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Effect of Food Simulants and Ultrasound Treatment on Barrier Properties of Polyolefins

INTRODUCTION Polyolefins (polyethylene and polypropylene) are one of the most commonly used food packaging materials. They are used in direct contact with food since they are chemically inert, thermosealable and provide an excellent gas and moisture barrier. The main role of packaging is to protect the product from unfavourable external factors, including gases, in order to preserve the durability and desired product characteristics. METHODOLOGY The impact of food simulants and ultrasound treatment on barrier properties of water vapour (DIN 53 122 Part 1) and oxygen (ISO/DIS 15 105 1 ; ASTM D1434 82) of linear low density polyethylene (PE-LLD) and polypropylene/acrylic/polyvinylidene chloride (PP/Ac/PVDC) was investigated. The food simulants used were: 10% (v/v) ethanol and 3% (w/v) acetic acid. The bags were made of the studied material and filled with selected food simulants. In order to simulate the conditions of pasteurization and ultrasound effect, the samples were subjected to ultrasound water bath treatment for 5, 15 and 30 min at 60°C (2C) and the amplitude of 100%. RESULTS AND DISCUSSION Results indicated that PE-LLD and PP/Ac/PVDC have different barrier properties for water vapour and oxygen at the tested conditions. The permeability coefficient of PP-LLD show the highest values at 40°C. The solubility and permeability coefficients of PP/Ac/PVDC increase with temperature increase. CONCLUSIONS PP/Ac/PVDC shows better barrier properties on water vapour and oxygen than PE-LLD. At the same tested conditions (selected food simulants and time/temperature conditions), permeation coefficients (S, D, P) showed different behaviour for the same polymeric material.

food simulants, permeation, polyethylene, polypropylene, ultrasound

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