Oxygen scavenging polyolefin nanocomposite films containing an iron modified kaolinite of interest in active food packaging applications.

摘要

A synthetic iron containing kaolinite was evaluated as an oxygen scavenger additive for food packaging plastics having an active performance of ca. 43 ml O₂/g at 100% RH and of ca. 37 ml O₂/g of additive at 50% RH. The corresponding polyolefin films containing 10 wt.% of the active filler also exhibited significant oxygen scavenger activity (up to 4.3 ml of oxygen/g composite, at 24 degrees C and 100% RH). The effect of oxygen scavenging capacity of HDPE films with temperature and %RH was also assessed. The oxygen permeability tests carried out after inactivation of the additive suggested that the iron containing clay plays in fact a dual oxygen fighting role: active performance (trapping and reacting with molecular oxygen) as well as a passive barrier performance (imposing a more tortuous diffusion path to the permeant). Migration tests into two food simulants indicated that iron (from active ingredient) and aluminum (from clay migration) are hardly detectable in commonly used simulants. This study suggests that there is significant potential for the use of this novel oxygen scavenger additive to constitute active packaging of value in the shelf-life extension of oxygen sensitive food products. Industrial relevance: Oxygen penetration in food and beverages leads to, for instance, oxidative rancidity of unsaturated fats, loss of vitamin C, browning of fresh meat, oxidation of aromatic flavor oils and pigments and fostering the growth of aerobic spoilage microorganisms. These undesirable effects on the product quality indicate that the elimination or exclusion of oxygen is one of the main targets for preserving foods and beverages in the food packaging industry. The industrial relevance of this study is very significant because it proves that the technology generated and characterized in the paper can uniquely fight oxygen by two means, i.e active and passive performance. This should enable the food packaging industry to package foods in relatively inexpensive, low barrier commodity plastic materials such as polyolefins, that will allow the shelf-life extension of the packaged products with a safe use, since migration of the components is negligible