A method for processing cherry tomatoes by freeze-drying combined with pressure difference puffing drying and cherry tomato crisp particles

Abstract

This invention belongs to the field of fruit and vegetable processing technology, specifically relating to a method for processing cherry tomatoes using freeze-drying combined with pressure differential puffing drying, and resulting in cherry tomato crisps. This invention employs an integrated freeze-drying and pressure differential puffing drying method. After scoring the surface of cherry tomato slices, they are sequentially frozen, with the cut side facing down for vacuum freeze-drying, and then with the cut side facing up for pressure differential puffing drying. Vacuum freeze-drying better preserves the natural color, flavor, and nutrients; the instantaneous pressure difference promotes internal moisture migration and tissue puffing, improving the internal pore structure of the product, giving the cherry tomato crisps a better crisp texture and fluffy characteristics. Furthermore, this invention optimizes the arrangement of the slices, which helps to shorten the drying time, reduce the outflow of contents and deformation during pressure differential puffing, and improve the product's appearance integrity, shaping stability, and crisp quality. The cherry tomato crisps exhibit minimal color variation, uniform overall coloring, sufficient hardness, and stable crispness.

Description

Technical Field

[0001] This invention belongs to the field of fruit and vegetable processing technology, specifically relating to a method for processing cherry tomatoes by freeze-drying combined with pressure differential puffing drying and cherry tomato crisps. Background Technology

[0002] Cherry tomatoes (Lycopersicon esculentum var. cerasiforme A.Gray), also known as mini tomatoes or cherry tomatoes, are popular among consumers due to their vibrant color, rich flavor, and sweet-sour taste, combining the characteristics of both vegetables and fruits. However, cherry tomatoes have a high water content and vigorous respiration metabolism, making them highly susceptible to dehydration, softening, tissue collapse, and rotting after harvest. This makes them unsuitable for long-term storage and long-distance transportation, hindering further increases in their industrial added value. Current cherry tomato processing methods mainly focus on fresh consumption, preservation, canning, preserves, and powdered products, while the development of high-quality crispy granule products suitable for the snack food market remains relatively insufficient. For example, Chinese patent CN101073369A discloses a method for preparing cherry tomato preserves, mainly using methods such as soaking, vacuum drying, or heat pump drying. The resulting products are primarily preserves, which differ significantly from crispy granule snack foods in terms of product form, taste characteristics, and processing methods. Summary of the Invention

[0003] The purpose of this invention is to provide a method for processing cherry tomatoes by freeze-drying combined with pressure differential puffing, to prepare crisp cherry tomato snack foods with low shrinkage, minimal color variation, uniform overall coloring, sufficient hardness and stable crispness, crisp texture and not easily broken, thereby improving the added value of cherry tomato processing and the level of commercial utilization.

[0004] This invention provides a method for processing cherry tomatoes using freeze-drying combined with differential pressure puffing, comprising the following steps: Cut cherry tomatoes and make incisions on their skin to obtain pre-treated cherry tomatoes; The cherry tomatoes were frozen to obtain frozen cherry tomatoes; The frozen cherry tomatoes, with the cut side facing down, are subjected to vacuum freeze-drying to obtain dried cherry tomatoes. The dried cherry tomatoes, with their cut surfaces facing upwards, are subjected to differential pressure puffing followed by instant pressure release and vacuum drying until the moisture content is 5-10%, resulting in cherry tomato crisps. The differential pressure expansion treatment method includes: heating and pressurizing to 80~95℃, 1.5~2.0 bar, and then holding for 5~15 minutes.

[0005] Preferably, the cherry tomato is a yellow cherry tomato.

[0006] Preferably, the moisture content of the dried cherry tomatoes is 45% to 55%.

[0007] Preferably, the vacuum freeze-drying process takes 14 to 18 hours and the pressure is 30 to 100 Pa.

[0008] Preferably, the parameters for the vacuum freeze-drying process are: -25℃ for 2 hours, -15℃ for 2 hours, -5℃ for 2 hours, 5℃ for 2 hours, 15℃ for 2 hours, 25℃ for 2 hours, 35℃ for 2 hours, and 45℃ for 0 to 4 hours.

[0009] Preferably, the vacuum drying process is performed at a pressure of 30~100 Pa, a temperature of 60~65 °C, and a time of 1.5~2.5 h.

[0010] Preferably, the freezing treatment is performed at a temperature of -35 to -45°C for 24 to 30 hours.

