1、XX 大学 毕业论文 外文文献 1 中文 2387 字 外文文献 The zein study progress Abstract This paper introduces the composition of the zein, zein extraction, bleaching, and the application of research. Keywords: zein protein； application Zein (zein) 1821 isolated from corn, and from this has been the concern of scientists.
2、 However, because of the lack of lysine, tryptophan and other essential amino acids, so its biological value. Gliadin insoluble in water limits its application in food. Are sold as low-value feed protein, only 200 U.S. dollars per ton on the international, the domestic price of 2,500 yuan. Gliadin h
3、ydrophobic, has a strong heat resistance and lipid, protein proline, alanine, leucine, gliadin film formation, adhesion, gel resistance Exterior features, enteric and antioxidant characteristics. In the food industry, zein can be used as a film former, that is to spray a coating is formed in the sur
4、face of the food, moisture, oxidation, thereby extending the shelf-life. Sprayed on the fruit, but also increase the gloss. In addition, but also the long-term for drug capsule. Therefore, the development of new uses of gliadin to get more and more attention of researchers at home and abroad.Zein ca
5、n be extracted from corn flour, can also be extracted from corn corn residue after the separation of starch and the low cost of the latter. Extracted from corn residue gliadin commercial production began in 1939. Current global zein produced mainly by the United States and Japan, according to the pu
6、rity of $ 1040 per kilogram. Zein is a product of high commercial value, but China also failed to form the scale of production, less related research. This paper describes the new progress made in recent years zein Institute. 1. The composition of the zein Zein, corn proteins, including both alpha a
7、nd beta. alpha-Zain can be dissolved in the volume fraction of 95% ethanol solution of alpha-Zain histidine, arginine, proline, methionine content of less. beta-Zain can be dissolved in a volume fraction of 60% ethanol solution, due to the unstable beta-Zain nature, prone to precipitation and solidi
8、fication, is not suitable for industrial production. Therefore, the industrial production of commonly used XX 大学 毕业论文 外文文献 2 alpha-Zain. 2.Extraction of zein extracted with ethanol, isopropanol extraction and ultrasonic extraction. Ethanol extraction method is used more. The ethanol extract of the g
9、eneral method is to use 90% 95% ethanol solution was extracted, diluted with water 60% ethanol to re-extraction, centrifugation. However, the extract thus obtained contains the gliadin and more corn lipid, can not meet the requirements of the production of film and the preparation of gliadin protein
10、 product of high purity. Most of the lipid addition of n-hexane or ethanol was removed by extraction, but this will increase the cost, and the effect is not very good. The method through multiple dilution of the extract was repeatedly extracted, can be obtained more than 90% of the protein content b
11、elow 10% of the lipid content of the extract. Experiments show that the first diluted with ethanol to 55%, and then the extract was diluted to 50% extract extracted from this portion of the material was pelleted by centrifugation gliadin protein, wherein the lipid content is much lower than after on
12、ly one step will ethanol diluted to 40% protein extracted lipid content. In this method can produce a high purity zein 3 zein applications 3.1 antioxidants Zein hydrolyzate with antioxidant activity. Global Research successfully developed a fatty acid dissolved in a solution of zein and dried fixed
13、oils, for example, linoleic acid and 4 times the amount of gliadin, the spray-dried powder obtained was dissolved in ethanol, has a high resistance oxidation and oxidation stability. The fish oil fatty acids with 2 times the amount of zein dissolved in 80% ethanol and dried to obtain a film, monogly
14、cerides, diglycerides, triglycerides and the zein is dissolved in ethanol, respectively, film, both strong antioxidant activity. Accordingly, the zein is easily oxidized in the highly unsaturated fatty acid Antioxidant and maintain stability against oxidation of the most suitable materials. Very sig
15、nificant role in the oils and fats in foods, many potential applications. 3.2 Alternate gum base Zein alternative made of gum base has many advantages, chewing gum adhesion, biodegradable, easy to digest. These properties are not synthetic gum base. Application of corn Gliadin alternative to chewing
16、 gum base is expanding gliadin applications in other areas of food via. The Zhang Zhong developed of zein Alternate gum base chewing gum, using a 25% substitution of the resulting chewing gum XX 大学 毕业论文 外文文献 3 having a similar nature with 100% of the gum base chewing gum, both preferably viscoelasti
17、c and hardness, a long time to chew characteristics, but also taste like chewing gum, and also having a nutritional, partially digestible characteristics. In addition, the researchers also developed a zein, soy protein isolate and concentrated aloe juice made of nutrition and health care chewing gum
18、. 3.3 Perishable role Zein amino terminus with leucine, alanine, proline, and other non-polar hydrophobic group, and therefore has a strong hydrophobicity, which was dissolved in ethanol solution can be made of an edible coating film . Such membranes in the case of without adding any crosslinking ag
19、ents, tanning agents, with a good moisture resistance, such a film forming speed is faster, the storage stability under high-temperature and high-humidity conditions, good barrier properties against oxygen and carbon dioxide, and have a certain antibacterial function. Currently, fresh meat coating m
20、aterial chitosan, soy protein, wheat gluten, carrageenan gum, Wangxue Rong first zein as a coating Ingredients beef fresh strawberries fresh strawberries very thin skin, in harvesting and transportation process vulnerable to microbial infection and dehydration fast, easy to lose their luster, the de
21、cline in the value of the goods. Has yet to find the ideal preservation methods, equality zein plastic wrap strawberry fresh experiments. Composite preservative: gliadin 1.75%, 0.3% sucrose, 0.18% glycerol, and supplemented with 0.02% emulsifiers and preservatives, preservation effect is better. 3.4
22、 candy shelf Candy deterioration phenomenon is water-absorbing deformation, zein film has a water resistance coating candy enhance the appearance of better shape retention. This edible film coating also avoids the need to deal with the problem of plastic packaging materials. Wenjing study found that
23、 oleic acid and glycerol, shellac complex protein membrane waterproof best viewed from the outside coated with oleic acid and shellac membrane protein epidermal best, better shape retention, enjoy a taste changed little Paul fragrance than ideal, not the highest water absorption of the coating. The
24、best edible composite wrap film, preferably the ratio of 0.4mL3% glycerol 0.3mL oleic acid, 0.3mL shellac, 10 ml of 10% gliadin, at 40 C under the film formation 3.5 Drug Delivery Materials In recent years, the microsphere technique is widely used in the treatment of many diseases the microsphere drug concentration of the drug in the blood can be maintained, carrying the drug to reach a particular cell or tissue. A wide
