Method for preserving waxberries through ethanol and water alternate ultrasonic atomization
By alternating ultrasonic atomization treatment of bayberries with ethanol and water, the problems of single preservation effect and chemical residue in existing technologies are solved. A dynamic balance of water retention, color protection and antibacterial properties is achieved, which extends the storage period of bayberries and maintains fruit quality.
Patent Information
- Application Number
- CN202510995456.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-18
- Publication Date
- 2025-10-28
AI Technical Summary
Existing bayberry preservation technologies are unable to achieve synergistic regulation of multiple factors such as water retention, color protection, and antibacterial properties, and there are risks of chemical residues and damage to fruit quality. In particular, high humidity environments can easily induce mold growth, affecting the storage period and market competitiveness of the fruit.
The bayberry was treated with alternating ultrasonic atomization of ethanol and water. The ultrasonic atomization system generated ethanol mist and water mist with a particle size ≤10μm, which were sprayed alternately on the surface of the fruit to achieve dynamic balance control of water retention, color protection and antibacterial properties, and avoid the risk of mold caused by excessive humidity.
It effectively inhibits the growth of mold and yeast, slows down fruit dehydration, maintains fruit firmness and color, extends storage period, and has no chemical residues, making it suitable for green food preservation.
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Figure CN120836595A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preserving bayberries using alternating ultrasonic atomization of ethanol and water, belonging to the field of agricultural product preservation technology. Background Technology
[0002] The Chinese bayberry (Myrica rubra Seib & Zucc.) is a typical high-sugar, high-moisture berry, exhibiting a pronounced climacteric respiration pattern upon ripening. Furthermore, lacking a natural waxy outer skin and with a soft flesh texture, the fruit is susceptible to mechanical damage and microbial contamination after harvest, making it prone to dehydration and spoilage, resulting in a short fresh consumption period and significant challenges in preservation. Typically, at room temperature, the weight loss of Chinese bayberries exceeds 5% within 24 hours of harvest. Moreover, the high sugar and moisture content of Chinese bayberries provides a suitable growth environment for spoilage microorganisms such as molds and yeasts, with microbial contamination rates reaching approximately 80% after 72 hours of storage. Therefore, effectively delaying quality deterioration during storage without introducing chemical residues has become a key research focus in post-harvest preservation technology for Chinese bayberries.
[0003] Current methods for preserving bayberries mainly include refrigeration, water misting, and modified atmosphere packaging. Refrigeration can inhibit microbial growth and fruit respiration to some extent, but it is difficult to effectively prevent fruit dehydration and softening, and it involves high equipment investment and energy consumption, making it mainly suitable for short-term transportation and sales. Water misting, as a non-thermal physical preservation method, can effectively maintain fruit surface moisture and reduce the rate of water loss. However, high humidity environments can easily induce the growth of mold and other microorganisms, posing a risk of secondary contamination. In recent years, some studies have also attempted to introduce green preservation technologies such as modified atmosphere packaging and slightly acidic electrolyzed water to extend the storage period of bayberries. However, overall, existing preservation technologies still have the following limitations: (1) Most preservation technologies have a single functional objective, focusing on reducing respiratory metabolism, inhibiting bacteria or retaining water, and lack a synergistic regulation strategy of multiple factors; (2) The treatment methods are mainly macroscopic contact methods, which are difficult to effectively cover hidden areas such as fruit surface wrinkles, gaps and fruit stems, resulting in blind spots in the technology's influence; (3) Some treatment methods have adverse effects on fruit quality, such as weakened flavor, deteriorated color and softened tissue, which affect its market competitiveness.
[0004] In summary, current technologies lack a green preservation method that simultaneously achieves water retention, color protection, antibacterial properties, and quality maintenance. In particular, under residue-free conditions, there is a lack of systematic and highly stable quality control strategies. Summary of the Invention
[0005] To overcome the shortcomings of existing technologies, this invention provides a method for preserving bayberries by alternating ultrasonic atomization of ethanol and water, which solves the current problem of bayberry preservation and achieves an effective combination of water retention, color protection, antibacterial properties, and quality maintenance.
[0006] To achieve the above technical objectives, the present invention adopts the following technical solution;
[0007] A method for preserving bayberries using alternating ultrasonic atomization of ethanol and water includes the following steps:
[0008] Select ripe, fresh bayberries free from rot and insect infestation, and place them in a clean and ventilated environment for air cleaning (to remove surface dust and some attached moisture) to obtain pre-treated bayberries.
