Effect of different storage conditions in semi-industrial tanks on the shelf-life of extra virgin olive oil.

During one year the effect of the use of different temperatures and atmospheres during the storage of an extra-virgin olive oil in semi-industrial tanks was investigated. The oil was stored in three different tanks immediately after the extraction process. Each tank had a capacity of 250 l. Initially all the tanks were filled up completely. Two of the tanks were saturated with nitrogen. Only one of the three tanks was refrigerated. The oils remained in this condition for six months. After this period the tanks were partially emptied to half, in order to simulate the frequently storage condition in the industrial mill plant. The oils remained in this conditions for another six months. The oils were sampled every 30 days for analysis. The analytical parameters considered were: free acidity degree, peroxide value, ultra violet indices ( K-232, k(270), Delta K), total phenol content and induction time. Our results show both temperature and the atmosphere that had influence on the extra virgin olive oil shelf life in a semi-industrial storage plant.