CN101746557A - Whey protein/gelatin edible compound film and preparation method thereof - Google Patents

Abstract

The invention discloses a whey protein/gelatin edible compound film which belongs to the field of food-packaging materials. The compound film is made from whey protein solution and gelatin solution which are added with plasticizer and blended, wherein the weight ratio between whey protein and gelatin is 1-99:99-1. The thickness of the edible compound film is 80 Mu m to 110 Mu m. The weight percentage concentration of the whey protein solution is 8 percent to 10 percent, and the weight percentage concentration of the gelatin solution is 8 percent to 10 percent. The invention also discloses a preparation method for the compound film. The compound film has a high nutritive value and is cheap, and the mechanical properties of the film can be controlled by regulating the compound proportion of whey protein and gelatin in order to adapt to packages for different purposes.

Description

A kind of lactalbumin/gelatin edible compound film and preparation method thereof

Technical field

The invention belongs to the packaging material for food field, particularly a kind of lactalbumin/gelatin edible compound film and preparation method thereof.

Background technology

Packing is food necessary part in processing and circulation, and its radical function is the product preservation, also will provide convenience for the customer in use simultaneously.The conventional plastic packing are cheap, and are easy to process, be widely used, but are easy to generate pernicious gas and peculiar smell, and can only work as waste after can't being degraded by microorganisms, using abandons, cause " white pollution ", destroyed ecology environment, have influence on human health.Along with the continuous enhancing of people's environmental consciousness in recent years, " green package " material substitution product that meets continuable development principle is favored, the existing a lot of report of the progress of associated safety, degradable package material, wherein edible film product, environmental protection safe, nontoxic, edible and have trophism concurrently and characteristics such as local flavor and receiving much concern with it.

Edible film is that a class is a raw material with edibility material (protein, polysaccharide and fat etc.), by the formed film with porous network structure of intermolecular interaction.It is easily by biodegradation, non-environmental-pollution; Have barrier property, can prevent between food component the food spoilage that the migration because of moisture and other material causes; Can be used as the carrier of flavour of food products agent, sweetener, nutrition fortifier, antioxidant, anti-microbial agents etc.Disclosed edible packaging film mainly is to be that be processed on the basis with edible raw materials such as protein, fat, polysaccharide or its compounds.

It is the preparation method of the edible film of matrix with the lactalbumin that Chinese patent CN101167536 discloses a kind of, and this application is with the WPC-80 primary raw material, prepares by interpolation plasticizer glycerine.Whey isolate protein (WPI) film nutritive value is higher, and film forming is better, but price is higher, and edible film is the feed stock cost height with the whey isolate protein all, is restricted in actual applications; Gelatin (Gelatin) also is a kind of good filmogen, and the film mechanical strength height of formation, elasticity are good, has unique just melt in the mouth characteristic, and wide material sources, low price.Gelatin form by the knot of animal or epidermal tissue in the collagen partial hydrolysis and obtain, be a kind of abundant natural macromolecular material of originating, possess hydrophilic property is strong, good film-forming property, side-chain radical reactivity height, can form between jelly and colloidal sol and the gel and exist reversible conversion, be many good physics and chemical property such as typical both sexes dielectric characteristic.Contain 18 seed amino acids in the protein of gelatin, wherein 7 kinds essential by human body, be a kind of desirable protein sources.Lactalbumin and gelatin have good compatibility, therefore can be composite with arbitrary proportion, prepare a kind of engineering properties controlled, be of high nutritive value and cheap edible film.By domestic and international patent documentation, journal and other documents of publishing (as the internet) are retrieved, the present invention does not at home and abroad appear in the newspapers.

Summary of the invention

The invention provides a kind of lactalbumin/gelatin edible compound film and preparation method thereof.

A kind of lactalbumin/gelatin edible compound film, described edible composite membrane are made lactoalbumin soln and gelatin solution mixing under the situation of adding plasticizer, and wherein, the mass ratio of lactalbumin and gelatin is 1-99: 99-1.

