Fruit coating agent and method for preparing cellulose nanofiber therefor

Abstract

An embodiment of the present invention may provide a method for preparing a cellulose nanofiber for a fruit coating agent, the method comprising: a step for adding an enzyme to refined wheat or oat cellulose and thereby performing an enzyme treatment; and a step for subjecting the enzyme-treated refined wheat or oat cellulose to high-pressure homogenization and thereby preparing a cellulose nanofiber as a coating agent for coating fruit.

Description

Fruit coating agent and method for producing cellulose nanofibers therefor

[0001] The present invention relates to a fruit coating agent and a method for producing cellulose nanofibers therefor.

[0002] Finding the right coating for foods such as fresh fruits, vegetables, cheese, bakery products, raw and cooked eggs, fresh and processed meats, and seafood products is a challenging task. Coatings applied to food must be edible and act as a barrier against moisture, gases, and / or UV rays, as well as undesirable microorganisms. Furthermore, the coating must be completely harmless to the consumer, transparent or nearly transparent in the visible range, and free of any unpleasant odors or tastes. Furthermore, edible coatings that are promising packaging materials due to one or more unique functional properties often suffer from poor water resistance (high water solubility). Extensive research and development has been devoted to simultaneously satisfying all of these criteria.

[0003] Recently, in response to modern consumer lifestyles that prioritize convenience and health, the market for cutting and packaging fresh fruit for immediate consumption has been gaining traction. However, because cut fruits and peeled strawberries, like those without skin, spoil more quickly than whole fruits, conventional coating technologies cannot be directly applied to them. This means that compared to whole fruits, cut fruits and strawberries have a higher moisture content on the cut surface and surface, are in direct contact with air, and are in an environment with a high potential for microbial growth. Therefore, coating technologies that take into account the unique characteristics of each fruit are crucial for maintaining freshness, enhancing food safety, preserving texture and flavor, improving distribution and storage efficiency, and reducing plastic use through appropriate packaging. These coating technologies, which take into account environmental impacts, are crucial. Previously, US 2016-0324174 A1, EP 0577739 A1, etc. attempted to apply carboxymethyl cellulose as a coating agent for cut fruits, but it was pointed out that it was not suitable for preserving cut fruits due to low adhesive strength and the problem of deformation of the sensory characteristics of fresh fruits, and the problem of forming an uneven coating layer was pointed out. In addition, previous US 9826750 B2, KR 2019-0110570 A, etc. proposed cellulose nanofibers for coating whole fruits, but there is a limitation that it cannot be directly applied to cut fruits, which have significantly different characteristics from whole fruits.

[0004] The present invention can provide an excellent fruit coating agent and a method for producing cellulose nanofibers therefor in terms of freshness maintenance, food stability improvement, texture and taste preservation, distribution and storage efficiency, and environmental impact.

[0005] The embodiment may provide a method for producing cellulose nanofibers for a fruit coating agent, comprising the steps of: adding an enzyme to refined wheat or oat cellulose for enzymatic treatment; and subjecting the enzyme-treated refined wheat or oat cellulose to high-pressure homogenization to produce cellulose nanofibers as a coating agent for application to fruits.

[0006] In another aspect, the enzyme includes beta-glucanase, cellulase, xylanase, and alpha-amylase, and can provide a method for producing cellulose nanofibers for a fruit coating agent by treating the enzyme reaction at 50° C. for 5 to 6 hours.

[0007] In another aspect, a method for producing cellulose nanofibers for a fruit coating agent can be provided by subjecting the enzyme-treated wheat or oat refined cellulose to high-pressure homogenization treatment in the range of 3 to 20 times.

[0008] In another aspect, a method for producing cellulose nanofibers for a fruit coating agent may be provided, comprising: a step of subjecting wheat or oat refined cellulose to high-pressure homogenization; a step of adding an enzyme to the high-pressure homogenized wheat or oat refined cellulose to perform enzyme treatment to produce cellulose nanofibers as a coating agent for application to fruits.

[0009] In another aspect, the fruit is an avocado, and the coating agent can provide a method for producing cellulose nanofibers for a fruit coating agent applied to a cut surface of the avocado.

