Have you ever used ultrasonic homogenizer for seaweed?

Have you ever used ultrasonic homogenizer for seaweed?

Introduction to Ultrasonic Seaweed Extraction Technology

I. Introduction

Seaweed, as a precious resource given to mankind by the ocean, is rich in a variety of bioactive ingredients, such as polysaccharides, proteins, fatty acids, alkaloids, polyphenols and pigments. These ingredients have shown great application potential in many fields such as medicine, food, cosmetics, and environmental protection. For example, kelp sulfate polysaccharides can be used in medicine, health foods, and antiviral feed additives, which are of great significance to protecting people's health and promoting livestock and poultry breeding safety. However, how to extract these bioactive ingredients efficiently and environmentally friendly has always been the focus of scientific researchers and related industries. Traditional extraction methods, such as solvent extraction and acid-base extraction, have problems such as low extraction efficiency, long time, high energy consumption, and great damage to active ingredients. With the continuous advancement of science and technology, ultrasonic-assisted extraction technology has emerged and gradually emerged in the field of seaweed active ingredient extraction.

II. Principle of Ultrasonic-Assisted Extraction

Ultrasound is a sound wave with a frequency higher than 20kHz. When it acts on a liquid medium, it will produce a series of unique physical effects, which are the key to achieving efficient seaweed extraction.

1. Cavitation effect: When ultrasonic waves propagate in liquid, they will form periodic pressure changes. In the negative pressure stage, tiny bubbles (cavitation nuclei) in the liquid will expand rapidly; in the positive pressure stage, the bubbles will collapse sharply. This instantaneous collapse of bubbles will generate extremely high temperatures (up to 5000K) and pressures (over 100MPa), forming strong shock waves and microjets. These extreme conditions can effectively destroy the cell wall and cell membrane structure of seaweed, making it easier for the biologically active components in the cells to be released into the extraction solvent. For example, when extracting polysaccharides from seaweed, the impact force generated by the cavitation effect can break the constraints of the cell wall and allow the polysaccharides to dissolve quickly.

2. Mechanical vibration effect: The high-frequency vibration of ultrasonic waves can cause strong mechanical vibrations of the liquid medium and seaweed particles. This vibration accelerates the relative movement between the extraction solvent and the seaweed particles, increases the penetration rate of the solvent into the seaweed, and thus promotes the diffusion of active ingredients from the seaweed into the solvent. Taking the extraction of protein from seaweed as an example, mechanical vibration allows the solvent around the protein to be quickly renewed, accelerating the dissolution rate of the protein.

3. Thermal effect: During the propagation of ultrasound, part of the energy will be absorbed by the medium and converted into heat energy, resulting in an increase in the temperature of the system. Appropriate temperature rise can reduce the viscosity of the extraction solvent, increase the diffusion coefficient of the molecule, and further improve the extraction efficiency. However, it should be noted that excessively high temperatures may damage some heat-sensitive bioactive components, so the ultrasonic conditions should be reasonably controlled in practical applications. When extracting some antioxidant components from seaweed, appropriate thermal effects can promote their dissolution without causing them to be oxidized and inactivated.

III. Advantages of ultrasonic-assisted extraction in the extraction of active ingredients from seaweed

Compared with traditional extraction methods, ultrasonic-assisted extraction technology has many significant advantages in the extraction of active ingredients from seaweed.

1. Efficient and fast: Many studies have shown that ultrasonic-assisted extraction can significantly shorten the extraction time. For example, when extracting kelp sulfate polysaccharides, cyclic ultrasonic extraction is used, and the extraction time can be shortened from several hours or even longer in traditional methods to 30 minutes. This not only greatly improves production efficiency, but also reduces the degradation of active ingredients that may be caused by long-term extraction. When extracting fucoidan from brown algae, ultrasonic-assisted extraction can achieve a single-stage extraction rate of more than 95%, greatly improving the extraction rate of the target component.

2. Energy saving and environmental protection: During the ultrasonic-assisted extraction process, the corresponding energy consumption is greatly reduced due to the shortened extraction time. At the same time, this technology can reduce the use of organic solvents, and even in some cases, more environmentally friendly solvents can be used, such as water-based natural deep eutectic solvents. For example, when extracting polyphenols from commercially cultivated fucoidan kelp, the use of water-rich natural deep eutectic solvents (WRNADES) combined with ultrasonic-assisted extraction not only improves the extraction efficiency, but also reduces the harm of organic solvents to the environment, and promotes the development of environmentally friendly production processes in seaweed biorefining.

3. Improve product quality: The effect of ultrasound is relatively mild, and while effectively extracting bioactive ingredients, it can better maintain their structure and activity. Taking the extraction of phycobilisomes as an example, it is difficult to obtain ideal phycobilisomes from Dracaena by chemical and mechanical crushing methods, but complete phycobilisomes can be obtained by ultrasonic treatment with a frequency of 20-50kHz and a voltage of 60V for 10 minutes. When extracting some medicinal ingredients from seaweed, ultrasonic-assisted extraction can ensure the activity of the ingredients and improve their medicinal value.

4. Wide range of applications: Ultrasonic-assisted extraction technology is suitable for the extraction of various types of seaweed and different bioactive ingredients. Whether it is green algae, brown algae or red algae, whether it is polysaccharides, proteins, polyphenols or pigments, efficient extraction can be achieved by optimizing ultrasonic conditions. For example, the extraction of β-carotene from salt algae and protein from spirulina have shown good results.