Method for improving vacuum pulse drying efficiency and product quality of juicy peaches

Abstract

The invention belongs to the technical field of agricultural product processing, and particularly relates to a method for improving vacuum pulse drying efficiency and product quality of juicy peaches. The method comprises the following steps: firstly, finishing grading screening of juicy peaches according to maturity, peeling the screened juicy peaches, and slicing to obtain juicy peach slices; mixing ethanol, cane sugar and an aqueous solution to form a binary mixed solution; and perforating the juicy peach slices, immersing the juicy peach slices into a binary mixed solution, and then carrying out vacuum pulse drying to obtain the dehydrated juicy peach slices. According to the processing method disclosed by the invention, by adopting a processing method of combining maturity grading screening, perforation synergy and'ethanol + cane sugar 'binary mixed solution dipping pretreatment, the drying time of the juicy peach slices is remarkably shortened, the vacuum pulsating drying efficiency, sweetness and rehydration rate of the juicy peach slices are improved, the volume shrinkage is reduced, and the processing quality is improved. And a new method is provided for industrial quality-improving and efficiency-improving production of the dehydrated juicy peach slices. The method is simple, environment-friendly and wide in application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural product processing, and particularly relates to a method for improving the vacuum pulsation drying efficiency and product quality of peaches. Background Art

[0002] Peaches are popular among consumers because of their fragrant flesh and rich nutrition, but fresh peaches are not resistant to storage and the picking period is concentrated. In order to extend the supply cycle of peaches and increase economic benefits, drying is considered an effective solution. Among them, vacuum pulsation drying is a commonly used drying method in industrial production, which has the advantages of low cost, simple operation, and high product quality. However, vacuum pulsation drying also has some problems that need to be improved urgently, namely: low drying efficiency, quality deterioration, high energy consumption and other "one high and two low" problems. These prominent problems further limit the application of vacuum pulsation drying technology and become a severe challenge facing the field of fruit and vegetable drying and processing at this stage.

[0003] In recent years, drying pretreatment technology has gradually become a hot topic in the field of peach drying due to its low energy consumption, high efficiency, and non-thermal characteristics. For example, physical field technologies such as ultrasound, pulsed electric field, freeze-thaw, etc., improve drying efficiency by destroying the tissue structure and cell structure of fruits and vegetables and reducing the resistance of internal water to diffuse outward. However, it is undeniable that the application of these pretreatment technologies has improved the drying characteristics, but their application requires the use of professional ultrasonic equipment, pulsed electric field equipment, freezing equipment, etc. to generate third effects such as acoustic cavitation, electroporation, and ice crystal growth to form microchannels, which has high production costs and complex operations. Based on the production method of low equipment cost and simple operation, the application of these pretreatment technologies is significantly limited.

[0004] In addition to improving the drying characteristics of peaches by destroying the cell structure through physical fields, osmotic pre-dehydration of hypertonic solutions has also been applied to the pre-drying treatment of peaches and other fruits and vegetables. Pre-dehydration reduces the subsequent drying load and improves the drying process efficiency. At present, in industrial applications, the osmotic dehydration of peaches is mainly based on a single high-concentration sucrose solution. Since osmotic dehydration only relies on osmotic pressure difference for dehydration, its low efficiency is a significant disadvantage. In response to this problem, some scholars have combined physical field technology (ultrasound, pulsed electric field, freeze-thaw) with osmotic dehydration technology for pre-drying of peaches and other fruits and vegetables. Although certain effects have been achieved based on a single technology, the purpose of low equipment cost, simple operation and efficient process has not been significantly broken through.

[0005] Therefore, faced with the prominent problems of "one high and two lows" in the field of vacuum pulsation drying of peaches, as well as the high cost of equipment, complex operation, and low efficiency of osmotic dehydration of current drying pretreatment technology, on this basis, technical methods with low equipment cost, simple operation, and high process efficiency urgently need to be researched and broken through. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, the present invention aims to solve one of the problems; it provides a method for improving the vacuum pulsation drying efficiency and product quality of peaches, thereby improving the vacuum pulsation drying efficiency of peach slices, while also inhibiting the appearance deformation of peach slices to a certain extent, improving the sweetness and rehydration characteristics, and providing a new method for industrial quality improvement and efficiency enhancement production of dehydrated peach slices.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] A method for improving the efficiency and product quality of vacuum pulsation drying of peaches, the specific steps are as follows:

[0009] First, peaches are graded and screened according to their maturity, and the screened peaches are peeled and sliced ​​to obtain peach slices; then ethanol, sucrose and an aqueous solution are mixed to form a binary mixed solution; the mass percentage of ethanol in the binary mixed solution is 65-85%, and the mass percentage of sucrose is 5-15%; the peach slices are perforated and immersed in the binary mixed solution, the immersion temperature is 25-37°C, and the time is 15-45 minutes; after the immersion, the dehydrated peach slices are obtained by vacuum pulse drying.

