Preparation method of comprehensive fruit and vegetable slices
By combining microwave vacuum drying with vacuum freeze drying, the problems of long drying time and high energy consumption in the prior art are solved, a more efficient and lower-cost production process is achieved, and the quality and nutritional value of the product are guaranteed.
Patent Information
- Application Number
- CN202411974710.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-03-18
AI Technical Summary
In the preparation process of fruit and vegetable slices, the existing freeze-drying method has a long drying time, high energy consumption and high production costs. In the long-term drying process, the problems of stratification and uneven moisture are easily encountered, resulting in uneven product quality.
The combination of microwave vacuum drying and vacuum freeze-drying is used to achieve a water loss of 80% to 90% through microwave vacuum drying, and then vacuum freeze-drying is carried out to control the drying curve and conditions to ensure the retention of nutritional value.
It significantly shortens the drying time, reduces energy consumption, improves production efficiency, reduces production costs, and ensures the stability of the product quality and high retention rate of nutritional value.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the field of food processing and relates to a method for preparing comprehensive fruit and vegetable slices. Background Art
[0002] With the improvement of people's living standards, the public's demand for edible fruits and vegetables has gradually increased, and market demand has promoted the research and development of a new generation of fruit and vegetable products. Freeze-dried mixed fruit and vegetable slices are made from a variety of fresh fruits and vegetables through freeze-drying. They are widely welcomed by consumers because of their convenience in carrying, eating and rich nutritional elements. Freeze-drying can better preserve the natural quality and nutritional value of fruits and vegetables, but the single freeze-drying method has a long drying time, resulting in a long production cycle, high production energy consumption and high production cost. In addition, during the long freeze-drying process, the product will be stratified and the quality of each slice will be uneven due to uneven water volatilization. Therefore, it is necessary to further study the preparation process of mixed fruit and vegetable slices. Summary of the invention
[0003] The invention provides a method for preparing comprehensive fruit and vegetable slices. The method comprises the following steps: subjecting a fruit and vegetable mixed pulp to microwave vacuum drying and then to vacuum freeze drying.
[0004] In some embodiments, the water loss after the microwave vacuum drying step is 80% to 90% of the mass of pure water added to the fruit and vegetable mixed pulp.
[0005] In some embodiments, the conditions of the microwave drying step are: vacuum degree of 0.095 MPa, microwave power of 1200w-1800w, and time of the microwave drying step is 1.5h-2h.
[0006] In some embodiments, the freeze-drying curve of the vacuum freeze-drying is: 50°C-2h, 60°C-2h, 70°C-2h, 60°C-5h, vacuum degree ≤90Pa, cold trap temperature ≤-30°C.
[0007] In some embodiments, the fruit and vegetable mixed pulp includes vegetables, fruits, polydextrose, whole milk powder, resistant dextrin, and purified water.
[0008] In some embodiments, the vegetables include organic bok choy, organic cucumber, organic purple cabbage, organic green cabbage, organic carrot, organic baby cabbage, and organic shiitake mushrooms; and the fruits include cantaloupe, grapes, blueberries, and apples.
[0009] In some embodiments, the method for preparing the fruit and vegetable mixed pulp is: weigh out the edible part of each vegetable, steam at 85-95° C. for 10-15 minutes, drain, mix with the remaining materials and beat, and then disperse through a colloid mill to obtain the fruit and vegetable mixed pulp.
[0010] The preparation method of the comprehensive fruit and vegetable slices provided by the present invention has the following characteristics:
[0011] (1) The prepared products have uniform thickness and color and stable quality;
[0012] (2) Combine microwave vacuum drying with vacuum freeze drying, screen specific drying sequences and water conversion points, and explore the process with the highest nutritional value retention. The total phenol retention rate of the prepared comprehensive fruit and vegetable slices is as high as 95.29%, the proanthocyanidins retention rate is as high as 97.81%, and the vitamin C retention rate is as high as 96%, which can fully meet the needs of consumers.
