Brewer's grain composite film for food packaging and preparation method of brewer's grain composite film
By preparing beer grains composite film, the problem of difficult degradation of petroleum-based polymer packaging materials is solved, resource recycling and environmental protection are achieved, and high-performance degradable food packaging materials are provided.
Patent Information
- Application Number
- CN202410480289.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-22
- Publication Date
- 2025-10-24
AI Technical Summary
Existing food packaging materials are mainly petroleum-based polymers, which are difficult to degrade, leading to serious plastic pollution problems and the lack of effective utilization of brewer's grains resources.
Using beer grains and biodegradable polyvinyl alcohol as the matrix, a food packaging film with strong mechanical properties, high barrier properties and good preservation performance is prepared through freeze drying, grinding, mixing, centrifugation and vacuum drying.
It realizes the resource recycling of brewer's grains, provides biodegradable food packaging materials, solves the problems of resource waste and environmental pollution, and has good mechanical properties and preservation properties.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a preparation method of a beer dreg composite film for food packaging and belongs to the field of biodegradable food film processing. BACKGROUND
[0002] The beer dreg is a solid residue in the beer production process and is composed of barley husks and seed coats, accounting for 85% of total by-products. About 2 kg of beer dregs are produced for every 100 liters of beer, and the ingredients include water (75-80%), cellulose (15-25%), hemicellulose (20-40%) and the like. Due to high water content and rich nutrition, the beer dregs are prone to corruption, have high transportation cost and are often sold at a low price as animal feed or organic fertilizer. Part of the beer dregs is used for biological refining or biogas production, but the beer dregs that are not properly treated or deteriorated can only be landfilled, wasting resources and affecting the environment.
[0003] At present, most of the packaging materials are petroleum-based polymers such as polyethylene and polypropylene, which have good performance but cannot be degraded and recycled. With the aggravation of plastic pollution, it is urgent to find natural and degradable alternative materials. The cellulose and hemicellulose in the beer dregs have excellent properties and are suitable for being used as film materials. The beer dregs are prepared into a composite film, which can be used as a biodegradable food packaging material and realizes resource recycling.
[0004] Therefore, the beer dregs are used to prepare a biodegradable packaging material, which not only solves the problem of resource waste, improves the utilization value, but also provides a new choice for the environmental protection industry, and has far-reaching significance. SUMMARY
[0005] The application aims to prepare a beer dreg composite film for food packaging, which is prepared by taking beer dregs and a biodegradable polymer polyvinyl alcohol as a matrix, and has strong mechanical properties, high barrier property, good fresh-keeping performance and biodegradability.
[0006] To achieve the above-mentioned purpose, the application provides the following technical scheme: a preparation method of a beer dreg composite film for food packaging, comprising the following steps:
[0007] (1) drying fresh beer dregs through a freeze dryer;
[0008] (2) grinding the dried beer dregs into powder through a grinder, screening, sealing and storing for standby use;
[0009] (3) adding an adhesive and water and accelerating the mixing by microwave treatment;
[0010] (4) removing air bubbles in the mixture by centrifugal homogenization;
[0011] (5) pouring the mixture into a mold for molding, drying in a vacuum drying oven and demolding to obtain the product.
[0012] Further, in step (1), the fresh brewer's grains were dried in a freeze dryer for 72h.
[0013] Further, in step (2), the dried brewer's grains were ground and sieved through a 200 mesh sieve to obtain particles of 74um in size.
[0014] Further, in step (3), the dried brewer's grains were mixed with a binder in a ratio of 4:6, wherein the binder was a mixture of polyvinyl alcohol (PVA) and glycerol (Gl) in a ratio of 2:1, and water was added to the mixture in a ratio of 1:5.
[0015] Further, in step (4), the centrifuge was set to a speed of 3000rpm for 3min.
[0016] Further, in step (5), the vacuum drying oven was set to a temperature of 45°C for 3h. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 Flow chart for the preparation of the brewer's grains composite film;
[0018] Figure 2 Sample image of fresh brewer's grains;
[0019] Figure 3 Sample image of dried brewer's grains;
[0020] Figure 4 Sample image of brewer's grains powder;
[0021] Figure 5 Sample image of the brewer's grains composite film at different concentrations;
[0022] Figure 6 Microscopic image of the surface of the brewer's grains composite film at different concentrations;
[0023] Figure 7 Thickness measurement of the brewer's grains composite film at different concentrations;
[0024] Figure 8 Transmittance measurement of the brewer's grains composite film at different concentrations
[0025] Figure 9 Luminance measurement of the brewer's grains composite film at different concentrations;
[0026] Figure 10 Red-green color measurement of the brewer's grains composite film at different concentrations;
[0027] Figure 11 Yellow-blue color measurement of the brewer's grains composite film at different concentrations;
[0028] Figure 12 The maximum tensile force at break of the beer dreg composite film was measured for different concentrations of beer dregs;
[0029] Figure 13 The maximum tensile length at break of the beer dreg composite film was measured for different concentrations of beer dregs. DETAILED DESCRIPTION
[0030] The method of the present application is described in detail below with reference to specific examples. This detailed description should not be considered limiting of the present application, but rather as a description of certain aspects, features, and embodiments of the present application. The beer dregs used in the present application were obtained from Chongqing Jiawei Beer Co., Ltd., and the polyvinyl alcohol (PVA) and glycerol (Gl) were both purchased.