[0009] An ultrasonic atomization system was used to process ethanol solution and sterile water respectively, generating ethanol mist and water mist with droplet size ≤10μm;
[0010] After cleaning, the bayberries are laid flat on a spray rack at room temperature and then enter the mist spraying preservation stage. First, ethanol mist spraying is performed, followed by water mist spraying. Then, ethanol mist spraying and water mist spraying are alternated at certain intervals, with ethanol mist spraying and water mist spraying being operated independently and not simultaneously. After a period of time, the mist spraying preservation is completed, thus achieving the preservation treatment of the bayberries.
[0011] Furthermore, the temperature for air cleaning is 25±1℃, the wind speed is 4m / s, and the air cleaning time is 15min.
[0012] Furthermore, the concentration of the ethanol solution is 75% (v / v).
[0013] Furthermore, the ultrasonic atomization system processes at a frequency of 1.7MHz and a power of 300W.
[0014] Furthermore, the specific operation of alternating between ethanol mist spraying and water mist spraying at certain intervals is as follows: every 3.0 hours, perform ethanol mist spraying for 5-20 seconds, and after 40 minutes, perform water mist spraying for 2-10 minutes; and so on, alternating between ethanol mist spraying and water mist spraying.
[0015] Furthermore, the duration is 3-5 days.
[0016] The beneficial effects of this invention are:
[0017] (1) This invention uses ethanol mist treatment to act on the surface of bayberry fruit for a short time, which can effectively inhibit major spoilage microorganisms such as mold and yeast. In addition, this invention uses water mist treatment to create a relatively stable high humidity state in the environment, which helps to slow down the loss of fruit moisture and reduce the shriveling of the fruit pulp caused by water loss. More importantly, this invention creatively utilizes the periodic alternation of ethanol and water treatment to achieve sterilization while avoiding the risk of mold growth caused by excessive humidity, achieving a dynamic balance between antibacterial and humidity control, and achieving unexpected technical effects.
[0018] (2) The present invention uses ultrasonic atomization to atomize ethanol and aqueous solution into fine droplets with a particle size ≤5 / 10μm through the cavitation effect of high frequency ultrasound, thereby enhancing the penetration.
[0019] (3) This invention does not add traditional chemical preservatives. Ethanol and water are both volatile or degradable media. There are no harmful residues after treatment. It is suitable for other post-harvest preservation scenarios with high safety requirements, such as green food and organic fruits. Attached Figure Description
[0020] Figure 1 The results for the water loss rate (A), hardness (B), ΔE value (C), anthocyanin retention rate (D), total bacterial count (E), mold and yeast count (F), and relative conductivity (G) of each embodiment and comparative example of bayberry are shown. Detailed Implementation
[0021] The present invention will now be described in detail with reference to the accompanying drawings, but the invention is not limited to these embodiments. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the invention. These modifications and improvements all fall within the scope of protection of the present invention.
[0022] Example 1:
[0023] Select ripe, fresh bayberries free from rot and insect infestation, place them in a clean and ventilated environment, and clean them with air for 15 minutes at a temperature of 25±1℃ and a wind speed of 4m / s. The airflow removes surface dust and some of the attached moisture from the bayberries, resulting in cleaned bayberries.
[0024] An ultrasonic atomization system was used to process 75% (v / v) ethanol solution and sterile water at a frequency of 1.7 MHz and a power of 300 W, respectively, to generate ethanol mist and water mist with droplet size ≤10 μm.
[0025] After cleaning, the bayberries were laid flat on a spray rack at room temperature and entered the mist spraying preservation stage. The specific operation was as follows: first, ethanol mist spraying was performed for 10 seconds, followed by water mist spraying for 5 minutes; then, every 3.0 hours, ethanol mist spraying was performed for 10 seconds, followed by water mist spraying for 5 minutes after 40 minutes, and so on, alternating between ethanol mist spraying and water mist spraying. The ethanol mist spraying and water mist spraying were performed independently and not simultaneously; the spraying treatment was terminated after 5 days.
