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2017
Book Article
Titel
Migration of acetaldehyde scavengers from PET bottles
Abstract
Acetaldehyde scavengers are widely used in polyethylene terephthalate (PET) mineral water packaging in order to reduce the concentration of acetaldehyde in the PET bottle wall. In the same ratio as the acetaldehyde reduction, the migration of acetaldehyde is reduced. Traces of acetaldehyde in mineral water result in an off flavor. The odor threshold of acetaldehyde in water is between 10 and 25 mg/L. The main substance used as acetaldehyde scavenger is 2-aminobenzamide which chemically binds acetaldehyde during preform manufacturing. A large excess of 2-aminobenzamide is typically added to the PET melt. This is the main drawback of acetaldehyde scavengers. The scavenger itself can migrate and has to be evaluated in food law compliance testing of PET mineral water bottles. The specific migration limit of 2-aminobenzamide is 50 mg/L in the European Union. In the USA, the maximum amount of 2-aminobenzamide in the PET wall is restricted to 500 mg/kg. Typical food simulants like ethanol/water mixture pose the risk of overestimation of the migration due to swelling of the PET matrix, especially at high temperatures like 60 °C. Therefore migration modeling has been used for the prediction of the migration at the end of shelf life in the case of 2-aminobenzamide. Validation data for the prediction of the migration by use of diffusion modeling are given in this article. Migration testing for 10 days at 40 °C into non-swelling food simulants like 3% acetic acid, 10% ethanol and 20% ethanol approximately simulates storage for 1 year at room temperature. The actual legally recommended storage conditions, for maximum of 10 days at 60 °C into 3% acetic acid and ethanolic food simulants, however, lead to a strong increase in the migration of 2-aminobenzamide compared to the realistic migration.