Volatile Compounds and Off-odors Analysis of Recycled PLA for Packaging Applications: An Essential Factor for Ensuring Food Safety and Quality

Abstract

Recent European guidelines support the use of recycled and biodegradable packaging for food applications. The approval of such packaging must not alter food’s taste or be harmful to health. In this work, PLA pellets were subjected to a post-consumer contamination procedure, washing process, and mechanical recycling, under common conditions of the recycling industry. HS-SPME-GC-MS and HS-SPME-GC-O-MS methods were used to detect volatile compounds and off-odor profiles. 33 different volatile compounds were identified in all samples. Intentionally added and non-intentionally added substances (IAS and NIAS) were identified, including benzaldehyde, benzyl alcohol, and dimethyl-1,4-dioxane-2,5-dione. The relationship between the formation of different NIAS and the PLA recycling process steps was determined. 14 different odor compounds such as benzyl alcohol, benzaldehyde, nonanal, decanal, dodecanal, 2,3-dimethylnaphthalene and 2,4-di-tert-butylphenol were detected and classified into 4 aroma groups (Toasted, Flower, Green and Chemical). The results obtained are essential for the food safety of recycled plastic material for food contact.