FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




The significance of edible coatings in the osmotic dehydration of frozen strawberries


The objective of this work was to determine the influence of covering frozen strawberries with semipermeable edible coatings on the cell sap leakage from the tissue during thawing and on mass transfer during osmotic dehydration with special regard to water loss and solid gain. Nine different coatings were made of low-methyled pectin and sodium alginate used separately or in combination with potato starch. The osmotic process was held up in 61.5% saccharose solution for 180 min at 30°C under continuous agitation. In order to determine barrier properties of the coatings the cell sap loss from fruits after 180 min of thawing in ambient conditions was calculated. It was found that applying of semi-permeable coatings on the surface of frozen strawberries influenced significantly cell sap loss during thawing. It had also an impact on the solids incorporated into the tissue during the osmotic process. In the consequence of increasing the concentration of coating solutions (concentrations ranging from 0.75% up to 4%) the thickness of coatings was increasing. Taking into consideration the ratio of water loss to solid gain the best results were achieved for strawberries covered with coatings containing sodium alginate.


strawberries, osmotic dehydration, barrier properties of edible coatings