Phenolic compounds of virgin olive oil: influence of paste preparation techniques

An experimental investigation was carried out on olive oils of the Ogliarol a Salentina and Coratina cultivars to assess the influence of the two diffe rent olive grinding techniques and kneading process on the quality of the o ils. The experimental data obtained showed that resistance to oxidation, to tal phenols and phenolic compounds analysed for HPLC were higher in the Cor atina oils than in the Ogliarola oils. The use of hammer-crushers plus knea der rather than stone mills plus kneader always produced significant increa ses in the total phenols. Resistance to oxidation was assessed by the Ranci mat method and showed a significant correlation with the amounts of total p henols and of an unidentified substance (peak I) which was conspicuously pr esent amongst the substances evaluated for HPLC. (C) 1998 Elsevier Science Ltd. All rights reserved.