阅读说明：本技术 一种肉桂精油可食膜及其制备方法 (Cinnamon essential oil edible film and preparation method thereof ) 是由 吴雪辉 周悦 于 2020-03-06 设计创作，主要内容包括：本发明公开了一种肉桂精油可食膜及其制备方法,该制备方法包括淀粉糊化、非均相体系制备、非均相体系分散物质微粒化、反向交替旋转涂膜及烘干,本发明制得的成膜液悬浮稳定性和均匀性高,最终制得的膜组分分散均匀,有效提高膜的稳定性能；制膜工序中无需进行脱气消泡处理,缩短时间,节约能源和成本；烘干采用了真空常压脉动干燥机,通过实现真空干燥与间歇式干燥的结合,迅速烘干膜中的水分,最终制备成的膜表面光滑细密无气孔,有效提高了肉桂精油可食膜的阻隔性能；且所用原料天然绿、安全无毒,所制得的膜具有可食性；本发明所得可食膜具有良好的机械性能、阻隔性能和抑菌性能,在作为食品保鲜的包装材料方面具有良好的应用前景。(The invention discloses an edible cinnamon essential oil film and a preparation method thereof, wherein the preparation method comprises starch gelatinization, heterogeneous system preparation, micronization of heterogeneous system dispersed substances, reverse alternate rotation film coating and drying; degassing and defoaming treatment is not needed in the film preparation process, so that the time is shortened, and the energy and the cost are saved; the drying adopts a vacuum normal-pressure pulsation dryer, the moisture in the film is quickly dried by combining the vacuum drying and the intermittent drying, the surface of the finally prepared film is smooth, fine and pore-free, and the barrier property of the cinnamon essential oil edible film is effectively improved; the used raw materials are natural green, safe and nontoxic, and the prepared film has edibility; the edible film obtained by the invention has good mechanical property, barrier property and antibacterial property, and has good application prospect in the aspect of being used as a packaging material for food preservation.)

1. The preparation method of the cinnamon essential oil edible film is characterized by comprising the following steps:

s1, adding water into oxidized hydroxypropyl starch, and heating and stirring to prepare 4-8% of starch pasting liquid;

s2, cooling the starch pasting liquid obtained in the step S1 to room temperature, adding cinnamon essential oil, a plasticizer and a surfactant into the starch pasting liquid, and stirring to obtain a heterogeneous system blending liquid;

s3, mechanically homogenizing the heterogeneous system blend liquid prepared in the step S2 for 3-6 min according to a periodic variation rule of micronization for 30-40S, suspension for 10-20S, micronization for 20-30S and suspension for 10-20S to obtain a stable and uniform film forming liquid;

s4, pouring the film forming liquid prepared in the step S3 into a glass dish, alternately rotating and coating the film clockwise and anticlockwise, standing and drying to obtain the cinnamon essential oil edible film.

2. The method according to claim 1, wherein the mass volume ratio of the added cinnamon essential oil, the plasticizer and the surfactant to the starch gelatinization liquid in step S2 is 0.5-3%, 0.5-2% and 0.5-2%, respectively.

3. The method according to claim 1, wherein the cinnamon essential oil is one or more of cinnamon bark essential oil, cinnamon leaf essential oil and cinnamon twig essential oil.

4. The method of claim 1, wherein the cinnamon essential oil is extracted by an ohm-assisted extraction method, a supercritical carbon dioxide extraction method, or a subcritical fluid extraction method.

5. The method according to claim 1, wherein the plasticizer in step S2 is one or more selected from glycerol, sorbitol, and polyethylene glycol; the surfactant is one or more of polysorbate-80, lecithin or span-80.

6. The method of claim 1, wherein the mechanical homogenizing in step S3 is performed by one or more of a high-speed dispersion homogenizer, a vacuum high-pressure homogenizer, and a microfluid ultra-high pressure homogenizer.

7. The method according to claim 1, wherein the heating and stirring temperature in step S1 is 60-100 ℃, the stirring speed is 60-180 r/min, and the stirring time is 25-45 min; and S2, stirring at a rotating speed of 500-2000 r/min for 10-20 min.

