Application of ultra-high pressure combined with low-temperature plasma treatment in improving the aroma content of fruit juice during storage

Abstract

The application provides application of ultrahigh pressure combined with low-temperature plasma treatment in improving aroma content during juice storage, and belongs to the technical field of food storage.The application provides application of ultrahigh pressure combined with low-temperature plasma treatment in improving aroma content during juice storage.Ultrahigh pressure and low-temperature plasma treatment are carried out on juice, ultrahigh pressure destroys the cell wall and membrane structure of microorganisms, low-temperature plasma attacks intracellular biological macromolecules through free radicals, and the combination of the two makes the total number of colonies decrease by greater than or equal to 4 log CFU / mL, reaching the commercial sterility standard; meanwhile, ultrahigh pressure combined with low-temperature plasma treatment is adopted in the juice preparation process, which can avoid the degradation of esters and heat-sensitive aldehydes caused by high temperature, and low-temperature plasma can also promote the release of key aroma substances and improve the richness of aroma.

Description

Technical Field

[0001] This invention belongs to the field of food storage technology, specifically relating to the application of ultra-high pressure synergistic low temperature plasma treatment in improving the aroma content of fruit juice during storage. Background Technology

[0002] Fruits such as peaches and oranges are rich in vitamins, minerals, dietary fiber, and various aroma compounds, including esters, aldehydes, alcohols, and terpenes. These aroma compounds give fruit juice its unique flavor and quality. However, traditional fruit juice processing methods, such as pasteurization, ultra-high temperature sterilization, and hot filling, often lead to a significant loss of aroma compounds and may also produce unpleasant off-flavors, such as a cooked taste, seriously affecting the quality of the juice and consumer acceptance.

[0003] Ultra-high pressure technology, as a non-thermal processing technology, can effectively kill microorganisms and inactivate enzymes at lower temperatures, reducing the impact of heat on food quality. Although it can reduce the loss of aroma substances to some extent, the effect of reducing the loss of aroma substances is poor. How to improve the aroma content of juice during storage is still an urgent problem to be solved in the juice preparation process.

[0004] Therefore, providing a method that can significantly increase the content of key aromas in fruit juice is of great significance for improving fruit juice quality. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide the application of ultra-high pressure synergistic low-temperature plasma treatment in improving the aroma content of fruit juice during storage. In the process of preparing finished fruit juice, ultra-high pressure and low-temperature plasma treatment can significantly improve the aroma content of fruit juice during storage.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides the application of ultra-high pressure synergistic low temperature plasma treatment in improving the aroma content of fruit juice during storage.

[0008] Preferably, the pressure of the ultra-high pressure treatment is 200-600 MPa; the time of the ultra-high pressure treatment is 2-10 min.

[0009] Preferably, the power of the low-temperature plasma treatment is 50-150W, the gas flow rate is 5-10L / min, and the treatment time is 1-5min.

[0010] Preferably, the low-temperature plasma treatment uses argon as the working gas, and the gas gap distance is 2-5 cm.

[0011] This invention provides a method for increasing the aroma content of fruit juice during storage, comprising the following steps:

[0012] The juice is subjected to low-temperature plasma treatment to obtain low-temperature plasma-treated juice.

[0013] The juice treated with low-temperature plasma is then subjected to ultra-high pressure treatment to obtain the finished juice.

[0014] Preferably, the pressure of the ultra-high pressure treatment is 200-600 MPa; the ultra-high pressure treatment time is 2-10 min.

[0015] Preferably, the power of the low-temperature plasma treatment is 50-150W, the gas flow rate is 5-10L / min, and the treatment time is 1-5min.

[0016] Preferably, the low-temperature plasma treatment uses argon as the working gas, and the gas gap distance is 2-5 cm.

[0017] Preferably, the method for preparing the fruit juice includes:

[0018] Fresh fruit is cut into pieces to obtain fruit pulp; after the fruit pulp is treated to protect its color, it is mixed with water and homogenized to obtain juice.

[0019] Alternatively, fresh fruit can be pressed to extract juice.

[0020] Preferably, the color-protecting treatment includes mixing the fruit pulp with a vitamin C aqueous solution with a mass concentration of 0.5% to 2%, and the color-protecting treatment time is 8 to 12 minutes.

