阅读说明：本技术 一种超声联合循环冻融处理南瓜果肉的方法 (Method for treating pumpkin pulp by ultrasonic combined circulating freeze-thawing ) 是由 范柳萍 绰尔鹏 李进伟 于 2021-07-06 设计创作，主要内容包括：本发明公开了一种超声联合循环冻融处理南瓜果肉的方法,属于果蔬精深加工技术领域。本发明以新鲜籽用南瓜为原料,进行超声波联合循环冻融预处理再远红外干燥来提高籽用南瓜果肉干燥品质。与常规远红外干燥工艺相比,本发明采用超声波联合循环冻融预处理的籽用南瓜果肉远红外干燥方法,结合了超声波、循环冻融预处理各自的优势,与不经预处理直接远红外干燥的籽用南瓜果肉产品相比,提高了籽用南瓜远红外干燥效率,使干燥时间缩短了25％～40％,产品外观完整率高,更接近新鲜籽用南瓜果肉颜色,皱缩率小,硬度、脆度适中,游离酚类含量、单体酚含量均显著高于常规远红外干燥。(The invention discloses a method for treating pumpkin pulp by ultrasonic combined circulating freeze-thawing, belonging to the technical field of deep processing of fruits and vegetables. The invention takes fresh pumpkin for seeds as raw material, and improves the pulp drying quality of the pumpkin for seeds by ultrasonic wave combined cycle freeze-thaw pretreatment and far infrared drying. Compared with the conventional far infrared drying process, the seed pumpkin pulp far infrared drying method adopting ultrasonic wave combined circulating freeze-thaw pretreatment combines the advantages of ultrasonic wave and circulating freeze-thaw pretreatment, improves the far infrared drying efficiency of seed pumpkin compared with the seed pumpkin pulp product directly subjected to far infrared drying without pretreatment, shortens the drying time by 25-40%, has high product appearance integrity rate, is closer to the color of fresh seed pumpkin pulp, has small wrinkle shrinkage rate, moderate hardness and brittleness, and has free phenol content and monomer phenol content which are obviously higher than those of the conventional far infrared drying.)

1. The method for pretreating the pumpkin pulp is characterized by adopting ultrasonic combined circulating freeze-thawing to pretreat the pumpkin pulp.

2. The method of claim 1, wherein the pumpkin pulp is sonicated prior to the circulating freeze-thaw process.

3. The method according to claim 1 or 2, wherein the sonication conditions are: placing pumpkin pulp in an ultrasonic condition with the frequency of 20-25 KHz and the power of 60-360W, and carrying out ultrasonic treatment in deionized water at the temperature of 25-30 ℃ for 10-30 min, wherein the material-liquid ratio is 1: 5-1: 6.

4. the method according to any one of claims 1-3, wherein the cyclic freeze-thaw treatment conditions are: the pumpkin pulp is frozen in a low-temperature refrigerator at the freezing temperature of-20 to-30 ℃ until the central temperature is-15 to-20 ℃, and then is unfrozen in the environment of 20 to 25 ℃ for 1 to 3 times.

5. Use of the pretreatment of any one of claims 1-4 to prepare a pumpkin product.

6. A method for preparing dried pumpkin fruit meat, which is characterized in that pumpkin is cut into slices, the pumpkin slices are processed by adopting the pretreatment of any one of claims 1 to 4, and then the dried pumpkin fruit meat is obtained by drying.

7. The method of claim 6, wherein the drying comprises hot air drying, infrared drying, or vacuum freeze drying.

8. The method according to claim 7, characterized in that the infrared drying conditions are: the far infrared wavelength range is 5-15 mu m, the distance between a far infrared light source and seed pumpkin pulp is 8-10 cm, the far infrared drying temperature is 60-80 ℃, and the drying time is 1-2 hours.

9. Dried pumpkin pulp obtained by the method according to any one of claims 6 to 8.

10. A food product comprising the dried pumpkin pulp of claim 9.

Technical Field

The invention relates to a method for treating pumpkin pulp by ultrasonic combined circulating freeze thawing, belonging to the technical field of deep processing of fruits and vegetables.

