Effect of CO2 in fruit storage atmosphere on olive oil quality

Abstract

Olive fruits (Olea europaea, cv. "Picual") were stored at 5°C and four different atmospheres (% CO₂/% O₂/%N₂: 0/21/78; 5/20/75; 10/19/71 and 20/17/63). At 5°C the enrichment of the fruit storage atmosphere with concentrations of CO₂ above 5% resulted in a linear increase of the acidity of extracted oils after 60 days of fruit storage time. This fact showed a strong relationship with the appearance of fruit decay. Simple refrigeration of fruits at 5°C for 60 days was sufficient to maintain the commercial quality of "virgin extra" in oil extracted from them. Oils obtained from fruits stored at 5°C in CO₂ enriched atmospheres showed lower peroxide index and UV absorbance (270 nm), but developed off-flavor. Therefore, > 5% CO₂ concentrations in storage atmosphere of olive fruits for oil production at 5°C must be avoided.