A method for accelerating aging of ebonite based on specific microwave field treatment

Abstract

The application relates to the technical field of aquatic product processing, in particular to a method for accelerating the aging of fish skin based on specific microwave field treatment. A microwave source with a specific frequency is used to irradiate the fish skin under the condition of strictly controlled low temperature and in a specific time sequence mode, so that the natural aging process of the fish skin is simulated and accelerated safely and effectively. The method can shorten the aging period of the fish skin significantly and maintain or even improve the final quality of the fish skin, and solves the problems of the prior art.

Description

Technical Field

[0001] This invention relates to the field of aquatic product processing technology, specifically to a method for accelerating the aging of fish maw based on specific microwave field treatment. Background Technology

[0002] Fish maw, the dried swim bladder of fish, is rich in collagen and various trace elements. It is believed to nourish the kidneys and replenish essence, as well as nourish yin and improve complexion. Often used in soups, it is a traditional and prized tonic ingredient in my country. Traditional experience indicates that properly aged fish maw has a reduced fishy smell, better texture, and improved tonic effects. However, traditional aging relies mainly on natural storage, which takes 3-5 years or even longer, and is prone to mold and insect infestation, resulting in inconsistent quality. This method has the following inherent drawbacks:

[0003] The process is extremely lengthy, requiring significant capital and storage space, and incurring high costs.

[0004] Uncontrollable quality: It is greatly affected by environmental temperature and humidity, and is prone to mold, insect infestation or rot, which leads to a decline in quality or even scrap.

[0005] Inefficiency: It cannot meet market demand and restricts the large-scale development of the industry.

[0006] Currently, while some technologies attempt to accelerate food aging (such as alcoholic beverages and vinegar), for example, Chinese patent CN115944104A describes an intelligent rice noodle aging device and its aging process. This device sequentially transports rice noodles to independent, sealed constant-temperature and humidity low-temperature aging chambers, medium-temperature aging chambers, high-temperature aging chambers, re-steaming chambers, and secondary medium-temperature aging chambers for sequential aging. By setting parameters such as the aging environment temperature, humidity, and transit time of the rice noodles within each aging chamber, it addresses the problems of discontinuous aging processes, low yields, and significant energy waste in existing rice noodle production. Chinese patent CN114886086A discloses a fermented soybean protein food and its preparation method, which uses fermentation for aging. However, effective methods for applying this to dried aquatic products rich in collagen, such as fish maw, are rarely reported.

[0007] Conventional microwave technology is mainly used for the rapid heating, drying, or sterilization of food. In the field of fish maw processing, microwave technology is currently mainly used for physical processing such as drying and puffing, as well as for the auxiliary extraction of fish skin gelatin. If applied directly to fish maw, the excessively high temperature (far exceeding 70°C) would cause severe protein denaturation and charring, destroying its gelatinous and nutritional components, completely failing to achieve the goal of "simulating natural aging and improving quality." Therefore, there is an urgent need in this field for an efficient and controllable microwave processing method to accelerate the aging of fish maw while ensuring quality. Summary of the Invention

[0008] The technical problem this invention aims to solve is that conventional microwave technology is mainly used for the rapid heating, drying or sterilization of food. If applied directly to fish maw, the excessively high temperature (far exceeding 70°C) will cause severe denaturation and charring of the protein, destroying its gelatinous and nutritional components, making it impossible to achieve the goal of "simulating natural aging and improving quality".

[0009] To address the problems of existing technologies, this invention provides a method for accelerating the aging of fish maw based on specific microwave field treatment. By using a microwave source of a specific frequency and irradiating the fish maw under strictly controlled low temperature conditions in a specific time sequence, the natural aging process can be safely and effectively simulated and accelerated. This method provides a way to significantly shorten the aging cycle of fish maw and maintain or even improve its final quality, thus overcoming the shortcomings of existing technologies.