Background

The pumpkin for seed is a generic name of pumpkin having seed as main edible organ or processed object, and belongs to the genus Cucurbita of the family Cucurbitaceae. The annual output of the seed pumpkin in China is 30-40 ten thousand tons, and the first pumpkin occupies the world. At present, the pumpkin for seeds has been developed on an initial scale, but mainly pumpkin seeds are taken as main materials, and the comprehensive development of pulp resources is relatively lagged. Because farmers do not harvest seeds in time after the pumpkin is ripe, but directly break the pumpkin to extract seeds when the pulp is about to rot, and then discard the pulp in the field, great economic loss, resource waste and environmental pollution are caused. However, the pumpkin pulp used as the seed is rich in bioactive substances, mainly comprising phenols, carotenoid, soluble sugar, protein, vitamin, mineral substances, trace elements and the like. Therefore, in order to give full play to resource advantages, save energy, reduce emission and increase the economic income of growers, the comprehensive development and utilization of the pumpkin pulp for seeds are of great value.

However, the water content of the fresh pumpkin pulp for seeds is between 80 and 90 percent, and the fresh pumpkin pulp for seeds is easy to rot and deteriorate due to mechanical damage, growth of microorganisms, mildew and the like during harvesting and storage, so that the sensory and nutritional quality of the pumpkin for seeds is influenced, and the pumpkin for seeds is difficult to store for a medium and long term or supply all the year round, so that the pumpkin can be dehydrated and dried for storage. The common drying method for fruits and vegetables relates to various drying modes such as hot air drying, infrared drying, vacuum freeze drying and the like. Wherein, far infrared drying is economic suitable for and sample handling capacity is big because its drying rate is faster than other drying methods, uses more in the industrialization is used. However, when the far infrared ray is dried, the infrared ray is easily absorbed by water vapor and the like and is lost, so that the energy utilization rate is reduced, and the application of the far infrared ray is limited. Therefore, the problem to be solved in the seed pumpkin pulp drying is how to improve the quality and the drying rate of the dried seed pumpkin slices.

Disclosure of Invention

[ problem ] to provide a method for producing a semiconductor device

The technical problems to be solved in practice by the invention are as follows: provides a pretreatment method for improving the drying quality of seed pumpkin pulp.

[ technical solution ] A

According to the invention, through carrying out ultrasonic wave combined cycle freeze-thaw pretreatment on the pumpkin pulp for seeds, the drying rate of the pumpkin pulp for seeds can be obviously improved, and the appearance, the contents of phenols and carotenoids of the pumpkin pulp for seeds after drying can be ensured. Freeze-thaw refers to the process of freezing an item at low temperature followed by rewarming and thawing at high temperature. After the plant tissue is subjected to freezing and thawing treatment for one time or repeatedly, the tissue structure of the plant tissue is loosened and scattered in different degrees, the freezing and thawing process can promote the removal of the moisture of the plant tissue and the formation of a porous structure, the concentration of solution in an unfrozen area near ice crystals is gradually increased in the freezing process, a system generates a chemical potential difference driven transfer process, and semi-bound water or even bound water in the tissue structure is stripped to be free water, so that the drying process is promoted to a certain degree. Ultrasound is a mechanical vibration that acts on the object by being applied to an elastic medium, and produces thermal effects, mechanical effects, and cavitation to the ultrasound object by mutual mechanical vibration with the medium. Meanwhile, the ultrasonic wave can accelerate the mass and heat transfer coefficient of the late drying of the fruits and vegetables and improve the drying rate. The invention aims to provide a method for improving the seed pumpkin pulp drying quality by ultrasonic combined circulating freeze-thaw pretreatment, which can remarkably improve the drying rate and simultaneously remarkably improve the sensory quality, the phenols and the carotenoid content of a seed pumpkin pulp dry product compared with the traditional far infrared drying.

The first purpose of the invention is to provide a pumpkin pulp pretreatment method, which adopts ultrasonic combined cycle freezing and thawing to pretreat the pumpkin pulp.

In one embodiment of the present invention, preferably, the pumpkin pulp is first subjected to ultrasonic treatment and then to a circulating freeze-thaw treatment.

In one embodiment of the invention, the sonication conditions are: placing pumpkin pulp in an ultrasonic condition with the frequency of 20-25 KHz and the power of 60-360W, and carrying out ultrasonic treatment in deionized water at the temperature of 25-30 ℃ for 10-30 min, wherein the material-liquid ratio is 1: 5-1: 6.

in one embodiment of the invention, the cyclic freeze-thaw treatment conditions are: the pumpkin pulp is frozen in a low-temperature refrigerator at the freezing temperature of-20 to-30 ℃ until the central temperature is-15 to-20 ℃, and then is unfrozen in the environment of 20 to 25 ℃ for 1 to 3 times.