8. The method according to claim 1, wherein the ratio of the amount of the deposition solution used in step S4 to the radius of the glass dish is 20 to 40 ml: 5-8 cm; and S4, standing for 5-15 min.

9. The method according to claim 1, wherein the drying in step S4 is vacuum normal pressure pulse drying, negative pressure circulation drying or vacuum microwave drying, the drying temperature is 40-60 ℃, and the drying time is 1-2.5 h.

10. The cinnamon essential oil edible film prepared by the method of any one of claims 1 to 9.

Technical Field

The invention relates to the field of food packaging materials, in particular to an edible cinnamon essential oil film and a preparation method thereof.

Background

The food packaging film is a packaging article which is coated on the surface of food and is used for protecting and preserving the food. Nowadays, most of food packaging films are synthetic plastic packaging films using fossil fuels as raw materials. However, the wide application of synthetic plastic food packaging films and their difficult degradation characteristics put great pressure on environmental management, and chemical substances such as phthalate esters which may be contained therein pose certain threats to human health. Compared with synthetic packaging materials, the edible film has the advantages of safety, no pollution, reproducibility, degradability and the like. Along with the enhancement of the environmental awareness of people and the improvement of the preservation quality and the packaging requirement of food, the development of a green and natural edible food packaging film has good prospect. The edible film is a film or a coating which takes natural high molecular substances such as polysaccharide, protein, lipid and the like as main film forming matrixes and is supplemented with edible plasticizers or cross-linking agents and the like, molecules of all film forming agents interact to form a net structure through a certain processing procedure, and the net structure is covered on the surface of food in the forms of dipping, spraying, wrapping, coating and the like to prevent the interference and the damage of oxygen, moisture, microorganisms and the like, so that the edible film has a protective effect. They can be classified into polysaccharide membranes, protein membranes, lipid membranes and composite membranes according to the difference of the membrane-forming substrates.

At present, related research on edible packaging films is also related, and patent CN110183859A discloses a preparation method of a tensile waterproof starch film, wherein pre-crosslinked modified alkaline starch is used and hydroxylated epoxy soybean oil is added when the tensile waterproof starch film is prepared, and polysiloxane is added in an additive, so that the waterproofness and tensile strength of the product are further improved. However, excessive additives, plasticizers or their polymer degradation byproducts generated in the reaction and residual solvents in the polymerization reaction can migrate from the film to the food, thereby causing flavor loss and even toxic and side effects. Patent CN201510324831.9 discloses a preparation method of an edible tara gum film with hydrophobic property, the film material prepared by the patent has good hydrophobicity and tensile strength, and can effectively block and block ultraviolet rays, but the elongation at break of the film is poor, so that the application range of the film in food packaging materials is narrowed. Patent CN108623829A discloses a surface hydrophobic modified starch film and a preparation method thereof, wherein the surface modification method is adopted to carry out hydrophobic modification on the starch film, so that the water resistance of the starch film is improved to a great extent, but the mechanical strength of the starch film is not high. Patent CN109369934A discloses a preparation method of a water-blocking starch film, in the process of preparing the starch film by the method, the amount of processing aids added is large and various, the operation is complicated, and the cost is not saved. With the development of food storage and preservation technologies in China, the problems of poor water resistance, poor mechanical strength and the like of the edible film are solved, and the antibacterial effect of the edible film is to be improved.

Therefore, research and development of the edible film which is simple in preparation process, excellent in mechanical strength and barrier property and has an antibacterial function simultaneously has important application value for providing a novel packaging material, improving the functionality of the packaging material and expanding the application range of the edible film.

Disclosure of Invention

The invention aims to provide an edible cinnamon essential oil film with strong mechanical property, good barrier property and antibacterial property and a preparation method thereof. According to the method, various preparation steps of the edible film are optimized and controlled, substrates with different properties are effectively compounded, and the advantages of various components are fully exerted, so that the method for preparing the edible film of cinnamon essential oil is obtained.

