Effects of different factors on stickiness of apple leathers

Apple leathers (ALs) are restructured food products made by dehydration of a thin layer of apple puree, resulting in a thin and flexible sheet. AL are composed mainly by low-weight carbohydrates which are highly hygroscopic, so AL become sticky when stored at ambient relative humidity (RH). Stickiness in food could be considered as a negative or positive aspect. In this work, four factors affecting stickiness of AL were studied (ingredients, RH, surface rugosity and compression time), both to decrease and to increase it. Surface rugosity of AL had the greatest impact on stickiness, being the smoothest side stickier than the roughest side. The RH at which AL were conditioned and the ingredients used in this work also had a great influence on the adhesion force. In this manner, stickiness can be modified (increasing or decreasing) according to the specific requirements for using AL in different applications. (C) 2014 Elsevier Ltd. All rights reserved.