Light protection performance of wrapping films to prevent the photo-oxidation of extra virgin olive oil during storage in glass bottles

Abstract

Packaging material plays an important role in minimizing food waste in the supply chain. This study evaluated the light-protective effects of wrapping films as a secondary packaging material on the deterioration of extra virgin olive oil after exposure to sunlight for 5 weeks. Milky white polyethylene terephthalate (MW-PET) and aluminum oxide vapor-deposited polyethylene terephthalate (AV-PET) were used on bottles of different transparency (clear or amber glass) as the primary packaging material. Wrapping the bottles with either PET film resulted in protection against fatty acid release and secondary oxidation of the oils upon exposure to sunlight, but no protection against the primary oxidation of the oils. Although sunlight exposure induced the degradation of minor components, including chlorophyll and carotenoid pigments, in oils stored in clear glass bottles with no film, in oils stored in clear and amber glass bottles with either type of PET film, these compounds were partially protected from degradation during storage. In addition, sunlight exposure induced a decrease in E2-hexenal, which has a positive olive aroma in oils stored in clear glass bottles with no film, but this decrease was not observed to the same extent in oils stored in clear and amber glass bottles with either PET film. The light-protective effects of the AV-PET film were significantly higher than those of the MW-PET film. These results showed that secondary packaging with these PET films provided more effective protection against sunlight-induced oxidative deterioration of extra virgin olive oil during storage in primary materials, such as glass bottles, compared with storage in glass bottles with no secondary packaging.

Keywords

• olive oil
• oxidation
• packing film
• storage
• glass bottle
• light protection
• food waste