[0010] The present invention provides a fruit coating agent that is resistant to damage caused by external force during transportation and has mechanical properties that enhance the efficiency of distribution and storage of fruits, and a method for manufacturing cellulose nanofibers therefor.

[0011] In addition, the embodiment can provide a fruit coating agent capable of preventing moisture loss and oxidation of fruit and a method for producing cellulose nanofibers therefor.

[0012] In addition, the embodiment can provide a fruit coating agent capable of maintaining the texture and taste of the fruit and a method for producing cellulose nanofibers therefor.

[0013] In addition, the embodiment can provide a fruit coating agent that increases the stability of fruit by inhibiting the growth of microorganisms and a method for producing cellulose nanofibers therefor.

[0014] Figure 1 is a flow chart of a method for manufacturing cellulose nanofibers for a fruit coating agent according to an embodiment of the present invention.

[0015] Figure 2 (a) shows an experimental image of the dispersion of sugarcane powder according to the number of HPH cycles, and (b) shows an experimental image of the dispersion of wheat bran according to the number of HPH cycles.

[0016] The results of the comparison of crystallinity by material in Fig. 3 are shown.

[0017] FIGS. 4 and 5 are flowcharts of a method for manufacturing cellulose nanofibers as a coating agent for application to fruits according to various embodiments of the present invention.

[0018] Figures 6a and 6b show a comparison of the properties and transparency of a coating agent manufactured according to an embodiment of the present invention and a control group.

[0019] Figures 7 and 8 show the primary properties of a cut avocado after applying a coating agent manufactured according to an embodiment of the present invention.

[0020] Figure 9 shows the change in relative weight according to the change in daily appearance.

[0021] Figures 10a and 10b show the daily sensory tests.

[0022] Figures 11a, 11b, 11c, and 11d show the results of daily microbial tests.

[0023] The present invention is capable of various modifications and embodiments. Therefore, specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, as well as the methods for achieving them, will become clear with reference to the embodiments described in detail below together with the drawings. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various forms. In the following embodiments, terms such as first, second, etc. are not used in a limiting sense but are used for the purpose of distinguishing one component from another. Furthermore, the singular expression includes plural expressions unless the context clearly indicates otherwise. Furthermore, terms such as "include" or "have" indicate the presence of a feature or component described in the specification, and do not preemptively exclude the possibility that one or more other features or components may be added. Furthermore, in the drawings, the sizes of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to what is shown.

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the drawings, identical or corresponding components are given the same reference numerals and redundant descriptions thereof will be omitted.

[0025] Figure 1 is a flowchart of a method for manufacturing cellulose nanofibers for a fruit coating agent according to an embodiment of the present invention. Furthermore, Figure 2 (a) shows experimental images of the dispersion of sugarcane powder according to the number of HPH cycles, and Figure 2 (b) shows experimental images of the dispersion of wheat bran according to the number of HPH cycles. Furthermore, Figure 3 illustrates the results of a comparison of crystallinity by material.

[0026] Referring to FIG. 1, a method for manufacturing cellulose nanofibers for a fruit coating agent according to an embodiment of the present invention (S100) may include a step of performing enzyme treatment by adding an enzyme to wheat or oat purified cellulose (S110) and a step of manufacturing cellulose nanofibers as a coating agent to be applied to fruits by performing high-pressure homogenization treatment on the enzyme-treated wheat or oat purified cellulose (S120).

[0027] The term "fruit" herein refers to a fruit cut from a raw fruit with a peel for easy consumption. However, this is not a limitation, and the coating agent according to an embodiment of the present invention can also be applied to fruits without peel, such as strawberries.

[0028] - Cellulose raw material

[0029] The cellulose raw material can be either a raw or refined cellulose raw material. The raw cellulose raw material can be any one of the following, but is not limited to: burdock root bark, tangerine peel, agar, kelp, seaweed, bamboo leaves, buckwheat, sorghum, wheat bran, rice bran, and rice husk. The refined cellulose raw material can be any one of the following, but is not limited to: commercially available sugarcane (SCF30), sugarcane (SCF500), bamboo (BF30), bamboo (BF500), wheat (WF200), wheat (WF600), and broadleaf trees (HF600-30).