The preparation method comprises the steps of preparing starch pasting liquid, preparing a heterogeneous system, micronizing a dispersed substance of the heterogeneous system, coating by reverse alternate rotation and drying. In the preparation of the cinnamon essential oil edible film, the dispersed substances in the heterogeneous system blend liquid are micronized, the suspension stability and uniformity in the prepared film-forming liquid dispersion system are improved, the finally prepared film components are uniformly dispersed, and the stability and application value of the film are effectively improved; degassing and defoaming treatment is not needed in the film preparation process, so that the process flow is shortened, and energy and cost are effectively saved. The drying adopts a vacuum normal-pressure pulsation dryer, the moisture in the film is quickly dried by combining the vacuum drying and the intermittent drying, the surface of the finally prepared film is smooth, fine and pore-free, and the barrier property of the cinnamon essential oil edible film is effectively improved. The adopted raw materials are natural, green, safe and nontoxic, and the prepared film has edibility; the prepared cinnamon essential oil edible film has good mechanical property, barrier property (such as water resistance, light resistance, oil resistance and the like) and bacteriostatic property, and has good application prospect when being used as a packaging material for food preservation.

Therefore, the first object of the invention is to provide a preparation method of an edible film containing cinnamon essential oil.

The invention also aims to provide the cinnamon essential oil edible film prepared by the method.

In order to achieve the purpose, the invention is realized by the following scheme:

the invention provides a preparation method of an edible cinnamon essential oil film, which specifically comprises the following steps:

s1, adding water into oxidized hydroxypropyl starch, heating and stirring to prepare 4-8% starch pasting liquid;

s2, cooling the starch pasting liquid obtained in the step S1 to room temperature, adding cinnamon essential oil, a plasticizer and a surfactant into the starch pasting liquid, and stirring to obtain a heterogeneous system blending liquid;

s3, mechanically homogenizing the heterogeneous system blend liquid prepared in the step S2 for 3-6 min according to a periodic variation rule of micronization for 30-40S, suspension for 10-20S, micronization for 20-30S and suspension for 10-20S to obtain a stable and uniform film forming liquid;

s4, pouring the film forming liquid prepared in the step S3 into a glass dish, alternately rotating and coating the film clockwise and anticlockwise, standing and drying to obtain the cinnamon essential oil edible film.

Starch is a main matrix component of edible films due to the advantages of wide biological sources, low price, good film forming property, safety, no toxicity, good biocompatibility and the like, but the application of starch in the food industry is severely restricted due to the strong hydrophilicity of starch polysaccharide, relatively weak water vapor barrier effect, poor water resistance and insufficient mechanical strength, and researchers also take corresponding measures to improve, for example, starch with high amylose content is selected to prepare starch films, or starch is modified to improve the property of starch, or lipid is added into starch films to improve the water resistance of starch films, or auxiliary agents are added to improve the mechanical property. According to the invention, the oxidized hydroxypropyl starch is used when the cinnamon essential oil edible film is prepared, the existence of carboxyl in the structure of the oxidized hydroxypropyl starch also plays a role in steric hindrance on the aggregation and aging of amylose, so that the starch is not thickened and hardened in the pasting and cooling processes, the starch paste also shows better fluidity, the used oxidized hydroxypropyl starch has the advantages of low viscosity, strong ageing resistance and the like, the stability to heat, acid and shearing and the film forming property are improved, and compared with other starches, the prepared film has the advantages of smooth and uniform surface, no bubbles, better mechanical property and better barrier property.

According to the method, the thickness of the membrane can be controlled not to be too thin or too thick by controlling the volume of the poured film forming liquid by adopting a reverse alternate rotary coating method, the thickness range of the finally prepared edible cinnamon essential oil membrane is 0.1124-0.1472 mm, and a better application effect can be achieved. In the process of preparing the cinnamon essential oil edible film, defoaming treatment is not needed, so that the process flow can be effectively shortened, and energy and cost are saved.

