Ultrasonic Extraction of Edible Oils
Edible Oil Production Intensified by Sonication
Ultrasonic extraction is widely used to release valuable intracellular matter from plant material. Targeted extracts include lipids / fatty acids, proteins, vitamins, polyphenols and other bioactive compounds. As a process intensifying technique, ultrasonic extraction of edible oils, such as extra virgin olive oil, avocado oil, sunflower seed oil, flaxseed oil amongst others, increases the yield of extracted oil (fatty acids), shortens the extraction time and reduces or avoids solvent consumption. Being a non-thermal extraction technique, the working principle of ultrasonically-assisted extraction is based on the phenomenon of acoustic cavitation. Acoustic a.k.a. ultrasonic cavitation creates intense shear forces, which disrupt cell walls and increase the mass transfer between cell interior and the surrounding solvent. This makes ultrasonic extraction the superior technique when it comes to the release and isolation of compounds entrapped in plant cells.
- higher yield
- shorter extraction time
- no or reduced solvent consumption
- non-thermal process
- high nutritional quality
- easy and safe to use
- fast RoI
Case Studies for Ultrasonic Edible Oil Extraction
Ultrasonic extraction has been tested and proven to be efficient with various oil seeds and fruits.
Ultrasonic Sunflower Oil Extraction
Moradi et al. (2018) investigated the influence of ultrasonically assisted extraction on oil yield and nutrient composition from hulled and non-hulled sunflower seeds. They used a UP400S (400watts, 24kHz) ultrasonicator to extract sunflower oil from sunflower seeds using n-hexane as solvent.
In order to evaluate the extraction results, oil was also extracted via conventional batch solvent extraction and Soxhlet extraction using n-hexane for all extraction methods.
Ultrasonic extraction of sunflower oil gave the highest oil yields with 45.44 ± 0.27% and 23.71 ± 0.22% for non-hulled and hulled sunflower seeds, respectively. In the ultrasonically depleted sunflower meals were less than 4% and 5% of residual oil for non-hulled and hulled sunflower seed left.
The extraction time required when ultrasonic extraction was applied was reduced to only 105 min while Soxhlet extraction required 6 hrs and solvent batch extraction required a processing time of 10 hrs.
Gas chromatography analysis showed that the ultrasonically-assisted extraction enhances the quality of the extracted oils and α-linolenic acid significantly.
Ultrasonic Extra Virgin Olive Oil Extraction
Servili et al. (2019) integrated an 4kW ultrasonicator UIP4000hdT into a conventional olive oil malaxation line. The mechanical treatment of olive paste via sonication improves the performance of the extraction process, increasing the extraction capacity of olive oil mills. Since pressure is an important factor, sonication was performed using an ultrasonic flow cell with cascatrode at 3.5 bar. Ultrasonic extraction did not cause any alterations to the main legal quality parameters and showed a positive impact to the phenolic composition of the extra virgin olive oil (EVOO) at elevated pressure of 3.5 bar. Ultrasonic assisted malaxation of olive paste results in higher yields and improved phenolic composition of the EVOO.
Click here, to read more about ultrasonically assisted malaxation of extra virgin olive oil!
Ultrasonic Avocado Oil Extraction
Martinez-Oadilla et al. (2018) showed in their study that sonication using a UIP1000hdT (20kHz, 1000W) for the treatment of the non-malaxed avocado puree improved extractability by 15–24% additional oil recovery.
Click here to read more about the ultrasonic extraction of avocado oil!
Ultrasonic Flaxseed Oil Extraction
Gutte et al. (2015) used ultrasonication to extract oil from ground flaxseed using n-hexane as solvent. Alternatively, dichloromethane, petroleum ether or ethanol can be used as solvents. The ultrasonic extraction improved the extraction yield by 11.5% using a similar solvent amount to conventional extraction. The chromatographic analysis showed that there were no significant effects such as degradation on α-Linolenic acid (ω-3) by the ultrasonic extraction. The study shows that sonication increases the extraction yield of edible oil and reduces the extraction time whilst maintaining a high nutritional profile of the flaxseed oil.
Synergistic Effects of Ultrasonic Oil Extraction
Ultrasonic extraction can be applied as a single method to release oil from seeds and oil-rich fruits or it can be integrated or retro-fitted into conventional / already existing edible oil production facilities to increase oil yield and quality. Ultrasonic extraction systems can be easily installed as pre-or post-treatment of malaxation, in combination with Soxhlet extraction or behind a mechanical oil press or expeller.
Hielscher Ultrasonics extraction equipment is easily installed, requires only very little space (small footprint) and can be thereby retrofitted into existing oil mills. With robustness and industrial grade, Hielscher industrial ultrasonicators are built for 24/7 operation under heavy load and in demanding environments.
Increase your oil yield and quality with Hielscher Ultrasonics!
High-Performance Ultrasonic Extractors for Edible Oil Production
For the food-grade processing of edible oils on industrial level, high-performance ultrasonic equipment is required to process large volume streams of oil seeds in a continuous flow-through system. Hielscher Ultrasonics is long-experienced and trusted supplier of high-performance ultrasonic extraction equipment, which is worldwide integrated in food manufacturing plants.
