Quality Changes of Extra Virgin Olive Oil Packaged in Coloured Polyethylene Terephthalate Bottles Stored Under Different Lighting Conditions (original) (raw)
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Abstract: The effect of packaging materials and lighting conditions on quality of extra virgin olive oil (EVOO) was investigated during six months. The results highlighted an influence of light and type of packaging material on EVOO-quality with storage time. At shelf, all packages maintained EVOO at the end of storage in terms of acidity, peroxide value, K232, while K270 exceeded limit of EVOO in glass and PET-stored oil. Loss of phenols was the highest in glass-stored oil and the lowest in high-density polyethylene (HDPE)-stored oil. In terms of sensory evaluation, glass-stored oil lost EVOO grade after three months and its edible compliance after six months, while HDPE-stored oil maintained EVOO grade 90 days and was virgin after six months. In extended lighting, acidity, peroxide value and K232 did not exceed EVOO grade, while K270 exceeded EVOO grade after 30 days in glass and polyethylene terephthalate (PET)-stored oil and after 90 days in HDPE. The loss of phenols was the largest in glass and smallest in HDPE-stored oil. Glass stored-oil lost organoleptic edible compliance before 90 days, while that in PET was virgin at 90 days and that in HDPE maintained EVOO quality 90 days. At the end of experiment, oils in all packages were not edible. In dark, all packages maintained oil in EVOO quality in terms of all indices. The loss of phenols was marginal but was the least in glass and the highest in HDPE. It was concluded that HDPE bottles conserve stored olive oil at shelf or illumination better than PET or glass, while in dark, glass was superior over plastic.
The quality of extra virgin olive oil (EVOO) is intimately affected by packaging material and storage temperature. In this study, the influence of packaging materials and elevated temperature on EVOO quality was investigated during six months. At ambient temperatures, oil maintained EVOO when stored in glass, polyethylene terephthalate (PET), high density polyethylene (HDPE), cans and Pottery in terms of chemical tests (acidity, peroxide value, K232, and K270). Loss of phenols was the highest in pottery-stored oil and the lowest was found in glass-stored oil. Only PET-stored oil maintained the EVOO grade in terms of sensory evaluation when stored at room temperature. At elevated temperature, oil stored in all packaging materials lost extra virgin quality in terms of chemical tests. The loss of phenols was the largest in HDPE and smallest in cans-stored oil. Sensory evaluation, maintained glass-stored oil and PET-stored oil as EVOO. This study has reaffirmed that at both storage temperatures, the best container in maintaining the EVOO quality was glass and the worst was pottery. Grading of stored olive oil under investigation using sensory evaluation solely was not sufficient. Also it was clear that the absorption coefficient K270 was the most sensitive determinant chemical test that determines the quality of stored olive oil and could be used as a rapid indicator test.
Extra virgin olive oil overall quality assessment during prolonged storage in PET containers
The aim of this study was to investigate the changes occurring in bottled extra virgin olive oil (EVOO) during prolonged storage in different PET containers. The changes of quality indexes, sensory parameters, phenolic antioxidants and pigments of EVOO where evaluated in relation to prolonged storage (12 months). Two EVOO samples were selected on the basis of their different acidity levels and phenolic content and where bottled in transparent or red PET bottles. Bottles where placed in dark or light conditions, the latter simulating the normal conditions found on the market. Results showed a significant decrease of a-tocopherol and chlorophylls during the first months of storage, and light exposure greatly Influenced these parameters. Tocopherols seems to have a crucial role in controlling and slowing down oil oxidation. Alpha-tocopherol showed a greater effect respect to biophenols in reducing photooxidation processes. In relation to the container characteristics, it was observed that colored red bottles did not showed a sufficient protection against light with respect to transparent PET bottles, while good protection of global quality was obtained only through storage in the dark. These results suggest the importance to find containers with suitable barrier properties against light in order to extend the EVOO shelf-life bottled in PET containers.
Packaging Technology and Science, 2008
The shelf life of extra virgin olive oil (EVOO) and sunflower oil (SO) bottled in containers with different levels of oxygen scavenger (OS) and stored at room temperature under diffuse lighting conditions for 6 months has been evaluated. Four packaging materials were tested: glass, polyethyleneterephthalate (PET), PET including 1% of OS (PET 1%) and PET including 5% of OS (PET 5%). Free acidity, peroxide value (PV), spectrophotometric indices (K232, K270, ΔK), antioxidant (biophenols and tocopherols) content, pigment (chlorophylls and carotenoids) change and the amount of oxygen dissolved in the oil were monitored during storage. A significant influence of the packaging material on the quality decay was not found. The differences in the shelf life observed between oils bottled in PET and oils bottled in glass are attributable to a difference in the initial content of dissolved oxygen in the oils. The study showed the usefulness of monitoring changes in dissolved oxygen level, antioxidant (phenols and tocopherols) and pigment (chlorophyll and carotenoids) profiles during oil storage. The change of these compounds could in fact supply important information on the oxidation processes that occur in bottled oils and on the effectiveness of the material employed in oil packaging. Copyright © 2007 John Wiley & Sons, Ltd.