On the hottest edible packaging

Edible packaging theory (Part 2)

4 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 been at the world leading level in the development and application of animal and vegetable gum EPF. 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 film-forming agent, 5% - 10% glycerol or ethylene glycol as plasticizer, and 3% - 10% CaCl2 as 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; 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 produce a uniform edible film, which is only 0.2-0.3mm thick. It is mainly used for the packaging of fruits and vegetables. Recently, Japan uses deacetylated chitosan as raw material to produce an edible packaging paper for packaging fast-food noodles, condiments, etc. Shinya et al. (1993) kneaded chitosan and resin together and extruded them 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 a fresh-keeping material, which can be used to package meat and fish food. Ji Weizhi et al. (2001) after adding glycerol to chitosan membrane, the membrane surface is smooth, the water vapor transmission and permeability of the membrane are improved, and the tensile strength is reduced; 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

2 edible protein packaging film

edible films based on protein mainly include soybean protein isolate film, zein film, wheat gluten film and whey protein film

2.1 soy protein isolate membrane

was successfully developed by the research team led by Frederick F. Shi of the United States. It mainly uses the protein extracted from soybeans to produce film base materials similar to plastics, which are mixed with plasticizers such as glycerol and sorbitol to produce multi-purpose EPF with good strength, elasticity and moisture resistance

2.2 edible packaging film of wheat gluten

wall et al. (1969) made edible film of wheat gluten with lactic acid as plasticizer. The strength of purified gluten film is higher than that of commercial gluten film. Aydt and Weller dissolved wheat gluten protein in ethanol, and added glycerol, ammonia, etc. as plasticizers, the EPF prepared has strong toughness and translucency, and has a good ability to isolate O2 and CO2, but its moisture-proof and moisture-proof properties are poor

2.3 edible packaging film of zein

aydt and kaning dissolved zein in glycol or isopropanol solution, and EPF prepared with glycerol, propylene glycol or acetylglycerol as plasticizer has excellent insulation and moisture resistance to O2 and CO2, and is stable in high temperature storage. If lysozyme and other bacteriostasis are added to zein, it can also be made into edible packaging with antibacterial function, which can control the growth of pathogenic bacteria in food and food corruption caused by microorganisms. The water vapor permeability of modified corn gluten membrane developed by Li Yongxin et al. (1996) is equivalent to that of corn gluten membrane with a small amount of plasticizer, and its mechanical properties are significantly improved

2.4 whey protein edible packaging film

whey protein has only been used as the matrix material of EPF in recent years. Mchueh and krochta (1994) made whey protein EPF with whey protein as raw material and glycerol and sorbitol as plasticizers, which has the characteristics of water permeability, low oxygen permeability and high strength. Maynes and krochta (1994) added oil to whey protein to form an edible film, which can reduce water vapor transmission and improve its mechanical strength. At the same time, the edible film of casein was also studied in depth

3 edible packaging film of microbial copolyester

this kind of film is 3-hydroxybutyl ester, 3-hydroxyamyl ester, 4-hydroxybutyl ester The system used to treat the largest garbage belt in the Pacific Ocean is EPF made of caprolactone and other polyester designed by a non-profit technology company called "the ocean cleanup". At present, microbial copolyester EPF has been researched and developed by Britain and the United States, and has attracted the attention of researchers all over the world. Yin Xiaomei et al. (1998) added glycerol to the pullulan produced by the fermentation of pullulan sprouting, and the edible pullulan film has high gas resistance and tensile strength

4 the research and application of polysaccharide, protein and fatty acid composite edible packaging film

composite EPF is the current development trend. The Department of food engineering of the University of Wisconsin combines protein and fat with different proportions, among which the highest export amount in January and may is acid and polysaccharide, to make an EPF that can meet the needs of different food packaging. Deand, Duxbury (1983) of the United States and ITO (1991) of Japan have prepared edible tableware and food packaging containers with plant protein and wheat flour respectively. Arvanito ryannis and biliaberis (1998) made sodium caseinate and starch composite edible film with polyol as plasticizer, and studied its heat sealing, air permeability, moisture permeability and so on. Chinese scientific and technological workers have also successfully developed composite EPF. Chen Yanyan et al. (1996) studied the effects of raw material properties, processing conditions, crosslinking agents, pH value and lubricants on starch protein plastics. The edible sodium alginate stearic acid composite film developed by Liu Jian et al. (1999) has good water vapor barrier performance and oil barrier. The gelatin film, sodium alginate composite film and methyl cellulose composite film developed by Kan Jianquan et al. (1999) have good heat sealing, gas, oil and moisture resistance. Qiu Houyuan et al. (2000) made Edible Cassava starch composite film with cassava starch as the main film-forming primary quality, supplemented by reinforcing agent and plasticizer, which has good mechanical properties and permeability

with the development of modern food industry, food packaging is constantly updated, and a new type of food packaging technology materials that can improve the contradiction between environmental protection of packaging materials - edible packaging stands out. Edible packaging materials developed abroad in recent years generally take protein and starch that can be digested and absorbed by human body as basic raw materials to produce invisible food packaging films that do not affect the flavor of food

the United States uses protein extracted from soybeans to produce plastic like substances as food packaging materials,