[0011] Preferably, the number of scratches is 1 to 3, and the length of each scratch is 0.5 to 1.5 cm.

[0012] Preferably, the cutting method is longitudinal cutting.

[0013] The present invention provides cherry tomato crisps obtained by the cherry tomato processing method described above.

[0014] Beneficial effects: This invention provides a method for processing cherry tomatoes, employing an integrated freeze-drying and differential pressure puffing drying method. After cutting the cherry tomatoes, incisions are made on the peel surface, followed by freeze-drying. The cut side is then placed face down for vacuum freeze-drying (freeze-drying). The cut side is then heated and pressurized to 80-95°C and 1.5-2.0 bar for 5-10 minutes, followed by instantaneous depressurization and vacuum drying until the moisture content is 5-10%, yielding cherry tomato crisps. Freeze-drying allows for pre-drying of cherry tomatoes under low temperature and low pressure conditions, better preserving their nutritional components, color, and flavor, and maintaining a good porous skeletal structure. Differential pressure puffing utilizes instantaneous pressure changes to promote internal moisture migration and tissue puffing, improving the internal pore structure of the product and enhancing the crispness and texture of the cherry tomato crisps. Furthermore, this invention optimizes the slicing arrangement during the drying process, which helps shorten drying time, reduce leakage and deformation during differential pressure puffing, and improve the product's appearance integrity, shaping stability, and crispness. The results of the embodiments show that the processing method of the present invention can effectively shorten the processing cycle of cherry tomatoes, and the resulting cherry tomato crisps have low shrinkage, small color variation, uniform overall coloring, sufficient hardness and stable crispness, crisp taste and are not easily broken, thus improving the sensory quality and commercial value of the product, extending the storage period, and increasing the added value of cherry tomatoes.

[0015] Furthermore, this invention specifies that the cherry tomato variety is yellow cherry tomato, which has sufficient hardness and stable crispness after processing, has a crisp texture and is not easily broken, and has the lowest shrinkage rate, the least color variation and the most uniform overall coloring compared to other cherry tomato varieties. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0017] Figure 1 The effect of different placement methods on the moisture content of freeze-dried cherry tomatoes; Figure 2 Images showing the appearance of freeze-dried and pressure-differential puffed cherry tomatoes with different arrangement methods; Figure 3 Statistical results of hardness of different varieties of cherry tomatoes after freeze-drying and pressure differential puffing; Figure 4 Statistical results on the crispness of different varieties of cherry tomatoes after freeze-drying and pressure differential puffing; Figure 5 Images showing the appearance of different varieties of cherry tomatoes before and after freeze-drying and pressure differential puffing. Detailed Implementation

[0018] This invention provides a method for processing cherry tomatoes using freeze-drying combined with differential pressure puffing, comprising the following steps: Cut cherry tomatoes and make incisions on their skin to obtain pre-treated cherry tomatoes; The cherry tomatoes were frozen to obtain frozen cherry tomatoes; The frozen cherry tomatoes, with the cut side facing down, are subjected to vacuum freeze-drying to obtain dried cherry tomatoes. The dried cherry tomatoes, with their cut surfaces facing upwards, are subjected to differential pressure puffing followed by instant pressure release and vacuum drying until the moisture content is 5-10%, resulting in cherry tomato crisps. The differential pressure expansion treatment method includes: heating and pressurizing to 80~95℃, 1.5~2.0 bar, and then holding for 5~15 minutes.

[0019] This invention involves cutting cherry tomatoes and making incisions on their skin to obtain pre-treated cherry tomatoes.

[0020] In one embodiment, the cutting method described in this invention is longitudinal cutting. In another embodiment, the cherry tomato is cut in half. The reason for choosing longitudinal cutting rather than transverse cutting is that the septa inside the cherry tomato are arranged longitudinally, dividing the fruit into several ovary chambers. These chambers contain seeds and a translucent, mucilaginous substance. Longitudinal cutting does not sever the septa, allowing them to continue protecting the seeds and mucilaginous substance. Transverse cutting, on the other hand, severs all the septa, exposing the seeds and mucilaginous substance to the outside, which can easily lead to loss during processing.

