How olive washing and storage affect fruit ethanol and virgin olive oil ethanol, ethyl esters and composition.

BACKGROUND: Olives are stored for a short time after harvesting pending processing in the oil mills. Furthermore, olives are often washed prior to fruit storage. In this work we study how washing and storage affect fruit ethanol content and the effect on virgin olive oil ethanol content and quality. RESULTS: Olive storage produced an increase in the fruit ethanol content, achieving values six times higher when storage was in silos. Washing the olives resulted in an increase in fruit ethanol content, although when washed olives were processed immediately no difference was found. The increase in fruit ethanol content during storage was reflected in higher oil ethanol concentration. Similarly, olive washing resulted in oils with higher ethanol concentration. Industrial conditions gave more important increases in oil ethanol content than that from olives processed by hand. For quality parameters all the olive oils were classified as 'extra virgin'. In general, oils showed a slight decrease in some sensory attributes. At industrial scale after 24 h storage oils were classified as 'virgin' because sensory defects were found. CONCLUSION: Olive storage should be avoided or reduced to less than 12 h; if possible, olives should not be washed before storage since this practice favors losses in sensory characteristics and the synthesis of ethanol, a precursor of ethyl esters. © 2020 Society of Chemical Industry.

Settling of virgin olive oil from horizontal screw solid bowl in static conditions.

This work was aimed to study the clarification efficiency of natural decantation in settling tank on virgin olive oil obtained from a two-ways continuous process. For this purpose, the impurities content of the virgin olive oil were monitored during settling process in settling tank at two different depths. Efficiency of purging system was determined for two days. The experiments were performed at industrial scale during three crop years. During the first minutes of settling was observed an ascent of the smaller organic particles of the oil. Then, most of the virgin olive oil impurities were settled at 300 min, independently of the initial content of virgin olive oil. Finally, oil decantation showed slower rate. Higher clarification values were obtained for those decanter oils with higher impurities content, achieving clarification percentages between of 62.69 and 95.91% at 48 h of settling. The highest settling efficiency was observed for those decanter oils with initial higher impurities content. The purging system used in the settling tanks was not able to remove the most of settled impurities since a considerable amount of the impurities remained in the tank after 48 h, between 13.6 and 71.41% for the studied oils. In the tank purges was observed important oil losses. Therefore, decantation was not an efficient system for oil clarification since its settling capacity varied depending on the initial impurities content and due to the settled impurities can not be removed fully by purging system.