[0026] The water loss rate, firmness, ΔE value, anthocyanin retention rate, total bacterial count, mold and yeast count, and relative conductivity of the bayberries were measured on days 0, 1, 2, 3, 4, and 5 of the treatment. The specific detection methods are as follows:
[0027] (1) Water loss rate
[0028]
[0029] Where W0 is the fresh weight (kg), W t The mass (kg) of the product after processing for t days.
[0030] (2) Hardness
[0031] The hardness (N) of the equatorial surfaces of the bayberry was determined using a texture analyzer. The parameters were: compression speed: 1.0 mm / s; compression distance: 6 mm; initial force: 0.375 N.
[0032] (3) Color difference value (ΔE value)
[0033] The color parameters L, a, and b of the bayberry were measured using a colorimeter. Based on the color parameters of fresh bayberries, the color difference value (ΔE value) was calculated as follows:
[0034]
[0035] Where L0, a0, and b0 are the color parameters of fresh bayberries, respectively. t a t and b t The values represent the color parameters of the bayberries after treatment for t days.
[0036] (4) Anthocyanin retention rate
[0037] Anthocyanin content was determined using a pH differential method, and the results are expressed as anthocyanin retention rate. 0.5 mL of the supernatant was taken, and 4 mL of 0.1 M HCl-KCl buffer (pH 1.0) was added. After mixing, the solution was analyzed at a wavelength of 510 nm (A). 510 Measure the absorbance. Take another 0.5 mL of the supernatant, add 4 mL of 0.5 M acetate-sodium acetate buffer (pH 4.5), mix well, and measure at 700 nm (A). 700 )Measure absorbance.
[0038]
[0039] Where DF is the dilution factor, H t H0 represents the anthocyanin content of bayberries after treatment for t days, and H0 represents the anthocyanin content of fresh bayberries.
[0040] (5) Total bacterial count and mold and yeast count
[0041] Total bacterial count was determined according to GB 4789.2-2022; mold and yeast count was determined according to GB 4789.15-2016. Results are expressed as log CFU / g.
[0042] (6) Relative conductivity
[0043] Weigh 10g of fruit pulp slices, add 25mL of deionized water, and let stand at room temperature for 2 hours. Then measure its conductivity (L1). Subsequently, place the sample in a boiling water bath for 20 minutes to fully release the cell contents. After cooling to room temperature, measure its conductivity (L2). The higher the relative conductivity, the greater the degree of cell damage.
[0044]
[0045] Example 2:
[0046] Select ripe, fresh bayberries free from rot and insect infestation, place them in a clean and ventilated environment, and air clean them for 15 minutes at a temperature of 25±1℃ and a wind speed of 4m / s to remove surface dust and some attached moisture.
[0047] An ultrasonic atomization system was used to process 75% (v / v) ethanol solution and sterile water at a frequency of 1.7 MHz and a power of 300 W, respectively, to generate ethanol mist and water mist with droplet size ≤10 μm.
[0048] After cleaning, the bayberries were laid flat on a spray rack at room temperature and entered the mist spraying preservation stage. The specific operation was as follows: first, ethanol mist spraying was performed for 20 seconds, followed by water mist spraying for 2 minutes; then, every 3.0 hours, ethanol mist spraying was performed for 20 seconds, followed by water mist spraying for 2 minutes after 40 minutes, and so on, with ethanol mist spraying and water mist spraying being performed independently and not at the same time; the spraying treatment was terminated after 5 days.
[0049] The water loss rate, firmness, ΔE value, anthocyanin retention rate, total bacterial count, mold and yeast count, and relative conductivity of bayberries were measured on days 0, 1, 2, 3, 4, and 5 of the treatment, respectively; the specific detection methods are as described in Example 1.
[0050] Example 3:
[0051] Select ripe, fresh bayberries free from rot and insect infestation, place them in a clean and ventilated environment, and air clean them for 15 minutes at a temperature of 25±1℃ and a wind speed of 4m / s to remove surface dust and some attached moisture, thus obtaining cleaned bayberries.
[0052] An ultrasonic atomization system was used to process 75% (v / v) ethanol solution and sterile water at a frequency of 1.7 MHz and a power of 300 W, respectively, to generate ethanol mist and water mist with droplet size ≤10 μm.