[0021] In one embodiment, the cherry tomato described in this invention is a yellow cherry tomato. There are many varieties of cherry tomatoes, and different varieties vary in fruit size, skin thickness, soluble solids content, tissue density, and processing resistance. These differences further affect the heat and mass transfer behavior during processing and the tissue remodeling effect during the puffing stage. When processing different cherry tomato varieties, there are significant differences in drying rate, shape retention, crispness, and sensory quality. This invention, through comparison of different cherry tomatoes, finds that the freeze-drying combined with pressure differential puffing processing method is particularly suitable for yellow cherry tomatoes. It achieves the lowest shrinkage rate, minimal color variation, and most uniform overall coloring while ensuring sufficient hardness, stable crispness, a crisp texture, and resistance to breakage.

[0022] In one embodiment, the number of scratches in this invention is 1 to 3. In another embodiment, the length of each scratch is 0.5 to 1.5 cm; in yet another embodiment, the length of each scratch is 1.0 cm. This invention does not involve peeling, thus preserving dietary fiber, lycopene, and other active nutrients in the cherry tomato skin, reducing nutrient loss and improving overall product quality. It also helps maintain the integrity and appearance of the cherry tomato after cutting, thereby improving product shape. The scratches on the fruit skin surface in this invention accelerate the drying rate. Cherry tomato skin contains wax and cuticle, which severely hinders moisture removal during drying. Conventional processing often uses methods such as heat peeling or alkaline peeling to remove the skin before further processing. This invention, while preserving the skin, creates 0.5 to 1.5 cm scratches on the skin surface, providing a migration channel for moisture removal during drying and accelerating the drying rate.

[0023] The pretreated cherry tomatoes are obtained, and the present invention freezes the pretreated cherry tomatoes to obtain frozen cherry tomatoes.

[0024] In one embodiment, the freezing temperature of the present invention is -35 to -45°C; in another embodiment, the freezing temperature of the present invention is -40°C. In one embodiment, the freezing time of the present invention is 24 to 30 hours; in another embodiment, the freezing time of the present invention is 26 to 28 hours. The present invention's freezing treatment of cherry tomatoes can extend the length of the scratches and increase the drying speed.

[0025] After obtaining the frozen cherry tomatoes, the present invention freeze-dries the frozen cherry tomatoes with the cut side facing down to obtain dried cherry tomatoes.

[0026] After cherry tomatoes are sliced, their cut surface tissue is exposed, and the pericarp structure remains relatively intact. Different placement methods affect the moisture migration path, heating uniformity, and product shape retention. Using a reverse placement method with the cut surface facing down during the freeze-drying stage facilitates the migration of internal moisture from the cherry tomatoes, promoting the drying process, shortening the time required for subsequent combined drying, and resulting in a more intact sample with less collapse and deformation. When the cut surface faces up, the contact area between the material and the heating plate is relatively small, resulting in poor heat transfer and low drying efficiency. This invention optimizes the placement of cherry tomatoes during freeze-drying by selecting a cut surface facing down, improving drying efficiency and enhancing the product's appearance.

[0027] The reason why this invention chooses freeze drying instead of other drying methods is that other drying methods are not conducive to the subsequent expansion of pressure differential expansion drying. For example, hot air drying will cause the sample to collapse and fail to expand.

[0028] In one embodiment, the vacuum freeze-drying time of the present invention is 14-18 hours; in another embodiment, the vacuum freeze-drying time is 16 hours. In one embodiment, the pressure of the vacuum freeze-drying process is 30-100 Pa; in another embodiment, the pressure is 20-80 Pa; in yet another embodiment, the pressure is 50 Pa. In one embodiment, the parameters for the vacuum freeze-drying process are: -25°C for 2 hours, -15°C for 2 hours, -5°C for 2 hours, 5°C for 2 hours, 15°C for 2 hours, 25°C for 2 hours, 35°C for 2 hours, and 45°C for 0-4 hours. The present invention improves the processing effect by optimizing the pre-drying time of the vacuum freeze-drying process. Cherry tomatoes have a high water content. If the freeze-drying time is too short, the internal water content of the material will be too high, which can easily lead to leakage of contents, tissue collapse, and morphological deformation during the subsequent differential pressure puffing process. If the freeze-drying time is too long, it will increase the processing cycle and energy consumption, and may reduce the tissue puffing effect in the subsequent puffing stage. This invention compares the product states after vacuum freeze-drying for different times followed by differential pressure puffing. It was found that when vacuum freeze-drying for 14-18 hours, especially after 16 hours, is followed by differential pressure puffing, the samples have both good appearance integrity and form a good puffed pore structure and crisp texture, resulting in a better overall processing effect.