The second purpose of the invention is to provide an application of the pretreatment in preparing pumpkin products.

The third purpose of the invention is to provide a method for preparing the dried pumpkin fruit meat, which comprises the steps of slicing the pumpkin, processing the pumpkin slices by adopting the pretreatment, and drying to obtain the dried pumpkin fruit meat.

In one embodiment of the invention, the drying comprises hot air drying, infrared drying and vacuum freeze drying.

In one embodiment of the present invention, the infrared drying conditions are: the far infrared wavelength range is 5-15 mu m, the distance between a far infrared light source and seed pumpkin pulp is 8-10 cm, the far infrared drying temperature is 60-80 ℃, and the drying time is 1-2 hours.

In one embodiment of the invention, the method comprises the steps of:

(1) peeling, removing seeds and slicing: peeling the cleaned seeds with pumpkin, removing the seeds, and cutting into slices with the thickness of 2-4 mm by using a slicing machine;

(2) ultrasonic pretreatment: and (2) placing the pumpkin pulp for seeds in the step (1) in ultrasonic conditions of frequency of 20-25 KHz and power of 60-360W, and carrying out ultrasonic treatment in deionized water at the temperature of 25-30 ℃ for 10-30 min, wherein the material-liquid ratio is 1: 5-1: 6.

(3) and (3) circulating freeze-thaw treatment: freezing the pumpkin pulp for seeds in the step (2) in a low-temperature refrigerator at the freezing temperature of-20 to-30 ℃ to the central temperature of-15 to-20 ℃, and then unfreezing the pumpkin pulp at the temperature of 20 to 25 ℃ for 1 to 3 times;

(4) far infrared drying: and (4) spreading the pumpkin pulp for seeds processed in the step (3) in a far infrared drying tray for far infrared drying until the pumpkin pulp reaches the drying end point, wherein the safe water content is 7-8%. The far infrared drying conditions are as follows: the far infrared wavelength range is 5-15 mu m, the distance between a far infrared light source and seed pumpkin pulp is 8-10 cm, the far infrared drying temperature is 60-80 ℃, and the drying time is 1-2 hours.

The fourth purpose of the invention is to provide the dried pumpkin pulp prepared by the method.

The fifth purpose of the invention is to provide a food containing the south melon fruit jerky.

The invention has the beneficial effects that:

according to the invention, a specific pretreatment process combining low-frequency ultrasound and circulating freeze-thaw pretreatment is adopted, compared with direct far-infrared drying, the seed pumpkin pulp far-infrared drying rate is remarkably improved, the drying time is reduced by 25% -40%, the color of the dried seed pumpkin pulp is closer to the color of fresh seed pumpkin pulp, the wrinkle rate is small, the hardness and brittleness are moderate, and the retention rate of phenols and carotenoids is high.

Drawings

FIG. 1 is a graph showing the drying curves of the pumpkin pulp for seed used in examples 1 to 5 and comparative examples 1 to 2.

FIG. 2 is a graph showing the drying rate of the pumpkin pulp for seed used in examples 1 to 5 and comparative examples 1 to 2.

Detailed Description

The present invention is described in further detail below with reference to specific examples, but the embodiments of the present invention are not limited to these examples.

1. Method for measuring moisture content

The moisture content was determined with reference to GB 5009.3-2016.

2. The detection method of the chromatic aberration comprises the following steps: basing the colorimeter on CIE L^*a^*b^*In the mode, fresh pumpkin pulp for seeds is used as a color difference measuring standard for standard sample measurement. Randomly selecting 5 points on the surface of the same pumpkin pulp for measurement. Measure L^*，a^*，b^*The value, Δ E, was calculated according to the following formula. Wherein L is₀ ^*、a₀ ^*And b₀ ^*Is the color parameter of the fresh seed pumpkin.

3. Hardness and brittleness measurement method: a TA-XTplus type of physical analyzer was used. The measurement conditions were as follows: the probe P/25, the speed before the test is 2mm/s, the test speed is 2mm/s, the speed after the test is 2mm/s, the trigger force is 5.0g, and a 75% compression test is carried out.