Hielscher Ultrasonics’ sophisticated ultrasonicators can be precisely controlled and give the operator full control over the important process parameters such as amplitude, pressure, temperature and sonication time.
The extensive range of accessories such as sonotrodes (probes), booster horns, flow cell reactors and further add-ons enable to configure the ultrasonic extraction system specifically for the processed raw material and the targeted output.
Hielscher Ultrasonic high-power ultrasonicators easily process slurries with a high solid content, meaning a high ratio of solids (seeds) to solvent
Temperature Control during Ultrasonic Processing
As ultrasound-assisted extraction is a non-thermal processing method, the thermal degradation of heat-sensitive nutritional compounds can be prevented. Hielscher ultrasonic flow cell reactors come with a cooling jacket for heat dissipation. Additionally, the energy input can be exactly adapted to optimal processing conditions, e.g. by using the pulsation mode of the ultrasonic extractor. The ultrasonic extraction of edible oils at low temperatures avoids thermally induced decomposition of the extracted oils and minimizes the loss of bioactive compounds.
Ultrasonic Process Monitoring
All Hielscher digital ultrasonicators – from lab to industrial size – are equipped with an intelligent software, which makes it easy to precisely control, monitor and revise the ultrasonic process. Amplitude, energy input limit, pulse cycles and sonication time can be pre-set via the user-friendly software. Via colour touch-display the menu can be easily accessed and is intuitively to handle. The browser remote control enables the operator to operate and monitor the ultrasonic system remotely.
All important ultrasonic process data (such as amplitude, temperature, pressure, net energy, total energy, time and date) are automatically stored on an integrated SD-card. The automatic data protocolling is highly valued in the food and pharma industry, since it allows the food manufacturer to revise the processing condition of any sonicated lot. This enables for process standardisation, continuously high quality output and the implementation of Good Manufacturing Practices (GMP).
Hielscher Ultrasonics’ industrial ultrasonic processors can deliver very high amplitudes. Amplitudes of up to 200µm can be easily continuously run in 24/7 operation. For even higher amplitudes, customized ultrasonic sonotrodes are available. The robustness of Hielscher’s ultrasonic equipment allows for 24/7 operation at heavy duty and in demanding environments.
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
|Batch Volume||Flow Rate||Recommended Devices|
|1 to 500mL||10 to 200mL/min||UP100H|
|10 to 2000mL||20 to 400mL/min||UP200Ht, UP400St|
|0.1 to 20L||0.2 to 4L/min||UIP2000hdT|
|10 to 100L||2 to 10L/min||UIP4000hdT|
|n.a.||10 to 100L/min||UIP16000|
|n.a.||larger||cluster of UIP16000|
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Literature / References
- Negin Moradi, Masoud Rahimi, Atefeh Moeini, Mohammad Amin Parsamoghadam (2018): Impact of ultrasound on oil yield and content of functional food ingredients at the oil extraction from sunflower. Separation Science and Technology, 53:2, 2018. 261-276.
- 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.
- Krishna B. Gutte, Akshaya K. Sahoo, Rahul C. Ranveer (2014): Effect of ultrasonic treatment on extraction and fatty acid profile of flaxseed oil. Oilseeds & fats Crops and Lipids Journal 22(6) 2015.
- Laura Patricia Martínez-Padilla, Lisa Franke, Xin-Qing Xu, Pablo Juliano (2018): Improved Extraction of Avocado Oil by Application of Sono-Physical Processes. Ultrasonics Sonochemistry 40, Jan. 2018. 720-726.
Facts Worth Knowing
Edible oils are typically a liquid at room temperature, although some oils that contain saturated fat, such as coconut oil, palm oil and palm kernel oil can be solid. Edible oils are mostly vegetable oils as well as fruit-derived oils such as olive oil and avocado oil. Vegetable oils such as soybean oil, canola oil / rapeseed oil, corn oil, peanut oil, sesame oil, sunflower oil, safflower oil, palm oil, mustard oil, rice bran oil, pumpkin seed oil, coconut oil and other seed oils are widely used as cooking oils and in condiments (e.g. salad dressings, marinades, sauces, dips etc.). Vegetable oils are commonly used as cooking oil alternative for animal-based fats like butter and lard.
Margarine is a popular butter substitute based on refined vegetable oils (e.g. from safflower, sunflower, soybean, cottonseed, rapeseed, or olive oil). Read more about ultrasonic margarine production!
Edible oils such as olive oil, rapeseed oil, sunflower oil, or grape seed oil can be flavoured by infusing them with aromatic plants such as herbs (e.g.rosemary, basil, etc.), fruits (e.g citrus, orange, raspberry), chillies or garlic. Sonication is used to infuse vegetable oils with herbal extracts. Read more about ultrasonic maceration and infusion!
Oils and fats – the difference: Fats are solid at room temperature, whilst oils are liquid. Unsaturated fats such as polyunsaturated and monounsaturated fatty acids belong to the category of oils. Fats are mostly animal-derived and contain mostly saturated fatty acids. Common fats are butter, lard and tallow.