[0010] To achieve the above objectives, this invention utilizes the following technical solution: a method for accelerating the aging of fish maw based on specific microwave field treatment. The dried fish maw is placed in a 433MHz microwave field for irradiation treatment, with the temperature of the fish maw material controlled to not exceed 70℃ throughout the entire treatment process. Microwave treatment can effectively disrupt the covalent cross-linking and triple helix structure of collagen, promoting moderate degradation of collagen. The 433MHz microwave wavelength is relatively long, with a penetration depth far exceeding that of the conventional 2450MHz, enabling uniform heating across the entire thickness of the fish maw and avoiding the problem of surface overheating while the internal temperature remains low. Furthermore, 433MHz equipment is mature, cost-effective, and suitable for industrial applications. Moreover, the 433MHz microwave generates a volumetric thermal effect within the fish maw through both dipole polarization and ion conduction mechanisms, causing the fish maw to heat up uniformly from the inside out. This thermal effect accelerates the physical and chemical aging of collagen in the fish maw, thereby achieving the effect of traditional long-term natural aging in a shorter time. The temperature should not exceed 70℃ to prevent excessive heat from denaturing the fish maw's proteins and damaging its gelatinous and nutritional components. During microwave processing, fiber optic temperature sensors are placed at five points on the fish maw: upper left, upper right, center, lower left, and lower right. These sensors monitor the overall microwave processing temperature in real time, ensuring that each point remains below 70 degrees Celsius. If any point exceeds 70 degrees Celsius, the microwave power is immediately reduced.

[0011] Furthermore, the microwave source is a solid-state microwave source to ensure frequency stability and precise power control.

[0012] Furthermore, the irradiation treatment is an intermittent process. First, a microwave irradiation is performed with a power of 2-4 kW, a duration of 1 min 20 s to 1 min 40 s, and a temperature of 55-58℃. The fish maw is then removed, allowed to cool naturally at room temperature, and stored for half a day to 30 days to allow the internal substances of the fish maw to fully transform and reach equilibrium. The equilibrium is determined by a change in texture hardness of less than 5% or a change in moisture content of less than 0.5%. Once equilibrium is reached, the next irradiation treatment can be performed. Subsequently, the next microwave irradiation is performed with the same parameters as the first microwave irradiation. This process is repeated for 2-12 cycles.

[0013] Furthermore, the irradiation treatment method is a long-term pulsed treatment, using continuous pulsed microwaves to irradiate the fish maw at a power of 200W-4kW, a duration of 1-300s, and an interval of 1-5 hours for repetition; the total duration of the entire continuous treatment cycle is 0.5-5 days. This treatment allows the fish maw sufficient time to complete its aging process; fish maw itself has a dense texture and low moisture content, resulting in a slow aging rate, requiring ample time to complete the aging process. Adding continuous pulsed microwaves can accelerate the aging process of fish maw, but it still requires sufficient time; therefore, continuous, intermittent pulsed microwaves are more beneficial for the aging of fish maw.

[0014] The beneficial effects of this invention are as follows:

[0015] (1) Revolutionary improvement in efficiency: shortening the natural aging cycle of several years to several days or weeks greatly improves production efficiency.

[0016] (2) Excellent and controllable quality: By controlling the temperature to not exceed 70℃, the protein and other nutrients in the fish maw are not destroyed, and the final product can be comparable to or even better than traditional aged fish maw in terms of taste, flavor and expansion rate.

[0017] (3) The effect is scientifically verifiable: The fish maw treated by the method of this invention has significant differences in molecular structure (such as protein secondary structure and crystallinity) compared with untreated fish maw through Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis, proving that the method does indeed induce essential changes similar to natural aging.

[0018] (4) Stable and reliable process: 433MHz low-frequency microwave is used, which has strong penetration and uniform heating, avoiding local overheating; the solid-state microwave source is stable and suitable for industrial production. Attached Figure Description

[0019] Figure 1 It is the result of Fourier transform infrared spectroscopy. Detailed Implementation

[0020] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0021] The following embodiments can be understood as illustrating only a part of the structure or method of the present invention, or as a combination of embodiments explaining the broader structure or method of the present invention. Unless otherwise specified, all raw materials of the present invention are commercially available.

[0022] In the following embodiments, the device uses a 433MHz industrial solid-state microwave generator and is equipped with a fiber optic temperature measuring instrument to monitor the material temperature in real time.

[0023] Example 1:

[0024] 150 g of fish maw (moisture content 14.1%, thickness 4 mm, origin: Xiamen, Fujian) that was free from insect infestation, odor, and spoilage was selected. Surface impurities were removed, and the maw was packaged in a retort pouch and placed in a 433 MHz microwave oven. The microwave power was set to 3 kW, the processing temperature to 56 °C, and the processing time to 1 min 30 s. After processing, the fish maw was removed and stored at room temperature for 48 h. A second microwave treatment was then performed with the parameters remaining unchanged. After this second treatment, the moisture content decreased from 14.1% to 12.8%, and this sample was designated as high-power microwave-treated fish maw sample (number MW-1).