[0053] After cleaning, the bayberries were laid flat on a spray rack at room temperature and entered the mist spraying preservation stage. The specific operation was as follows: first, ethanol mist spraying was performed for 5 seconds, followed by water mist spraying for 10 minutes; then, every 3.0 hours, ethanol mist spraying was performed for 5 seconds, followed by water mist spraying for 10 minutes after 40 minutes, and so on, with ethanol mist spraying and water mist spraying being performed independently and not at the same time; the spraying treatment was terminated after 5 days.
[0054] The water loss rate, firmness, ΔE value, anthocyanin retention rate, total bacterial count, mold and yeast count, and relative conductivity of bayberries were measured on days 0, 1, 2, 3, 4, and 5 of the treatment, respectively; the specific detection methods are as described in Example 1.
[0055] Comparative Example 1:
[0056] Select ripe, fresh bayberries free from rot and insect infestation, place them in a clean and ventilated environment, and air clean them for 15 minutes at a temperature of 25±1℃ and a wind speed of 4m / s to remove surface dust and some attached moisture, thus obtaining cleaned bayberries.
[0057] An ultrasonic atomization system was used to process a 75% (v / v) ethanol solution at a frequency of 1.7 MHz and a power of 300 W to generate ethanol mist with droplet size ≤10 μm.
[0058] After cleaning, the bayberries were laid flat on the spray rack at room temperature and entered the mist spraying preservation stage. First, ethanol mist spraying was performed for 10 seconds, and then ethanol mist spraying was performed again for 10 seconds every 3.0 hours. The spraying treatment was terminated after 5 days.
[0059] The water loss rate, firmness, ΔE value, anthocyanin retention rate, total bacterial count, mold and yeast count, and relative conductivity of bayberries were measured on days 0, 1, 2, 3, 4, and 5 of the treatment, respectively; the specific detection methods are as described in Example 1.
[0060] Comparative Example 2:
[0061] Select ripe, fresh bayberries free from rot and insect infestation, place them in a clean and ventilated environment, and air clean them for 15 minutes at a temperature of 25±1℃ and a wind speed of 4m / s to remove surface dust and some attached moisture, thus obtaining cleaned bayberries.
[0062] Sterile water was treated using an ultrasonic atomization system at a frequency of 1.7 MHz and a power of 300 W to generate water mist with droplet size ≤10 μm.
[0063] After cleaning, the bayberries were laid flat on the spray rack at room temperature and entered the mist spraying preservation stage. They were sprayed directly with water mist for 5 minutes, and then sprayed with water mist for 5 minutes every 40 minutes for 5 days before the spraying treatment was terminated.
[0064] The water loss rate, firmness, ΔE value, anthocyanin retention rate, total bacterial count, mold and yeast count, and relative conductivity of bayberries were measured on days 0, 1, 2, 3, 4, and 5 of the treatment, respectively; the specific detection methods are as described in Example 1.
[0065] Comparative Example 3:
[0066] Select ripe, fresh bayberries free from rot and insect infestation, place them in a clean and ventilated environment, and air clean them for 15 minutes at a temperature of 25±1℃ and a wind speed of 4m / s to remove surface dust and some attached moisture, thus obtaining cleaned bayberries.
[0067] An ultrasonic atomization system was used to process 75% (v / v) ethanol solution and sterile water at a frequency of 1.7 MHz and a power of 300 W, respectively, to generate ethanol mist and water mist with droplet size ≤10 μm.
[0068] After cleaning, the bayberries were laid flat on the spray rack at room temperature and entered the mist spraying preservation stage. The specific operation was as follows: ethanol mist spraying (duration 10s) and water mist spraying (duration 5min) were carried out simultaneously. Then, every 3.0h, ethanol mist spraying for 10s and water mist spraying for 5min were carried out simultaneously. The two spraying methods overlapped in time and the spraying treatment was terminated after 5 days.
[0069] The water loss rate, firmness, ΔE value, anthocyanin retention rate, total bacterial count, mold and yeast count, and relative conductivity of bayberries were measured on days 0, 1, 2, 3, 4, and 5 of the treatment, respectively; the specific detection methods are as described in Example 1.
[0070] The results of water loss rate, firmness, ΔE value, anthocyanin retention rate, total bacterial count, mold and yeast count, and relative conductivity of bayberries in Examples 1-3 and Comparative Examples 1-3 are shown below. Figure 1 .