[0030] - Crystallinity and transparency

[0031] The smaller the particle size of the cellulose raw material, the more advantageous it may be for forming a coating film.

[0032] The raw materials for the coating film can be selected based on the XRD crystallinity of the multiple cellulose raw materials.

[0033] XRD crystallinity (X-ray Diffraction Crystallinity) is a method used to measure the crystallinity of a material. XRD, or X-ray diffraction, is a technique for examining the crystal structure within a material. By analyzing the diffraction pattern that occurs when X-rays are irradiated on a sample, the crystal structure and state of the material can be determined. Crystallinity is an indicator of how well a material is crystallized, that is, how regular and repetitive its structure is. The higher the crystallinity of a material, the more ordered and regular its structure is.

[0034] There is a significant correlation between XRD crystallinity and particle size. Generally, crystallinity increases as particle size increases. Larger particles contain more atoms, and these atoms are more likely to form a more ordered and well-defined crystal structure, which can manifest as clearer and more defined diffraction peaks in XRD analysis.

[0035] When analyzing the XRD crystallinity (%) of several cellulose raw materials, it was shown as sugarcane 57.7 (%), bamboo leaves 34.1, wheat 56.0, buckwheat 29.2, sesame seed coat 32.0, sorghum 32.1, tangerine peel 19.5, wheat bran 19.1, rice bran 19.8, kelp 57.9, and rice hull 26.8, and wheat bran, rice bran, tangerine peel, and rice hull were confirmed to be raw materials with low crystallinity (Segal method). In addition, the degree of dispersion increased as the number of high-pressure homogenization (HPH) treatments increased.

[0036] As can be seen from the comparative results of dispersion by number of HPH treatments in Fig. 2, unrefined raw materials have transparency issues due to color, etc. compared to refined raw materials. Therefore, considering appropriate transparency and low crystallinity, refined cellulose raw materials such as oats, wheat, and bamboo can be preferred cellulose raw material candidates applied in the method for manufacturing cellulose nanofibers for fruit coating according to the embodiment.

[0037] In addition, as can be seen from the results of the comparison of crystallinity by material in Fig. 3, wheat or oat refined cellulose raw materials having lower crystallinity than sugarcane powder (SCF30) can be a desirable cellulose raw material candidate applied in the method for manufacturing cellulose nanofibers for fruit coating according to the embodiment.

[0038] SCF30 (particle size: 40 um, substrate: sugarcane, crystallinity (%) 56)

[0039] SCF500 (particle size: 500 μm, substrate: sugarcane, crystallinity (%) 66)

[0040] BF30 (particle size: 40 um, substrate: bamboo, crystallinity (%) 60)

[0041] BF500 (particle size: 500 μm, substrate: bamboo, crystallinity (%) 63)

[0042] WF200 (particle size: 250 um, substrate: bamboo, crystallinity (%) 63)

[0043] WF600 (particle size: 80 um, substrate: wheat, crystallinity (%) 67)

[0044] HF600-30 (particle size: 35 um, substrate: oat, crystallinity (%) 50)

[0045] BPWC-P (particle size: 30~50um, substrate: broadleaf wood, crystallinity (%) 82)

[0046] - Nozzle clogging problem during ultra-high pressure dispersion treatment

[0047] As the number of HPH treatments increases, the qualitative characteristics of the film, such as transparency and thickness, can be improved. Furthermore, film formation can be achieved even with highly crystalline sugarcane pulp (70%). This suggests that the difficulty in film formation is due more to aggregation than to the crystallinity of the raw material. Therefore, securing sufficient HPH treatments is crucial to resolving film formation failures.

[0048] However, nozzle clogging during HPH (High Pressure Dispersion) processing, or high-pressure homogenization, is a major operational issue for high-pressure homogenizers. During this process, the mixture to be treated passes through the nozzle under extremely high pressure, and issues such as particle size, concentration, and viscosity can cause nozzle clogging.

[0049] When HPH treatment was performed on oat refined cellulose raw material, only a very slight nozzle clogging symptom occurred once in one treatment. However, in the case of sugarcane refined cellulose raw material, nozzle clogging occurred even after five treatments, and pressure control became difficult, making HPH treatment impossible. Therefore, considering HPH treatment, oat refined cellulose raw material rather than sugarcane is a suitable cellulose raw material applied in the method for manufacturing cellulose nanofibers for fruit coating according to the embodiment.

