Why is a Probe-Type Ultrasonicator Best for Mushroom Extraction?
Are you wondering why your mushroom extraction using an ultrasonic bath or an ultrasonic cleaning tank does not give you the desired extract yield? Learn here all you need to know about the rigid chitin-containing cell walls of mushrooms, the best extraction technique and suitable solvents!
Why Do I Need Intense Forces for Mushroom Extraction?
All edible mushrooms have cell walls made of chitin, the same material that makes up crustacean and insect shells. Chitin is a very strong material, which gives mushroom cells a high toughness. The cell wall creates a barrier to the intracellular compartments, which contain the bioactive molecules of mushrooms. Important mushroom molecules are for instance α- and β-glucans, polysaccharides, terpenes, antioxidants, vitamins or hallucinogenic compounds. Each mushroom species features an unique array of bioactive compounds. In order to release these health-promoting substances from the mushroom cells, the cell walls must be broken down. Due to its chitin content, the disruption of mushroom cell is a challenging task and requires some knowledge and sophisticated equipment.
Breaking Chitin-Containing Mushroom Cell Walls with Sonication
Whilst chitin is a great source of fiber, prebiotics and antioxidants, the problem is, that humans do not have the ability to break down chitin. This means also, that when you consume raw untreated mushrooms, you won’t benefit from many of the bioactive compounds in mushroom, because they are entrapped within cells, which are protected by strong chitin-containing cell walls.
Ultrasonic extraction makes bioactive compounds from mushrooms bioavailable, so that the human body can absorb the nutrient fast and completely. Additionally in ultrasonic mushroom extracts the beneficial nutrients are concentrated so that even small amount of the mushroom extract give the desired health-promoting results.
Ultrasonication for Mushroom Extraction
Ultrasonication is a process in which high-frequency sound waves are used to create cavitation bubbles in a liquid. When these bubbles collapse, they create intense localized shear forces that can break down cells and release the contents of the cells into the liquid.
In mushroom extraction, ultrasonication can be used to break down the cell walls of the mushrooms and release their bioactive compounds into a solvent. There are two types of ultrasonicators: bath-type and probe-type.
Why Does my Ultrasonic Bath Gives Poor Mushroom Extraction Results?
A bath-type ultrasonicator is a device in which the sample is placed in a container filled with the solvent, and ultrasonic waves are applied to the entire container. This method is known as fairly ineffective, as as ultrasonic bath distributes ultrasonic energy unevenly and with a low intensity. As in an ultrasonic bath the mushroom sample is sonicated indirectly, the ultrasound cannot penetrate deep into the sample. The ultrasound waves have to go through the walls of vessel before they hit the mushroom material. Thereby, the already low intensity ultrasound waves of the ultrasonic tank are even further diminished.
Intense Ultrasound Extraction using an Ultrasonic Probe
On the other hand, a probe-type ultrasonicator is equipped with a tip – the so-called sonotode or probe – that can be inserted directly into the sample, allowing for more focused and localized application of ultrasonic energy. This results in a significantly more efficient cell disruption and extraction of bioactive compounds, especially in dense or hard-to-reach areas of the sample.
The focused and localized application of ultrasonic energy provided by the probe-type ultrasonicator ensures that the chitin is subjected to a sufficient amount of energy to be broken down.
Additionally, the probe can be moved around to different areas of the sample creating additional macro-mixing to ensure that all parts of the mushroom are adequately sonicated. This is particularly important for mushrooms with thick cell walls or dense structures, where it can be challenging to ensure complete extraction using other methods.
- More complete extraction
- Higher yields
- High-quality extracts
- Rapid process
- Cold / non-thermal process
- Compatible with any solvent
- Easy and safe to operate
- Low maintenance
Ultrasonic Probe vs Ultrasonic Bath for Mushroom Extraction
In summary, the high-intensity of probe-type sonication is necessary to break down the chitin in the mushroom cell walls and release the bioactive compounds. The focused and localized application of ultrasonic energy provided by the probe-type ultrasonicator ensures that the chitin is adequately sonicated, resulting in more efficient and thorough extraction of bioactive compounds from the mushrooms.
A probe-type ultrasonicator is generally considered to be more efficient for mushroom extraction, as it can provide more uniform and thorough extraction of bioactive compounds compared to a bath-type ultrasonicator.
Read more about the differences in ultrasonic processing using an ultrasonic probe vs an ultrasonic bath!
What is the Ideal Solvent for Ultrasonic Mushroom Extraction?
Ultrasonication as extraction method is compatible with any solvent. This means that choosing the right solvent must be done considering the mushroom species and the bioactive compounds, which should be extracted.