[0010] Furthermore, the maturity of the fresh peaches is differentiated according to the Chinese commercial standard "Fresh peaches SB / T 10090-92", with a maturity of five to ten percent, a horizontal diameter of 7-9 cm, and a vertical diameter of 7-9 cm.

[0011] Furthermore, the peach slices have a thickness of 3-5 mm and a diameter of 2-3 cm.

[0012] Furthermore, the tool for perforating the peach slices includes a puncture needle, which evenly perforates the peach slices.

[0013] Furthermore, the perforation has a diameter of 0.3-0.5 mm and a number of holes of 10-16 holes / cm. 2 .

[0014] Furthermore, the mass percentage of ethanol in the binary mixed solution is 75-85%, and the mass percentage of sucrose is 5-10%.

[0015] Furthermore, the immersion conditions are a temperature of 25-30° C. and a time of 15-30 min.

[0016] Furthermore, the vacuum pulsation drying heating temperature is 60° C., the vacuum degree is 0.05 MPa, and the pulse interval is 15 min.

[0017] Beneficial effects of the present invention:

[0018] (1) The present invention selects the most suitable peach maturity for drying before pretreatment. This method improves the drying efficiency and product quality based on the physiological characteristics of the peach itself.

[0019] (2) The present invention adopts the "ethanol + sucrose" binary mixed solution immersion treatment technology, which removes part of the water from the peaches through the high permeability of the binary mixed solution and reduces the subsequent drying load; secondly, ethanol treatment can dissolve cell membrane components, improve cell permeability, and reduce the resistance of intracellular water to diffuse outward during the drying process. At the same time, it can also solidify the tissue structure of the peach slices and prevent excessive deformation of the product appearance after drying; thirdly, during the immersion process, sucrose penetrates into the tissue, which plays a role in increasing the sweetness of the product and improving the taste.

[0020] (3) The present invention artificially punctures the peach slices before impregnation with the binary mixed solution to form a large number of micropores, which can promote water migration, thereby enhancing the effect of ethanol impregnation and subsequent drying efficiency, and at the same time can improve the rehydration characteristics of the dried product.

[0021] (4) The present invention combines maturity screening and puncture with the pretreatment technology of immersion in a binary mixed solution of "ethanol + sucrose", thereby improving the vacuum pulsation drying efficiency of peach slices. At the same time, it also inhibits the appearance deformation of peach slices to a certain extent, improves the sweetness and rehydration characteristics, and provides a new method for industrial production of dehydrated peach slices with improved quality and efficiency. DETAILED DESCRIPTION

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] It should be understood that the terms used in the present invention are only used to describe particular embodiments and are not intended to limit the present invention.

[0024] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0025] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0026] Comparative Example 1:

[0027] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, no mold, 70% ripe, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Vacuum pulse drying is carried out under the conditions of heating temperature 60℃, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, sugar-acid ratio, rehydration ratio, and volume shrinkage of the dried peach slices are measured. The specific detection method is as follows:

[0028] (1) Rehydration ratio:

[0029] Soak the dehydrated peach sample in distilled water at 25°C, take out the sample every 10 minutes, wipe the surface moisture of the sample slightly, weigh it, and then place it in distilled water to continue rehydration until the sample mass is constant. The rehydration ratio (RR) of the dehydrated peach sample is calculated according to the following formula:

[0030]

[0031] Where w t is the mass of the sample at t (g); w0 is the mass of the sample before rehydration (g).

[0032] (2) Sugar-acid ratio: The rehydrated sample was homogenized and filtered through three layers of gauze to extract the juice. The soluble solid content was measured at 25°C using a refractometer; the total titratable acid content was obtained by NaOH titration and expressed as the citric acid content of the sample. The sugar-acid ratio is soluble solids / total titratable acid.

[0033] (3) Volume shrinkage:

[0034] Fresh and dehydrated peach samples were filled with 400-mesh ultrafine quartz sand in a 100-mL measuring cylinder and their volumes were measured. The volume shrinkage ratio (VSR) of the samples before and after drying was calculated using the following formula:

[0035]

[0036] Where v0 is the volume of the peach sample before drying (cm 3 );vd is the volume of the dried peach sample (cm 3 ).

[0037] The tests of the above physical and chemical indicators were repeated three times, and the results were averaged.