[0021] The beneficial effects of this invention are:

[0022] This invention provides the application of ultra-high pressure combined with low-temperature plasma treatment in improving the aroma content of fruit juice during storage. In the process of preparing finished fruit juice, the fruit juice is treated with ultra-high pressure and low-temperature plasma. Ultra-high pressure disrupts the cell walls and membrane structures of microorganisms, while low-temperature plasma attacks intracellular biomolecules through free radicals. The combined effect reduces the total bacterial count by ≥4 log CFU / mL, achieving commercial sterility standards. Simultaneously, the use of ultra-high pressure combined with low-temperature plasma treatment during fruit juice preparation avoids the degradation of esters and heat-sensitive aldehydes caused by high temperatures. Low-temperature plasma also promotes the release of key aroma substances, significantly enhancing the aroma richness of the fruit juice during storage. The results of the examples show that, compared to ultra-high pressure treatment alone, low-temperature plasma treatment alone, or traditional heat sterilization, the use of ultra-high pressure combined with low-temperature plasma treatment significantly increases or to a certain extent improves the content of aroma substances such as hexanal, trans-2-hexenal, benzaldehyde, 3-hexen-1-ol, trans-2-hexenol, linalool, ethyl acetate, hexyl acetate, and propionic decyl lactone in the fruit juice after 8 days of storage. In summary, the use of ultra-high pressure combined with low temperature plasma treatment in the preparation of fruit juice can significantly improve the aroma content and quality of the juice during storage. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The images show the aroma substance detection results of the juices prepared in Example 1 and Comparative Examples 1-4 after preparation and after 8 days of storage.

[0025] Figure 2 The images show the results of bacterial and mold detection after the fruit juices prepared in Example 1 and Comparative Examples 1-4 were completed and after 8 days of storage. Detailed Implementation

[0026] This invention provides the application of ultra-high pressure combined with low-temperature plasma treatment in improving the aroma content of fruit juice during storage. As an optional embodiment of this invention, the fruit juice can be treated using an ultra-high pressure combined with low-temperature plasma method to obtain the finished fruit juice, thereby improving the aroma content during storage. As an optional embodiment of this invention, the fruit juice is sealed and stored during the storage period; the storage temperature of the fruit juice during storage can be 4°C. Preferably, in the ultra-high pressure combined with low-temperature plasma treatment, low-temperature plasma treatment is performed first, followed by ultra-high pressure treatment.

[0027] As an optional embodiment of the present invention, the pressure of the ultra-high pressure treatment can be 200-600 MPa, or 200, 250, 300, 320, 350, 400, 450, 500, 550, or 600 MPa; the ultra-high pressure treatment time can be 2-10 min, or 2, 3, 4, 5, 6, 7, 8, 9, or 10 min. As an optional embodiment of the present invention, the initial temperature of the ultra-high pressure treatment can be 10-20℃, or 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20℃.

[0028] As an optional embodiment of the present invention, the low-temperature plasma treatment can be performed using a dielectric barrier discharge (DBD) plasma device; the power of the low-temperature plasma treatment can be 50-150W, or 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 150W; the gas flow rate of the low-temperature plasma treatment can be 5-10L / min, or 5, 6, 7, 8, 9, or 10L / min; the treatment time of the low-temperature plasma can be 1-5min, or 1, 2, 3, 4, or 5min. As an optional embodiment of the present invention, the low-temperature plasma treatment uses argon as the working gas, and the gas gap distance can be 2-5cm, or 2, 3, 4, or 5cm.

[0029] This invention employs ultra-high pressure and low-temperature plasma methods to treat fruit juice during preparation. Ultra-high pressure disrupts the cell walls and membrane structures of microorganisms, while low-temperature plasma attacks intracellular biomolecules through free radicals. The combined effect of these two methods reduces the total bacterial count by ≥4 log CFU / mL, achieving commercial sterility standards. Simultaneously, the use of ultra-high pressure combined with low-temperature plasma treatment during fruit juice preparation avoids the degradation of esters (such as hexyl acetate) and heat-sensitive aldehydes (such as hexanal) caused by high temperatures. Low-temperature plasma also promotes the release of key aroma compounds (such as α-terpineol), enhancing aroma richness. The combined ultra-high pressure and low-temperature plasma method in the finished fruit juice preparation process synergistically enhances the aroma content of the juice, significantly improving its aroma content during storage and thus its overall quality.

