KR20030062823A - A process of preparing for edible film - Google Patents

Abstract

PURPOSE: A method for preparing an edible film is provided, wherein the edible film shows excellent mechanical properties and oxygen blocking property and is used as various films and a food packing bag. CONSTITUTION: The method comprises the steps of mixing 20-80 wt% of glycerol and water based on the weight of a film, heating the mixture to 60-100 deg.C and slowly adding 10-70 wt% of starch to the mixture based on the weight of film to dissolve it to prepare a starch solution; adding 10-70 wt% of pectin to water based on the weight of a film, and dissolving it at a room temperature to prepare a pectin solution; mixing the starch solution and the pectin solution; and pouring the obtained mixture solution on a film mold plate to evaporate moisture to prepare an edible film. Preferably the amount of water in preparation of the starch solution or the pectin solution is controlled to be 10-50 times based on the weight of starch or pectin.

Description

Process for preparing edible film {A process of preparing for edible film}

The present invention relates to a method for producing an edible film, which is composed of starch and pectin and is water soluble, easily biodegradable by anaerobic and aerobic microorganisms.

An object of the present invention is to provide a water-soluble, biodegradable and edible and at the same time excellent in mechanical properties and oxygen barrier properties, such as a pesticide bag film and packaging materials that require various biodegradability, disposable use or edible requiring water solubility It is for producing a useful film such as food packaging containers, such as ramen soup bags that require sex.

As a conventional technique for manufacturing the water-soluble, biodegradable and edible film as described above, in Korean Patent Laid-Open Nos. 2000-65347 and 1999-69788, starch is dissolved in caustic soda solution, polyvinyl alcohol or hydrochloric acid solution, and the like. After that, a method for producing a film is proposed. However, the method is not suitable for food and has a problem in that the biodegradability is also reduced.

On the other hand, U.S. Patent No. 5,639,518, etc. proposes a method of manufacturing a mixed resin or film by mixing starch grains with a mother resin, but in this case, the interface between the mother resin and the starch grains is bad, so that the physical properties of the final product are degraded. there was.

In order to solve this problem, U.S. Patent No. 4,654,233 proposes a method of denaturing a hydroxyl group of starch by ether group, ester group or acetate group, but in this case, the manufacturing process is complicated and the environment is polluted due to solvent use. There was a problem.

In addition, US Pat. No. 5,510,401 proposes a method of preparing starch resins or films by adding plasticizers such as glycerin to granulated starch and mixing them at high temperature and high pressure in a biaxial compressor. However, even in this case, due to the high brittleness and strong water absorption of the plasticized starch can not be used alone as a film, it can be used only in the composition mixed with the existing mother resin.

When mixed with the existing mother resin as described above, there is a problem that the physical properties of the final product is lowered due to the low interfacial adhesion with the mother resin.

In order to solve the above problems, U.S. Patent No. 5,629,416 proposes a method of preparing crosslinked ether starch, and U.S. Patent No. 5,639,865 proposes a method of graft polymerization of polycaprolactone simultaneously with the preparation of thermoplastic starch. In the case of starch resin is too high viscosity of the starch resin or starch film is difficult to manufacture, there was a problem that does not have water solubility and edible.

Meanwhile, German Patent No. 680396 et al proposes a film using pectin, but a divalent cation or the like should not be included and did not have water solubility.

In addition, U.S. Patent No. 4,129,134 and the like also propose a method for preparing a film by crosslinking pectin with methoxyl, there was a problem that is not edible.

In addition, US Patent No. 5,451,763 proposes a method of preparing a film by pouring a solution of starch and pectin dissolved in water and then evaporating water. However, in the case of the above method, since starch is not easily dissolved in water, oxygen starch resistance is deteriorated because only starch having an amylose component of 40% or more must be used.

The present invention seeks to provide a method for preparing a film which is edible as pectin and starch, and which is water soluble and biodegradable. In another aspect, the present invention is to provide a method for producing a film having water solubility, biodegradability and edible, and also excellent oxygen shielding and mechanical properties.

1 is a scanning electron microscope (SEM) photograph of a cross section of a conventional film mainly containing starch and pectin.

Figure 2 is a scanning electron microscope (SEM) photograph of the enlarged cross section of the film produced by the present invention

Method for producing an edible film of the present invention for achieving these problems is (i) heating a solution mixed with 20 to 80% by weight of glycerol and water relative to the film weight to 60 ~ 100 ℃, and then the film weight To prepare a starch solution by slowly adding and dissolving 10 to 70% by weight of starch, and (ii) adding 10 to 70% by weight of pectin to water and dissolving it at room temperature to prepare a pectin solution. Iii) preparing a mixed solution by mixing the starch solution and the pectin solution, and (iii) pour the mixed solution on a film-forming plate to evaporate water.

