EFFECT OF CO2 IN FRUIT STORAGE ATMOSPHERE ON OLIVE OIL QUALITY

Olive fruits (Olea europaea, cv. ''Picual'') were stored at 5-degrees-C and four different atmospheres (% CO2/% O2/%N2: 0/21/78: 5/20/75; 10/19/71 and 20/17/63). At 5-degrees-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 appearence of fruit decay. Simple refrigeration of fruits at 5-degrees-C for 60 days was sufficient to mantain the commercial quality of ''virgin extra'' in oil extracted from them. Oils obtained from fruits stored at 5-degrees-C in CO2 enriched atmospheres showed lower peroxide index and UV absorbance (270 nm), but developed off-flavor. Therefore, greater-than-or-equal-to 5% CO2 concentrations in storage atmosphere of olive fruits for oil production at 5-degrees-C must be avoided.