[0050] -Step of enzymatic treatment by adding enzyme to wheat or oat refined cellulose (S110)

[0051] In the step (S110) of adding an enzyme to refined wheat or oat cellulose and performing enzyme treatment, the enzyme applied may be beta-glucanase, cellulase, xylanase, or alpha-amylase. Products containing the above enzymes include Viscozyme Wheat FG and Viscoflow MG. In addition, the enzyme applied in step S110 includes Laminex Super 3G. LAMINEX Super 3G is an enzyme complex that hydrolyzes beta-glucan, pentosan, and related carbohydrates. LAMINEX Super 3G is produced through fermentation using selected strains of Trichoderma reesei and Penicillum funiculosum.

[0052] The manufactured products Viscozyme Wheat FG, Viscoflow MG, and Laminex Super 3G are mixed in a ratio of 1:1:1 and mixed with wheat or oat refined cellulose, and enzyme-treated at 50°C for 5 hours or within a range of 5 to 6 hours to obtain enzyme-treated wheat or oat refined cellulose.

[0053] - A step (S120) of manufacturing cellulose nanofibers as a coating film for application to fruits by high-pressure homogenizing enzyme-treated wheat or oat refined cellulose.

[0054] Enzyme-treated wheat or oat refined cellulose can be decomposed into nanofibers by HPH treatment within a range of 3 to 20 times, thereby producing cellulose nanofibers as a coating film for application to fruits.

[0055] FIGS. 4 and 5 are flowcharts of a method for manufacturing cellulose nanofibers as a coating agent for application to fruits according to various embodiments of the present invention.

[0056] Referring to FIG. 4, a method for manufacturing cellulose nanofibers as a coating agent to be applied to fruits according to various embodiments of the present invention (S200), a step of homogenizing wheat or oat purified cellulose (S210), a step of enzymatically treating wheat or oat purified cellulose (S220), and a step of ultra-high pressure dispersion treatment of the enzyme-treated wheat or oat purified cellulose (S230) may be included. Referring to FIG. 5, a method for manufacturing cellulose nanofibers as a coating agent to be applied to fruits according to various embodiments of the present invention (S300) may be included, a step of homogenizing wheat or oat purified cellulose (S210), a step of ultra-high pressure dispersion treatment of wheat or oat purified cellulose (S220), and a step of enzymatically treating wheat or oat purified cellulose (S230). In the step of homogenizing wheat or oat refined cellulose (S210, S310), the wheat or oat refined cellulose can be homogenized at 8,000 rpm for 10 minutes using a homogenizer.

[0057] The coating prepared as described above can be applied to fruit. The coating can be applied to the cut surface or to the surface of fruit, such as peelless strawberries. The fruit coated with the coating can be dried under specific conditions.

[0058] -Daily appearance

[0059] Figures 6a and 6b show a comparison of the properties and transparency of a coating agent manufactured according to an embodiment of the present invention and a control group. Furthermore, Figures 7 and 8 show the properties of a coating agent manufactured according to an embodiment of the present invention applied to cut avocados.

[0060] As a result of comparing the properties and transparency of films manufactured with Wheat (WF-600) HPH 20P times, Oat (HF600-30) HPH 20 times, and CNF, Refined CNF (RE-CNF), and Enzymatic CNF (EN-CNF) of M Company (Moby Dick New Materials Co.), and films manufactured with Sugarcane Pulp HPH 20 times, it can be seen that while Sugarcane Pulp shows good transparency, it has the problem of nozzle clogging due to the HPH treatment mentioned above, whereas the coating agent according to the Example shows significantly better transparency than the control group.

[0061] In addition, as a result of examining the daily appearance changes of avocados, as shown in Fig. 7, the control group showed a rapid darkening of color and a strong drying phenomenon from the first day, but the groups treated with each cellulose nanofiber showed a relatively mild drying phenomenon in general. In addition, it was confirmed that the surface color darkened and the surface drying phenomenon due to the drying phenomenon of the circle and surface continued until the 5th day, and there was almost no change in the appearance of the circle after the 5th day. In addition, the drying phenomenon was confirmed to be somewhat slower in pea, bamboo-derived cellulose nanofiber, wheat 20P (HPH treated 20 times), and oat 20P from Company M (Mobic, Mobidic New Materials Co.), and in particular, as shown in Fig. 8, it can be seen that wheat 20P has a good ability to maintain the color of the circle similar to that of day 0 even on the 7th day.