4. Method for measuring volume shrinkage: by volume exclusion, the shrinkage Y is (V)₁-V₂)/(V₁-V₀) In the formula: v₁Is the volume of millet and pumpkin pulp for seeds before drying, cm³；V₁Volume of semen Setariae and dried fructus Cucurbitae Moschatae pulp in cm³；V₀Is millet volume, cm³。

5. The method for measuring the content of free phenol comprises the following steps: grinding dried seed pumpkin pulp into powder by adopting a spectrophotometry method according to Yu and other (2020, Food Chemistry) documents, weighing 1g of seed pumpkin powder, placing the powder into a beaker, adding 30.0mL of ethanol with the volume fraction of 70% according to the feed-liquid ratio of 1:30(m/V), extracting for 40min, repeatedly adding the ethanol to extract the seed pumpkin powder for 3 times according to the extraction conditions, merging the filtrates, carrying out rotary evaporation by using a rotary evaporator until the filtrates are dried, dissolving the filtrates by using methanol, fixing the volume to 10mL, keeping the mixture at the temperature of-4 ℃ in the dark and storing the mixture to be detected. Respectively taking 0.5mL of the above prepared pumpkin extract for seed, adding 0.5mL of 1mol/L Folin phenol, reacting for 5min, and adding 2.0mL of Na₂CO₃(7.5% w/v), 10mL with deionized water, shaking and water bath at 70 ℃ for 30 min. After cooling, the absorbance (A) of the seed pumpkin extract was measured at 750 nm. And calculating the content of phenol in the seed pumpkin extract according to a gallic acid standard curve. The method for measuring the content of the monomeric phenol comprises the following steps: gradient elution with solvent A (water containing 0.1% acetic acid) and solvent B (acetonitrile containing 0.1% acetic acid) using a HPLC chromatographic system equipped with a Waters Atlantis C18 reverse phase analytical column (15cm long. times.4.6 mm inner diameter. times.3 μm thick) using the following procedure was performed using the high performance liquid method: 30% B (0-5 min); linear gradient to 40% B (5-10 min); linear gradient to 45% B (10-20 min); linear gradient to 100% B (20-22min) and linear gradient to 7% B (22-25 min). The flow rate was 0.6mL/min and the column temperature was 30 ℃.

6. The determination method of the carotenoid content comprises the following steps: adopts a spectrophotometric method, refers to Yao et al (2020, Food Chemistry) literature, and comprises the following specific steps: adding 50mL of extractive solution (containing 50% n-hexane, 25% acetone, and 25% ethanol) into 1g of pumpkin powder for seed, extracting in dark for 40min, and repeatedly adding the extractive solution until the pumpkin powder is colorless. The combined supernatants were then transferred to a separatory funnel. Then an equal volume of ethyl acetate was added and mixed well, left to stand, the organic layer was collected and dried under a stream of nitrogen, then re-dissolved with acetonitrile, methanol and dichloromethane (6:2:2, v/v/v). Absorbance (A) was recorded at 450nm using n-hexane as a blank. Wherein V is the total volume (mL) of the extracting solution, M is the mass (g) of the pumpkin powder for seeds,(2560) is the extinction coefficient of beta-carotene in n-hexane.

Carotenoid mass fraction

Example 1:

a method for improving the drying quality of pumpkin pulp for seeds by ultrasonic wave combined circulating freeze-thaw pretreatment comprises the following steps:

(1) cleaning and impurity removing: selecting ripe and fresh pumpkin seeds, and putting the pumpkin seeds in flowing water to clean and remove soil on the surfaces of the pumpkin seeds;

(2) peeling, removing seeds and slicing: peeling and removing seeds of the seeds cleaned in the step (1) by using pumpkin, and cutting the seeds into slices with the thickness of 3mm by using a slicing machine;

(3) ultrasonic pretreatment: and (3) placing the pumpkin pulp for seeds in the step (2) in ultrasonic conditions of 20KHz frequency and 360W power, and carrying out ultrasonic treatment for 30min in deionized water at the temperature of 25 ℃, wherein the material-liquid ratio is 1: 5.

