Influence of olive crushing temperature on phenols in olive oils

Abstract

 An experimental investigation was carried out to evaluate the influence the different temperatures at which olives are hammer-crushed and paste kneaded had on the quality of oil and particularly on the phenolic components. The results obtained showed that temperature influenced the diffusion of phenolic compounds in oil. Greater amounts of hydroxytyrosol, tyrosol, caffeic acid, hydroxycaffeic acid and oleuropeine were measured in oils obtained from previously refrigerated olives. Kneading brought about a reduction of total phenols when it was performed on olives crushed at a higher temperature (18  °C) while it led to a slight increase when it was executed on pastes of previously refrigerated olives (6  °C).