Quality parameters were unaltered by crushing speed, but extraction efficiency and chlorophylls content increased with faster hammer mill rotor speed in a continuous industrial process.
Researchers have analyzed how modifying the hammer mill rotor speed affects the extraction efficiency, quality, phenolics, volatiles and sensory profile of olive oils from super-high-density planted Arbosana olives processed in an industrial facility.
The study, Impact of industrial hammer mill rotor speed on extraction efficiency and quality of extra virgin olive oil, will be published in the March 2018 journal Food Chemistry.
The team included Selina Wang and Juan Polari of the University of California at Davis; David Garcí-Aguirre of Corto Olive Co.; and Lucía Olmo-Garcia and Alegría Carrasco-Pancorbo of the University of Granada.
The results revealed that quality parameters such as free fatty acidity (FFA), peroxide value (PV), UV absorbances, diaclyglycerols (DAGs) and Pyropheophytins (PPP) were unaltered by crushing speed, but extraction efficiency and chlorophylls content increased linearly with faster hammer mill rotor speed in a continuous industrial process.
Quantitative values of total phenols and some individual phenolic compounds, such as 3,4‑DHPEA-EDA and p‑HPEA-EDA, increased with rotor speed. Similarly, the level of triterpenic compounds, such as oleanolic acid and maslinic, increased significantly when higher crushing speeds were applied.
“This is not only the first study on the effect of hammer mill speed in the industrial scale olive oil processing facility but the first peer-reviewed article on olive oil processing published from a U.S. institution,” said Wang. “It also showcased the collaboration between academia and industry” to identify a relatively minor production adjustment that producers can employ to improve yield along with certain aspects of EVOO quality.
When asked why the hammer speed led to higher phenol levels in the research, Wang said her team hypothesized that “the escalated cutting action on the olive fruit potentially released more phenolic compounds resulting in higher levels in the oil by decreasing the oil droplets diameter, augmenting the oil/water emulsion interphase area and facilitating the mass transfer of phenols to the lipid phase after the action of β‑glucosidase.”
Higher levels of phenolic compounds would increase the shelf life of an oil and lead to greater health benefits to consumers.
More articles on: olive oil milling, olive oil research, UC Davis Olive Center
Jan. 15, 2024
Oleocanthal: Behind the Health Benefits of Olive Oil's Famous Phenol
Found solely in extra virgin olive oil, oleocanthal demonstrates potent anti-inflammatory properties and has been linked to beneficial impacts on cancer and dementia.
Aug. 14, 2023
Italy Set to Invest €100M for Olive Mill Upgrades
Starting in 2026, funds will be dispersed to millers across the country to upgrade equipment and technologies.
May. 1, 2023
Researchers Develop Simplified Way to Determine Polyphenol Contents of Olive Oil
The new method uses laser-engraved paper and a smartphone to determine polyphenols in a sample.
Mar. 7, 2024
Ancient Olive Groves on Capri Are Reservoirs of Biodiversity
Researchers traced the origins of the island’s olive trees to Crete and mainland Italy and discovered 21 new varieties.
Nov. 6, 2023
Polyphenol in EVOO May Shield Kidneys from Diabetes-Related Damage, Study Finds
Researchers investigated the use of dihydroxyphenylglycol, a polyphenol present in extra virgin olive oil, to treat kidney disease caused by type 1 diabetes.
Oct. 11, 2023
How Air Pollution Affects Olive Oil Quality in California
Producers and researchers weigh in on the impact of wildfire smoke and air pollution on the local olive oil industry.
Dec. 19, 2023
Olive Center Works to Educate Next Generation of Ag. Pros
The Olea Learn program teaches undergraduates the necessary agronomic and business skills to run an olive farming and olive oil production business.
Apr. 22, 2024
How Oleuropein Influences Extra Virgin Olive Oil Taste and Health Benefits
Along with oleocanthal and hydroxytyrosol, oleuropein is one of the main polyphenols found in extra virgin olive oil that determines its sensory characteristics and health benefits.