Preferably, the mass volume ratio of the added cinnamon essential oil, the plasticizer and the surfactant to the starch gelatinization liquid in the step S2 is 0.5-3%, 0.5-2% and 0.5-2%, respectively.

Most preferably, the mass volume ratio of the added cinnamon essential oil, the plasticizer and the surfactant to the starch gelatinization liquid in the step S2 is 1.5%, 1% and 1% respectively.

Preferably, the cinnamon essential oil is one or more of cinnamon bark essential oil, cinnamon leaf essential oil and cinnamon branch essential oil.

Most preferably, the cinnamon essential oil is cinnamon bark essential oil.

Compared with cinnamon leaf essential oil and cinnamon branch essential oil, the cinnamon bark edible film has the advantages that the cinnamon bark essential oil extracted from cinnamon bark by an ohm-acid salt auxiliary extraction method is more in bioactive component types and higher in content, the cinnamon bark essential oil is higher in bacteriostasis, sterilization and antioxidation performance, and the application range of the cinnamon bark edible film is expanded.

Preferably, the cinnamon essential oil is extracted by an ohm-salt auxiliary extraction method, a supercritical carbon dioxide extraction method or a subcritical fluid extraction method.

More preferably, the cinnamon essential oil is extracted by an ohm-acid salt auxiliary extraction method under the auxiliary conditions of a voltage of 100-300 v and a sodium chloride solution with a mass-volume ratio of 0.5-3%.

Compared with the traditional cinnamon essential oil extraction process, in the ohm salt auxiliary extraction process, the extraction current generates energy sum required by extraction through plant tissues, and the heating generation mode is that resistance is rapidly converted from electric energy to heat energy in the ohm process, so that the extraction time is greatly shortened, meanwhile, the temperature required by extraction is also remarkably reduced by adding NaCl, the yield of cinnamon essential oil extracting solution extracted by the ohm salt auxiliary extraction process is higher, and the active ingredients of the cinnamon essential oil are greatly reserved.

Most preferably, the cinnamon essential oil is extracted by an ohm-salt assisted extraction method with the assistance of 200v of voltage and 1% by mass/volume sodium chloride solution.

Preferably, the plasticizer in step S2 is one or more of glycerin, sorbitol, and polyethylene glycol.

Most preferably, the plasticizer of step S2 is glycerol.

Preferably, the surfactant in step S2 is one or more of polysorbate-80, lecithin or span-80.

Most preferably, the surfactant of step S2 is polysorbate-80.

In addition, the uniformity and stability of the cinnamon essential oil edible film are improved by adding glycerin as a plasticizer and polysorbate-80 as a surfactant. The glycerol can effectively improve the plasticity and the flexibility of the film by virtue of the interaction between the hydroxyl groups of the glycerol and the starch molecules, and further improve the mechanical property of the film. The polysorbate-80 serving as a surfactant has strong emulsibility, and is added into cinnamon essential oil membrane liquid, so that cinnamon essential oil can be more uniformly and stably distributed in the mixed membrane liquid, the internal structure of the membrane is optimized, a more uniform and compact network structure is formed, and the performance of the membrane is improved. The polysorbate-80 and the glycerin are added into the cinnamon essential oil edible film liquid together, so that the mechanical strength and the barrier property of the cinnamon essential oil edible film are effectively improved.

Preferably, the mechanical homogenization in step S3 is performed by using one or more of a high-speed dispersion homogenizer, a vacuum high-pressure homogenizer, and a microfluid ultrahigh-pressure homogenizer.

Most preferably, the mechanical homogenization of step S3 is performed by a micro-jet ultra-high pressure homogenizer, and the mechanical homogenization time is 5 min.

Preferably, the mechanical homogenization in the step S3 is mechanically homogenized for 5min according to a periodic variation rule of "micronization 35S-pause 15S-micronization 25S-pause 15S", and the substances in the prepared film-forming liquid system are uniformly and stably dispersed, so that the cinnamon essential oil edible film with uniformly and stably dispersed components is finally prepared.

Preferably, the heating and stirring temperature in the step S1 is 60-100 ℃, the stirring speed is 60-180 r/min, and the stirring time is 25-45 min.