[0030] This invention provides a method for increasing the aroma content of fruit juice during storage, comprising the following steps:

[0031] The juice is subjected to low-temperature plasma treatment to obtain low-temperature plasma-treated juice.

[0032] The juice treated with low-temperature plasma is then subjected to ultra-high pressure treatment to obtain the finished juice.

[0033] This invention does not specifically limit the source of the fruit juice; any conventional fruit juice in the art can be used. As an optional embodiment of this invention, the fruit juice can be freshly prepared. This invention does not specifically limit the preparation method of the fruit juice; any conventional preparation method in the art can be used.

[0034] As an optional embodiment of the present invention, the method for preparing the juice includes: cutting fresh fruit into pieces to obtain pulp pieces; treating the pulp pieces for color protection, mixing them with water, and homogenizing them to obtain juice; or, pressing fresh fruit to extract juice.

[0035] This invention does not specifically limit the type of fruit used; any conventional fruit in the art can be used. Preferably, the method for preparing fruit juice according to this invention involves using a method suitable for the specific type of fruit. As an optional embodiment of this invention, the fruit includes peaches and / or oranges; the peaches include nectarines and / or yellow peaches.

[0036] As an optional embodiment of the present invention, when the fresh fruit is a peach or similar fruit, the method for making juice from the fresh fruit includes: cutting the fresh fruit into pieces to obtain pulp pieces; performing a color-protecting treatment on the pulp pieces, then mixing them with water and homogenizing to obtain juice. As an optional embodiment of the present invention, the fresh fruit can be a fruit with a maturity of 80-90%. After obtaining the fresh fruit, the present invention preferably washes the fruit, removes the stems, peel, and pits, and then cuts it into pieces. The present invention does not have a particular limitation on the method of cutting the fruit; any conventional cutting method in the art can be used. As an optional embodiment of the present invention, the volume of the pulp pieces can be 1-2 cm. 3 It can also be 1, 1.5 or 2 cm. 3After obtaining the fruit pulp, the present invention performs a color-protecting treatment on the fruit pulp. As an optional embodiment of the present invention, the color-protecting treatment includes mixing the fruit pulp with a vitamin C aqueous solution with a mass concentration of 0.5% to 2%; the mass concentration of vitamin C in the vitamin C aqueous solution can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2.0%; the mixing method can be immersing the fruit pulp in the vitamin C aqueous solution; the color-protecting treatment time can be 8 to 12 minutes, or 8, 9, 10, 11, or 12 minutes; the color-protecting treatment temperature can be room temperature. After the color-protecting treatment is completed, the present invention preferably mixes the color-protected fruit pulp with water. In an optional embodiment of the present invention, the water includes purified water; the mass ratio of the fruit pulp to water can be 1:(4-8), or 1:4, 1:5, 1:6, 1:7, or 1:8. After mixing the fruit pulp with water, the present invention preferably adds an antioxidant to the mixture before homogenization. In an optional embodiment of the present invention, the antioxidant includes sodium D-isoascorbate; the antioxidant is preferably added based on the mass of water added to the mixture; the amount of antioxidant added is preferably 0.05% to 0.2% of the water mass, or 0.05%, 0.10%, 0.15%, or 0.20%. In an optional embodiment of the present invention, the pulping speed can be 10000-15000 r / min, or 10000, 11000, 12000, 13000, 14000, or 15000 r / min; the pulping time can be 3-5 min, or 3, 4, or 5 min. After pulping, a fruit juice slurry is obtained. After obtaining the fruit juice slurry, the present invention preferably removes the residue from the slurry and then homogenizes it. The present invention preferably removes the residue from the fruit juice slurry by sieving; the sieve aperture can be 200 mesh. As an optional embodiment of the present invention, the homogenization speed can be 2000-3000 r / min, or 2000, 2500, or 3000 r / min; the homogenization time can be 3-5 min, or 3, 4, or 5 min. The present invention preferably uses pulping and homogenization to ensure that the particle size in the fruit juice is ≤5μm, thereby improving the stability of the fruit juice. After pulping and homogenization, the present invention obtains fruit juice.

