The impact of food simulations and ultrasound treatment on the barrier characteristics of polyolefins

Među najčešće korištenim materijalima za pakiranje hrane su poliolefini (polietilen i polipropilen). Uloga ambalaže je da zaštiti proizvod od nepovoljnih vanjskih čimbenika među kojima su i plinovi kako bi trajnost i željene karakteristike proizvoda bile očuvane. U ovom radu je istraživan utjecaj simulanata hrane i tretmana ultrazvukom na barijerna svojstva na vodenu paru i plin kisik linearnog polietilena niske gustoće (PE-LLD) i polipropilena s prevlakom akril/poliviniliden klorida (PP/Ac/PVDC). Korišteni simulanti hrane su otopine 10%-tnog etanola i 3%-tne octene kiseline. Od polimernih materijala varenjem su načinjene vrećice i napunjene navedenim otopinama. Kako bi se simulirali uvjeti pasterizacije i utjecaja ultrazvuka, uzorci su podvrgnuti tretmanu ultrazvuka u trajanju 5, 15 i 30 min pri 60°C i amplitudi od 100%. Istraživanje je pokazalo da PE-LLD i PP/Ac/PVDC međusobno pokazuju različita barijerna svojstva za vodenu paru i plin kisik pri ispitivanim uvjetima. Koeficijent permeabilnosti kao i propusnost za PP-LLD pokazuju najveće vrijednosti pri 40°C. Koeficijenti topljivosti i permeabilnosti te propusnost za PP/Ac/PVDC povećavaju se s porastom temperature. Različite otopine simulanata hrane pri istim ispitivanim uvjetima za iste materijale daju različite rezultate.Polyolefins (polyethene and polypropylene) are one of the most commonly used food packaging materials. The role of packaging is to protect the product from unfavourable external factors, including gases, in order to preserve the durability and desired product characteristics. In this paper, the impact of food simulants and ultrasound treatment on barrier properties of water vapour and oxygen gas of linear low density polyethylene (PE-LLD) and polypropylene/acrylic/polyvinylidene chloride (PP/Ac/PVDC) was investigated. The food simulants used were solutions of 10% ethanol and 3% acetic acid. The bags were made of the studied material and filled with mentioned food simulants. In order to simulate the conditions of pasteurization and ultrasound effect, the samples were subjected to ultrasound treatment for 5, 15 and 30 min at 60°C and the amplitude of 100%. These results indicated that PE-LLD and PP/Ac/PVDC have different barrier properties for water vapour and oxygen gas at the tested conditions. The permeability coefficient as well as permeation of PP-LLD show the highest values at 40°C. The solubility and permeability coefficients and permeation of PP/Ac/PVDC increase with temperature increase. Different food simulants, at the same tested conditions, for the same materials give different results