[0029] In one embodiment, the dried cherry tomatoes of this invention have a moisture content of 45% to 55%; in another embodiment, the moisture content of the dried cherry tomatoes of this invention is 50%. This invention, by controlling the moisture content of the cherry tomatoes at the end of vacuum freeze-drying and combining it with differential pressure puffing treatment, is beneficial to improving the puffing effect and the quality of the finished product. This invention freeze-dries the cherry tomatoes to a moisture content of 45% to 55% under vacuum, and then performs differential pressure puffing drying, ensuring that the material maintains a suitable internal moisture content when entering the puffing stage. This facilitates the generation of puffing force during the subsequent pressure relief process, promoting the formation of a more uniform porous structure and enhancing the crispness of the product.

[0030] After obtaining the dried cherry tomatoes, the present invention performs differential pressure puffing treatment on the cut side of the dried cherry tomatoes, followed by vacuum drying treatment to obtain cherry tomato crisps.

[0031] In the pressure differential puffing drying stage, cherry tomatoes are processed by laying them flat with the cut side facing upwards. If the cut side is placed downwards during puffing, the internal contents of the cherry tomatoes are prone to leaking out during the heating, pressurization, and depressurization processes, leading to severe deformation of the product shape and affecting the integrity and commercial value of the finished product. Therefore, this invention adopts a staged placement method, with the tomatoes placed upside down during the vacuum freeze-drying stage and laid flat during the pressure differential puffing drying stage. This method not only improves drying efficiency but also helps maintain the crisp appearance and quality of the cherry tomato pieces.

[0032] As one implementation method, the differential pressure expansion treatment of the present invention includes: heating and pressurizing to 80°C and 1.9 bar, and then holding for 10 minutes. The present invention limits the temperature and pressure of the pressurization, which can improve the expansion effect.

[0033] In one embodiment, the pressure of the vacuum drying process according to the present invention is 30~100 Pa; in another embodiment, the pressure of the vacuum drying process according to the present invention is 20~80 Pa; in yet another embodiment, the pressure of the vacuum drying process according to the present invention is 50 Pa. In one embodiment, the temperature of the vacuum drying process according to the present invention is 60~65℃; in yet another embodiment, the temperature of the vacuum drying process according to the present invention is 62℃. In one embodiment, the time of the vacuum drying process according to the present invention is 1.5~2.5 h; in yet another embodiment, the time of the vacuum drying process according to the present invention is 2 h.

[0034] This invention features a simple process that combines vacuum freeze-drying and differential pressure puffing drying. This combined drying technology can process cherry tomatoes, which are easily perishable after harvest and have a short shelf life, into crisp granules that are easy to store and transport. This improves the textural quality of the cherry tomato granules, thereby increasing their added value and commercial utilization. Cherry tomatoes have high water content, soft texture, and high sugar and acid content. Pre-drying with vacuum freeze-drying helps retain their natural color, flavor, and nutrients. Further combining this with differential pressure puffing drying technology utilizes instantaneous pressure changes to promote moisture migration and tissue puffing within the material, improving the internal pore structure of the product and resulting in cherry tomato granules with a superior crisp texture and fluffy characteristics.

[0035] Given the advantages of the cherry tomato processing method provided by this invention, the cherry tomato crisps obtained by the cherry tomato processing method described above also fall within the scope of protection of this invention. The cherry tomato crisps obtained by this invention have low shrinkage, minimal color variation, uniform overall coloring, sufficient hardness, stable crispness, and a crisp texture that is not easily broken.

[0036] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, provides a method for processing cherry tomatoes using freeze-drying combined with differential pressure puffing and drying, and cherry tomato crisps, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0037] Preliminary Example 1 (1) Fresh, mature, and undamaged yellow cherry tomatoes (Huangxing No. 7) with an initial moisture content of 91.77% were selected as raw materials. The peel was retained, and the tomatoes were washed with clean water to remove surface dirt and impurities and drain the surface moisture. The washing water met the requirements of GB 5749.

[0038] (2) Cut the washed yellow cherry tomatoes in half lengthwise and make 1, 2 or 3 1cm long scratches evenly on their skin.

[0039] (3) Arrange the halved yellow cherry tomatoes evenly on a freezing tray and freeze them in a freezer at -20℃, -40℃ or -80℃ for 24 hours, or freeze them in liquid nitrogen. Detect the length of different scratches. The results are shown in Table 1.

