Stainless Steel Bottles for Extra Virgin Olive Oil Packaging: Effects on Shelf-Life

The quality changes in extra virgin olive oil afforded by the conservation in bottles of different materials were assessed in a 12-month shelf-life test. Transparent clear glass (TCG), green coloured glass (CG) and stainless steel (SS) 250-ml bottles were studied (in triplicates) alternating natural and fluorescent light to simulate the ‘in the drugstore’ conditions. Every 2 months, the quality decay was assessed by monitoring some chemicals parameters and by sensory evaluation. Principal component analysis evidenced a clustering of the samples as a function of storage time and bottle type. The SS bottles showed the best storage per- formances, whereas only minor differences were detected in TCG and CG. A large variability was detected within the replicated glass bottles, probably as a consequence of some uncontrolled variations in the light exposure. This was confirmed by the measure of light intensity over the storing surface, which showed a large variability (15%) around an average value of 380 lux. Under light exposure, a limited antioxidant effect of phenolic compounds was recorded. Only some specific phenols seem to play an important role in oil protection against oxidation.