Decolorization of plant extracts

At present, there are many methods and processes for decolorization of traditional Chinese medicine, but they can be classified by the following methods ）`, S5 J-V ා C9 x'n-1 It is the most common, simplest and less effective method to remove pigment according to the difference of solubility in different solvents 1 Water extraction and alcohol precipitation: it can remove a small part of water-soluble pigment Alcohol extraction and water sedimentation: most of the fat soluble pigments can be removed 0 d0h9 W1 I, 1 K: J9 g (alternatively use two methods),% A2 R8 K3 Z + N1 R5} - K2 Acid base precipitation method: for example, when the impurity pigment is some phenolic acid components such as flavonoids, anthraquinone, etc., it can adjust the pH value below 3, and precipitate 2、 According to the distribution ratio of pigment in two-phase solvent, a ා R / z1f) l + n7v ා x can be removed For example, when the impurity pigment is some phenolic acid components such as flavonoids and anthraquinone, the method of adjusting the pH to more than 12 can be used to extract with organic solvent At this time, because the pigment exists in the form of dissociation, it is not suitable to be extracted 5 p $h ා P; M z) y $d5z 1 D, G5 {'m! Y & v% G2 @ & L1 Physical adsorption: (the adsorption force is intermolecular force) 5 [+ @, O' g4h8 {(H9 f8j (1) polar adsorbent: such as silica gel, alumina It can remove hydrophilic pigment , g) P7 E2 e, H6 y * A: X (2) non-polar adsorbent: such as activated carbon, pulp, talcum powder, diatomite It can remove lipophilic pigment Activated carbon is an excellent adsorbent, it has a strong adsorption capacity for pigment, bacteria, pyrogen and other impurities, and it also has a filtering effect #B3 G2 R (c7q, W: P) has a large number of micropores and voids, with a surface area of 200-500m2 / g Adsorption principle: because most pigments have a double bond structure, they are easy to adsorb Methods of use: cold adsorption, heat adsorption, carbon assisted filtration, column chromatography 2 Chemical adsorption: X7} 5 `'r & | * M9 ^ 0 N1 | (1) for example, alkaline alumina can be used to remove some phenolic acid pigments such as flavonoids and anthraquinone 4? $R "P!} (Q1 F9 B (2) ion exchange resin method: phenolic acid pigments such as flavonoids and anthraquinone can be removed by anion exchange resin $G2 H "| 5 P7 s) ^ 9 O3 Semi chemical adsorption: polyamide and macroporous resin The adsorption principle is hydrogen bonding, and macroporous resin has some van der Waals effect Polyamide can form hydrogen bond with phenolic and flavonoid hydroxyl groups through amido carbonyl in the molecule It can also form hydrogen bonds with quinones and carbonyls on fatty acids through free amines on amide bonds ; y W']' Z S; G3 a* @ Four Depigmentation by precipitation method * z+ T, q! Y L5 w9 X+ Q representative substance: lime milk Common concentration: 20% - 30% -M - [0 K $e; M R + [3 D decolorization principle: calcium ion in lime milk can combine with effective components and impurities in medicine liquid to form calcium chelate and calcium salt precipitation Under the action of sulfuric acid, flavonoids, anthraquinone, phenols, saponins, some alkaloids and calcium ions can be decomposed and dissolved in water But tannin, some protein, organic acid, polar pigment and polysaccharide can not be decomposed (| 1 \, q3h3m] 5W5 Pigment removal by flocculant 1 Common flocculants are as follows: (1) gelatin: tannin affects the stability of liquid medicine and is easy to change color Gelatin and tannin administrative complex can be used to precipitate together with suspended particles in water: K × T & Q / Q {: t5a3 K; G 2 [: @ (2) ZTC1 + 1 natural clarifier:, C $m-k2 T $C can be divided into four types: type I: deproteinized type II: decolorized type 2C "Q 1 G & [; M5 X7 @ 1C III: oral liquid of traditional Chinese medicine and granule type, which can replace alcohol precipitation method to remove unstable components and aid filtration Type IV: injection type, mainly to improve the clarity (3) 101 juice clarifier: (4) chitin and chitosan: chitosan is made by acetylation of chitin They are all natural cationic flocculants #V) T n $a × D "~ 2 Factors affecting clarification effect (1) dosage% o% F7 [& O" I &! A2 × 2q8 t (2) preparation concentration and adding sequence of clarifier.?% F6 C × 8 (L% ~, M-A $J2A G0w (3) the concentration of the solution itself (4) the effect of temperature during flocculation (5) the effect of pH of the solution (6) the effect of stirring speed and time% R) K / p1K & H% w '] - D J (7) the effect of flocculation settling time 0 m8n1u $J (W, m #, h 6 Ultrafiltration is the most commonly used technology for pigment removal by membrane separation ）A! T & h'r) w! I + I4 O + D "Q / O in addition, I also found a color removal function of hydrogen peroxide (H2O2), also known as hydrogen peroxide, which belongs to dangerous chemicals and toxic and harmful substances, is a strong oxidant with disinfection, sterilization, bleaching and other functions, widely used in industrial and medical fields In the food industry, hydrogen peroxide, as a food additive, is mainly used for disinfection, sterilization of dairy products, bread fermentation, decolorization of food fiber, and also as a production and processing aid At the same time, hydrogen peroxide also exists in air, water, human and plant, microorganism, food and beverage At present, there is no standard about the content of hydrogen peroxide in China According to international standards, it is safe to eat 10 to 24 milligrams a day.