[0040] Table 1. Scratch length elongation rate (%) under different freezing methods

[0041] Note: Different capital letters in the same line indicate significant differences. P <0.05, different lowercase letters in the same column represent significant differences ( P <0.05).

[0042] As shown in Table 1, the elongation rate of scratch length varies significantly depending on the freezing temperature of cherry tomatoes, with the highest elongation rate observed at -40℃. The more scratches present, the greater the elongation rate. Therefore, the optimal freezing conditions are determined to be 3 scratches, frozen at -40℃ for 24 hours.

[0043] Example 1 (1) Select fresh, mature, and undamaged red cherry tomatoes (Fortes) as raw materials with an initial moisture content of 91.33%. Retain the peel, wash with clean water to remove surface dirt and impurities, and drain the surface moisture. The washing water shall comply with the provisions of GB 5749.

[0044] (2) Cut the washed red cherry tomatoes in half lengthwise and make three 1cm long scratches evenly on their skin.

[0045] (3) Arrange the halved red cherry tomatoes evenly on a freezing tray and freeze in a -40℃ freezer for 24 hours.

[0046] (4) Place the frozen red cherry tomatoes in a vacuum freeze-drying equipment with the cut side facing down (upside down), turn on the compressor, circulation pump and vacuum system to freeze-dry, the vacuum degree is 50pa, the process parameters for the freeze-drying stage are: -25℃ for 2h, -15℃ for 2h, -5℃ for 2h, 5℃ for 2h, 15℃ for 2h, 25℃ for 2h, 35℃ for 2h, 45℃ for 0~4h, that is, the vacuum freeze-drying time is 14~18h.

[0047] Comparative Example 1 Same as Example 1, except that in step (4) vacuum freeze drying, the cut side is placed upwards (flat).

[0048] Test Example 1 Red cherry tomatoes from Example 1 (reverse freeze-drying) and Comparative Example 1 (horizontal freeze-drying) were freeze-dried separately, and their moisture content was calculated. The results are as follows: Figure 1 As shown.

[0049] according to Figure 1 It can be seen that the drying rate of the reverse freeze-drying in Example 1 is much greater than that of the horizontal freeze-drying in Comparative Example 1.

[0050] Example 2 Red cherry tomatoes obtained from different vacuum freeze-drying times in Example 1 were placed with the cut side facing up in a differential pressure puffing drying device. The temperature and pressure were increased to 80°C and 1.9 bar and maintained for 10 minutes. The pressure was then released instantaneously, and the tomatoes were vacuum dried at 50 Pa and 60°C for 2 hours to obtain red cherry tomato crisps.

[0051] Comparative Example 2 Red cherry tomatoes obtained from different vacuum freeze-drying times in Comparative Example 1 were placed with the cut side facing up in a differential pressure puffing dryer. The temperature and pressure were increased to 80℃ and 1.9 bar and maintained for 10 minutes. The pressure was then released instantaneously, and the tomatoes were vacuum dried at 50 Pa and 60℃ for 2 hours to obtain red cherry tomato crisps.

[0052] Test Example 2 The red cherry tomato crisps obtained in Example 2 (reverse freeze-drying + horizontal pressure differential puffing drying) and Comparative Example 2 (horizontal freeze-drying + horizontal pressure differential puffing drying) were taken respectively, and their appearance was observed. The results are as follows: Figure 2 As shown.

[0053] according to Figure 2 It can be seen that, under the same freeze-drying time, compared with Example 2, the red cherry tomato crisps obtained by freeze-drying on flat surface followed by differential pressure puffing drying in Comparative Example 2 collapsed severely and had uneven color. The red cherry tomato crisps in Example 2 had a better appearance.

[0054] Example 3 A method for preparing yellow cherry tomato crispy granules comprises the following steps: (1) Fresh, mature, and undamaged yellow cherry tomatoes (Huangxing No. 7) with an initial moisture content of 91.77% were selected as raw materials. The peel was retained, and the tomatoes were washed with clean water to remove surface dirt and impurities and drain the surface moisture. The washing water met the requirements of GB 5749.

[0055] (2) Cut the washed yellow cherry tomatoes in half lengthwise and make three 1cm long scratches evenly on their skin.

[0056] (3) Arrange the halved yellow cherry tomatoes evenly on a freezing tray and freeze in a -40℃ freezer for 24 hours.

