Views:26 Author:Site Editor Publish Time: 2019-09-01 Origin:Site
Application of high-intensity ultrasonic technology in food field
High-intensity ultrasonic waves, due to their high energy, generate strong pressure, shear and high temperatures in the medium, which can change the physical structure of the medium and promote certain chemical changes. The application of high-intensity ultrasonic technology in the food industry is extensive. Early applications include cell disruption, liquid degassing, ultrasonic cleaning of ultrasonic homogenized emulsions, and dispersion of precipitates. In recent years, high-intensity ultrasonic waves have been continuously used in new fields of the food industry.
1.Promote oxidation reaction
High-intensity ultrasonic waves generate high pressure and high temperatures, causing water molecules to cleave and release free radicals. The researchers found that ultrasound technology can clearly observe the role of promoting oxidation of alcoholic beverages. However, this accelerated oxidation reaction does not necessarily improve the taste of the beverage.
2, the role of enzymes
In general, prolonging the contact time of the enzyme-containing system with high-intensity ultrasonic waves can reduce the activity of the enzyme, which may be caused by the high-intensity ultrasonic wave generating high pressure, high temperature and strong shear force to degrade the gastric protein. However, for some enzymatic reactions, short-term application of ultrasound can accelerate the enzyme-catalyzed reaction. This effect is most likely due to the fact that the ultrasonic waves cause the aggregated molecules to re-crack and disperse, thereby making it easier for the enzyme to fully contact the substrate and accelerate the reaction.
3, ultrasonic sterilization
High-intensity ultrasonic waves are used to kill microorganisms because they produce high pressure, strong shear and high temperatures. At present, ultrasonic sterilization technology has been applied to the food industry. Ultrasonic sterilization is more effective when used in combination with sterilization techniques such as heat treatment and chlorination.
4, filter, accelerate diffusion
High-intensity ultrasonic waves promote the passage of molecules through the filter membrane and porous surfaces. The principle of ultrasonic assisted filtration and accelerated diffusion is that the sound flow movement and the liquid flow movement do not interfere with each other under the condition of high intensity ultrasonic field, and the accelerated diffusion can shorten the drying and rehydration time of the food. Ultrasonic and reverse osmosis times can also be shortened by applying ultrasonic waves through continuous cleaning of the interface.
5, ultrasound tenderization
Extending the action time of meat and ultrasound can give the meat a distinct tenderization effect. Treatment of meat with ultrasound can release muscle fibrin rapidly, and myofibrillin mainly acts as a blocking agent for various components in meat products. Therefore, ultrasonic technology can improve the physical properties of meat products such as water retention, tenderness and cohesion.
6, improve the crystal
The substance crystallizes only when its temperature is lower than its own melting point. High-intensity ultrasonic waves generate a large number of small bubbles and constantly changing pressures and temperatures that destroy the solid-liquid two-phase equilibrium, thereby reducing the freezing point required for crystallization nucleation. The crystal size and content can be improved by controlling the intensity, duration and frequency of the ultrasonic waves. Experiments have shown that applying the cooled sucrose solution to ultrasonication can greatly increase the amount of sucrose crystals. Ultrasonic modified crystallization processing can be a method of improving the performance of many foods. Improvements in the taste of edible mayonnaise products, ice cream, chocolate and cream, such as ultrasound, are based on this mechanism.
7, ultrasonic extraction
The high-intensity ultrasonic wave can form a high-energy sound field, and the sonic cavitation effect of the solution on the sound field can be used to ultrasonically extract the target substance. The main factors affecting the ultrasonic extraction rate are the frequency, power, duration of action, and solvent type and concentration of the ultrasonic wave.
Researchers have explored ultrasound extraction. For example, the extraction of glycyrrhizic acid by ultrasonication and the application of ultrasonic to increase the extraction rate of soy protein are significantly higher than the traditional hot extraction method, which may be due to the increase of heat sensitive protein in the soy protein component. Ultrasonic action can increase the protein water extraction rate of high temperature defatted soy flour from whole protein.