[0013] (3) Compared with the vacuum freeze-drying method alone, the preparation method provided by the present invention shortens the time by 31.58%, reduces the energy consumption by 28.57%, significantly improves the production efficiency, and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 This is a real picture of the comprehensive fruit and vegetable slices obtained in Example 1;
[0015] Figure 2 This is a real shot of the comprehensive fruit and vegetable slices obtained in Comparative Example 1;
[0016] Figure 3 It is a schematic diagram of using a vernier caliper to measure the thickness of the triangle of the integrated fruit and vegetable slice. DETAILED DESCRIPTION
[0017] The following specific embodiments are further detailed descriptions of the present invention.
[0018] In the present invention, unless otherwise specified, the scientific and technical terms used in the present invention have the meanings commonly understood by those skilled in the art. In addition, the laboratory operation steps used in the present invention are all conventional steps widely used in the corresponding fields.
[0019] the term:
[0020] The term "comprising" should be interpreted as open ended, indicating the presence of the listed elements but not excluding the existence, occurrence or addition of any other one or more elements that are not listed.
[0021] All ranges recited herein include those endpoints of the range between the two values recited. All values recited herein, whether or not stated, include the expected degree of experimental error, technical error, and instrumental error for the given technique used to measure the value.
[0022] In the present invention, unless otherwise specified, % is a percentage of weight / weight (w / w).
[0023] In the present invention, the fruit used is its edible part, usually the part without the core and / or seeds and the peel, such as the pulp of cantaloupe after removing the cantaloupe peel and cantaloupe seeds; the pulp of apple after removing the apple peel and apple core; the pulp of grape after removing the grape skin and grape seeds; the pulp and peel of blueberry.
[0024] In the present invention, the ingredients of the mixed fruit and vegetable slices may also include other food auxiliary materials to further enrich the taste of the fruit and vegetable slices. For example, oatmeal crumbs, oatmeal pulp powder, puffed oats, nut crumbs, etc. may be added as other auxiliary materials.
[0025] The following examples are intended to illustrate the present invention but are not intended to limit the scope of the present invention in any way.
[0026] Example 1
[0027] A method for preparing a comprehensive fruit and vegetable slice comprises the following steps:
[0028] (1) Preparation of fruit and vegetable mixed slurry: The edible part of each vegetable was weighed according to the formula in Table 1, steamed at 95°C for 10 min, drained, mixed with the remaining materials and slurried, and then dispersed in a colloid mill to obtain a fruit and vegetable mixed slurry, which was then injected into a mold.
[0029] Table 1 Ingredients of Fruit and Vegetable Mixed Pulp
[0030] Material Name Weight ratio (%) Organic Bok Choy 6 Organic cucumber 6 Organic purple cabbage 2 Organic green cabbage 2 Organic carrots 2 Organic baby cabbage 2 Organic Shiitake Mushrooms 2 cantaloupe 3 Grape 4 blueberry 4 apple 3 Polydextrose 7.5 Whole milk powder 2.5 Resistant dextrin 4 Pure water 50
[0031] (2) Microwave vacuum drying: The mold filled with fruit and vegetable puree is weighed and placed in a microwave vacuum drying furnace. The microwave vacuum drying conditions are: vacuum degree of 0.095 MPa, microwave power of 1200 W, drying for 2 h, taking out and weighing to calculate the water loss. At this time, the water loss is 80% of the mass of the initially added pure water, and then taking it out of the drying furnace.
[0032] (3) The mold filled with fruit and vegetable puree is placed in a cold storage at -30°C for quick freezing.
[0033] (4) The mold injected with the fruit and vegetable puree is placed in a freeze dryer for vacuum freeze drying. The freeze drying curve is: 50°C-2h, 60°C-2h, 70°C-2h, 60°C-5h. The vacuum degree is set to ≤90Pa, and the cold trap temperature is ≤-30°C.
[0034] (5) Demolding to obtain the mixed fruit and vegetable slices.
