微胶囊（Microcapsule）

1、微胶囊（Microcapsule）Application and development of microencapsulation technology in food additivesJudging from the domestic situation, the application of microencapsulation technology in food industry is still very limited, and the commercial products processed by it are not used much. At present, Chin

2、a has more than 500 dairy processing enterprises, and milk and dairy products in China is a very promising industry. The competition among enterprises is becoming more and more intense, so that the survival of the fittest can be satisfied. Therefore, adding some nutrients to the healthy dairy will h

3、ave greater market space. B has been applied to breakfast cereals, dairy products, coated foods, biscuits, candies and other good products. This shows that polyunsaturated fatty acid microcapsule products in the domestic potential market is very large. We can X according to the special needs of diff

4、erent groups of people, the production of EPA, DHA ratio of different products. The use of various health care functions do not package and fatty acid has the infant food and old food as the carrier, vigorously push the product application in food, to improve peoples health and have a positive role

5、in improving the quality of intelligence, economic and social benefits are very significant oilIn 1930s, researchers discovered a class of spherical particles ranging in diameter from microns to millimeters, consisting of fine polymer shells and different nuclear layer materials, which researchers c

6、alled MC. A nuclear layer substance can be a solid, a liquid, or a gas. The so-called micro capsule technology (Microencapsulation), in fact, refers to the use of natural or synthetic polymer coating material, solid, liquid, or even small sac nuclear material gas become coated with the diameter of 1

7、um 5000um range (usually in 5um 400um between the size of a micro capsule) the semipermeable membrane or sealing technology.The micro capsule products in the food industry, the active component of isolation protection, in the printing industry, the pharmaceutical industry pressure sensitive color co

8、py paper in the targeted drug and cosmetic industry in spices and other fine chemical adhesives have outstanding advantages. With the development of microencapsulation and microsphere technology, the field of application is becoming wider and wider. Many materials can be obtained by a variety of met

9、hods with certain composition and shape characteristics of microcapsule products. If the composite particles prepared with microcapsule technology are combined with other fine chemical materials, the mechanical strength and other properties of the composite can be greatly improved.At the end of the

10、1940s, the microcapsule technology has achieved breakthrough results. For example, DE Wurster in the United States successfully prepared microcapsule for drug coating by air suspension method, and still called air suspension method Wurster. After that, B K Green of American NCR company successfully

11、prepared microencapsulated gelatin microcapsules by the method of phase separation and coacervation, and was widely used in carbon free carbon paper. It has achieved great success in business. At the end of 1950s to 60s, people began to study the aggregation method used in the preparation of microca

12、psules, to 1970s after microencapsulation technology has matured, has gradually expanded the scope of application, the micro capsule technology got greater development.The micro capsule technology is the development of a versatile and new technology rapidly, has become a hot research area of food sc

13、ience and technology in the field of micro capsule technology applied in food industry, solve some problems of the food industry, the food industry has greatly promoted the transformation from junior to senior agricultural primary processing industry. It is one of the key high-tech research and deve

14、lopment in twenty-first Century, and the superfine grinding technology, membrane separation technology, supercritical fluid extraction, molecular distillation technology, biological technology and technology combined with hot pressing reaction, show a bright future for the development and applicatio

15、n of high technology in food industry.The microcapsules formed by microencapsulation technology are diverse in shape, can be spherical or irregular shapes. The outer surface of the capsule is smooth and folded. The microcapsule membrane can be either monolayer or bilayer or multilayer structure, and

16、 the core material encapsulated by the capsule can be either single or multinucleated.The micro capsule technology selection in encapsulational materials usually need according to the specific requirements of specific products, not only requires encapsulational material to form a layer of film on th

17、e adhesion of core material, but also the encapsulational material does not react with core material, permeability, hygroscopicity, solubility and stability, clarity and other factors also take into account the product. Sometimes encapsulational material is also often associated with coloring agent

18、and surface active agent, antioxidant and plasticizer etc. some quality improver in combination, so that the product exhibits certain plasticity and attractive appearance, easy to distinguish between different products.Before understanding the characteristics of microcapsules, it is necessary to mak

19、e clear the purpose of using microcapsule technology to produce products. The product from the liquid into a solid state, the character will change? Whether you need to control the release? Improved stability and liquidity? Sometimes in order to adapt to the application requirements of special produ

20、cts, some properties of microcapsules may be changed, these changes include: physical shape and the cost of material composition, release mechanism, particle size, final product.When choosing specific encapsulation methods, we should pay special attention to the following characteristics(1) wettabil

21、ity of heartwood. Coacervation is the formation of second liquid phases in a polymer solution. There are many ways, such as adding non solvent, changing the temperature, pH value, etc. At this point, the wettability of heartwood determines the success or failure of encapsulation. Proper wetting is d