[0038] Embodiment 1:

[0039] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.3mm on the surface of the peach slices, with 10 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 65% / 15%) and immerse at 25°C for 15 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0040] Embodiment 2:

[0041] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, 90% ripe, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.4mm on the surface of the peach slices, with 16 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 85% / 5%) and immerse at 25°C for 15 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0042] Embodiment 3:

[0043] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, 90% ripe, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.3mm on the surface of the peach slices, with 16 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 75% / 10%) and immerse at 25°C for 15 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0044] Embodiment 4:

[0045] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, 70% ripe, without mold or rot, with a horizontal diameter of 7-9 cm and a vertical diameter of 7-9 cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.5mm on the surface of the peach slices, with 13 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 75% / 10%) and immerse at 25°C for 30 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0046] Embodiment 5:

[0047] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, without mold or rot, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.5mm on the surface of the peach slices, with 10 holes / cm 2. Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 85% / 5%) and immerse at 37°C for 15 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. For specific detection methods, refer to Comparative Example 1.

[0048] Embodiment 6:

[0049] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, 70% ripe, without mold or rot, with a horizontal diameter of 7-9 cm and a vertical diameter of 7-9 cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.4mm on the surface of the peach slices, with 13 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 65% / 15%) and immerse at 25°C for 30 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0050] Embodiment 7:

[0051] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, 70% ripe, without mold or rot, with a horizontal diameter of 7-9 cm and a vertical diameter of 7-9 cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.5mm on the surface of the peach slices, with 16 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 85% / 5%) and immerse at 25°C for 30 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0052] Embodiment 8:

[0053] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.4mm on the surface of the peach slices, with 16 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 75% / 10%) and immerse at 37°C for 30 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. For specific detection methods, refer to Comparative Example 1.

[0054] Embodiment 9:

[0055] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.3mm on the surface of the peach slices, with 13 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 75% / 10%) and immerse at 25°C for 45 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0056] Embodiment 10:

[0057] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, 90% ripe, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.5mm on the surface of the peach slices, with 13 holes / cm 2. Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 65% / 15%) and immerse at 25°C for 15 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0058] Embodiment 11:

[0059] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, 90% ripe, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.4mm on the surface of the peach slices, with 10 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 65% / 15%) and immerse at 37°C for 30 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. For specific detection methods, refer to Comparative Example 1.

[0060] Embodiment 12:

[0061] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, 70% ripe, without mold or rot, with a horizontal diameter of 7-9 cm and a vertical diameter of 7-9 cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.3mm on the surface of the peach slices, with 10 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 85% / 5%) and immerse at 25°C for 30 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0062] Embodiment 13:

[0063] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, without mold or rot, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.4mm on the surface of the peach slices, with 13 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 85% / 5%) and immerse at 25°C for 45 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0064] Embodiment 14:

[0065] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, 70% ripe, without mold or rot, with a horizontal diameter of 7-9 cm and a vertical diameter of 7-9 cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.4mm on the surface of the peach slices, with 10 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 75% / 10%) and immerse at 25°C for 45 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0066] Embodiment 15:

[0067] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, without mold or rot, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.5mm on the surface of the peach slices, with 16 holes / cm 2. Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 65% / 15%) and immerse at 37°C for 45 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. For specific detection methods, refer to Comparative Example 1.

[0068] Embodiment 16:

[0069] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, 90% ripe, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.5mm on the surface of the peach slices, with 10 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 75% / 10%) and immerse at 25°C for 45 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0070] Embodiment 17:

[0071] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, 70% ripe, without mold or rot, with a horizontal diameter of 7-9 cm and a vertical diameter of 7-9 cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.3mm on the surface of the peach slices, with 16 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 65% / 15%) and immerse at 25°C for 45 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. Refer to Comparative Example 1 for the specific detection method.

[0072] Embodiment 18:

[0073] Based on the Chinese commercial standard "Fresh peach SB / T 10090-92", select fresh peaches of uniform size, free of mold and rot, 90% ripe, with a horizontal diameter of 7-9cm and a vertical diameter of 7-9cm, and make peach slices (taking thickness / diameter: 3mm / 3cm as an example). Use a puncture needle to puncture holes with a diameter of 0.3mm on the surface of the peach slices, with 13 holes / cm 2 . Then mix ethanol, sucrose and aqueous solution to form a binary mixed solution; then place the punctured peach slices in an "ethanol + sucrose" mixed solution (ethanol / sucrose: 85% / 5%) and immerse at 37°C for 45 minutes. Vacuum pulsation drying is carried out under the conditions of heating temperature 60°C, vacuum degree 0.05MPa, and pulse interval 15min, and the drying is stopped when the dry basis moisture content of the sample is lower than 0.1g / g. After drying, the drying time, rehydration ratio and volume shrinkage rate of the dried peach slices are measured. For specific detection methods, refer to Comparative Example 1.