[0057] (4) Place the frozen yellow cherry tomatoes in a vacuum freeze-drying equipment with the cut side facing down (upside down), turn on the compressor, circulation pump and vacuum system to freeze-dry, the vacuum degree is 50pa, and the process parameters for the freeze-drying stage are: -25℃ for 2h, -15℃ for 2h, -5℃ for 2h, 5℃ for 2h, 15℃ for 2h, 25℃ for 2h, 35℃ for 2h, and 45℃ until the moisture content of the yellow cherry tomatoes reaches 50%.

[0058] (5) Place the freeze-dried yellow cherry tomatoes in a pressure differential puffing drying device with the cut side facing up, heat and pressurize to 80°C and 1.9 bar and maintain for 10 min, then release the pressure instantly and vacuum dry at 50 Pa and 60°C for 2 h to obtain yellow cherry tomato crisps.

[0059] Comparative Example 3 A method for preparing red cherry tomato crispy granules comprises the following steps: (1) Select fresh, mature, and undamaged red cherry tomatoes (Fortes) as raw materials with an initial moisture content of 91.33%. Retain the peel, wash with clean water to remove surface dirt and impurities, and drain the surface moisture. The washing water shall comply with the provisions of GB 5749.

[0060] (2) Following steps (2) to (5) of Example 3, the red cherry tomatoes were sliced, scratched, frozen, vacuum freeze-dried and pressure differential puffed to obtain red cherry tomato crisps.

[0061] Comparative Example 4 A method for preparing green cherry tomato crispy granules comprises the following steps: (1) Select fresh, mature, and undamaged green cherry tomatoes (Qingxia 66) as raw materials with an initial moisture content of 89.43%. Retain the peel, wash with clean water to remove surface dirt and impurities, and drain the surface moisture. The washing water shall comply with the provisions of GB 5749.

[0062] (2) Following steps (2) to (5) of Example 3, green cherry tomatoes were sliced, scratched, frozen, vacuum freeze-dried and pressure differential puffing dried in sequence to obtain green cherry tomato crisps.

[0063] Comparative Example 5 A method for preparing black cherry tomato crispy granules comprises the following steps: (1) Select fresh, mature, and undamaged black cherry tomatoes (colorful stars) as raw materials with an initial moisture content of 92.13%. Retain the peel, wash with clean water to remove surface dirt and impurities, and drain the surface moisture. The washing water shall comply with the provisions of GB 5749.

[0064] (2) Following steps (2) to (5) of Example 3, black cherry tomatoes were sliced, scratched, frozen, vacuum freeze-dried and pressure differential puffing dried in sequence to obtain black cherry tomato crisps.

[0065] Comparative Example 6 A method for preparing orange cherry tomato crisps comprises the following steps: (1) Select fresh, mature orange cherry tomatoes (Jinfei) without mechanical damage or rot as raw materials. The initial moisture content is 91.13%. Retain the peel, wash with clean water to remove surface dirt and impurities, and drain the surface moisture. The washing water shall comply with the provisions of GB 5749.

[0066] (2) Following steps (2) to (5) of Example 3, orange cherry tomatoes were sliced, scratched, frozen, vacuum freeze-dried, and pressure differential puffed to obtain orange cherry tomato crisps.

[0067] Comparative Example 7 A method for preparing pale yellow cherry tomato crisps comprises the following steps: (1) Fresh, ripe, and free from mechanical damage and rot are selected as light yellow cherry tomatoes (white crystals) with an initial moisture content of 90.87%. The peel is retained, and the tomatoes are washed with clean water to remove surface dirt and impurities and drain the surface moisture. The washing water meets the requirements of GB 5749.

[0068] (2) Following steps (2) to (5) of Example 3, the pale yellow cherry tomatoes were sliced, scratched, frozen, vacuum freeze-dried and pressure differential puffed to obtain pale yellow cherry tomato crisps.

[0069] Test Example 3 1. Samples: Cherry tomato crunches obtained in Example 3 and Comparative Examples 3-7.

[0070] 2. Referring to existing technology (Research on the regulation of texture and structure of yellow peach puffed crisps by impregnation pretreatment [D]. Shenyang Agricultural University, 2019.), the hardness and crispness of the samples were tested, and the results are as follows: Figures 3-4 As shown in Table 2.

[0071] Table 2. Hardness and crispness of different cherry tomato crunchy granules

[0072] Note: Different lowercase letters in the same column indicate significant differences. P <0.05).