Mushrooms contain a variety of bioactive compounds such as polysaccharides, beta-glucans, triterpenoids, phenolic compounds, and ergosterol, which have been shown to possess various health benefits. Extraction of these bioactive compounds from mushrooms can be achieved using various solvents, each with its advantages and disadvantages. Here are some of the commonly used solvents for the extraction of bioactive compounds from mushrooms:
- Water: Water is a common solvent for the extraction of bioactive compounds from mushrooms. Polysaccharides and beta-glucans are water-soluble, making it an ideal solvent for the extraction of these compounds. Water is also a safe and non-toxic solvent, making it an ideal solvent for food and medicinal products.
- Ethanol: Ethanol is a polar solvent that is commonly used for the extraction of phenolic compounds and triterpenoids from mushrooms. Ethanol can also be used to extract polysaccharides and beta-glucans, but at a lower yield than water.
- Aqueous Ethanol: Aqueous ethanol means a mixture of water and ethanol. The ratio of water to ethanol can be adjusted to requirements. The use of aqueous ethanol as a solvent has several advantages over the use of water or ethanol alone. First, the addition of ethanol to water can improve the solubility of certain bioactive compounds that are not very soluble in water alone, such as some phenolic compounds and triterpenoids. Second, the use of aqueous ethanol can result in higher extraction yields compared to water or ethanol alone, as it can extract a wider range of bioactive compounds.
The choice of the ethanol concentration in the aqueous ethanol solvent depends on the polarity of the bioactive compounds being extracted. A higher concentration of ethanol (70-100%) may be used for the extraction of less polar compounds, while a lower concentration of ethanol (30-50%) may be used for the extraction of more polar compounds.
- Methanol: Methanol is another polar solvent that can be used for the extraction of phenolic compounds from mushrooms. Methanol is toxic, so it should be used with caution. A sophisticated purification is required to remove methanol after extraction.
- Acetone: Acetone is a non-polar solvent that is commonly used for the extraction of ergosterol from mushrooms. Acetone is flammable and toxic, so it should be used with caution.
- Hexane: Hexane is a non-polar solvent that can be used for the extraction of lipophilic compounds from mushrooms. Hexane is flammable and toxic, so it should be used with caution.
The choice of solvent for the extraction of bioactive compounds from mushrooms depends on the type of compound being extracted and the intended application. Water and aqueous ethanol are generally the safest and most commonly used solvents for the extraction of bioactive compounds from mushrooms. However, other solvents such as ethanol, methanol, acetone, and hexane may be used for specific applications or when water extraction is not sufficient. It is important to use these solvents with caution and follow appropriate safety procedures.
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Literature / References
- Valu, Mihai-Vlad; Liliana Cristina Soare; Nicoleta Anca Sutan; Catalin Ducu; Sorin Moga; Lucian Hritcu; Razvan Stefan Boiangiu; Simone Carradori (2020): Optimization of Ultrasonic Extraction to Obtain Erinacine A and Polyphenols with Antioxidant Activity from the Fungal Biomass of Hericium erinaceus. Foods 9, No. 12, 2020.
- Valu, M.-V.; Soare,L.C.; Ducu, C.; Moga, S.; Negrea, D.; Vamanu, E.; Balseanu, T.-A.; Carradori, S.; Hritcu, L.; Boiangiu, R.S. (2021): Hericium erinaceus (Bull.) Pers. Ethanolic Extract with Antioxidant Properties on Scopolamine-Induced Memory Deficits in a Zebrafish Model of Cognitive Impairment. Journal of Fungi 2021, 7, 477.
- Asadi, Amin; Pourfattah, Farzad; Miklós Szilágyi, Imre; Afrand, Masoud; Zyla, Gawel; Seon Ahn, Ho; Wongwises, Somchai; Minh Nguyen, Hoang; Arabkoohsar, Ahmad; Mahian, Omid (2019): Effect of sonication characteristics on stability, thermophysical properties, and heat transfer of nanofluids: A comprehensive review. Ultrasonics Sonochemistry 2019.
Facts Worth Knowing
Chitin as Building Block of Fungal Cell Walls
Chitin is a multipolymeric material widely found in many classes of fungi including Ascomycetes, Basidiomycetes, and Phycomycetes. Chitin is a tough molecule that can form into long chains and meshes, providing a 3D skeleton around fungal cells. Fungal chitin is present in the structural membranes and cell walls of mycelia, stalks, and spores and gives the cell structure of mushrooms high strength and rigidity. The biopolymer chitin is a modified polysaccharide that contains nitrogen; it is synthesized from units of N-acetyl-D-glucosamine (GlcNAc) and is characterized by a high molecular weight.