Bionanocomposites based on polysaccharides and fibrous clays for packaging applications

The present paper reports the use of sepiolite and palygorskite fibrous clays as fillers to improve the mechanical and barrier properties of films based on neutral or negatively charged polysaccharides, such as hydroxypropylmethylcellulose, carboxymethylcellulose, alginate, pectin, and xanthan. The interaction established between the polysaccharide chains and the clay fibers, as well as the physicochemical characteristics of the resulting bionanocomposites are characterized by several techniques. These materials are processed as self-standing films that not only exhibit improved mechanical properties and water resistance, but also a significant barrier to UV light and reduced water absorption capacity, which make them very attractive for use in food packaging or coatings. Moreover, fibrous clays previously modified with the hydrophobic protein zein are also evaluated as fillers in alginate matrices, focusing on the improvement of water resistance, as well as of light and gas barrier properties, especially towards oxygen, which are of special interest for potential application in the food packaging sector. (C) 2015 Wiley Periodicals, Inc.