[0037] In an optional embodiment of the present invention, when the fresh fruit is an orange or similar fruit, the present invention extracts juice by pressing the fresh fruit. The present invention does not specifically limit the method of pressing to extract juice; any conventional pressing method in the art can be used. After pressing to extract juice, the present invention preferably further includes coarse filtration and blending of the obtained raw juice. In an optional embodiment of the present invention, the coarse filtration is performed using a 100-mesh sieve; the blending involves mixing the filtrate obtained from the coarse filtration with ascorbic acid; the amount of ascorbic acid added is 0.05% of the mass of the filtrate. After blending, juice is obtained.

[0038] After obtaining the juice, the present invention subjectes the juice to low-temperature plasma treatment to obtain low-temperature plasma-treated juice. As an optional embodiment of the present invention, the low-temperature plasma treatment can be performed using a dielectric barrier discharge (DBD) plasma device; the power of the low-temperature plasma treatment can be 50–150 W, or 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 150 W; the gas flow rate of the low-temperature plasma treatment can be 5–10 L / min, or 5, 6, 7, 8, 9, or 10 L / min; the treatment time of the low-temperature plasma can be 1–5 min, or 1, 2, 3, 4, or 5 min. As an optional embodiment of the present invention, the low-temperature plasma treatment uses argon as the working gas, and the gas gap distance can be 2–5 cm, or 2, 3, 4, or 5 cm.

[0039] After obtaining the juice treated with low-temperature plasma, the present invention subjectes the juice to ultra-high pressure treatment to obtain the finished juice. As an optional embodiment of the present invention, the pressure of the ultra-high pressure treatment can be 200–600 MPa, or 200, 250, 300, 320, 350, 400, 450, 500, 550, or 600 MPa; the ultra-high pressure treatment time can be 2–10 min, or 2, 3, 4, 5, 6, 7, 8, 9, or 10 min. As an optional embodiment of the present invention, the initial temperature of the ultra-high pressure treatment can be 10–20°C, or 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20°C. Preferably, the ultra-high pressure treatment is performed by filling the juice into a sterilized polyethylene bottle and sealing it.

[0040] After the ultra-high pressure treatment is completed, the present invention preferably further includes filtering the obtained juice and then bottling it. As an optional embodiment of the present invention, the filtering method includes filtering the juice through a 200-mesh sieve. The present invention does not specifically limit the bottling method; any conventional bottling method in the art can be used.

[0041] The method described in the above technical solution of this invention, through low-temperature plasma treatment and ultra-high pressure treatment, can synergistically increase the content of aroma substances in the juice during storage, thereby improving the juice quality. As an optional embodiment of this invention, the juice is preferably sealed during storage. This invention does not specifically limit the sealing method; any conventional sealing method in the art can be used.

[0042] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0043] Example 1

[0044] A method for increasing the aroma content of fruit juice during storage includes the following steps:

[0045] 1. Raw material pretreatment: Select 5 kg of peaches that are 80-90% ripe, wash them under running water, remove the stems, skin and pits, and cut them into 1-2 cm pieces. 3 Fruit pulp chunks.

[0046] 2. Color protection treatment: Immerse the pulp pieces in a 1 wt.% vitamin C aqueous solution at room temperature for 8 minutes to inhibit polyphenol oxidase activity and prevent browning.

[0047] 3. Pulping and Homogenization: After the color-protecting treatment, the fruit pulp chunks are mixed with purified water at a mass ratio of 1:4. Then, sodium D-isoascorbate is added as an antioxidant at a concentration of 0.1 wt.% of the purified water mass. The mixture is pulped at 12000 rpm for 4 minutes, and then filtered through a 200-mesh sieve to remove residue. The filtrate is homogenized at 2500 rpm for 4 minutes to ensure a particle size ≤5 μm, thereby improving juice stability and obtaining homogenized juice.