22、ifficult when liquid heartwood is difficult to dissolve in condensed matter. Thus, the degree of encapsulation will be low, i.e., the encapsulation rate is very low. As long as the heartwood is moist, it is easier to be encapsulated than liquid heartwood. In principle, the degree of wetness of the s

23、olid is easily defined in the process of agglomeration. In practice, it is difficult to accurately measure the moistening humidity and expansion coefficient of the heartwood surface. Test of heartwood wettability degrees, often in the actual operation method of condensed capsule, to see whether hear

24、twood entrapped and determined.(2) the solubility of heartwood. In condensation, the key requirement is that heartwood is insoluble in the polymer. In some cases, heartwood used in polymers is not necessarily soluble, but is more biodegradable. In the case of spray drying, the heartwood is evenly di

25、spersed in the aqueous polymer solution by emulsification, because water evaporates rapidly from the wall material, while the heartwood evaporates and spreads very little.(3) permeability, elasticity and solubility of wall materials. The permeability of aggregate determines the release rate and rele

26、ase rate of the heartwood. The microcapsules must have a certain strength and can withstand a certain process, but they also need to break under certain pressureDissolve and release heartwood under certain conditions. The type of polymer, the size of the gel, the size of the love, and the thickness

27、of the wall determine the permeability and elasticity and solubility of the wall.(4) other properties. Because of the influence of humidity and humidity, the wall material is loose and agglomerate. In the drying process, the most difficult to overcomeThe problem may be that the wall material is tack

28、y. Similar to the spray coating, there is also the problem of polymer stickiness. In addition, many other properties, such as melting point, glass transition temperature, crystallinity, wall degradation rate, etc., are all issues to be considered.4. microcapsule functionThe sensitivity of ingredient

29、 through encapsulation, can change the color, shape, quality, volume, solubility, reactivity, heat resistance, storage for the original material, to be able to store the micro state of heartwood and released when needed.(1) isolate the interaction between materials and protect sensitive substancesWh

30、en the material is encapsulated, it can avoid the interference of external harmful factors such as oxygen, light, high temperature, water vapor and ultraviolet ray in the environment, and improve the stability of the processing and prolong the shelf life of the products. For example, the pigment in

31、tea beverage is unstable because of light, heat, acid and other factors. After embedding, it can form stable embedding material.(2) change the existing state, quality and volume of the materialAfter being encapsulated, the liquid heartwood can be changed into a fine powder solid, and its interior is

32、 still liquid,It can still maintain good liquid phase reaction; partial liquid spices, by embedding into solid particles, in order to facilitate the processing, storage and transportation; material encapsulated, its quality has increased, can also be made with air or hollow capsules and their volume

33、 increased.(3) conceal bad flavor and reduce volatilitySome food additives affect the quality of the added food because of odor or color. If it is encapsulated, it can conceal its bad flavor, colour and lustre, and change its use in food processing. The volatile food additive can inhibit volatilizat

34、ion after being encapsulated, reduce the loss in processing and reduce the cost. The natural aroma components in foods or beverages are significantly slowed down by volatilization, oxidation and thermal decomposition after encapsulation, so that the aroma is long-lasting and pleasant.(4) controlled

35、releaseThe release time and release rate can be controlled by microencapsulation. Using these characteristics, some volatile compounds can be retained in the food industry so that they can be released at the optimum conditions. Such as preservatives in beverage (such as sodium benzoate), sour agent

36、direct contact will cause failure, if the capsule can enhance the acid stability, and can play a role in anti-corrosion under the best condition, the time of preservatives. Through the design and selection of suitable wall material, special release mode can be realized to achieve special effects.(5)

37、 to reduce the toxicological effects of food additivesThe characteristics of controlled release can be used to control the biological availability of heartwood through proper design, especially for chemical synthesis additives. It is particularly important for reducing the toxicological effects of h

38、eartwood.5. ingredients of microcapsuleThe wall material of microcapsule is usually a film forming material. It has both natural and synthetic polymers. The composition of the wall determines the nature of the process and the product. The ideal wall material shall have the following properties:(1) i

39、n food processing and Zhu Cunzhong, the heartwood is sealed in its structure and separated from the external environment;(2) dispersing, emulsifying and stabilizing emulsions;(3) do not react with heartwood;(4) dissolve and release heartwood under proper conditions;(5) good operability, such as solv

40、ent used in food industry, such as water or ethanol, etc., and has good rheological properties at high concentration;(6) economy;However, almost no one can satisfy all of the above properties of the wall. In practical applications, they are often used in combination with other wall materials or antioxidants, surfactants, and synthetic agents.Microcapsule wall material is mainly natural macromolecule compound, synthetic macromolecule compound and its derivative. In the foo