CN101381420A - Continuous Extraction Method of Pectin, Tannin and Pigment in Persimmon Peel - Google Patents

Abstract

The invention discloses a method for continuous extraction of pectin, tannin and pigment in persimmon skin. The method is as follows: a. after pretreatment of persimmon skin, extract the pretreated pectin with water at a temperature greater than or equal to 70°C and less than 100°C; Persimmon skin to obtain extract and slurry; b. filtering the above extract with an ultrafiltration membrane with a cut molecular weight of 10,000-30,000, the intercepted part is pectin liquid, and the filtrate is adsorbed and separated by a large-pore resin to obtain tannin; c . The slurry obtained in step a is extracted with acetone at 60° C. to 70° C., and the extract is filtered, distilled and dried to obtain the pigment. The method has rich sources of raw materials, simple extraction method, and is more suitable for large-scale industrial production; the reagents used are relatively cheap, have low toxicity, strong operability, and the technology is easy to scale up, and the cost should be lower than the extraction cost of the current corresponding products. The product extracted by the method is safe and non-toxic, and the production process is simple and reasonable.

Description

Continuous Extraction Method of Pectin, Tannin and Pigment in Persimmon Peel

technical field

The invention relates to a method for extracting active ingredients from persimmon skin, in particular to a continuous extraction method for pectin, tannin and pigment in persimmon skin.

Background technique

As a by-product of persimmon deep processing, persimmon skin accounts for about 10-15% of the total weight of persimmons. Modern medical research shows that: persimmon skin contains more dietary fiber and pectin substances, which have a good effect on promoting human digestion and improving intestinal function, and pectin has a special role in stabilizing protein-containing beverages such as milk protein. The effect of avoiding aggregation due to the interaction between protein particles. The extracted pectin can be sold as a commodity, and can also be transformed into raw materials for producing jelly and pectin jelly on site.

Persimmon fruit is very rich in carotenoids and their fatty acid esters. Carotenoids are used as natural pigments for food coloring and have high safety; for humans and animals, some carotenoids are the most effective provitamin A. It can provide 30%-100% of the amount of vitamin A needed by humans; more importantly, carotenoids have certain antioxidant activity, which can inhibit lipid peroxidation and quench singlet oxygen, thus preventing cell oxidative damage, Prevention of cardiovascular diseases, especially in reducing the incidence of tumors has a significant effect;

Persimmon fruit is also rich in biologically active substances such as tannin (tannin, tannin), and mature persimmon tannin is mainly distributed in the persimmon skin. The astringency of the persimmon skin is mainly due to the tannin. When the persimmon is dehydrated, it is impossible to remove all the tannic acid in it. If it is eaten together with the skin, it is easy to form gastric persimmon stones, but on the other hand, tannin can stop bleeding and heal wounds. Antibacterial and antiallergic, especially anti-oxidation, anti-aging, anti-cancer, and prevention of cardiovascular and cerebrovascular diseases. In the beer and wine brewing industry, it has the effect of removing protein and improving taste. Therefore, as long as the tannin is used reasonably , will surely allow the gift of nature to serve mankind better.

At present, the utilization of persimmon skin at home and abroad is mainly aimed at the extraction and application of pectin, and there are few reports, while the extraction of tannins and carotenoids from persimmon skin has not been reported. In fact, in the use of persimmon skin to extract pectin During the process, tannins and pigments (carotenoids) are all thrown away as waste, which not only pollutes the environment, but also causes waste of resources.

Contents of the invention

The technical problem to be solved by the present invention is to provide a continuous extraction method of pectin, tannin and pigment in the persimmon skin for extracting effective components in the persimmon skin, so as to improve the utilization rate of the persimmon skin.

In order to solve the problems of the technologies described above, the present invention adopts following process steps:

a. After pretreating the persimmon skin, extract the pretreated persimmon skin with water at a temperature greater than or equal to 70°C and less than 100°C to obtain an extract and a slurry;

b. The above-mentioned extract is filtered with an ultrafiltration membrane with a cut molecular weight of 10,000-30,000, the intercepted part is the pectin liquid, and the filtrate is adsorbed and separated by a large-pore resin to obtain tannin;

c. The slurry obtained in step a is extracted with acetone at 60° C. to 70° C., and the extract is filtered, distilled, and dried to obtain the pigment.