(4) and (3) circulating freeze-thaw treatment: freezing the pumpkin pulp for seeds in the step (3) in a low-temperature refrigerator at the freezing temperature of-30 ℃ to the central temperature of-20 ℃, and then unfreezing the pumpkin pulp at the temperature of 25 ℃ for 3 times;

(5) far infrared drying: and (4) flatly paving the pumpkin pulp for seeds processed in the step (4) in a far infrared drying tray for far infrared drying until the moisture content reaches the drying end point to be 7%. The far infrared drying conditions are as follows: the far infrared wavelength is 15 μm, the distance from the far infrared light source to the pumpkin pulp for seed is 10cm, and the far infrared drying temperature is 60 deg.C.

(6) The color difference, volume shrinkage, hardness, brittleness, phenolic content and carotenoid content of the seed pumpkin were measured by the above-mentioned methods, and the results are shown in tables 1 and 2. The seed pumpkin far infrared drying efficiency is greatly improved, compared with a control group, the drying time is shortened by 40%, the product appearance is complete, the wrinkle rate is reduced by 35.66% compared with the control group, the hardness and brittleness are moderate, the color of the seed pumpkin is closest to the color of fresh seed pumpkin pulp, the content of free phenols is 41.74% higher than that of the control group, the content of monomer phenols is obviously higher than that of the control group, the content of the most main monomer phenol coumaric acid is 16.55% higher than that of the control group, and the content of carotenoid is 14.02% higher than that of the control group.

Example 2:

a method for improving the drying quality of pumpkin pulp for seeds by ultrasonic wave combined circulating freeze-thaw pretreatment comprises the following steps:

(1) same as in step (1) in example 1;

(2) same as step (2) in example 1;

(3) same as step (3) in example 1;

(4) differs from step (4) in example 1 in that the freeze-thaw treatment is cycled 2 times;

(5) same as in step (5) in example 1.

(6) The color difference, volume shrinkage, hardness, brittleness, phenolic content and carotenoid content of the seed pumpkin were measured by the above-mentioned methods, and the results are shown in tables 1 and 2.

The invention improves the far infrared drying efficiency of the seed pumpkin, compared with a control group, the drying time is shortened by 25%, the product appearance is relatively complete, the wrinkle shrinkage rate is reduced by 14.4% compared with the control group, the hardness and brittleness are moderate, the color of the seed pumpkin is relatively close to that of fresh seed pumpkin pulp, the content of free phenols is 14.33% higher than that of the control group, the content of monomer phenols is higher than that of the control group, wherein the content of the most main monomer phenol coumaric acid is 5.45% higher than that of the control group, and the content of carotenoid is 5.81% higher than that of the control group. The result shows that the ultrasonic combined cycle freeze-thaw cycle for 2 times of pretreatment can improve the drying efficiency and ensure the quality of the seed pumpkins to a certain extent, but the effect is lower than that of example 1, and the freeze-thaw frequency can influence the drying efficiency and quality of the seed pumpkins.

Example 3:

a method for improving the drying quality of pumpkin pulp for seeds by ultrasonic wave combined circulating freeze-thaw pretreatment comprises the following steps:

(1) same as in step (1) in example 1;

(2) same as step (2) in example 1;

(3) the difference from the step (3) in the example 1 is that the ultrasonic power is 120W, the ultrasonic frequency is 20KHz, the working temperature is 30 ℃, and the working time is 30 min;

(4) same as in step (4) in example 1.

(5) Same as in step (5) in example 1.

(6) The color difference, volume shrinkage, hardness, brittleness, phenolic content and carotenoid content of the seed pumpkin were measured by the above-mentioned methods, and the results are shown in tables 1 and 2.

The invention improves the far infrared drying efficiency of the seed pumpkin, compared with a control group, the drying time is shortened by 35%, the product appearance is relatively complete, the wrinkle shrinkage rate is reduced by 33% compared with the control group, the hardness and brittleness are moderate, the color of the seed pumpkin is closer to the color of fresh seed pumpkin pulp, the content of free phenols is 27.41% higher than that of the control group, the content of monomer phenols is higher than that of the control group, wherein the content of the most main monomer phenol coumaric acid is 12.4% higher than that of the control group, and the content of carotenoid is 12.73% higher than that of the control group. The results show that the ultrasonic power is 120W combined cycle freeze-thaw cycle for 3 times of treatment, the drying efficiency can be improved, the quality of the seed pumpkin is guaranteed to a certain extent, but the effect is lower than that of example 1, and the ultrasonic power influences the drying efficiency and quality of the seed pumpkin.