[0048] 4. Low-temperature plasma treatment:

[0049] A dielectric barrier discharge (DBD) plasma device with a processing power of 100W and an air gap distance (i.e., the distance between the plasma generator probe and the surface of the juice) of 3cm was used. Argon gas was introduced at a flow rate of 8L / min, and the homogenized juice was treated with low-temperature plasma for 3min.

[0050] 5. Ultra-high voltage treatment:

[0051] The juice treated with low-temperature plasma was placed into sterilized polyethylene bottles, sealed, and then placed in an ultra-high pressure device. Water was used as the conduction medium, and the initial temperature was 15℃. The treatment was carried out at a pressure of 500MPa for 5 minutes.

[0052] 6. Aseptically package to obtain the finished product.

[0053] The juice prepared in Example 1 is denoted as HPP+CP treatment group juice, or simply HPP+CP.

[0054] Comparative Example 1

[0055] A method for preparing fruit juice, with the same steps as in Example 1, differs in that: after obtaining homogenized fruit juice, the homogenized fruit juice is sterilized in a 95°C water bath for 5 minutes, so that the core temperature of the fruit juice reaches 90°C and is maintained for 30 seconds, and then cooled and packaged. That is, the traditional pasteurization method is used to process the fruit juice.

[0056] The juice prepared in Comparative Example 1 is denoted as the HT-treated juice, or simply HT.

[0057] Comparative Example 2

[0058] A method for preparing fruit juice, with the same steps as in Example 1, except that: after obtaining homogenized fruit juice, the homogenized fruit juice is directly packaged without any sterilization treatment.

[0059] The juice prepared in Comparative Example 2 is denoted as the CK treatment group juice, or simply CK.

[0060] Comparative Example 3

[0061] A method for preparing fruit juice, with the same steps as in Example 1, except that after obtaining homogenized fruit juice, it undergoes low-temperature plasma treatment but not ultra-high pressure treatment.

[0062] The specific parameters for low-temperature plasma treatment are as follows:

[0063] A dielectric barrier discharge (DBD) plasma device with a processing power of 120W and an air gap distance (i.e., the distance between the plasma generator probe and the surface of the juice) of 3cm was used. Argon gas was introduced at a flow rate of 8L / min, and the homogenized juice was treated with low-temperature plasma for 4min.

[0064] The juice prepared in Comparative Example 3 is denoted as the CP treatment group juice, or simply CP.

[0065] Comparative Example 4

[0066] A method for preparing fruit juice, with the same steps as in Example 1, except that after obtaining homogenized fruit juice, it is directly subjected to ultra-high pressure treatment without undergoing low-temperature plasma treatment.

[0067] The specific parameters for ultra-high pressure processing are as follows:

[0068] The homogenized juice was poured into sterilized polyethylene bottles, sealed, and placed in an ultra-high pressure device. Water was used as the conduction medium, and the initial temperature was 15℃. The juice was then treated at a pressure of 500MPa for 8 minutes.

[0069] The juice prepared in Comparative Example 4 is denoted as HPP-treated juice, or simply HPP.

[0070] Application Example 1

[0071] Key aroma compounds in the fruit juices prepared in Example 1 and Comparative Examples 1-4 were detected using GC-MS with an HP-5MS column and HS-SPME-GC-MS headspace solid-phase microextraction. Helium was used as the carrier gas at a flow rate of 1 mL / min. The initial temperature was 40°C, increased to 180°C at 3°C / min, and then increased to 250°C at 5°C / min, holding for 5 min. Mass spectrometry data of volatile compounds were compared with NIST08 data. The aroma properties of different volatile compounds in the fruit juice are shown in Table 1.

[0072] Table 1. Aroma properties of different volatile substances in peach juice.

[0073]

[0074]

[0075] After the juices were prepared in Examples 1 and Comparative Examples 1-4, the key aroma compounds of the juices were immediately tested, and the results are shown in Table 2.

[0076] Table 2. Content of key aroma compounds in the fruit juices prepared in Example 1 and Comparative Examples 1-4 (unit: mg / kg)

[0077]

[0078] The different letters in the table represent significant differences at the 5% level.

[0079] After the juices were prepared in Examples 1 and Comparative Examples 1-4, they were stored at 4°C for 8 days. The key aroma compounds of the stored juices were then tested, and the results are shown in Table 3.