Edible composite membrane of the present invention has good oil resistance, gas barrier properties.With lactalbumin and gelatin be primary raw material preparation complex film within the specific limits, change by compound proportion, can the controlled different compound edible film of nutrition of dissolubility of processing machinery performance, thus make it have purposes widely, satisfy the needs of Different Package.

The thickness of described edible composite membrane is 80～110 μ m.

The mass percent concentration of described lactoalbumin soln is 8～10%, and the mass percent concentration of gelatin solution is 8～10%.

A kind of preparation method of lactalbumin/gelatin edible compound film, carry out according to following control step:

(1) preparation of lactoalbumin soln: take by weighing the lactalbumin powder, add deionized water, after stirring is fully dissolved it, regulator solution pH value is 7～9,80～90 ℃ of heating 20～30min are cooled to room temperature, and the mass percent concentration of the lactoalbumin soln that makes is 8～10%;

(2) preparation of gelatin solution: take by weighing the gelatin powder, add deionized water, at room temperature heat 15～30min behind the swelling 30min in 35～60 ℃ of water-baths it is fully dissolved, solution is adjusted to pH7～9, the mass percent concentration of the gelatin solution that makes is 8～10%;

(3) lactoalbumin soln of step (1) and the gelatin solution of step (2) are mixed, wherein, the mass ratio of lactalbumin and gelatin is 1-99: 99-1, in mixed solution, add plasticizer then, mix and ultrasonic degas, obtain film forming liquid, wherein, the mass ratio of total protein is (0.3-0.5) in plasticizer and the solution: 1; Described total protein is lactalbumin and gelatin.

(4) film forming liquid is joined in the flat organism glass vessel, wherein, the consumption of film forming liquid is 0.08-0.1g/cm ², at 20-24 ℃, relative humidity is balance 48h at least under the condition of 54-58%, makes the edible composite membrane that thickness is 80～110 μ m.

Described plasticizer is glycerine or sorbierite.

Described lactalbumin preferred whey protein isolate (WPI).

Described gelatin solution and lactoalbumin soln mixing before concentration best consistent with the pH value.

Beneficial effect of the present invention: whey isolate protein costs an arm and a leg, and the adding of gelatin declines to a great extent the cost of its film, the basic no change of other physicochemical property of while film, because two kinds of albumen have fabulous compatibility, can arbitrary proportion composite, the film of making has controlled mechanical strength.Therefore, complex film of the present invention be a kind of engineering properties controlled, be of high nutritive value and cheap edible film.Be applicable to the packing of different field, such as: can be as the packing of condiment for instant noodles; The packing that is used for milk powder, soymilk powder, coffee, tealeaves etc.; The inner packing that is used for Chinese patent drug; Be used for various fruits and dried beef etc.Lactalbumin/gelatin-compounded edible package material is a kind of resource-type packing that do not have waste, and resource is utilized, and meets the friendly type social requirement of contemporary continuable development principle and built environment.

Description of drawings

Fig. 1 is the light transmittance of the complex film of embodiment 1 preparation at 200-800nm.

Fig. 2 is the light transmittance of the complex film of embodiment 1 preparation at 200-320nm.

Fig. 3 is the light transmittance of the complex film of embodiment 2 preparations at 200-800nm.

Fig. 4 is the light transmittance of the complex film of embodiment 2 preparations at 200-320nm.

The specific embodiment

In following examples about film thickness, pierce through intensity, pierce through distortion, the measuring method of steam permeable coefficient, aqueous ingredients, dissolubility and light transmittance is as follows:

(1) Determination of thickness method: measure thickness with digimatic micrometer.