Example 4:

a method for improving the drying quality of pumpkin pulp for seeds by ultrasonic wave combined circulating freeze-thaw pretreatment comprises the following steps:

(1) same as in step (1) in example 1;

(2) same as step (2) in example 1;

(3) the difference from the step (3) in the example 1 is that the ultrasonic power is 60W, the ultrasonic frequency is 20KHz, the working temperature is 30 ℃, and the working time is 20 min;

(4) same as step (4) in example 1;

(5) same as in step (5) in example 1.

(6) The color difference, volume shrinkage, hardness, brittleness, phenolic content and carotenoid content of the seed pumpkin were measured by the above-mentioned methods, and the results are shown in tables 1 and 2.

The seed pumpkin far infrared drying efficiency is greatly improved, compared with a control group, the drying time is shortened by 30%, the appearance integrity rate of the product is high, the wrinkle shrinkage rate is reduced by 28.58% compared with the control group, the hardness and brittleness are moderate, the color of the seed pumpkin is closest to the color of fresh seed pumpkin pulp, the content of free phenols is 19.63% higher than that of the control group, the content of monomer phenols is remarkably higher than that of the control group, the content of the most main monomer phenol coumaric acid is 6.67% higher than that of the control group, and the content of carotenoid is 10.3% higher than that of the control group. The results show that the drying efficiency can be improved by combining ultrasonic treatment with ultrasonic power of 60W and ultrasonic treatment for 20min for 3 times of circulating freeze-thaw cycle, but the effect is lower than that of example 1, and the drying efficiency and quality of the seed pumpkin can be influenced by the ultrasonic power and the ultrasonic time.

Comparative example 1: control group

The seed pumpkin adopts a far infrared drying method, which comprises the following steps: the pumpkin was processed according to the method of example 1 except that the far infrared drying alone was performed without the ultrasonic combined cycle freeze-thaw pre-treatment under the same conditions as in example 1. The prepared pumpkin product has serious appearance shrinkage, the shrinkage rate is as high as 85.89 +/-2.24%, the hardness is higher (11585 +/-25.63N), the color difference with fresh pumpkin pulp for seeds is maximum (21.52 +/-1.02), and the contents of phenolic substances and carotenoid are lower. The sample after the circulating freeze-thaw combined ultrasonic pretreatment has small shrinkage rate, moderate hardness and brittleness, and obviously higher free phenol content, monomer phenol content and carotenoid content than a control group, which shows that the drying efficiency is improved by adopting the ultrasonic freeze-thaw combined pretreatment, and simultaneously, the good appearance and the nutritional quality of the seed pumpkin are ensured, and the seed pumpkin pulp is favorably and efficiently processed and utilized.

Comparative example 2: single ultrasonic and far infrared drying

Pumpkins are treated in accordance with the method of example 1, except that the freeze-thaw cycle of example 1 is omitted and the other conditions are the same as in example 1. The prepared pumpkin is superior to single far infrared drying in appearance and nutritional quality, but the effect is inferior to ultrasonic combined freeze-thaw pretreatment, which shows that the drying efficiency is improved by adopting the circulating freeze-thaw combined ultrasonic pretreatment, the good appearance and nutritional quality of the seed pumpkin are ensured, and the seed pumpkin pulp is favorably and efficiently processed and utilized.

Comparative example 3: circulating freeze thawing and ultrasound

The pumpkin was processed by the method of example 1 except that the order of the step (3) and the step (4) was adjusted and other conditions were the same as in example 1. The prepared pumpkin is superior to single far infrared dried pumpkin in appearance and nutritional quality, but compared with the pumpkin prepared in example 1, the appearance is poor, the content of nutritional ingredients is low, the sequence of the circulating freezing and thawing and the ultrasonic wave has obvious influence on the seed pumpkin, and the ultrasonic wave first and then the circulating freezing and thawing are more beneficial to improving the quality of the seed pumpkin.

Comparative example 4: adjusting the number of circulating freeze thawing

Pumpkins are processed according to the method of example 1, except that the number of circulating freeze-thaw cycles in step (4) is adjusted to 5 times, and other conditions are the same as in example 1. The pumpkin prepared has poor appearance and low content of nutrient components, which indicates that the pulp of the seed pumpkin is damaged to a large extent due to excessive circulation times and is not beneficial to the good appearance and the retention of the nutrient components of the seed pumpkin. Therefore, the number of cycles is preferably 3.

TABLE 1

TABLE 2

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.