Optimization of malaxing conditions using CaCO3 as a coadjuvant: A method to increase yield and quality of extra virgin olive oil cv. Chemlali

- Olive oil yield depended on malaxation temperature, duration and added CaCO3.
- Response surface methodology was used to optimize olive oil yield and quality.
- The optimum was 1.6% of CaCO3 added to olive paste, malaxing at 31 °C for 20 min.
- An increase in oil yield of 2% was obtained without affecting the oil quality.

In the present work, the effect of parameters including calcium carbonate concentration, malaxation time and temperature on the yield and quality of Extra Virgin Olive Oils of Chemlali cultivar were studied. The balance between the quality and quantity of the extracted oil was determined. The optimal conditions were determined and the quadratic response surfaces were drawn from the mathematical models in order to ensure the best quality of the resulting oils. Response surface methodology (RSM) results indicate that adding a ratio of 1.6% of calcium carbonate to the olive paste at a malaxing temperature of 31 °C during 20 min has important advantages. Indeed, it increases oil yield by 2% and phenol and pigments contents without affecting the oil quality, as well as improves the antioxidant activity. Concerning fatty acid and steroids composition, no significant differences were found when comparing oils obtained with or without carbonate and all of them could be classified as “Extra Virgin Olive Oil” according to European norms.