to osmotic dehydration. This effect appears related to the preservation of the permeability to water and the surface potential of the bacteria.

Significance and Impact of the Study: Dehydration occurring during heating or during osmosis appears to have similar effects. As dehydration-induced damage is in correlation with osmotic response recovery and is hindered or buffered by the presence of trehalose, it may be related to water eliminated from biological structures involved in water permeation.