[0074] The drying time, rehydration ratio, sugar-acid ratio and volume shrinkage of the dried peach slices of Comparative Example 1 and Examples 1-18 are shown in Table 1.

[0075] Table 1 Comparative Examples and Examples Drying time, rehydration ratio, sugar-acid ratio and volume shrinkage of peach slices

[0076]

[0077]

[0078] It can be seen from the above results that: compared with comparative example 1, examples 1-18 treated with the method of the present invention significantly shortened the drying time of peach slices, improved the drying efficiency, and significantly improved typical product qualities such as rehydration, sugar-acid ratio, and volume shrinkage.

[0079] In addition, the process conditions of the treatment are also crucial; for example, the preparation of the "ethanol + sucrose" mixed solution is very important, and the dosage of ethanol and sucrose cannot be simply adjusted. Too high or too low dosages cannot obtain the best effect; for example, the immersion time, such as Example 1, immersion for 15 minutes, the effect is not good; generally speaking, it is believed that the longer the immersion time, the better the effect, but this is not the case. For example, in Examples 13 and 15, the immersion time is 45 minutes, and the results obtained under too long an immersion time are not the best. The present invention combines process and parameter improvements to achieve significant technical effects under suitable conditions; for example, the peach slices obtained in Example 7 (ethanol / sucrose: 85% / 5%; immersion at 25°C for 30 minutes) have the shortest drying time, the highest rehydration ratio and sugar-acid ratio, and the lowest volume shrinkage rate. Compared with Comparative Example 1, the vacuum pulsation drying time of peach slices obtained in Example 7 was shortened by 34.54%, the rehydration ratio was enhanced by 44.99%, the sugar-acid ratio was increased by 53.15%, and the volume shrinkage was reduced by 40.90%, achieving unexpected significant results.

[0080] Therefore, the method for improving the vacuum pulsation drying efficiency and product quality of peaches of the present invention can significantly shorten the dehydration time of peach slices, improve the rehydration effect, increase the sugar-acid ratio level and inhibit the excessive shrinkage of the volume of peach slices after drying, thereby providing a new method for industrialized efficient production of dehydrated peach slices, and also providing a high-quality peach product for the consumer market.

[0081] 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 this specification has described the present invention in detail with reference to the above embodiments, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof 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 improving the efficiency and product quality of vacuum pulsation drying of peaches, characterized in that: The specific steps are as follows: first, peaches are graded and screened according to maturity, and the screened peaches are peeled and sliced ​​to obtain peach slices; then, ethanol, sucrose and an aqueous solution are mixed to form a binary mixed solution; the mass percentage of ethanol in the binary mixed solution is 65-85%, and the mass percentage of sucrose is 5-15%; after perforating the peach slices, the peach slices are immersed in the binary mixed solution, the immersion temperature is 25-37°C, and the time is 15-45 minutes; after immersion, vacuum pulse drying is performed to obtain dehydrated peach slices.

2. A method for improving the vacuum pulsation drying efficiency and product quality of peaches according to claim 1, characterized in that: The maturity of the fresh peaches is distinguished according to the Chinese commercial standard "Fresh peaches SB / T 10090-92", and the maturity is between five and ten, with a horizontal diameter of 7-9 cm and a vertical diameter of 7-9 cm.

3. A method for improving the vacuum pulsation drying efficiency and product quality of peaches according to claim 1, characterized in that: The peach slices have a thickness of 3-5 mm and a diameter of 2-3 cm.

4. A method for improving the vacuum pulsation drying efficiency and product quality of peaches according to claim 1, characterized in that: The tool for perforating the peach slices comprises a puncture needle, which is used to evenly perforate the peach slices.

5. The method for improving the vacuum pulsation drying efficiency and product quality of peaches according to claim 1, characterized in that: The perforation diameter is 0.3-0.5 mm, and the number of holes is 10-16 holes / cm 2 .

6. The method for improving the vacuum pulsation drying efficiency and product quality of peaches according to claim 1, characterized in that: The mass percentage of ethanol in the binary mixed solution is 75-85%, and the mass percentage of sucrose is 5-10%.

7. The method for improving the vacuum pulsation drying efficiency and product quality of peaches according to claim 1, characterized in that: The immersion conditions are as follows: a temperature of 25-30° C. and a time of 15-30 min.

8. The method for improving the vacuum pulsation drying efficiency and product quality of peaches according to claim 1, characterized in that: The vacuum pulsation drying heating temperature is 60° C., the vacuum degree is 0.05 MPa, and the pulse interval is 15 min.

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