1. Traditional extraction method: The traditional method for extracting Beetroot Red is solid-liquid extraction, and the extraction methods include immersion, soaking and Soxhlet extraction. Solid-liquid extraction technology: The components in the solid mixture are separated by a solvent, so that the soluble components in the solid matter are dissolved and entered into the liquid phase, and then the solution is separated from the insoluble solid matter. Beetroot Red is generally dissolved in water, but if a certain proportion of methanol or ethanol is added, the beet red pigment in red beet can be completely extracted. In general, when extracting red beet pigment, first fully soak the red beet in a closed container with pure water or a solvent containing methanol, etc., and then stir it so that more beet red pigment enters the extract, and finally the solid is filtered by filtration. liquid separation. Although the traditional method for extracting Beetroot Red is time-consuming, it is very useful for extracting some thermally unstable substances because it operates completely at room temperature and does not require heat treatment.
2. New technology of Beetroot Red pigment extraction The new extraction techniques of Beetroot Red include γ-ray method, sonication method, ultrasonic-assisted technique, membrane treatment method, and high-voltage pulsed electric field method, etc. These techniques can be carried out at lower temperature, so they can be well maintained. biological activity and higher extraction efficiency.
1) Gamma Irradiation: The Beetroot Red is extracted from red beet by solid-liquid extraction. If it is pretreated by gamma rays, the extraction efficiency will be increased. The radiation dose is in the range of 2.5~10 k Gy. The extraction efficiency gradually increased with the increase of the dosage. Gamma rays improve the extraction of pigments mainly because rays can change the internal structure of plant tissues and promote the rupture of cell walls. Studies have shown that treating fresh Beetroot Red with low doses (1~2 kGy) of γ-rays can cause biochemical changes in the interior of red beet tissue and cell walls. Irradiated to study the biochemical properties of red beet and the stability of Beetroot Red . The results showed that there was no significant difference in the yield of extracted beet red pigment between the γ-ray treatment and the control, but if the radiation dose exceeded 10kGy, it would cause sugar beets. The red pigment structure changes, so the recommended dose of γ-ray does not exceed 10kGy.
2) High-voltage pulsed electric field: Because it is a non-thermal processing technology, the use of high-voltage pulsed electric field to electroporate cells can change the permeability of the cell wall and cell membrane, and make the cell contents seep out to achieve non-thermal sterilization. Effect. The high-voltage pulsed electric field is processed by applying short pulses of high voltage to the sample between the two electrodes for many times. Due to the advantages of short treatment time, small pollution, inhibition of microorganisms, passivation of enzymes and non-heating treatment, it can be better. to maintain the nutritional properties and quality of food.
3) Ultrasound-assisted extraction technology (Ultrasound-assisted extraction): Ultrasound-assisted extraction technology is a low-cost, environmentally friendly and fast extraction technology, which has broad prospects in the extraction of thermally unstable active substances. Since the ultrasonic wave can generate and transmit powerful energy, it can promote the better penetration of the solvent into each part of the sample matrix, increase the contact area between the solid phase and the liquid phase, and make the solute disperse into the solvent more quickly. It was found that ultrasonic wave significantly improved the extraction efficiency of Beetroot Red . Using ethanol and water 1:1, ultrasonic power of 80 W, and extraction time of 3 h, the yield of Beetroot Red increased by 8%.
4) Supercritical extraction technology (Supercritical Extraction): use supercritical CO2 as a solvent, select appropriate temperature and pressure, and use the excellent solubility of CO2 to dissolve the content of solid matter to achieve the purpose of separating specific active ingredients . When the Beetroot Red is exuded from the cells, the pigment will come into contact with various enzymes, and the peroxidase and polyphenol oxidase will quickly degrade the pigment, causing the quality of the Beetroot Red to decline. Studies have shown that when using high pressure CO2 to extract red beet juice, it was found that under the condition of 55 ℃ and 60 min, 37.5 MPa can reduce the activity of peroxidase by 86%, and 22.5 MPa can reduce the activity of polyphenol oxidase. The activity of the enzyme was reduced by 95%, and the change in enzyme activity was more sensitive to pressure than due to the critical state of CO2.
5) Membrane Processing: Membrane processing technology can achieve the purpose of enriching biologically active substances without heating. Different target compounds are extracted, purified, and concentrated, and so are the types of membrane treatments used, such as electrodialysis, microfiltration, ultrafiltration, reverse osmosis, electrodialysis, membrane distillation, and steam osmosis. ] Using ultra-fine filtration and reverse osmosis to purify and concentrate the Beetroot Red in red beet, it was found that the use of pectinase treatment could reduce the viscosity of the juice and improve the efficiency of pre-filtration, and found that adding invertase and pectinase, after Ultrafiltration can increase the yield of beet red pigment by a factor of three. The choice of different membrane types is the key to recovering the beet red pigment. Studies have shown that anisotropic membranes are the best system for the separation of Beetroot Red , increasing the recovery of Beetroot Red and reducing the level of soluble solids.