Effect of shelf conditions on the phenolic fraction and oxidation indices of monovarietal extra virgin olive oil from cv. ‘Taggiasca’

Abstract

The quality of monovarietal extra virgin olive oil from cv. ‘Taggiasca’ is influenced by many factors that have impact on shelf-life as well as on sensory and healthy properties of the product. The aim of the work was to recreate the conditions similar to those in consumer sales point (conditions of “shelf”), maintaining the olive oil packaged in dark-green bottles at room temperature (between 18 and 25 °C) under artificial light and away from heat sources, monitoring the oils up to 12 months from bottling with quarterly sampling for the main chemical, physico-chemical, and sensory parameters related to the quality. After one year of storage, an organoleptic alteration with reduction of the attributes ‘fruity’, ‘pungent’, and ‘bitter’, as well as the occurrence of ‘rancid’ defect, was observed. This alteration was found to be accompanied by a decrease in phenolic substances and tocopherols and an increase in primary and secondary oxidation products. The composition of the volatile fraction showed a slight increase of substances related to rancid defect, a constant trend of compounds related to fruitiness, and a slight decrease in alcohols. It can be concluded that the optimum time of storage of the oil under the above-mentioned conditions is approximately 9 months.