[0025] like Figure 1 Fourier transform infrared spectroscopy (FT-IR) results showed that, compared with the untreated raw sample, the Amide A band of MW-1 shifted from 3285.26 cm⁻¹ to 3293.06 cm⁻¹, indicating a weakening of hydrogen bond strength; the Amide B band intensity increased and a small peak appeared; the peak shapes and intensities of Amide I, II, and III bands were all enhanced, indicating that the secondary structure of fish maw collagen changed from an ordered triple helix to a disordered random coil, which is a significant manifestation of collagen aging. As shown in Table 1, the X-ray diffraction (XRD) results showed that the total peak area of ​​MW-1 was smaller than that of the raw sample. Based on the conclusion in the literature that "the older the swim bladder, the smaller the peak area," this treatment method effectively accelerated the aging of fish maw. In summary, high-power microwave treatment (3 kW, 56 °C, two treatments) yielded the best aging effect for fish maw and is suitable for large-scale online aging treatment of fish maw.

[0026] Table 1: X-ray diffraction results

[0027] MW-1 1378.03 3152.16 4530.19 MW-2 1006.74 3695.87 4702.61 raw 1172.51 5112.65 6285.16

[0028] Example 2:

[0029] 150 g of Jinlongyu fish maw (moisture content 13.9%, thickness 4 mm, origin: Xiamen, Fujian) that was free from insects, odor, and spoilage was selected. Surface impurities were removed, and the maw was packaged in a retort bag and placed in a 433 MHz microwave device. The microwave power was set to 300 W, the processing temperature to 52 °C, and the processing time to 300 s. After a 5-hour interval, the microwave treatment was repeated for a total of 10 times. The moisture content decreased from 13.9% to 10.2%. After the treatment, the maw was stored at room temperature and recorded as the low-power microwave fish maw sample (number MW-2).

[0030] like Figure 1 Fourier transform infrared spectroscopy (FT-IR) results showed that, compared with the untreated raw sample, the Amide A band of MW-2 shifted from 3285.26 cm⁻¹ to 3291.07 cm⁻¹, the intensity of the Amide B band increased, and the peak shapes and intensities of Amide I, II, and III bands were all enhanced. This indicates that the secondary structure of fish maw collagen has transformed from an ordered triple helix to a disordered random coil, which is a significant manifestation of collagen aging. As shown in Table 1, the X-ray diffraction (XRD) results showed that the peak area of ​​MW-2 was smaller than that of the raw sample. Based on the conclusion in the literature that "the older the swim bladder, the smaller the peak area," this treatment method accelerates the aging of fish maw. After soaking, the treated group of fish maw had a soft and glutinous texture, rich collagen, and mellow flavor, comparable to the quality of fish maw naturally aged for 3 years. In conclusion, low-power microwave intermittent multiple treatments (300 W, 52 °C, 10 treatments) showed superior aging effects and are suitable for storing fish maw in a microwave-controlled warehouse.

[0031] Comparative Example 1: (High-frequency microwave comparison):

[0032] The same fish maw was processed using a standard 2450MHz microwave oven. Even with very careful control, the fish maw still suffered from localized overheating and charring on the surface due to excessively rapid heating and insufficient penetration, while the interior remained unprocessed, resulting in severely compromised quality.

[0033] Comparative Example 2: (High Temperature Comparison):

[0034] The present invention uses a 433MHz microwave source, but the fish maw is treated at 85℃ for 30 minutes. After treatment, the fish maw becomes hard, the expansion rate decreases significantly, the collagen denatures, and it loses its original quality.

[0035] Conclusion: The comparative examples demonstrate that the selection of a 433MHz frequency and a temperature range not exceeding 70°C in this invention are crucial, non-obvious technical features, and their technical effects are unexpected.

[0036] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0037] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0038] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A method for accelerating the aging of fish maw based on specific microwave field treatment, characterized in that: The dried fish maw was irradiated in a 433MHz microwave field, and the temperature of the fish maw material was controlled not to exceed 70℃ throughout the entire treatment process.

2. The method as described in claim 1, characterized in that: The microwave source is a solid-state microwave source.

3. The method as described in claim 1 or 2, characterized in that: The irradiation treatment is an intermittent process. First, microwave irradiation is performed with a power of 2-4 kW, a duration of 1 min 20 s to 1 min 40 s, and a temperature of 55-58℃. The fish maw is then removed, allowed to cool naturally at room temperature, and stored for half a day to 30 days. Then, microwave irradiation is performed again with the same parameters as the first irradiation. This process is repeated for 2-12 cycles.

4. The method as described in claim 1 or 2, characterized in that: The irradiation treatment method is a long-term pulsed treatment, which uses continuous pulsed microwaves to irradiate the fish maw. The power is 200W-4kW, the time is 1-300s, the interval is 1-5h, and the total duration of the entire continuous treatment cycle is 0.5-5 days.

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