[0080] The aroma compounds of the juices prepared in Examples 1 and Comparative Examples 1-4 were detected after preparation and after 8 days of storage. Figure 1 As shown.

[0081] Table 3. Content of key aroma compounds in the fruit juices prepared in Examples 1 and Comparative Examples 1-4 after 8 days of storage (unit: mg / kg)

[0082]

[0083]

[0084] Note: Significance of different letters at the 5% level in the table.

[0085] From Tables 2-3 and Figure 1 It can be seen that, after 8 days of storage, the treatment of homogenized juice with ultra-high pressure and low-temperature plasma significantly increases the content of aroma substances such as hexanal, benzaldehyde, trans-2-hexenol, linalool, and propionic decyl lactone in the juice compared to ultra-high pressure treatment alone, low-temperature plasma treatment alone, or traditional heat sterilization treatment. It can also increase the content of aroma substances such as trans-2-hexenol, 3-hexen-1-ol, ethyl acetate, and hexyl acetate in the juice to a certain extent.

[0086] Example 2

[0087] A method for increasing the aroma content of fruit juice during storage includes the following steps:

[0088] 1. Raw material pretreatment: Select 5 kg of yellow peaches that are 80-90% ripe, wash them under running water, remove the stems, skin and pits, and cut them into 1-2 cm pieces. 3 Fruit pulp chunks.

[0089] 2. Color protection treatment: Immerse the pulp pieces in a 1.2wt.% vitamin C aqueous solution at room temperature for 10 minutes to inhibit polyphenol oxidase activity and prevent browning.

[0090] 3. Pulping and Homogenization: After the color-protecting treatment, the pulp and purified water are mixed at a mass ratio of 1:5. Sodium D-isoascorbate is then added as an antioxidant at a concentration of 0.1 wt.% of the purified water mass. The mixture is pulped at 12000 rpm for 4 minutes, and then filtered through a 200-mesh sieve to remove residue. The filtrate is then homogenized at 3000 rpm for 5 minutes to ensure a particle size ≤5 μm, thereby improving juice stability and obtaining homogenized juice.

[0091] 4. Low-temperature plasma treatment:

[0092] A dielectric barrier discharge (DBD) plasma device with a processing power of 150W and an air gap distance (i.e., the distance between the plasma generator probe and the surface of the juice) of 3cm was used. Argon gas was introduced at a flow rate of 8L / min, and the homogenized juice was treated with low-temperature plasma for 5min.

[0093] 5. Ultra-high voltage treatment:

[0094] The juice treated with low-temperature plasma was placed into sterilized polyethylene bottles, sealed, and then placed in an ultra-high pressure device. Water was used as the conduction medium, and the initial temperature was 15℃. The treatment was carried out at a pressure of 550MPa for 10 minutes.

[0095] 6. Aseptically package to obtain the finished product.

[0096] Comparative Example 5

[0097] A method for preparing fruit juice, with the same steps as in Example 2, except that after obtaining homogenized fruit juice, it undergoes low-temperature plasma treatment but not ultra-high pressure treatment.

[0098] The specific parameters for low-temperature plasma treatment are as follows:

[0099] A dielectric barrier discharge (DBD) plasma device with a processing power of 150W and an air gap distance (i.e., the distance between the plasma generator probe and the surface of the juice) of 3cm was used. Argon gas was introduced at a flow rate of 8L / min, and the homogenized juice was treated with low-temperature plasma for 5min.

[0100] Comparative Example 6

[0101] A method for preparing fruit juice, with the same steps as in Example 2, except that after obtaining homogenized fruit juice, it is directly subjected to ultra-high pressure treatment without undergoing low-temperature plasma treatment.

[0102] The specific parameters for ultra-high pressure processing are as follows:

[0103] The homogenized juice was poured into sterilized polyethylene bottles, sealed, and placed in an ultra-high pressure device. Water was used as the conduction medium, and the initial temperature was 15℃. The juice was then treated at a pressure of 550MPa for 10 minutes.

