Influence of calcium carbonate on extraction yield and quality of extra virgin oil from olive (Olea europaea L. cv. Coratina)

• Calcium carbonate significantly increases the oil yield with respect to control.
• The amount of calcium carbonate needed depends on the ripening degree of olives.
• Calcium carbonate does not show any evident effect on oil quality.

The aim of the research was to evaluate the effect of calcium carbonate (1%, 2%, and 4% of addition) at two different particle sizes (2.7 μm and 5.7 μm), added at the beginning of the malaxation phase, on both the extraction yield and the quality of oil obtained from Coratina olives at different ripening index. The results showed that calcium carbonate significantly increased the extraction yield of olive oil, more than affecting chemical indices. In particular, for less ripened olives, 1–2% of larger particle size calcium carbonate addiction determined a significant increase of the extraction effectiveness, ranging from 4.0 to 4.9%, while more ripened olives required higher amounts of coadjuvant (2–4% when using the larger particle size and 4% when using the smaller one), with a significant increase of the extraction yield up to 5%. Moreover, an increase of pungent perception was observed in some cases when adding calcium carbonate to more ripened olives.