• Ultrasonically-assisted extraction and malaxation make the production of extra virgin olive oil more efficient.
• The ultrasonic process intensification results in higher EVOO yield, higher nutritional quality and shorter malaxation.
• Sonication increases the antioxidant and polyphenol content in extra virgin olive oil.

Ultrasonically-Assisted Malaxation

Malaxation, a basic step of the mechanical olive oil extraction process, can be significantly improved by sonication. The malaxation efficiency depends on the rheological characteristics of olive paste as well as the process parameters of malaxation, such as time and temperature. These factors influence the yield and quality of virgin olive oil heavily.
When powerful ultrasound waves are applied to the olive paste, cavitation occurs. Cavitation is the formation, growth and implosion of gas bubbles during alternating pressure cycles. Ultrasonic cavitation breaks cell structures so that soluble compounds are released from the olive plant tissue and mass transfer is improved. Thus, the extraction rate and yield is significantly improved by ultrasonication. Oils from sonicated olive pastes show lower bitterness and higher content of tocopherols, chlorophylls and carotenoids, too.
Sonication is a mild, non-thermal food processing technology that allows to release the oil and active compounds (e.g. antioxidants, phenolics, vitamins) from the olive paste. The continuous inline process, where the olive paste passes the ultrasound cavitation zone, allows for a very uniform processing. Sonication is very beneficial to the process temperature, too: The ultrasonic treatment gives an instanteneous heating and reduces the pre-heating time of the olive paste drastically, afterwards the process temperature can be easily maintained at an optimal process temperature (e.g. 28-30ºC).

Scheme of olive oil extraction line: A. cleaning section; B. crusher; C. cavity pump; D. US machine; E. 6-malaxer section; F. horizontal centrifuge; G. vertical centrifuges.
(author and copyrigth: M. Servili et al. 2019; no copyright violation is intended.)

Industrial Ultrasonic Extraction Systems

Hielscher ultrasonics supplies ultrasonic extractors and ultrasonic food processing systems adapted to your process requirements. We spec our sonication systems to the customer’s specifications such as capacity / throughput, olives (raw material), oil sort and quality, space, and retrofitting into existing production streams. By pumping the olive paste through an ultrasonic reactor chamber, the ultrasonic waves are applied very uniformly through the olive paste so that a very homogeneous product quality is achieved.
One of the major advantages of Hielscher’s sonication systems is the full control over all process parameters. Sonication intensity, temperature and pressure can be completely controlled so that the sonication process can be perfectly optimized in regards to yield and quality standards.
The industrial grade of our ultrasonic systems allows for 24/7 operation and hazzle-free processing.

Sonication improves the extraction and malaxation of virgin olive oil.

Advantages of Hielscher’s Ultrasonic Extraction Systems:

• full process control
• adaptable to customer requirements
• safe operation
• easy assembly & cleaning
• robustness & industrial grade (24/7)
• low, almost neglectable maintenance costs
• small space requirements
• easy retrofitting

Nutritionally Enriched Olive Oil

Applying ultrasound waves during the maceration / malaxation step enables to improve the nutritional value of olive oil by enriching it in phenolic compounds and vitamins from olive leaves. By extracting phenolic compounds such as α-tocopherol and oleuropein from olive leaves and adding them to the olive oil, the nutritional quality of the olive oil can be enhanced.

Flavored Olive Oil

Herbs and spices such as basil, sage, rosemary, garlic, lemon peel, peppers, ginger, rosemary sprigs, etc. can be used to infuse olive oil. The intense extraction effects of sonication help to release the flavor of the herbal / spice substrate much more complete and faster. Click here to read more about ultrasonic extraction!

Our ultrasonic systems are highly versatile and can be used in several process stages of your process. If you want to process your olive oil further, you can use your ultrasonic system to create fine size emulsions, e.g. to manufacture olive oil vinagrettes, dressings or sauces.