[0035] Example 2
[0036] (1) The formula and preparation process of the fruit and vegetable mixed pulp are the same as those in Example 1 and injected into the mold.
[0037] (2) Microwave vacuum drying: The mold filled with fruit and vegetable puree is weighed and placed in a microwave vacuum drying furnace. The microwave vacuum drying conditions are: vacuum degree of 0.095 MPa, microwave power of 1800 W, drying for 1.5 h, taking out and weighing to calculate the water loss. At this time, the water loss is 90% of the mass of the initially added pure water, and then taking it out of the drying furnace.
[0038] (3) The mold filled with fruit and vegetable puree is placed in a cold storage at -30°C for quick freezing.
[0039] (4) The mold injected with the fruit and vegetable puree is placed in a freeze dryer for vacuum freeze drying. The freeze drying curve is: 50°C-2h, 60°C-2j, 70°C-2j, 60°C-5j, the vacuum degree is set to ≤90Pa, and the cold trap temperature is ≤-30°C.
[0040] (5) Demolding to obtain the mixed fruit and vegetable slices.
[0041] Comparative Example 1
[0042] (1) The formula and preparation process of the fruit and vegetable mixed pulp are the same as those in Example 1 and injected into the mold.
[0043] (2) The mold filled with fruit and vegetable puree is placed in a cold storage at -30°C for quick freezing.
[0044] (3) The mold injected with the fruit and vegetable puree is placed in a freeze dryer for vacuum freeze drying. The freeze drying curve is: 50°C-5h, 60°C-2h, 70°C-2h, 70°C-5h, 60°C-5h, 50°C-3h. The vacuum degree is set to ≤90Pa, and the cold trap temperature is ≤-30°C.
[0045] (4) Demolding to obtain the mixed fruit and vegetable slices.
[0046] Compared with comparative example 1, the drying time of embodiment 1 is shortened from 19 hours to 13 hours, and the energy consumption is reduced by 28.57%. Figure 1 and Figure 2 As shown, the fruit and vegetable slices obtained in Example 1 have uniform color on the top and bottom and a crispy taste; the fruit and vegetable slices obtained in Comparative Example 1 have uneven color on the top and bottom and a relatively soft taste. It is speculated that this is because the drying time is too long, resulting in material sedimentation and uneven water evaporation. The thickness of the mixed dried fruits and vegetables obtained in Example 1 and Comparative Example 1 was measured with a vernier caliper at the triangle (such as Figure 3 The standard deviation of the triangle thickness is calculated as follows: Example 1 is 0.0216, and Comparative Example 1 is 0.26217. The thickness of the fruit and vegetable slices obtained in Example 1 is more uniform.
[0047] Comparative Example 2
[0048] (1) The formula and preparation process of the fruit and vegetable mixed pulp are the same as those in Example 1 and injected into the mold.
[0049] (2) Microwave vacuum drying: The mold filled with fruit and vegetable puree is weighed and placed in a microwave vacuum drying furnace. The microwave vacuum drying conditions are: vacuum degree of 0.095 MPa, microwave power of 2000 W, drying for 2 h, taking out and weighing to calculate the water loss. At this time, the water loss is 95% of the mass of the initially added pure water, and then taking it out of the drying furnace.
[0050] (3) The mold filled with fruit and vegetable puree is placed in a cold storage at -30°C for quick freezing.
[0051] (4) The mold injected with the fruit and vegetable puree is placed in a freeze dryer for vacuum freeze drying. The freeze drying curve is: 50°C-2h, 60°C-2h, 70°C-2h, 60°C-5h. The vacuum degree is set to ≤90Pa, and the cold trap temperature is ≤-30°C.
[0052] (5) Demolding to obtain the mixed fruit and vegetable slices.
[0053] Comparative Example 3
[0054] (1) The formula and preparation process of the fruit and vegetable mixed pulp are the same as those in Example 1 and injected into the mold.