(2) pierce through the measuring method of performance

Use TMS-Pro matter structure instrument measure film pierce through intensity (PS, N/mm) and pierce through distortion (PD, mm).Piercing through intensity calculates by formula (1):

$\mathrm{PS}=\frac{F_p}{L}---\left(1\right)$

In the formula: F _P---maximum pierces through power (N)

The thickness of L---membrane sample (mm)

(3) measuring method of steam permeable coefficient (WVP)

With reference to GB 1037-88 method, adopt the cup method of intending, and suitably measure after the adjustment.The aqueous vapor transmission coefficient calculates by formula (3):

$\mathrm{WVP}(g\·\mathrm{mm}/m^2\·d\·\mathrm{kPa})=\frac{W\×x}{A\×T\×\mathrm{\ΔP}}---\left(2\right)$

In the formula, the weightening finish of W---moisture vapor transmission cup (g)

The thickness of X---film (mm)

A---film exposed area (cm ²)

T---interval time of measurement (h)

The aqueous vapor pressure reduction (kPa) of Δ P---film both sides

(4) aqueous ingredients and deliquescent measuring method

Taking by weighing quality is m ₀Film be placed on dry 24h in 105 ℃ the baking oven, weigh, calculate dry before and after the film quality loss be Δ m.Taking by weighing quality is m ₁The dry film of (≈ 0.1g) is put into the culture dish that fills 40ml water, dissolves 24h down at 22 ℃.Afterwards film is pulled out, blotted the moisture on film surface, under 105 ℃ condition, be dried to constant weight again, claim to such an extent that quality is m with filter paper ₂

$\mathrm{MC}(\%)=\frac{\mathrm{\&Delta;m}}{{\mathrm{<figure-callout\; id="0"\; label="m"\; filenames="H2009102429699E00011.png,H2009102429699E00012.png"\; state="\{\{state\}\}">m</figure-callout>}}_0}\&times;100\%---\left(3\right)$

$S(\%)=\frac{m_1-m_2}{m_1}\&times;100\%---\left(4\right)$

(5) measuring method of light transmittance and diaphaneity

Adopt UV-VIS spectrophotometry to measure film at OD ₂₀₀-OD ₈₀₀The time absorption value, draw light transmittance.

Embodiment 1

(1) preparation of whey isolate protein solution: take by weighing the lactalbumin powder, add deionized water, stir 2h it is fully dissolved, regulate pH to 8, the water-bath of putting into temperature and be 80 ℃ heats 30min, is cooled to room temperature, wherein, the mass percent concentration of WPI solution is 10%.

(2) preparation of gelatin solution: take by weighing the gelatin powder, add deionized water, at room temperature in 55 ℃ of water-baths, heat 15min behind the swelling 30min it is fully dissolved, be cooled to room temperature, solution is adjusted to pH8, and the mass percent concentration of the gelatin solution of preparation is 10%.

(3) above-mentioned two kinds of solution are mixed, wherein, the mass ratio of whey isolate protein and gelatin sees Table 1, adds glycerine then, wherein, the quality of glycerine, with the ratio of the quality sum of whey isolate protein and gelatin be 0.4: 1, stirring at room temperature fully mixes it, and ultrasonic degas gets film forming liquid.

(4) respectively draw 5g film forming liquid and pour in the self-control organism glass ware (diameter 8cm), and in climatic chamber (22 ℃, RH=56%) drying, balance 48h, film forming, film thickness is about 100 μ m.

Through test, the index of each film such as table 1, Fig. 1 and Fig. 2, wherein, whey isolate protein represents that with W gelatin is represented with G.

The thickness of table 1 film, mechanical characteristics, aqueous ingredients, dissolubility and moisture-vapor transmission