[0073] according to Figures 3-4 As shown in Table 2, black and yellow cherry tomato granules exhibit higher hardness and crispness, while red varieties show the lowest. In subsequent production, black and yellow varieties are suitable for developing granule products, as they have sufficient hardness and stable crispness, resulting in a crisp texture that is not easily broken.

[0074] 3. Referring to existing technology (The Influence of Oils on the Texture of Fried French Fries and Its Mechanism [D]. Jiangnan University, 2021.), the shrinkage rate of the samples was tested, and the results are shown in Table 3.

[0075] Table 3 Shrinkage rate of different cherry tomato crisp pieces

[0076] Note: Different lowercase letters in the same line indicate significant differences. P <0.05), the same applies below.

[0077] As shown in Table 3, the yellow cherry tomato variety has the lowest shrinkage rate.

[0078] 4. Referring to existing technology (Research on pilot-scale process and quality control of microwave freeze-dried hawthorn using pulse-jet bed [D]. Jiangnan University, 2023), the color difference (ΔE), relative standard deviation of color (RSD), and color uniformity (UD) of the samples were tested. The results are as follows: Figure 5 As shown in Table 4.

[0079] Table 4. Color difference, standard deviation of color, and color uniformity of different cherry tomato crisp pieces

[0080] according to Figure 5 As shown in Table 4, the yellow variety has the largest ΔE, but its relative standard deviation (RSD) is small and its color uniformity (UD) is high. This indicates that the overall color change of yellow cherry tomatoes after drying is the largest, but the color variation between individuals within the variety is small and the overall color uniformity is good. The black variety has the smallest ΔE, but its RSD is relatively high and its color uniformity (UD) is the worst. This indicates that the overall color change of black cherry tomatoes before and after freeze-drying is small, but the color stability between individuals within the variety is large and the color uniformity is poor. The freeze-dried color change and uniformity characteristics of other color varieties are in between the two.

[0081] Based on the combined test results of hardness, brittleness, shrinkage, color difference, relative standard deviation of color, and color uniformity, the yellow variety is most suitable for vacuum freeze-drying followed by pressure differential puffing drying.

[0082] Comparative Example 8 A method for preparing yellow cherry tomato crisps differs from Example 3 in that it does not involve pressure differential puffing and drying. The specific preparation method consists of the following steps: (1) Select fresh, ripe, and undamaged yellow cherry tomatoes (Fortes) as raw materials, retain the peel, wash them with clean water to remove surface dirt and impurities, and drain the surface water; the water used for washing shall comply with the provisions of GB5749.

[0083] (2) Cut the washed yellow cherry tomatoes in half lengthwise and make three 1cm long scratches evenly on their skin.

[0084] (3) Arrange the halved yellow cherry tomatoes evenly on a freezing tray and freeze in a -40℃ freezer for 24 hours.

[0085] (4) Place the frozen yellow cherry tomatoes in a vacuum freeze-drying equipment with the cut side facing down (upside down), turn on the compressor, circulation pump and vacuum system to freeze-dry, the vacuum degree is 50pa, the freeze-drying process parameters are: -25℃ for 2h, -15℃ for 2h, -5℃ for 2h, 5℃ for 2h, 15℃ for 2h, 25℃ for 2h, 35℃ for 2h, 45℃ until the moisture content of the yellow cherry tomatoes reaches 5%~10%, and obtain yellow cherry tomato crisps.

[0086] Comparative Example 9 A method for preparing yellow cherry tomato crisps differs from Example 3 in that, after vacuum freeze-drying and before pressure differential puffing drying, a homogenization treatment is performed. The specific preparation method consists of the following steps: (1) Select fresh, ripe, and undamaged yellow cherry tomatoes (Fortes) as raw materials, retain the peel, wash them with clean water to remove surface dirt and impurities, and drain the surface water; the water used for washing shall comply with the provisions of GB5749.

[0087] (2) Cut the washed yellow cherry tomatoes in half lengthwise and make three 1cm long scratches evenly on their skin.

[0088] (3) Arrange the halved yellow cherry tomatoes evenly on a freezing tray and freeze in a -40℃ freezer for 24 hours.