[0071] The results above show that alternating ultrasonic atomization treatment with ethanol and water (Examples 1-3) can effectively delay the quality deterioration of bayberries within 1-5 days after harvest, and has a significant preservation effect. Specifically, in Example 1, the water loss rate of the bayberries was controlled to within 7% within 5 days, and the hardness could still reach 2.8N. In contrast, the bayberries in Comparative Example 1, which were sprayed with only ethanol, had a water loss rate of 10% and a hardness of 1.5N under the same conditions. This indicates that alternating spraying with ethanol and water can significantly alleviate the post-harvest water loss and softening of bayberries. In Examples 1-3, the bayberries in Example 3 (longer water spraying time) had a smaller ΔE value and a higher anthocyanin retention rate, but also a higher number of microorganisms. In contrast, Example 2 (longer ethanol spraying time) showed better antibacterial effect, but the ΔE value of the bayberries increased and the anthocyanin retention rate was lower. This indicates that by adjusting the spraying time ratio of ethanol and water, a balance can be maintained between antibacterial properties, color, and nutritional components, providing a certain degree of process flexibility. Throughout the treatment period (0-5 days), the relative conductivity of the bayberries in Examples 1-3 remained below 35%, while that of the bayberries in Comparative Example 3, which were sprayed simultaneously, rose to 47% on day 5. This indicates that alternating spraying can effectively slow down cell membrane damage and maintain fruit freshness. This illustrates that the conditions of this invention are specific and cannot be arbitrarily adjusted or replaced; otherwise, it will be impossible to effectively combine the functions of water retention, color protection, antibacterial properties, and quality maintenance of bayberries.
[0072] In summary, alternating ultrasonic atomization with ethanol and water demonstrates outstanding performance in maintaining fruit moisture, stabilizing color, inhibiting microbial growth, delaying quality deterioration, and avoiding chemical residues. It can serve as a green and efficient treatment method suitable for post-harvest preservation of bayberries. This method utilizes the alternating action of ethanol and water mist, under the assistance of ultrasound, to form fine and uniformly distributed droplets. These droplets can more thoroughly cover the fruit surface and its microstructure, enhancing the sterilization effect while reducing osmotic stress on the fruit pulp, thus maintaining good sensory characteristics and marketability. This method is simple to operate, has a short processing time, and is highly adaptable, showing promising application prospects.
[0073] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Therefore, although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.
Claims
1. A method for preserving bayberries using alternating ultrasonic atomization of ethanol and water, characterized in that, Follow these steps: Select ripe, fresh bayberries free from rot and insect infestation, and place them in a clean, well-ventilated environment for air cleaning to obtain pre-treated bayberries. An ultrasonic atomization system was used to process ethanol solution and sterile water respectively, generating ethanol mist and water mist with droplet size ≤10μm; After cleaning, the bayberries are laid flat on a spray rack at room temperature to enter the mist spraying preservation stage. First, ethanol mist spraying is performed, followed by water mist spraying. Then, ethanol mist spraying and water mist spraying are alternated at certain intervals, with the ethanol mist spraying and water mist spraying being operated independently and not at the same time. After a period of time, the mist spraying preservation is completed, thus achieving the preservation treatment of the bayberries.
2. The method for preserving bayberries by alternating ultrasonic atomization of ethanol and water according to claim 1, characterized in that, The air cleaning temperature is 25±1℃, the air speed is 4m / s, and the air cleaning time is 15min.
3. The method for preserving bayberries by alternating ultrasonic atomization of ethanol and water according to claim 1, characterized in that, The concentration of the ethanol solution is 75% (v / v).
4. The method for preserving bayberries by alternating ultrasonic atomization of ethanol and water according to claim 1, characterized in that, The ultrasonic atomization system processes at a frequency of 1.7MHz and a power of 300W.
5. The method for preserving bayberries by alternating ultrasonic atomization of ethanol and water according to claim 1, characterized in that, The specific operation of alternating between ethanol mist spraying and water mist spraying at certain intervals is as follows: spray ethanol mist for 5-20 seconds every 3.0 hours, and then spray water mist for 2-10 minutes after 40 minutes; and so on, alternating between ethanol mist spraying and water mist spraying.
6. The method for preserving bayberries by alternating ultrasonic atomization of ethanol and water according to claim 1, characterized in that, It lasts for 3-5 days.