Ultrasonic Extraction of Extra Virgin Olive Oil
- 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).
Benefits of Ultrasonic Olive Oil Extraction:
- higher yield
- more aromatic flavor and aroma
- lower bitterness
- higher antioxidant content
- longer shelf life
- intense green color
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.)
UIP4000hdT, a 4kW powerful ultrasonic processor for ext ra virgin olive oil malaxation and extraction
- Ultrasound system was applied to VOO industrial plant of 2 tons/h.
- High increase of oil yield was obtained from olives at an early maturity index.
- Ultrasound positively influences the phenolic content of VOO.
- Significant physical changes, increased extraction yield (22.7%), enhanced phenol content (10.1%) were observed in US-VOO compared to control oil extracted with a traditional process at an early maturity index.
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.
UIP4000hdT – a 4kW powerful ultrasonicator for the inline processing of extra virgin olive oil
Literature/References
- Agnese Taticchi, Roberto Selvaggini, Sonia Esposto, Beatrice Sordini, Gianluca Veneziani, Maurizio Servili (2019): Physicochemical characterization of virgin olive oil obtained using an T ultrasound-assisted extraction at an industrial scale: Influence of olive maturity index and malaxation time. Food Chemistry Volume 289, 15 August 2019, Pages 7-15.
- Servili M; Veneziani G.; Taticchi A.; Romaniello R.; Tamborrino A.; Leone A.(2019): Low-frequency, high-power ultrasound treatment at different pressures for olive paste: Effects on olive oil yield and quality. Ultrasonics Sonochemistry 59, 2019.
- Bejaoui, Mohamed Aymen; Beltran, Gabriel; Aguilera; Jiménez, Antonio (2016): Continuous conditioning of olive paste by high power ultrasounds: Response surface methodology to predict temperature and its effect on oil yield and virgin olive oil characteristics. LWT – Food Science and Technology 69, 2016. 175-184.
- Jiménez, Antonio; Beltrán, Gabriel; Uceda, M. (2007): High-power ultrasound in olive paste treatment. Effect on process yield and virgin olive oil characteristics. Ultrasonics Sonochemistry 14(6), 2007. 725-31.
More About Virgin Olive Oil
Olive oil consists mainly of triacylglycerols and has small quantities of free fatty acids (FFAs), glycerol, phosphatides, pigments, flavor compounds, sterols, as well as microscopic particles of the olive fruit. Oleic Acid is a monounsaturated omega-9 fatty acid that is with 55 to 83% the most dominant fatty acids of olive oil. If olive oil is made from low quality olive fruits or is not extracted carefully, the triacylglycerols are decomposed due to hydrolysis / lipolysis. By the hydrolytic / lipolytic reaction, the nutritionally high-grade triacylglycerols turn into free fatty acids. The free fatty acidity is the most important quality measurement of olive oil.
The high content of monounsaturated fatty acids and antioxidants in high-quality (extra) virgin olive oil can lower the risk of heart diseases and cancer. Furthermore, its anti-inflammatory effects can positively impact illnesses such as diabetes, hypertension, arthritis, and asthma.
Nutritional value of olive oil (per 100g / 3.5 oz / 103mL)
- Energy 3,701 kJ (885 kcal)
- Carbohydrates 0 g
- Fat 100 g
- saturated 14 g
- monounsaturated 73 g
- polyunsaturated 11 g
- omega-3 fat 0.8 g
- omega-6 fat 9.8 g
- protein 0 g
- vitamin E 14 mg
- vitamin K 62 μg
Besides its nutritional value, olive oil is a highly valued ingredient for skin care and cosmetical products. Due to its rich emollients, olive oil is a popular moisturizing additive in skin lotions and creams, exfoliating body scrubs and hair masks. Ultrasonic homogenizers are frequently used in the formulation and compounding process of skin care and cosmetic products. Ultrasonic shear forces create fine-size emulsions and dispersions. Ultrasonic encapsulation forms liposomes as carrier for active ingredients. Click here to learn more about the use of Hielscher’s ultrasonic mixers in the skin care and cosmetic industry!