[0089] (4) Place the frozen yellow cherry tomatoes in a vacuum freeze-drying equipment with the cut side facing down (upside down), turn on the compressor, circulation pump and vacuum system to freeze-dry, the vacuum degree is 50pa, and the process parameters for the freeze-drying stage are: -25℃ for 2h, -15℃ for 2h, -5℃ for 2h, 5℃ for 2h, 15℃ for 2h, 25℃ for 2h, 35℃ for 2h, and 45℃ until the moisture content of the yellow cherry tomatoes reaches 50%.

[0090] (5) Place the freeze-dried cherry tomatoes in a 4℃ freezer for 24 hours to allow them to dry evenly.

[0091] (6) Place the uniformly moistened yellow cherry tomatoes in a pressure differential puffing drying device with the cut side facing up, heat and pressurize to 80°C and 1.9 bar, maintain for 10 min, release pressure instantaneously, and vacuum dry at 50 Pa and 60°C for 2 h to obtain yellow cherry tomato crisps.

[0092] Test Example 4 1. Sample: Yellow cherry tomato crunchy pieces obtained from Example 3 and Comparative Examples 8-9.

[0093] 2. The basic properties of the sample were tested, and the testing indicators and methods are as follows: Hardness and brittleness: referring to existing technology (Influence of vacuum freeze-drying on the texture characteristics of pressure differential puffed dried fruit and vegetable crisps [J]. Transactions of the Chinese Society of Agricultural Engineering, 2024, 40(2): 144-154.). Shrinkage rate (%): Refer to existing technology (The Influence and Mechanism of Oil on the Texture of Fried French Fries [D]. Jiangnan University, 2021.).

[0094] The results are shown in Table 5.

[0095] Table 5. Basic properties of different yellow cherry tomato crunchy granules

[0096] As shown in Table 5, the cherry tomatoes of Example 3 have higher hardness and crispness than Comparative Example 8, but lower hardness than Comparative Example 9. Comparative Example 8 is not hard enough, while Comparative Example 9 is too hard and has an uneven surface with poor color uniformity. The cherry tomatoes of Example 3 have suitable hardness and crispness. The difference in transverse and longitudinal shrinkage rates between Example 3 and Comparative Example 8 is not significant. P >0.05), the shrinkage rates of the transverse and longitudinal diameters of Comparative Example 9 were significantly greater than those of Example 3 ( P <0.05).

[0097] 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 processing cherry tomatoes using freeze-drying combined with differential pressure puffing, characterized in that, Includes the following steps: Cut cherry tomatoes and make incisions on their skin to obtain pre-treated cherry tomatoes; The cherry tomatoes were frozen to obtain frozen cherry tomatoes; The frozen cherry tomatoes, with the cut side facing down, are subjected to vacuum freeze-drying to obtain dried cherry tomatoes. The dried cherry tomatoes, with their cut surfaces facing upwards, are subjected to differential pressure puffing followed by instant pressure release and vacuum drying until the moisture content is 5-10%, resulting in cherry tomato crisps. The differential pressure expansion treatment method includes: heating and pressurizing to 80~95℃, 1.5~2.0 bar, and then holding for 5~15 minutes.

2. The cherry tomato processing method according to claim 1, characterized in that, The cherry tomatoes mentioned are yellow cherry tomatoes.

3. The cherry tomato processing method according to claim 1, characterized in that, The moisture content of the dried cherry tomatoes is 45% to 55%.

4. The cherry tomato processing method according to claim 1, characterized in that, The vacuum freeze-drying process takes 14-18 hours and is carried out at a pressure of 30-100 Pa.

5. The cherry tomato processing method according to claim 4, characterized in that, The parameters for the vacuum freeze-drying process are: -25℃ for 2 hours, -15℃ for 2 hours, -5℃ for 2 hours, 5℃ for 2 hours, 15℃ for 2 hours, 25℃ for 2 hours, 35℃ for 2 hours, and 45℃ for 0~4 hours.

6. The cherry tomato processing method according to claim 1, characterized in that, The vacuum drying process is carried out at a pressure of 30~100Pa, a temperature of 60~65℃, and a time of 1.5~2.5h.

7. The cherry tomato processing method according to claim 1, characterized in that, The freezing process is carried out at a temperature of -35 to -45°C for 24 to 30 hours.

8. The cherry tomato processing method according to claim 1, characterized in that, The number of scratches is 1 to 3, and the length of each scratch is 0.5 to 1.5 cm.

9. The cherry tomato processing method according to claim 1, characterized in that, The cutting method is longitudinal cutting.

10. Cherry tomato crunches obtained by the cherry tomato processing method according to any one of claims 1 to 9.

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