Most preferably, the heating and stirring temperature in the step S1 is 80 ℃, the stirring speed is 100r/min, and the stirring time is 30 min.

Preferably, the rotation speed of the stirring in the step S2 is 500-2000 r/min, and the stirring time is 10-20 min.

Most preferably, the rotation speed of the stirring in the step S2 is 1500r/min, and the stirring time is 15 min.

Preferably, the ratio of the dosage of the deposition solution in the step S4 to the radius of the glass dish is 20-40 ml: 5-8 cm.

Preferably, the standing time in the step S4 is 5-15 min.

Most preferably, the standing time of step S4 is 10 min.

Preferably, the drying in step S4 is vacuum normal pressure pulse drying, negative pressure circulation drying or vacuum microwave drying, the drying temperature is 40-60 ℃, and the drying time is 1-2.5 h.

Most preferably, the drying in step S4 is vacuum normal pressure pulse drying, the drying temperature is 50 ℃, and the drying time is 1.5 h.

According to the method, vacuum pulsation drying is adopted in the preparation of the cinnamon essential oil edible film, and the combination of vacuum drying and intermittent drying is realized by adjusting the pressure state in a drying bin according to the periodic alternating change rule of the highest negative pressure and the normal pressure. The continuous cyclic variation of the pressure in the drying chamber can destroy the pressure balance state between the water vapor partial pressure of the material surface layer and the water vapor partial pressure of the drying medium in the drying chamber in the drying process, and the pressure difference between the water vapor partial pressure and the drying medium partial pressure is increased, so that the heat and mass transfer is accelerated, the drying time of the cinnamon essential oil edible film is greatly shortened, the drying efficiency is improved, and the processing cost is reduced. According to the invention, vacuum normal-pressure pulse drying is adopted for drying, the surface of the finally prepared cinnamon essential oil edible film is smooth and has no air holes, the water loss speed of each part of the film is uniform, and the stability of the film is better.

The cinnamon essential oil edible film prepared by the invention has good mechanical property and barrier property, and the performance parameters of the cinnamon essential oil edible film are that the tensile strength is 1.21-1.95 MPa, the elongation at break is 17.24-32.57%, the light transmittance is 24.73-35.03%, and the water vapor transmission coefficient is 1.25 × 10^-12～1.90×10^-12g.cm/cm²S.pa, oil permeability coefficient 0.1455-0.2136 g.mm/m²2 d. In addition, the prepared edible film also has good antibacterial performance, and the size parameter range of the antibacterial zone is as follows: 19.73-28.59 mm of escherichia coli, 27.66-42.32 mm of staphylococcus aureus, 24.55-33.60 mm of penicillium and 21.37-29.78 mm of yeast.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention isThe raw materials are natural, green, safe and nontoxic, and the prepared edible film has good mechanical property and barrier property, the tensile strength can reach 1.21-1.95 MPa, the elongation at break can reach 17.24-32.57%, the light transmittance can reach 24.73-35.03%, and the water vapor transmission coefficient can reach 1.25 × 10^-12～1.90×10^-12g.cm/cm²S.pa, the oil permeability coefficient can reach 0.1455-0.2136 g.mm/m²And 2d, has good antibacterial performance and has good application prospect in the aspect of being used as a packaging material for food preservation.

2. In the preparation of the cinnamon essential oil edible film, the dispersed substances in the heterogeneous system blend liquid are micronized, the suspension stability and uniformity in the prepared film-forming liquid dispersion system are improved, the finally prepared film components are uniformly dispersed, and the stability and application value of the film are effectively improved.

3. A vacuum normal-pressure pulsation dryer is adopted in the drying of the film, moisture in the film is quickly dried by combining vacuum drying and intermittent drying, the surface of the finally prepared film is smooth, fine and pore-free, and the barrier property of the cinnamon essential oil edible film is effectively improved.

4. In the film preparation process, degassing and defoaming treatment are not required, so that the process flow is shortened, and energy and cost are effectively saved.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.