The hottest edible packaging and its packaging mat

Edible packaging and the application of packaging materials (III)

4 the current situation of edible packaging film 1 polysaccharide edible packaging film

edible films based on plant polysaccharides or animal polysaccharides mainly include starch film, modified cellulose film, animal and plant glue film, chitosan film and glucomannan film

1.1 starch edible packaging film is the earliest type researched and developed in EPF. Foreign literature has been reported in the 1950s and 1960s, while domestic research is relatively late. In recent years, important progress has been made in the research and application of film-forming materials and processes and plasticizers. Researchers from the national starch and chemical company in New Jersey (1991) developed a new edible packaging material using maize as raw material. Wang Shuzhen (1993) made edible film with corn starch and potato starch as the main materials, supplemented by gelatin, glycerin, etc. is superior to glutinous rice paper in mechanical tension resistance, toughness, transparency and instant solubility. Gao qunyu et al. (1993) used isoamylase to de branch starch to form amylose, and its tensile strength, elongation and folding resistance increased after film formation. Liu Linwei et al. (1995) used epichlorohydrin and dicarboxylic acid as crosslinking agents to properly crosslink and modify corn starch film, which improved its tensile strength, reduced its moisture permeability and permeability, and partially reduced its water solubility. Yang Yigong et al. (1997) the esterified starch prepared from corn starch and nah2p04 can replace glutinous rice paper. Xia Yangyi et al. (1999) the elongation at break of edible starch film made with phosphorus oxychloride as crosslinking agent decreases with the increase of the amount of crosslinking agent, and the tensile strength and right angle tear strength first increase and then decrease

1.2 edible packaging film of modified cellulose

in recent years, countries all over the world attach great importance to the research and development of modified cellulose EPF. Japan recently launched EPF with soybean dregs as raw materials for the packaging of fast-food noodle seasonings. Production and research institutions in the United States have also achieved success in using hydroxypropyl methylcellulose (HPMC) to make edible cellulose films. Liu Linwei et al. (1995) fully dissolved methyl cellulose, and the edible film made by coating and drying has high strength, high temperature resistance and gas resistance; Then, with methyl cellulose and carboxymethyl cellulose as raw materials, stearic acid, palmitic acid, beeswax and agar as plasticizers and reinforcing agents, edible films with translucent, soft and smooth, instant, high tensile strength, low permeability and moisture permeability were made. Lai Fengying et al. (2001) C8) discussed the influence of solvent type on film-forming process, film barrier and film mechanical properties, and concluded that the optimal ratio of water to alcohol was 2 ∶ 1. In addition, China has also made important progress in the research of bagasse cellulose EPF

1.3 edible packaging film of animal and vegetable gum

Japan has always been the world leader in the development and application of animal and vegetable gum EPF, and the elongation at break also meets the required level. This kind of EPF is made from animal glue such as gelatin, bone glue, shellac, and plant glue such as glucomannan, carrageenan, pectin, sodium alginate, Prussian blue, etc. The carrageenan film developed by Mitsubishi man-made fiber company in Japan uses natural polysaccharides extracted from red algae as raw materials, which is translucent, tough and has good heat sealing performance. The collagen film developed by "Natick" in the United States is made of animal protein collagen. It has high strength, good water resistance and gas barrier, and is edible. It is used to package meat food without changing its flavor. Li Hongjun et al. (1993) selected 3.0% - 4.2% sodium alginate as the film-forming agent, 5% - 10% can modify the parameters of electronic universal experimental machine software or electromechanical parameters%, glycerol or ethylene glycol as the plasticizer, and 3% - 10% CaCl2 as the crosslinking agent. The edible food packaging film has good gloss, transparency and tensile strength, and is especially suitable for processing and making artificial casings. Wang Jiaxiang et al. (1994) took sodium alginate as the main raw material of the coating agent, calcified and solidified in CaCl2 solution, and the edible film formed by it has good elasticity and toughness, which is not only an indispensable basic production link of a large number of industrial and agricultural products; At the same time, the compound EPF of sodium alginate and edible gelatin was also developed. Li Xiaowen et al. (1999) used celery leaves as raw materials, added 3% sodium alginate and 3% glycerin to make a crisp, delicious, celery flavored edible celery paper food, which can be used for food packaging. Xie Qi et al. (1999) made edible colored vegetable paper with carrots as the base material and added sodium alginate, glycerin, etc., which has strong flexibility and certain water resistance. Kan Jianquan et al. (1999) adding 0.02% agar to gelatin edible film can significantly improve the mechanical strength and heat sealing strength of gelatin film; The tensile strength and right angle tear strength were improved by adding 0.2% glycerol. Li Bo et al. (2000) modified konjak glucomannan with alkali to make an edible and naturally degradable membrane material; Subsequently, konjak glucomannan and xanthan gum were blended to form a film, which showed good strength and water resistance. Luo Xuegang (2000) used konjak glucomannan as raw material, added 5% - 10% glycerol or sorbitol, 3% - 5% sodium alginate or gelatin, and mixed it in the presence of trace alkali. The high-strength edible konjak glucomannan film has good water resistance, heat resistance, decomposability and tensile strength. Yang Jun et al. (2001) studied the effects of konjac gum concentration, plasticizer type and concentration and drying temperature on the film-forming properties of edible konjac glucomannan. The results showed that the concentration of konjac gum was 8g/L, and the plasticizing effect of glycerol was the most significant. With the increase of its concentration, the tensile strength decreased, the elongation increased, and the moisture resistance significantly decreased. The drying temperature was ideal at 60 ℃. In addition, China also uses shellac, starch glue and bone glue to make edible packaging paper or packaging containers through special processes

1.4 Chitosan Edible Packaging Film

chitosan is the extract of shrimp, crab, insects and other crustaceans, that is, chitin is deacetylated after being treated with about 50% concentrated alkali. This kind of edible film was successfully developed by the California agricultural technology research center of the American Agricultural Research Institute. It combines chitosan with lauric acid with 12 carbon atoms to form a uniform edible film with a thickness of only 0.2-0.3mm, It is mainly used for the packaging of fruits and vegetables. Japan recently processed deacetylated chitosan as raw material into an edible packaging paper, which is used for packaging fast-food noodles, condiments, etc. Shinya et al. (1993) kneaded and extruded chitosan with resin to prepare food packaging containers. Osamu (1998) infiltrated the lactic acid solution of chitosan into the non-woven fabric made of regenerated cellulose to form fresh-keeping materials, which can be used for packaging meat and fish food. Ji Weizhi et al (2001) after adding glycerol to chitosan membrane, the surface of the membrane is smooth, the water vapor transmission and permeability of the membrane are improved, and the tensile strength is decreased; After adding stearic acid, lipid layer crystals appear on the surface, the permeability of the membrane is improved, and the water vapor transmission and tensile strength are decreased

(to be continued)