QUALITY EVALUATION OF HIGH BARRIER FLEXIBLE FILMS USED IN PACKAGING OF SOME FOODS

Abstract

The study was designed to assess the quality of biaxially oriented polypropylene (BOPP) bags used in food packaging. Transparent and aluminized BOPP films were drawn on-line from three leading production companies over a period of 5 months and subjected to physical and functional tests. These parameters included thickness, water vapor permeability (WVP), oxygen transmission rate (OTR), Tensile characteristics, heat seal temperature, seal strength, aluminum weight on metallized films and the force of transvers tension. On the other hand, the effect of packaging material films on potato chipsy and puffed corn was also followed up during storage which packed under air or modified atmosphere. The packed products were stored at three different temperatures up to 42 weeks. The obtained results showed that the most important factor in determining the functionality of BOPP films is not the thickness, but the quality and indegredity of the aluminum layer. It is recommended to use BOPP films (metallized and laminated) for the safe packaging of potato chips and puffed corn under the conditions that the aluminum layer not under 165 mg/ mg/m2 to assist the functional properties of the used films. Specifications of a good packaging that preserves the quality of food during the shelf life are as follows: aluminum layer weight between 200-250 mg/m2, transparency value should be between 1.1-1.8 OD, heat seal temperature is 136 C, water vapor permeability is the range of 0.16-0.20 gm H2O / m2.d and oxygen transmission rate lower than 45 cm3/m2.day. The moisture content of packed food did not exceeded 4% under nitrogen atmosphere after 36 weeks of storage in metallized BOPP, while peroxide value did not exceeded 0.31 mEq / kg for the same period of storage. The microbial analysis proved the absence of tested pathogenic bacteria, while the total bacterial count and number of yeast & molds remind under the numbers reported in the Egyptian Standards. It could be concluded that metallized and laminated BOPP bags are suitable for packaging and store potato chips and puffed corn for 6 months.