[0031] Fresh beer dregs were placed in a freeze dryer and dried for 72 h.
[0032] The dried beer dregs were ground into powder using a grinder, passed through a 200-mesh sieve, sealed, and stored for later use.
[0033] In a beaker, 50 ml of deionized water was added and heated to 90°C. Then, 4 g of polyvinyl alcohol (PVA) was added and stirred until completely dissolved using a magnetic stirrer.
[0034] In the above mixture, 2 ml of glycerol (Gl) was added, and the temperature was maintained at 80°C while stirring for 10 min.
[0035] In the above mixture, 4 g of beer dreg powder was added and thoroughly mixed by stirring. Then, the mixture was heated using a microwave oven, with each heating lasting 10 s, after which the mixture was removed and stirred. This process was repeated 6 times to thoroughly mix and promote gelation.
[0036] The above mixture was poured into a 50-ml centrifuge tube and centrifuged at a speed of 3000 rpm for 3 min.
[0037] The mixture after centrifugation was poured into a polytetrafluoroethylene round mold with a diameter of 50 mm and a depth of 1.5 mm, and the excess was removed using a scraper.
[0038] The mold was placed in a vacuum drying oven at a temperature of 45°C and dried for 3 h. After drying, the product was automatically demolded.
[0039] To explore the optimal addition amount of beer dregs in the beer dreg composite film, eight groups of comparisons were set from the blank control to 80% beer dreg concentration. Through comparative analysis, it was found that the composite film with 40% beer dreg concentration performed best in terms of comprehensive performance, and therefore this concentration was selected as the optimal addition amount of beer dregs in the beer dreg composite film.
[0040] The center thickness of the beer lees composite film product is 0.41 mm, and the edge thickness is 0.39 mm, showing uniform thickness distribution. Through 200 times microscopic observation, the surface morphology and structural characteristics of the film can be clearly analyzed. The colorimeter measurement results show the color characteristics of the product, providing an important basis for quality control. Using the ultraviolet spectrophotometer, the light transmittance data of the product at different wavelengths are obtained through formula conversion, providing key indicators for evaluating its optical performance.
[0041] In terms of mechanical property testing, the maximum tensile force and maximum tensile length of the beer lees composite film at break were determined by a universal testing machine. The sample was processed into a long rectangular strip with a length of 40 mm and a width of 10 mm, with a middle test spacing of 20 mm and a tensile speed of 50 mm / min. These data are of great significance for evaluating the mechanical properties of the product and its durability in actual application.
[0042] In summary, the beer lees composite film product has uniform thickness, specific color characteristics and good optical performance, and the mechanical property test results also show that it has good durability. These characteristics make the beer lees composite film have broad application prospects in the field of packaging materials.
[0043] Remarks:
[0044] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and they should be included in the scope of the claims of the present application.
Claims
1. A method for making a beer spent grain composite film for food packaging, characterized in that, The method comprises the following steps: (1) drying fresh beer lees in a freeze dryer; (2) grinding the dried beer lees into powder, sieving, sealing and storing for use; (3) adding a binder and water and accelerating mixing by microwave treatment; (4) removing bubbles in the mixture by centrifugal homogenization; (5) pouring the mixture into a mold, drying in a vacuum drying oven and demolding to obtain the product.
2. The method of claim 1, wherein the beer lees composite film is produced by the steps of: In step (1), the fresh beer lees are dried in the freeze dryer for 72 hours.
3. The method of claim 1, wherein the beer lees composite film is produced by the steps of: In step (2), after the beer lees are ground, they are sieved through a 200-mesh sieve, and the particle size is 74 um.
4. The method of claim 1, wherein the beer lees composite film is produced by the steps of: In step (3), the mixing ratio of the beer lees powder and the binder is 4:6, the mixing ratio of the binder polyvinyl alcohol (PVA) and glycerol (Gl) is 2:1, and water is added for mixing, with a solid-liquid ratio of 1:
5.
5. The method of claim 1, wherein the beer lees composite film is produced by the steps of: In step (4), the parameters of the centrifuge are set as follows: rotation speed, 3000 rpm; and time, 3 min.
6. The method of claim 1, wherein the beer lees composite film is formed by the steps of: In step (5), the parameters of the vacuum drying oven are set as follows: temperature, 45 DEG C; and time, 3 h.