Packaging has a major role in food processing. Plastics have a special position in the world today because of their various applications, such as food packaging. But they are not quite inert and have the ability to react with food. Migration of low molecular material to food is important because of food quality reduction and health affect. In the other hand flavor absorption by packaging materials also decrease food aroma and change package mechanical properties. Both of these reasons reduce food quality. In this study polyethylene terephethalate, and polyethylene interactions with yoghurt drink in three different pH (3.5, 4 and 4.5) andin three storage conditions (sun, room and frozen) was evaluated. On the study of migration, overall migration of both polymers, specific migration of Terephthalic acid (TPA) from PET and 1-hexene from PE measured by HPLC and GC Instruments. Lactic acid was used as yoghurt drink food simulant and sampling was done monthly during the specified time period. Then migration effect on mechanical property was evaluated by tensile test. In the case of flavor absorption by PET and PE polymers, bottles filled by yoghurt drink and the concentration of Acetaldehyde absorbed by bottles at three month storage at mentioned condition were measured. Results showed that rate of both polymers overall migration in all of treatments was lower than EU standards. Specific migration of TPA and 1-hexene increased with decreasing pH over time. Maximum immigration was seen in frozen state and minimum was at room condition. Tensile strength decreased with increasing specific migration for two polymers. Result of absorption experiments showed Acetaldehyde absorption rate dependent to time and pH. The highest absorption was seen in frozen state. Tensile test results showed that tensile strength was decreased when absorption increased. Keywords : Packaging, Polyethylene Terephthalate, Polyethylene, Migration, Absorption, Mechanical properties
