K.M. Schaich, N. Obinata, K. Yam
Controlled release packaging offers significant potential for extending shelf life of foods, cosmetics and pharmaceuticals by slowly releasing antioxidants and antimicrobials over time to replenish consumed active components originally present. However, release rates attainable with current packaging are too fast or too slow for practical use and development of this new technology has been hampered by lack of appropriate polymer films and limited information about factors controlling active compound migration. To investigate effects of altering polymer film morphology on release of tocopherols as model active compounds (antioxidants), polymer composition was modified by use of polymer blends and chaotic advection / Smart Blending was compared with conventional cast and blown film polymer processing. Polymer blends in conventional processing produced new morphologies release rates that were greater in range than single resins but still too fast for stabilization of foods during long-term storage. Combining polymer blends with Smart Blending made it possible to generate multiple morphologies with different release rates from a single polymer blend by varying the number of mixing cycles. Multilayer and fiber morphologies slowed migration, while dispersed structures open the molecular network and increase migration rates. Very slow release rates were attained by incorporating high proportions of polypropylene and to a lesser extent polystyrene with low density polyethylene, providing films more useful for long-term applications. Thus, smart blending offers significant promise for developing packaging delivering slow release of active compounds for long-term stabilization of foods, cosmetics and pharmaceuticals. "Control" of antioxidant or other active compound release will ultimately come from knowing what polymer composition and processing conditions to choose to produce specific release properties.
Schaich, K.M., Obinata, N. and Yam, K. (2008). DELIVERING NATURAL ANTIOXIDANTS VIA CONTROLLED RELEASE PACKAGING. Acta Hortic. 778, 53-64
DOI: 10.17660/ActaHortic.2008.778.5
controlled release packaging, polymer films, antioxidants, tocopherols, polymer blends, conventional cast film extrusion, Smart Blending, chaotic advection