[0104] Comparative Example 7

[0105] A method for preparing fruit juice, with the same steps as in Example 2, differs in that: after obtaining homogenized fruit juice, the homogenized fruit juice is sterilized in a 95°C water bath for 5 minutes, so that the core temperature of the fruit juice reaches 90°C and is maintained for 30 seconds, and then cooled and packaged. That is, the traditional pasteurization method is used to process the fruit juice.

[0106] Comparative Example 8

[0107] A method for preparing fruit juice, with the same steps as in Example 2, except that: after obtaining homogenized fruit juice, the homogenized fruit juice is directly packaged without any sterilization treatment.

[0108] Application Example 2

[0109] The key aroma compounds of the fruit juices prepared in Example 2 and Comparative Examples 5-8 were detected using the same method as in Application Example 1.

[0110] After the juices were prepared in Examples 2 and Comparative Examples 5-8, the key aroma compounds of the juices were immediately tested, and the results are shown in Table 4.

[0111] Table 4. Content of key aroma compounds in the fruit juices prepared in Example 2 and Comparative Examples 5-8 (unit: mg / kg)

[0112]

[0113] Note: Different letters in the table represent 5% significance differences.

[0114] After the juices were prepared in Examples 2 and Comparative Examples 5-8, they were stored for 8 days. The key aroma compounds of the stored juices were then tested, and the results are shown in Table 5.

[0115] Table 5 shows the content of key aroma compounds in the juices prepared in Example 2 and Comparative Examples 5-8 after 8 days of storage.

[0116]

[0117] Note: Different letters in the table represent 5% significance.

[0118] As shown in Tables 4 and 5, when homogenized juice is treated with ultra-high pressure and low-temperature plasma, the content of aroma compounds such as n-hexanal, trans-2-hexenal, benzaldehyde, 3-hexen-1-ol, trans-2-hexenol, linalool, ethyl acetate, and pro-decyl lactone can be significantly increased or to a certain extent increased after 8 days of storage, compared with ultra-high pressure treatment alone, low-temperature plasma treatment alone, or traditional heat sterilization treatment.

[0119] Application Example 3

[0120] After the juices were prepared in Examples 1 and Comparative Examples 1-4, the bacterial and mold content of the juices was immediately tested. At the same time, after the juices were stored at 4°C for 8 days, the bacterial and mold content of the stored juices was tested.

[0121] The results of bacterial and mold detection of the juices prepared in Examples 1 and Comparative Examples 1-4 after preparation and after 8 days of storage are as follows: Figure 2 As shown.

[0122] Depend on Figure 2 It was found that no bacteria or mold were detected in any of the experimental groups that underwent sterilization treatment, either during the preparation of the juice or after 8 days of storage. However, the juice that was directly sealed and stored after homogenization had a higher number of bacteria and mold. This indicates that the sterilization effect of each experimental group was significant and achieved good sterilization results.

[0123] Example 3

[0124] A method for increasing the aroma content of fruit juice during storage includes the following steps:

[0125] 1. Raw material pretreatment: Select 5 kg of fresh Gannan navel oranges with a maturity of 80-90%, wash them with running water, remove the peel and seeds, and then press to extract the juice.

[0126] 2. Coarse filtration and blending: The extracted juice is filtered through a 100-mesh sieve to remove large pieces of pulp; 0.05% ascorbic acid (antioxidant) is added and mixed evenly to obtain the blended juice.

[0127] 3. Low-temperature plasma treatment:

[0128] A dielectric barrier discharge (DBD) plasma device with a processing power of 100W and an air gap distance (i.e., the distance between the plasma generator probe and the surface of the juice) of 3cm was used. Argon gas was introduced at a flow rate of 8L / min, and the prepared juice was treated with low-temperature plasma for 3min.

[0129] 5. Ultra-high voltage treatment:

[0130] The juice treated with low-temperature plasma was placed into sterilized polyethylene bottles, sealed, and then placed in an ultra-high pressure device. Water was used as the conduction medium, and the initial temperature was 15℃. The treatment was carried out at a pressure of 320MPa for 5 minutes.

[0131] 6. The processed juice is then filtered through a 200-mesh filter and aseptically filled.