??WPI∶gelatin(w∶w)	??100∶0	??99∶1	??75∶25	??50∶50	??25∶75	??1∶99	??0∶100
								Thickness (μ m)	??96±12	??96±11	??95±10	??93±12	??96±8	??94±13	??94±12
Pierce through intensity (N/mm)	??48.02±1.04	??47.98±1.15	??35.05±3.59	??25.05±1.46	??32.92±2.94	??45.12±2.04	??45.37±2.72
								Pierce through distortion (mm)	??5.47±0.50	??5.51±0.48	??6.22±0.42	??6.60±0.26	??9.61±0.68	??12.31±1.33	??12.34±1.45
Aqueous ingredients (%)	??28.2±1.0	??28.1±1.4	??26.2±1.2	??25.7±1.1	??25.6±0.4	??23.7±0.6	??23.7±0.8
								Dissolubility (%)	??19.5±0.7	??19.8±0.6	??22.5±1.0	??25.1±1.3	??27.6±0.9	??33.8±2.1	??34.1±2.4
Moisture-vapor transmission (g.mm.h -1.m -2.kPa -1)	??1.6±0.04	??1.6±0.06	??1.6±0.05	??1.7±0.06	??1.8±0.10	??1.9±0.08	??1.9±0.10

By table 1 as seen, the thickness of the complex film after two kinds of albumen are composite is compared with the pure film of gelatin with the pure film of WPI does not have significant difference, pierces through intensity and reduces earlier afterwards to increase along with the increase of gelatine content, and at 50W: when 50G was composite, it was minimum to pierce through intensity; And along with the increase of gelatine content, pierce through distortion, dissolubility and the moisture-vapor transmission of film improve, and aqueous ingredients reduces.Therefore can change film strength, elasticity by the change of compound proportion, resistance is moist and dissolubility etc., and then satisfies purposes different in the virtual package.

Fig. 1 is the light transmittance of above-mentioned complex film in 200～800nm scope.In 300～800nm scope, the light transmittance of various complex films is basic identical, does not have significant difference; In 200～300nm near ultraviolet band, as shown in Figure 2, the light transmittance of each complex film is slightly different, and when mass ratio is 1W: during 99G, the light transmittance of film is higher than other complex films; As long as illustrate to exist a certain proportion of lactalbumin, complex film just to have uvioresistant ability preferably, therefore can keep out ultraviolet ray preferably, prolong the food shelf life.

Embodiment 2

(1) preparation of whey isolate protein solution: take by weighing the lactalbumin powder, add deionized water, stir 2h it is fully dissolved, regulate pH to 7, the water-bath of putting into temperature and be 90 ℃ heats 20min, is cooled to room temperature, wherein, the mass percent concentration of WPI solution is 8%.

(2) preparation of gelatin solution: take by weighing the gelatin powder, add deionized water, at room temperature in 35 ℃ of water-baths, heat 30min behind the swelling 30min it is fully dissolved, be cooled to room temperature, solution is adjusted to pH7, and the mass percent concentration of the gelatin solution of preparation is 8%.

(3) above-mentioned two kinds of solution are mixed, wherein, the mass ratio of whey isolate protein and gelatin sees Table 2, adds glycerine then, wherein, the quality of glycerine, with the ratio of the quality sum of whey isolate protein and gelatin be 0.5: 1, stirring at room temperature fully mixes it, and ultrasonic degas gets film forming liquid.

(4) respectively draw 5g film forming liquid and pour in the self-control organism glass ware (diameter 8cm), and in climatic chamber (22 ℃, RH=56%) drying, balance 48h, film forming, film thickness is about 85 μ m.

Through test, the index of each film such as table 2, Fig. 3 and Fig. 4, wherein, whey isolate protein represents that with W gelatin is represented with G.

The thickness of table 2 film, mechanical characteristics, aqueous ingredients, dissolubility and moisture-vapor transmission

??WPI∶gelatin(w∶w)	??100∶0	??99∶1	??75∶25	??50∶50	??25∶75	??1∶99	??0∶100
								Thickness (μ m)	??86±5	??86±5	??85±4	??86±7	??84±6	??83±8	??83±7
Pierce through intensity (N/mm)	??27.87±1.14	??27.76±1.09	??25.14±1.32	??23.87±1.74	??25.84±1.59	??26.21±1.97	??26.37±1.82
								Pierce through distortion (mm)	??5.10±0.47	??5.10±0.79	??6.19±0.31	??8.48±0.78	??9.19±1.32	??11.37±1.86	??11.54±1.78
Aqueous ingredients (%)	??35.2±1.3	??35.2±1.3	??33.7±1.2	??31.5±1.0	??30.9±1.1	??28.7±0.9	??28.7±0.9
								Dissolubility (%)	??21.3±0.9	??21.8±0.9	??25.1±1.7	??29.4±2.0	??32.1±2.4	??38.1±2.6	??38.1±2.7
Moisture-vapor transmission (g.mm.h -1.m -2.kPa -1)	??2.1±0.10	??2.1±0.19	??2.3±0.16	??2.4±0.06	??2.5±0.12	??2.7±0.21	??2.7±0.30

