Although ultrasonic/ultrasound-assisted extraction (UAE) is becoming increasingly popular in academia and industries, I cannot find any scientific literature that has addressed this issue.
Of course UAE's primary function is via cavitation bubbles inducing solvent pathways, penetrating into the cellular wall. But saying this, does UAE chemically alter natural compounds in the mixture in ways much different to traditional solvent extraction?
If not, are there any scientific studies that support this claim?
Is creating "solvent pathways" seen as a chemical alteration to natural compounds?
I believe I have read much contradictory literature involving such statements.
Sincerely,
Pete
Hi Peter
I have not read any studies about the changes you mention, however, I can tell you a little about my experience. I performed the extraction of compounds with 4 different methods, including ultrasound-assisted extraction, and analyzed them with UPLC-ESI/qTOF/MS, and found no differences in the compounds present in the extracts.
Yes it can!
Ultrasounds can induce sonocavitation. The energy of bubble collapse can degrade many compounda. Read my papers on cavitation based AOPs.
Regards
GB
Sometimes it would be happen (that depend to operator base and the setting of apparatus). Of course, i have not seen many cases about that (in the scientific reports). It is important to separation process would be done in appropriate precision and according to AOAC protocol. In fact, the separation is carried out based on physical phase of extractor (stationary and mobility). Among that, the intensity of the waves in the gaseous phase is very important.
Hamid Reza Farhang Grzegorz Boczkaj Gabriela Barragan Thanks, I am well aware of the process of cavitation (form & collapse, small bursts of energy) and the cellular effect induced by ultrasound.
However, there are no papers that I have come across that show evidence of chemical alteration to constituents.
Of course, the extraction process is an alteration in-itself, but does the cavitation process chemically alter anything else?
This is an excerpt from Feng et al 2019 (Chapter Analytical Methods of Isolation and Identification
):"2.1.8 Ultrasonic extraction method
It is a method of solvent extraction assisted by ultrasound. Ultrasonic wave is a kind of elastic mechanical vibration wave. The vibration frequency is as high as 20 KHz in elastic medium. The ultrasonic wave could vibrate the liquid medium. When the vibration is sparse, many small holes are formed in the medium. The instantaneous closure of these small holes can cause a pressure of up to thousands of atmospheric pressures. At the same time, the local temperature can rise to 1000°C. It can cause instantaneous rupture of the cell wall of plants and the whole organism, and make the solvent permeate into the cells of plants. This accelerates the dissolution of active ingredients in plants into solvents. Ultrasonic wave extraction could shorten the extraction time and improve the extraction efficiency, but could not change the structures of chemical constituents meanwhile."
Unfortunately ^ no reference/evidence provided of this claim
I have read articles where they document the effect of ultrasound on the plant cell matrix using Scanning Electron Microscopy, I can share them with you if you want. The effect on the compounds will depend more on the operating conditions of the equipment itself, as well as time, temperature, etc., and that applies to any method of extraction.
Gabriela Barragan Please do :). I would be interested to read them, thanks.
I share with you the doi of the articles:
Article Effect of extraction method on structure and antioxidant act...
Article Effects of extraction methods on the yield, chemical structu...
Article Effect of extraction methods on the properties and antioxida...
Article Effects of extraction methods on the antioxidant activities ...
I hope they are useful to you.
Thank you Gabriela Barragan and Dr. S. Kalidhasan
If I was to refine the question, it would be "how" does UAE alter the chemical structure of constituents differently compared to conventional solvent extraction or other extraction methods (such as microwave, supercritical CO2 or enzymatic), as each of these utilise different forms of energy for extraction.
It would be wise to say that based on the intensity of certain conditions during extraction/treatment, chemical altering can occur and research can observe these changes by measuring molecular weights of certain compounds and other methods I am not aware of.
- Badges
- Science topic
- Similar topics
- Analytical Chemistry
- Extraction