In addition, the production method of the present invention is supplied to a twin screw extruder, a solution of 10 to 70% by weight of pectin, 10 to 70% by weight of starch, 20 to 80% by weight of glycerol and water by weight of the film By extruding and cooling and cutting the extrudate to produce chips, and then supplying and extruding the prepared chips to a single screw extruder having a slit die attached thereto.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the present invention, the starch is not a starch containing more than a certain amount of amylose components, but the general starch is easily dissolved in water without using a solvent such as caustic soda to prepare a film, so that edible and at the same time improve the physical properties such as oxygen shielding Let's do it.

In the present invention, an edible film is prepared by the following two production methods.

In the first production method, 20 to 80% by weight, more preferably 30% by weight of glycerol (plasticizer) is mixed with water and then heated to 60 to 100 ° C, more preferably 80 ° C. At this time, the amount of water is preferably adjusted to 10 to 50 times, more preferably 20 times the weight of the starch. Subsequently, 10 to 70% by weight of starch is slowly added thereto to dissolve for 5 to 20 minutes to prepare a starch solution.

On the other hand, pectin of 10 to 70% by weight relative to the film weight is dissolved in water at room temperature to prepare a pectin solution. At this time, the amount of water is preferably adjusted 10 to 50 times, more preferably 20 times the weight of the pectin.

Next, the starch solution and pectin solution prepared as described above are mixed to prepare a mixed solution, and then poured into a film forming plate to evaporate water to prepare an edible film of the present invention.

In the second method of preparing an edible film of the present invention, 10 to 70% by weight of pectin, 10 to 70% by weight of starch, 20 to 80% by weight of glycerol, and water After preparing a mixed solution, the mixed solution is fed to a twin screw extruder and extruded to cool and cut the extrudate to produce chips.

At this time, the first feeding zone (Feeding Zone) of the twin screw extruder is preferably adjusted to 80 ℃, the second feeding zone (Feeding Zone) to 110 ℃, the discharge die is 95 ℃, the screw rotation speed is 50rpm respectively. . In addition, when preparing the mixed solution, the content of glycerol is 30% by weight relative to the weight of the film, and the water content is preferably 20 to 100 times, more preferably 50 times, of the pectin weight.

Subsequently, the chip prepared as described above is fed to an slit die-attached extruder and extruded, and then passed through a roll of about 50 ° C. to prepare an edible film of the present invention.

In the first and second methods, the film becomes too soft when the glycerol content is more than 80% by weight, and the plasticizer role is insufficient when the content is less than 20% by weight. In addition, when the starch content and the pectin content are out of the range of 10 to 70% by weight, respectively, there arises a problem that mechanical properties and oxygen permeability do not improve at the same time in a balanced manner.

The film produced by the method of the present invention is minimized the molecular weight reduction of the starch molecules by hydrolysis, the starch molecules are sufficiently dissolved in water and mixed with the pectin molecules and molecular units as shown in Figure 2 to improve the film properties, food packaging As a result, the ability to block oxygen, which causes decay, is improved.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Example 1

After mixing 40% by weight of glycerol relative to the weight of the film in 40 times the water of the starch, it is heated to 80 ℃, 20% by weight of starch relative to the weight of the film is slowly added dropwise to prepare a starch solution. On the other hand, pectin of 40% by weight relative to the film weight is added to water (20 times the weight of pectin) and dissolved at room temperature to prepare a pectin solution. Next, the starch solution and the pectin solution prepared as described above were mixed to prepare their mixed solution, and then the mixed solution was poured on a film molding plate to evaporate water to prepare an edible film of the present invention. The results of measuring the elastic modulus, tensile strength, elongation and oxygen permeability of the prepared film are shown in Table 2.

Example 2-Example 5

An edible film was prepared in the same process and conditions as in Example 1 except for changing the contents of glycerol, starch, pectin, and water as shown in Table 1. The results of measuring the elastic modulus, tensile strength, elongation and oxygen permeability of the prepared film are shown in Table 2.

