Structure-property relationships in osmo-air-dehydrated apricot cubes

Osmotic dehydration has been proposed in combination with air dehydration to improve quality attributes of air dried fruit pieces. The influence of the osmotic step and of the syrup composition on the chemical-physical properties, structure collapse and colour changes of osmo-air-dehydrated apricot cubes was studied. The relationship between shrinkage during air dehydration and 'glass'-'rubber' transitions of apricot tissue was also analysed. Colour attributes and geometric features were evaluated by image analysis and mathematical transformations were applied to the image parameters to estimate volume reduction related to absolute moisture content. Sugars added during the osmotic step help to slightly decrease shrinkage during the first phase of the subsequent air dehydration, furthermore the osmo-dehydrated apricot cubes showed the lowest structure collapse, retaining a better superficial appearance. The incorporation of sugars improved the colour stability during air dehydration, with sorbitol showing the highest protective effect.