[0132] Comparative Example 9

[0133] A method for increasing the aroma content of fruit juice during storage, with the same steps as in Example 3, except that: after obtaining the blended fruit juice, it is treated with an 85°C tubular sterilizer for 10 seconds to ensure that the core temperature of the fruit juice is ≥85°C. Then, it is rapidly cooled to 25°C, sealed, and placed into a sterile container.

[0134] Comparative Example 10

[0135] A method for increasing the aroma content of fruit juice during storage, with the same steps as in Example 3, except that: after obtaining the blended fruit juice, it is not sterilized, but sealed and placed in a sterile container for direct refrigeration at 4°C.

[0136] Comparative Example 11

[0137] A method for increasing the aroma content of fruit juice during storage, with the same steps as in Example 3, except that: after obtaining the blended fruit juice, it is not subjected to low-temperature plasma treatment, but directly subjected to ultra-high pressure treatment.

[0138] The conditions for ultra-high pressure treatment are:

[0139] The prepared juice was poured into sterilized polyethylene bottles, sealed, and placed in an ultra-high pressure device. Water was used as the conduction medium, and the initial temperature was 15℃. The juice was then treated at a pressure of 360MPa for 10 minutes.

[0140] Comparative Example 12

[0141] A method for increasing the aroma content of fruit juice during storage, with the same steps as in Example 3, except that: after obtaining the blended fruit juice, it is subjected to low-temperature plasma treatment instead of ultra-high pressure treatment.

[0142] The conditions for low-temperature plasma treatment are:

[0143] A dielectric barrier discharge (DBD) plasma device with a processing power of 120W and an air gap distance (i.e., the distance between the plasma generator probe and the surface of the juice) of 3cm was used. Argon gas was introduced at a flow rate of 8L / min, and the prepared juice was treated with low-temperature plasma for 5min.

[0144] Application Example 4

[0145] The key aroma compounds of the juices prepared in Example 3 and Comparative Examples 9-12 were detected using the same method as in Application Example 1. The aroma properties of different volatile compounds in the juices are shown in Table 6.

[0146] Table 6. Aroma properties of different volatile substances in orange juice.

[0147] Myrcene Myrcene Fresh, citrus leaf, woody notes Limonene Limonene Lemon, orange peel, and slightly sweet terpene aroma alpha-terpineol alpha-Terpineol Lilac, lavender, wood d-Carvone D(+)-Carvone Caraway, spicy, and slightly sweet herbal notes Linalool Linalool Citrus, roses, green grass trans-2-nonenal trans-2-Nonenal Fat, cucumber, wax hexanol Hexanal Fresh, fatty, leafy, fruity Valencia orangeene Valencene Sweet orange, mandarin orange peel, mellow 2-Octanone 2-Octanone Sweet aroma, slightly waxy feel

[0148] After the juices were prepared in Examples 3 and Comparative Examples 9-12, the key aroma compounds of the juices were immediately tested, and the results are shown in Table 7.

[0149] Table 7. Content of key aroma compounds (mg / kg) in the fruit juices prepared in Example 3 and Comparative Examples 9-12.

[0150]

[0151]

[0152] Note: Different letters in the table represent 5% significance.

[0153] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for increasing the aroma content of fruit juice during storage, comprising the following steps: The juice is subjected to low-temperature plasma treatment to obtain low-temperature plasma-treated juice. The juice treated with low-temperature plasma is then subjected to ultra-high pressure treatment to obtain the finished juice. The ultra-high pressure treatment is performed at a pressure of 200–600 MPa for 2–10 minutes. The power of the low-temperature plasma treatment is 50-150W, the gas flow rate is 5-10L / min, and the treatment time is 1-5min; the low-temperature plasma treatment uses argon as the working gas, and the gas gap distance is 2-5cm.

2. The method according to claim 1, characterized in that, The method for preparing the fruit juice includes: Fresh fruit is cut into pieces to obtain fruit pulp; after the fruit pulp is treated to protect its color, it is mixed with water and homogenized to obtain juice. Alternatively, fresh fruit can be pressed to extract juice.

3. The method according to claim 2, characterized in that, The color-protecting treatment includes mixing the fruit pulp pieces with a vitamin C aqueous solution with a mass concentration of 0.5% to 2%, and the color-protecting treatment time is 8 to 12 minutes.

Images