Manufacture conditions division Example 1 Example 2 Example 3 Example 4 Example 5 Glycerol% by weight of film 40 20 30 40 20 Starch weight to film weight 20 40 45 20 40 Pectin weight% to film weight 40 40 25 40 40 Weight of water to starch weight (times) 10 10 10 30 20

Film properties division Example 1 Example 2 Example 3 Example 4 Example 5 Modulus of elasticity (MPa) 584 1,102 686 730 760 Tensile Strength (MPa) 21.9 18.0 15.7 12.4 12.6 Elongation (%) 7.7 2.2 3.6 3.3 3.4 Oxygen permeability (cc / ㎡ / 24 hours) 1.3 1.7 2.0 1.7 1.7

Example 6

After mixing 40% by weight of pectin, 20% by weight of starch, 40% by weight of glycerol, and 10 times by weight of starch, water is fed to a twin screw extruder and extruded. The chips are prepared by cooling and cutting the water. At this time, the temperature of the first feeding zone of the twin screw extruder was adjusted to 80 ° C., the temperature of the second feeding zone to 110 ° C., the discharge die temperature to 95 ° C., and the screw rotation speed to 50 rpm. Subsequently, the chip is fed and extruded into a single screw extruder with a 11.4 cm slit die, and passed through a roll at 50 ° C. to produce a film. The results of measuring the elastic modulus, tensile strength, elongation and oxygen permeability of the prepared film are shown in Table 4.

Example 7-10

Except for changing the content of glycerol, starch, pectin and water as shown in Table 3 was prepared an edible film in the same process and conditions as in Example 6. The results of measuring the elastic modulus, tensile strength, elongation and oxygen permeability of the prepared film are shown in Table 4.

Manufacture conditions division Example 6 Example 7 Example 8 Example 9 Example 10 Glycerol% by weight of film 40 20 30 40 40 Starch weight to film weight 20 40 45 20 20 Pectin weight% to film weight 40 40 25 40 40 Weight of water to starch weight (times) 10 10 10 20 50

Film properties division Example 6 Example 7 Example 8 Example 9 Example 10 Modulus of elasticity (MPa) 265 3,100 1,630 1,690 1,650 Tensile Strength (MPa) 6.9 26.7 19.6 22.6 23.1 Elongation (%) 22.1 2.1 2.8 3.9 3.4 Oxygen permeability (cc / ㎡ / 24 hours) 1.7 1.7 2.0 1.2 1.3

Comparative Example 1

After adding 20% by weight of glycerol to 20 times the weight of starch in water, 20% by weight of starch is slowly added dropwise thereto to dissolve at room temperature for 10 minutes to prepare a starch solution. On the other hand, pectin of 40% by weight relative to the film weight is added to water (20 times the weight of pectin) and dissolved at room temperature to prepare a pectin solution. Next, the starch solution and the pectin solution prepared as described above were mixed to prepare their mixed solution, and then the mixed solution was poured on a film molding plate to evaporate water to prepare an edible film. The results of measuring the elastic modulus, tensile strength, elongation and oxygen permeability of the prepared film are shown in Table 6.

Comparative Example 2 to Comparative Example 4

Except for changing the glycerol content as shown in Table 5 was prepared an edible film in the same process and conditions as in Comparative Example 1. The results of measuring the elastic modulus, tensile strength, elongation and oxygen permeability of the prepared film are shown in Table 6.

Manufacture conditions division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Glycerol Content Per Film Weight 20 wt% 30 wt% 40 wt% 50 wt%

Film properties division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Modulus of elasticity (MPa) 253 184 168 124 Tensile Strength (MPa) 5.4 5.2 6.1 3.9 Elongation (%) 1.3 1.1 1.8 2.7 Oxygen permeability (cc / ㎡ / 24 hours) 24 26 31 34

In the present invention, starch can be sufficiently dissolved in water and mixed well with pectin up to the molecular unit level. As a result, the film prepared according to the present invention has excellent water solubility, biodegradability, and edibility, and also has excellent oxygen shielding and mechanical properties. For this reason, the film produced according to the present invention is very useful as a packaging material such as a pesticide bag requiring various biodegradability, a disposable packaging material requiring water solubility, or a food packaging container such as ramen soup bag requiring edible solubility.

Claims (3)

(Iii) A solution containing 20 to 80% by weight of glycerol and water in relation to the weight of the film is heated to 60 to 100 ° C, and then starch solution is slowly added and dissolved in 10 to 70% by weight of starch relative to the weight of the film. Manufacturing, (Ii) adding 10-70% by weight of pectin to the weight of the film in water and dissolving at room temperature to prepare a pectin solution, (Iii) preparing a mixed solution by mixing the starch solution and the pectin solution, (Iii) A method of producing an edible film, characterized in that the mixed solution is poured into a film forming plate to evaporate moisture. The method of claim 1, wherein the amount of water used to prepare the starch solution and the pectin solution is adjusted to 10 to 50 times the weight of the starch or pectin. Supplying a twin screw extruder, a solution containing 10 to 70% by weight pectin, 10 to 70% by weight starch, 20 to 80% by weight glycerol and 20 to 100 times the weight of pectin by weight By extruding, cooling and cutting the extrudate to produce chips, and then feeding and extruding the manufactured chips to a uniaxial extruder with a slit die.