Impact of industrial hammer mill rotor speed on extraction efficiency and quality of extra virgin olive oil

- Effect of hammer crusher rotor speed was studied during continuous olive oil extraction.
- Rotor speed increased extraction efficiency, phenolic and triterpenic compounds content in extra virgin olive oil.
- FFA, PV, UV absorbances, DAGs and PPP were not affected by changes in hammer mill rotor speed.
- Pungency increased with hammer mill rotor speed.
- Hammer mill rotor speed may be used to tailor minor components during industrial olive oil extraction.

Crushing is a key step during olive oil extraction. Among commercial crushers, the hammer mill is the most widely used due to its robustness and high throughput. In the present work, the impact of hammer mill rotor speed on extraction yield and overall quality of super-high-density Arbosana olive oils were assessed in an industrial facility. Our results show that increasing the rotor speed from 2400 rpm to 3600 rpm led to a rise in oil yield of 1.2%, while conserving quality parameters. Sensory analysis showed more pungency with increased rotation speed, while others attributes were unaffected. Volatile compounds showed little variation with the differences in crusher speed; however, total phenols content, two relevant secoiridoids, and triterpenoids levels increased with rotor speed. Hammer mill rotor speed is a processing variable that can be tuned to increase the extraction efficiency and modulate the chemical composition of extra virgin olive oil.