The beneficial effect produced by adopting the above-mentioned technical scheme is that the patent application of the present invention is a complete set of technical scheme for continuously extracting pectin, tannin and pigment from persimmon skin. The invention has abundant sources of raw materials, simple extraction method and is suitable for large-scale industrial production. In the method of the invention, the reagents used for extracting pectin, tannin and pigment from persimmon skin are relatively cheap and have low toxicity. The method has strong operability, the technology is easy to scale up, and the cost should be lower than the extraction cost of the current corresponding products. The product extracted by the method of the present invention is safe and nontoxic, and the pectin can be applied to the gelling agent of jelly and jam, can also be used to manufacture gelled candy and be used as a fruit base when producing yogurt, and can also be used as a food stabilizer and Thickener, etc.; tannin can be used for tanning in tanning; food anti-oxidation and anticorrosion; it can be used in beer and wine brewing liquid to remove protein and improve taste; it can also be used for beauty and whitening. The carotenoids in the pigment are directly extracted from natural plants (persimmon skin), with sweet taste, bright color, stable properties, simple and reasonable production process, and no means and agents that cause harmful changes in the pigment are used in the production process. Ideal natural pigments, added to food, not only make the food have a pleasing color, but also have the effect of nutrition and health care.

Detailed ways

Example 1:

1. Pretreatment of persimmon skin: select persimmon skin without mold, dry it at 60°C after cleaning, and crush the persimmon skin until the diameter is less than or equal to 2mm.

2. Leaching:

a. Beating and squeezing juice: add deionized water with a material-to-liquid ratio of 1:15 according to the actual weight of the persimmon skin, soak for 1 hour at 80°C-90°C, then beat into pulp, and put the beaten pulp into pulp. Put it into a press and press to obtain extract and slurry.

B, secondary extraction of slurry: add the deionized water that solid-liquid ratio is 1: 10 in the slurry of once leaching, adjust pH value with 1% (mass fraction) hydrochloric acid to be 4.5--5, at temperature Heat preservation and cooking at 80°C-90°C for 40-50 minutes, and pressing to obtain the extract and the slurry after secondary extraction.

3. Ultrafiltration membrane filtration: filter the above extract with ultrafiltration membrane, because the relative molecular weight of pectin is 30000-100000, while the relative molecular weight of tannin is only 500-3000, the experiment utilizes the molecular size difference between the two The difference is to use the ultrafiltration membrane with a cut molecular weight of 10000-30000 to intercept pectin until the pectin concentration reaches 2%-4%, so that pectin and tannin can be separated and pectin can be concentrated.

The concentrated pectin solution is spray-dried to obtain pectin powder; the filtrate is separated by adsorption of macroporous resin to purify tannins.

4. Acetone extraction: all the slurry was extracted with acetone, the extraction solid-liquid ratio was 1:20 g/ml, and the extraction was carried out at a temperature of 60° C. for 2 hours. The obtained extract was filtered, distilled under reduced pressure, and vacuum-dried to obtain a dark red pigment (carotenoid) solid. The extractant (acetone) can be recycled and reused. After calculation, the extraction rate under this condition is 79.38mg/100g.

Example 2:

1. Pretreatment of persimmon skin: select persimmon skin without mold, dry it at 60°C after cleaning, and crush the persimmon skin until the diameter is less than or equal to 2mm.

2. Leaching:

a. Beating and extracting squeezed juice: add deionized water with a material-to-liquid ratio of 1:15 according to the actual weight of the persimmon skin, soak for 2 hours at a temperature greater than or equal to 70°C and less than 100°C, and then crush it into pulp The crushed pulp is put into a press and squeezed to obtain the extract and the once-extracted pulp.

B, secondary extraction of slurry: add the deionized water that solid-liquid ratio is 1: 10 in the slurry of once leaching, adjust pH value with 1% (mass fraction) hydrochloric acid to be 3-5, at temperature Heat preservation and cooking at 70°C-90°C for 40-50 minutes, and press to obtain the extract and the pulp extracted twice.

3. Ultrafiltration membrane filtration: Use an ultrafiltration membrane with a cut molecular weight of 10,000-30,000 to intercept pectin until the pectin concentration reaches 2%-4%, so that pectin and tannin can be separated. The filtrate is separated by adsorption with macroporous resin to obtain purified tannins.

