FOOD SCIENCE ›› 2023, Vol. 44 ›› Issue (24): 306-315.doi: 10.7506/spkx1002-6630-20221011-100

• Safety Detection • Previous Articles     Next Articles

Physical Characterization and Volatile Organic Compound Monitoring of Recycled Polyethylene Terephthalate under Mechanical Recycling

ZENG Yan, JIN Lili, ZHU Lei, WU Yongning, LUO Shipeng, SHANG Guiqin, WANG Zhiwei, LIU Guihua, HU Changying   

  1. (1. Department of Food Science and Engineering, College of Science & Engineering, Jinan University, Guangzhou 510632, China; 2. Changzhou Industrial and Consumable Products Inspection Co. Ltd., Changzhou 213017, China; 3. China National Center for Food Safety Risk Assessment, Beijing 100022, China; 4. Nanjing Customs Testing Center for Dangerous Goods and Packaging, Changzhou 213000, China; 5. College of Packaging Engineering, Jinan University, Zhuhai 519070, China)
  • Online:2023-12-25 Published:2024-01-02

Abstract: In this study, physical characterization and monitoring of volatile organic compounds (VOCs) were investigated on recycled polyethylene terephthalate (rPET) from a mechanical recycling process and rPET bottles made with different rPET contents, with the aim of tracing the source of rPET and assessing its safety when use as a food contact material. It was found that rPET had a similar thermal stability to that of virgin PET (vPET). rPET bottles did not show any significant changes in groups or structure and exhibit similar crystallization and melting behaviors to vPET. However, there were minor mechanical scratches in the surface micromorphology of rPET bottles, and the color of rPET bottles became darker, greener and yellower as the content of recycled material increased. The solid-state polycondensation process was found to play an important role in the removal of VOCs, as detected by headspace gas chromatography-mass spectrometry (HS-GC-MS), resulting in a very small amount of residual VOCs in rPET. Four VOCs (acetaldehyde, glycol and nonanal at levels less than 1.00 mg/kg; 2-methyl-1,3 dioxolane at levels of 1.72-5.76 mg/kg) were detected in the rPET bottles. This study shows that rPET bottles are qualified for reuse in food contact in terms of thermal properties, structure, morphology and VOC residues, although there is variability in color.

Key words: mechanical recycling; recycled polyethylene terephthalate; physical characterization; volatile organic compounds; food contact materials

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