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Pullulan is an extracellular water-soluble mucopolysaccharide similar to glucan and xanthan gum produced by the fermentation of Aureobasidium pullulan. It is also known as pullulan and pullulan, and is transliterated as pullulan. It is a special microbial polysaccharide discovered in 1938. This polysaccharide is mainly composed of maltotriose linked through a-1,6 glycosidic bonds. Due to the unique structure and properties of this polysaccharide, it has broad application prospects in medicine, food, petroleum, chemical and other industries. Because it can be degraded and utilized by microorganisms in nature and does not cause environmental pollution, it is known as pollution-free plastic. On May 19, 2006, the Ministry of Health issued Announcement No. 8. Pullulan is one of the four new food additive products, which can be used in candies, chocolate coatings, film tablets, compound seasonings and fruit and vegetable juice beverages. Used as coating agent and thickener.
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Structure and properties of pullulan
The structure of pullulan
Pullulan is a polymer polysaccharide formed by combining glucose with x-1,4-glucosidic bonds to form maltotriose, and then combining x-1,6-glucosidic bonds with other maltotriose at both ends.
Properties of pullulan
Pullulan is a colorless, tasteless, and odorless polymer substance, an amorphous white powder, and a non-ionic, non-reducing polysaccharide. Its properties can be manifested in the following aspects:
1. Non-toxic and safe
According to the results of the acute, subacute and chronic toxicity tests and variability test of pullulan, even if the dosage of pullulan reaches the LD50 limit, pullulan will not cause any biological toxicity or abnormal state. production, so it is very safe to be used in the food and pharmaceutical industries.
2. Solubility
Pullulan can be quickly dissolved in cold or warm water. The dissolution rate is more than twice as fast as carboxymethyl cellulose, sodium alginate, polypropylene alcohol, polyvinyl alcohol, etc. The solution is neutral, non-ionized, and non-gelling. , does not crystallize.
3. Stability
The molecules of pullulan have a linear structure. Therefore, compared with other polysaccharides, the pullulan aqueous solution has lower viscosity and does not form colloids. It is a neutral solution with strong adhesion.
4. Lubricity
Pullulan is a Newtonian fluid with excellent lubricity despite its low viscosity. It has a thickening effect when used in food, and is most suitable for use in sauces, seasonings and other products.
5. Adhesion and solidification
Pullulan has very strong adhesive force and can be air-dried after spraying to stably bind food. It also has strong coagulation power and is most suitable as a binder when making tablets or granules.
6. Film coating
Pullulan has excellent coating properties and can be easily coated on surfaces such as food metals. At the same time, a water-soluble, five-color, transparent and strong film can be formed from the pullulan aqueous solution. It has properties such as gas barrier properties, aroma-maintaining properties, oil resistance, and electrical insulation properties. It can be used in food to add luster to the surface of the food and preserve its freshness.
7. Decomposability
According to the results of the in vivo enzyme digestion test or the growth test of white mice, pullulan is an indigestible polysaccharide similar to cellulose and agar. Pullulan is almost non-decomposed within a few hours under the action of digestive enzymes in the animal's digestive system. Special foods and beverages with low digestibility and low calories can be produced by utilizing the low digestibility of pullulan. On the other hand, pullulan, like starch, begins to decompose when it reaches about 250% C, and is carbonized thereafter. It does not produce toxic gases or high heat when burned.
8. Improve physical properties and maintain moisture
Adding a small amount of pullulan is effective in improving physical properties and retaining moisture. It can be used to improve food texture, improve quality, prevent aging and increase yield.
9. Formability and spinning properties
Simply add a certain amount of water to pullulan, heat, press, mold and spin to process edible and water-soluble molded products or fibers.
Application of pullulan in food industry
As food packaging materials
Pullulan aqueous solution has excellent film-forming properties, and the film has gloss and transparency. Good toughness. It is extremely stable to temperature changes and the film has good heat sealability. The finished product does not need to add plasticizers or stabilizers, and is non-toxic and harmless to food, the environment and the human body. Therefore, it is a very ideal water-soluble food packaging material.
Food films made from pullulan aqueous solution can be used to seal foods that are prone to oxidative deterioration and powdered foods with strong flavor such as soups, coffee, sauces, various spices, freeze-dried foods, etc., and can protect the appearance and aroma of foods. And can maintain stability for a long time.
In terms of preserving fruits and eggs, you can use pullulan or its derivatives, add an appropriate amount of chemical protective ingredients, and spray and dry them directly on the surface to form a film, which can effectively inhibit water, oxygen, carbon dioxide, etc. in fruits and eggs. It exchanges and reacts with the outside world, inhibits the respiration intensity of fruits and eggs, and reduces nutrient loss during storage, thereby achieving the purpose of preservation.
Used as a low-calorie food additive
Pullulan is a non-digestible and absorbable carbohydrate that is not absorbed by the intestines and can be excreted from the body. Will not cause high blood pressure, heart disease.
Obesity, etc., is a healthy food material that can be used as a low-calorie food additive to manufacture low-calorie foods and beverages. Recently, it was discovered that pullulan also has the effect of promoting the proliferation of bifidobacteria and treating constipation.
Used as food quality improver and thickener
Adding a small amount of pullulan during food processing can significantly improve food quality. For example, fish cakes can increase the flavor and quality. Adding a small amount of pullulan when making tofu can maintain the aroma of soybeans and simplify the process: soy sauce, condiments, pickles A small amount of pullulan added to foods such as candied fish and shrimps, delicious foods, etc. can stabilize their viscosity, increase their stickiness and make their taste smoother.
Application of pullulan in cosmetics
Because this polysaccharide has good water solubility, dispersibility, film-forming properties, hygroscopicity and non-toxicity, it can be used as a viscous filler in cosmetics: its price is much cheaper than hyaluronic acid used in cosmetics. But its effect is almost the same as that of hyaluronic acid.
The application of pullulan in medicine
In the pharmaceutical industry, using 20% pullulan instead of animal glue can simplify the production of anti-oxidation capsules; adding 5% to 10% pullulan can appropriately improve the flexibility, elasticity, and adhesion of soft capsules, making them It dissolves in predetermined areas of the gastrointestinal tract and releases its contents to enhance the efficacy of the drug.
Pullulan is widely used and has great economic value and huge development potential. But there has been no larger-scale production. It is expensive, mainly because of the difficulty in removing melanin, the high viscosity of the fermentation liquid, and the high cost of post-extraction. At present, it is only produced by Nippon Forest Biochemical Co., Ltd. abroad. Research on how to achieve both low pigment levels and high polysaccharide conversion rates and industrialization research is a current hot topic. The realization of fermentation automation and visualization is the forefront of international fermentation research today. . Through visual automatic control technology, controlling the fermentation process of Aureobasidium pullulans in specific forms can be controlled to obtain the best results. Translate to English for me.