Precipitate pectin from the retained pectin solution by alcohol precipitation method: add ethanol to the retained pectin solution, let the resulting alcohol-pectin mixture stand for 4-8 hours, filter, break up the filter cake and use 95% ethanol Wash and press filter again to obtain the finished pectin.

4. Acetone extraction: all the slurry was extracted with acetone, the extraction solid-liquid ratio was 1:20 g/ml, and the extraction was carried out at a temperature of 50° C. for 3 hours. The obtained extract was filtered, distilled under reduced pressure, and vacuum-dried to obtain a dark red carotenoid solid. The extractant can be recycled and reused.

After testing, in the continuous extraction method of pectin, tannin and pigment in this persimmon skin, the extraction rate of pectin is greater than 85%, the product purity is greater than 80%, the degree of gelation is greater than 120, the loss on drying is less than 11%, and the ash content is less than 5% %, heavy metal content (in pb) is less than 0.0015%, PH=2.8±0.2, and various indicators have reached the quality standard of pectin for food additives GBn246-85; the extraction rate of tannin is greater than 83%, and the product purity is greater than 75%; carotenoid The prime extraction rate is greater than 75%, and the purity is greater than 80%.

Claims (8)

1, a kind of continuous extraction method of pectin, tannin and pigment in persimmon skin, it is characterized in that the method adopts following processing steps: a. After pretreating the persimmon skin, extract the pretreated persimmon skin with water at a temperature greater than or equal to 70°C and less than 100°C to obtain an extract and a slurry; b. The above-mentioned extract is filtered with an ultrafiltration membrane with a cut molecular weight of 10,000-30,000, the intercepted part is the pectin liquid, and the filtrate is adsorbed and separated by a large-pore resin to obtain tannin; c. The slurry obtained in step a is extracted with acetone at 60° C. to 70° C., and the extract is filtered, distilled, and dried to obtain the pigment. 2. The continuous extraction method of pectin, tannin and pigment in persimmon skin according to claim 1, characterized in that the pretreatment process described in step a is: drying the persimmon skin at 60°C, The dried persimmon skin is crushed until the diameter is less than or equal to 2mm. 3. The continuous extraction method of pectin, tannin and pigment in persimmon skin according to claim 1, characterized in that the extraction process described in step a is: adding persimmon skin and water to the pretreated persimmon skin Deionized water with a weight ratio of 1:15 is soaked at a temperature greater than or equal to 70°C and less than 100°C for 1-2 hours, then the mixture of persimmon skin and water is crushed, and the crushed pulp is pressed. Extraction liquid and once-extracted slurry are obtained. 4. The continuous extraction method of pectin, tannin and pigment in persimmon skin according to claim 3, characterized in that the weight ratio of slurry and water is 1:10 to add to the slurry once leached. Ionized water, use hydrochloric acid with a mass fraction of 1-2% to adjust the mixture of the above-mentioned coarse residue and water to a pH value of 3-5; at a temperature greater than or equal to 70°C and less than 100°C, heat-preserve and cook the above-mentioned mixture after adjusting the pH value After 40-50 minutes, filter to obtain the extract and the slurry extracted twice. 5. The continuous extraction method of pectin, tannin and pigment in persimmon skin according to claim 4, characterized in that the mixture of the above-mentioned coarse residue and water is adjusted to a pH value of 4.5 with hydrochloric acid with a mass fraction of 1-2% —5. 6. The continuous extraction method of pectin, tannin and pigment in persimmon skin according to claim 1, characterized in that ethanol is added to the entrapped pectin solution in step b, and the obtained alcohol-pectin mixture is left to stand 4-8h, filter, break up the filter cake, wash with 95% ethanol by mass fraction, press filter again, and obtain pectin product. 7. The continuous extraction method of pectin, tannin and pigment in persimmon skin according to claim 6, characterized in that the pectin product is spray-dried to obtain pectin powder. 8. The continuous extraction method of pectin, tannin and pigment in persimmon skin according to any one of claims 1-7, characterized in that the extraction step in step c is as follows: the ratio of extraction material to liquid is 1:20g/ ml, extract at a temperature of 50-60°C for 2-3 hours, filter the obtained extract, distill under reduced pressure, and vacuum-dry to obtain a dark red solid pigment.