By table 2 as seen, after two kinds of albumen were composite, the thickness of complex film is compared with pure film did not have significant difference, pierced through intensity and reduced earlier afterwards to increase along with the increase of gelatine content, and at 50W: when 50G was composite, it was minimum to pierce through intensity; And along with the increase of gelatine content, pierce through distortion, dissolubility and the moisture-vapor transmission of film improve, and aqueous ingredients reduces.Therefore can change film strength, elasticity by the change of compound proportion, resistance is moist and dissolubility etc., and then satisfies purposes different in the virtual package.

Fig. 3 is the light transmittance of above-mentioned complex film in 200～800nm scope.In 300～800nm scope, the light transmittance of various composite films is basic identical, does not have significant difference; In 200～300nm near ultraviolet band, as shown in Figure 4, the light transmittance of each complex film is slightly different, and when the mass ratio of whey isolate protein and gelatin is 1W: during 99G, the light transmittance of film is higher than other complex films; As long as same explanation exists a certain proportion of lactalbumin, complex film just to have uvioresistant ability preferably, therefore can keep out ultraviolet ray preferably, prolong the food shelf life.

Claims (6)

1. a lactalbumin/gelatin edible compound film is characterized in that, described edible composite membrane is made lactoalbumin soln and gelatin solution mixing under the situation of adding plasticizer, and wherein, the mass ratio of lactalbumin and gelatin is 1-99: 99-1.

2. Whey protein edible single complex film according to claim 1 is characterized in that, the thickness of described edible composite membrane is 80～110 μ m.

3. Whey protein edible single complex film according to claim 1 is characterized in that, the mass percent concentration of described lactoalbumin soln is 8～10%, and the mass percent concentration of gelatin solution is 8～10%.

4. according to claim 1 or 3 described Whey protein edible single complex films, it is characterized in that described lactalbumin is a whey isolate protein.

5. the preparation method of a lactalbumin/gelatin edible compound film is characterized in that, carries out according to following control step:

(1) preparation of lactoalbumin soln: take by weighing the lactalbumin powder, add deionized water, after stirring is fully dissolved it, regulator solution pH value is 7～9,80～90 ℃ of heating 20～30min are cooled to room temperature, and the mass percent concentration of the lactoalbumin soln that makes is 8～10%;

(2) preparation of gelatin solution: take by weighing the gelatin powder, add deionized water, at room temperature heat 15～30min behind the swelling 30min in 35～60 ℃ of water-baths it is fully dissolved, solution is adjusted to pH7～9, the mass percent concentration of the gelatin solution that makes is 8～10%;

(3) lactoalbumin soln of step (1) and the gelatin solution of step (2) are mixed, wherein, the mass ratio of lactalbumin and gelatin is 1-99: 99-1, in mixed solution, add plasticizer then, mix and ultrasonic degas, obtain film forming liquid, wherein, the mass ratio of total protein is (0.3-0.5) in plasticizer and the solution: 1;

(4) film forming liquid is joined in the flat organism glass vessel, wherein, the consumption of film forming liquid is 0.08-0.1g/cm ², at 20-24 ℃, relative humidity is balance 48h at least under the condition of 54-58%, makes the edible composite membrane that thickness is 80～110 μ m.

6. the preparation method of Whey protein edible single complex film according to claim 5 is characterized in that, described plasticizer is glycerine or sorbierite.

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