[0062] - Change in relative weight

[0063] Figure 9 shows the change in relative weight according to the change in daily appearance.

[0064] Referring to Figure 9, according to the relative weight change according to the change in the properties of the avocado, the control group that did not apply anything showed a large amount of moisture evaporation on the first day, whereas all groups that applied cellulose nanofibers confirmed a relatively low moisture evaporation rate. Among them, it can be seen that the wheat 20P, oat 20P, and sugarcane 20P groups maintained weight at a slightly higher value, and in particular, it can be confirmed that wheat 20P had the best weight retention ability.

[0065] - Daily sensory test

[0066] Figures 10a and 10b show the daily sensory tests.

[0067] Referring to Figures 10a and 10b, the moisture and softness of the control group and each group coated with cellulose nanofibers were checked daily. As a result, it can be confirmed that on the first day, although there are differences in all groups, it feels like the moisture and softness have decreased by 40% to 50% or more. After the first day, it can be confirmed that both moisture and softness have decreased by a very slight difference. In addition, it can be seen that the preference scores are relatively high in the order of Wheat 20P, Oat 20P, and M group, and Wheat 20P in particular is at the top.

[0068] - Daily microbiological testing

[0069] Figures 11a, 11b, 11c, and 11d show the results of daily microbial tests.

[0070] Referring to Figs. 11a, 11b, 11c, and 11d, the results of checking the microorganisms in the avocado multi-group and treatment groups by day showed good detection values ​​for general bacteria and coliform bacteria until the second day, and it can be confirmed that general bacteria were detected on the fourth day. In addition, as can be seen from the results of 'ㄱ, ㄷ', in the results of the fourth day, the microorganisms were detected somewhat lower in the wheat 20P, M, and oat 20P groups than in the other groups, and particularly low values ​​were detected in the wheat 20P group and oat 20P group. On the other hand, as in 'ㄴ', it can be confirmed that coliform bacteria were not detected until the fourth day, and judging from the overall results of the microorganism test, the results showed low values ​​overall in oats or wheat cellulose, so the lowest value could be confirmed in oats, especially wheat cellulose.

[0071] Although the detailed description of the present invention has been described with reference to preferred embodiments of the present invention, it will be understood by those skilled in the art or having ordinary knowledge in the art that various modifications and changes can be made to the present invention without departing from the spirit and technical scope of the present invention as set forth in the claims below. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

[0072] The present invention relates to a fruit coating agent and a method for producing cellulose nanofibers therefor, and has industrial applicability.

Claims

1. A step of enzymatic treatment by adding enzymes to refined wheat or oat cellulose; A step of producing cellulose nanofibers as a coating agent for application to fruits by high-pressure homogenizing enzyme-treated wheat or oat refined cellulose; comprising; Method for producing cellulose nanofibers for fruit coating.

2. In paragraph 1, The enzymes include beta-glucanase, cellulase, xylanase, and alpha-amylase. Method for producing cellulose nanofibers for fruit coating.

3. In paragraph 2, Enzyme reaction treatment at 50℃ for 5 to 6 hours Method for producing cellulose nanofibers for fruit coating.

4. In paragraph 1, The above enzyme-treated wheat or oat refined cellulose is subjected to high-pressure homogenization 3 to 20 times. Method for producing cellulose nanofibers for fruit coating.

5. Step of high-pressure homogenization of wheat or oat refined cellulose; A step of producing cellulose nanofibers as a coating agent for application to fruits by adding enzymes to high-pressure homogenized wheat or oat refined cellulose and performing enzyme treatment; comprising; Method for producing cellulose nanofibers for fruit coating.

6. In clause 1 or clause 5, the fruit is an avocado. Method for producing cellulose nanofibers for fruit coating.

7. In paragraph 6, The above coating agent is applied to the cut surface of the avocado. Method for producing cellulose nanofibers for fruit coating.

Images