Effect of re-crystallization on tensile, optical and water vapour barrier properties of corn starch films containing fatty acids

[EN] Starch films are very hygroscopic and undergo crystallization during processing and storage. In this work, fatty acids (SA, PA and OA) were incorporated into starch films containing glycerol as plasticizer, in order to reduce the hygroscopic character of the films and to improve water vapour permeability. Microstructural, mechanical, barrier and optical properties were studied in both non-stored films and those stored for 5 weeks. Fatty acid addition affected the main properties of films since mechanical resistance was decreased, water vapour permeability was reduced and gloss and transparency were reduced. The degree of starch and FA crystallinity increased with storage time and gave rise to changes in film properties: films became stiffer, less effective as water vapour barriers and less transparent and glossy. Saturated fatty acids were more efficient at reducing WVP as compared to oleic acid, but these differences decreased after storage due to the greater increase in crystallization of the former as it has been observed by X-ray diffraction. © 2011 Elsevier Ltd.The authors acknowledge the financial support from Spanish Ministerio de Educacion y Ciencia throughout the project AGL2010-20694. A. Jimenez also thanks Conselleria de Educacio de la Comunitat Valenciana for the FPI grant. Author M.J. Fabra thanks the support of Campus de Excelencia Internacional from Universidad Politecnica de Valencia. The authors also acknowledge the Electronic Microscopy Service of Universidad Politecnica de Valencia for their assistance in the use of SEM and B. Mari for his assistance in X-ray diffraction analysis.Jiménez Marco, A.; Fabra Rovira, MJ.; Talens Oliag, P.; Chiralt, A. (2012). Effect of re-crystallization on tensile, optical and water vapour barrier properties of corn starch films containing fatty acids. Food Hydrocolloids. 26(1):302-310. doi:10.1016/j.foodhyd.2011.06.00930231026