[0055] (2) The mold filled with fruit and vegetable puree is weighed and placed in a freeze dryer for vacuum freeze drying: the freeze drying curve is: 50°C-2h, 60°C-2h, 70°C-2h, 60°C-5h, the vacuum degree is set to ≤90Pa, the cold trap temperature is ≤-30°C, and the water loss is calculated after taking out and weighing. At this time, the water loss is 20% of the mass of the pure water initially added.
[0056] (3) Microwave vacuum drying: Place the mold filled with fruit and vegetable puree into a microwave vacuum drying furnace. The microwave vacuum drying conditions are: vacuum degree of 0.095 MPa, microwave power of 1800 W, and take it out of the drying furnace after drying for 2 hours.
[0057] Nutrient retention testing
[0058] 100 g of the mixed dried fruits and vegetables obtained in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were respectively redissolved in water and filtered to obtain a test sample liquid; 100 g of the fruit and vegetable puree in Example 1 was measured and filtered to obtain a test sample liquid, and nutrient retention detection was performed in turn.
[0059] Total phenol content test
[0060] Using the FC method, take 0.5 mL of sample solution into a stoppered test tube, add 0.25 mL of FC reagent and then add 1.25 mL of sodium carbonate solution, shake the test tube, store the reaction sample in the dark for 40 minutes, and then measure the absorbance value at a wavelength of 725 nm.
[0061] Proanthocyanidin content detection
[0062] Using the n-butanol hydrochloric acid method, take 1 mL of sample solution into a stoppered test tube, add 6 mL of n-butanol hydrochloric acid solution and 0.2 mL of ammonium ferric sulfate solution in sequence, then heat in boiling water for 40 minutes and then cool rapidly. Use the reagent blank as a reference and measure its absorbance at a wavelength of 546 nm.
[0063] Vitamin C content detection
[0064] Pipette 10 ml of the sample solution into a 50 ml conical flask and quickly titrate with the calibrated 2,6-dichloroindophenol solution until the solution turns red. The end point is when the color does not fade for 15 seconds.
[0065] The results of nutrient retention test are shown in Table 2.
[0066] Table 2 Nutrient retention test results per 100g of comprehensive fruit and vegetable slices
[0067]
[0068] The above embodiments are intended to illustrate the essential content of the present invention, but are not intended to limit the protection scope of the present invention. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and protection scope of the technical solution of the present invention.
Claims
1. A method for preparing a comprehensive fruit and vegetable slice, characterized in that: The method comprises the following steps: firstly subjecting the fruit and vegetable mixed pulp to microwave vacuum drying and then subjecting the mixed pulp to vacuum freeze drying.
2. The preparation method according to claim 1, characterized in that The water loss after the microwave vacuum drying step is 80% to 90% of the mass of the pure water added to the fruit and vegetable mixed pulp.
3. The preparation method according to claim 1, characterized in that The conditions of the microwave drying step are: vacuum degree of 0.095 MPa, microwave power of 1200w-1800w, and time of the microwave drying step of 1.5h-2h.
4. The preparation method according to claim 1, characterized in that The freeze-drying curve of the vacuum freeze-drying is: 50°C-2h, 60°C-2h, 70°C-2h, 60°C-5h, vacuum degree ≤90Pa, cold trap temperature ≤-30°C.
5. The preparation method according to claim 1, characterized in that The fruit and vegetable mixed pulp comprises vegetables, fruits, polydextrose, whole milk powder, resistant dextrin and pure water.
6. The preparation method according to claim 5, characterized in that The vegetables include organic bok choy, organic cucumber, organic purple cabbage, organic green cabbage, organic carrot, organic baby cabbage, and organic shiitake mushrooms; and the fruits include cantaloupe, grapes, blueberries, and apples.
7. The preparation method according to claim 5, characterized in that The preparation method of the fruit and vegetable mixed pulp is as follows: weigh out the edible part of each vegetable, steam and cook at 85-95° C. for 10-15 minutes, drain, mix and pulp with the remaining materials, and disperse through a colloid mill to obtain the fruit and vegetable mixed pulp.