Debitterizing process for white cortex of Shatian pomelo

Abstract

The present invention provides a Shatian pomelo white skin layer debitterizing technology, and belongs to the field of pomelo peel processing technologies, and the technology comprises the following steps: peeling and dicing a Shatian pomelo to obtain a Shatian pomelo white skin layer, debitterizing the Shatian pomelo white skin layer, soaking and rinsing the debittered Shatian pomelo white skin layer, and then drying to obtain a finished product. The Shatian pomelo white skin layer is used as a research object, the debitterizing rate and the sensory score are used as index values, the influence of a single debitterizing method (blanching, saline water and enzymolysis) and a composite debitterizing method (blanching saline water compounding and blanching enzymolysis compounding) on the white skin layer debitterizing effect is explored, and the result shows that the blanching saline water compounding debitterizing effect (hot water for 2 minutes, 4% salt soaking for 4 hours and clear water soaking for 1 hour) is optimal; at the moment, the debitterizing rate is as high as 80.1%, the sensory score is 90, and the treatment time is shortened by 29% compared with that of a single debitterizing method.

Description

Technical Field

[0001] The present invention relates to the field of pomelo peel processing technology, and particularly to the debittering process of the white peel layer of Shatian pomelo. Background Art

[0002] Shatian pomelo is an excellent variety unique in Chinese pomelos, known as the "king of pomelos", and was approved as a national geographical indication protection product in 2004. Shatian pomelo is mainly for fresh consumption. In addition, some fresh fruits are processed into honey pomelo tea, fresh pomelo juice drinks, pomelo pulp cans, pomelo peel preserves, etc. Whether for fresh consumption or processed into pomelo products, a large amount of pomelo peel will be produced. The taste of pomelo peel is bitter, and most of it is discarded as waste. If such a large amount of pomelo peel cannot be processed in a timely and effective manner, it will not only be a waste of resources, but also cause serious environmental pollution. Therefore, it is necessary to comprehensively utilize the pomelo peel of Shatian pomelo.

[0003] Pomelo peel stuffed is a traditional delicacy.

[0004] Pomelo peel stuffed is made by sandwiching the white peel layer of Shatian pomelo with fillings. However, the pomelo peel has a bitter taste, and the existing pomelo peel debittering methods have poor effects and long time consumption. Therefore, it is necessary to design a debittering process for the white peel layer of Shatian pomelo. Summary of the Invention

[0005] The purpose of the present invention is to provide a debittering process for the white peel layer of Shatian pomelo, so as to solve the technical problems of poor effect and long time consumption of the existing pomelo peel debittering methods.

[0006] Debittering the waste pomelo peel and processing it into the white peel layer for use in pomelo peel stuffed can not only turn waste into treasure, effectively utilize the pomelo peel, improve the economic value of the pomelo peel itself, but also promote the industrial development of Shatian pomelo, a superior characteristic agricultural product, which is of great significance for promoting the income increase and prosperity of local farmers. In addition, it can also increase consumers' consumption options, so that they can use the finished white peel layer when making pomelo peel stuffed, saving the process of dealing with pomelo peel. At the same time, the white peel layer becomes a single-sale product, enabling consumers not to have to buy the whole pomelo just to eat pomelo peel stuffed, reducing consumption expenditure.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] The debittering process of the white peel layer of Shatian pomelo includes the following steps: peeling and cutting the Shatian pomelo to obtain the white peel layer of the pomelo, debittering the white peel layer of the pomelo, soaking and rinsing the debittered white peel layer of the pomelo, and then drying to obtain the finished product.

[0009] Further, the specific process of peeling and cutting Shatian pomelo to obtain the white pomelo peel layer is as follows: Separate the pomelo pulp from the pomelo peel, take the pomelo peel, cut off the yellow outer peel of the pomelo peel to obtain the white pomelo peel layer, and cut it into a triangular opening shape of 8 cm × 8 cm × 8 cm.

[0010] 3. The debittering process of the white pomelo peel layer according to claim 1, characterized in that the specific process of debittering the white pomelo peel layer is as follows: First, blanch the white peel layer for 2 minutes, then soak it in 4% brine for 1 hour and 4 hours respectively, soak it in clear water for 3 hours, and finally rinse, dehydrate and dry; Blanch the white peel layer for 2 minutes first, then soak it in 4% brine for 1 hour, 2 hours, 3 hours and 4 hours respectively, without soaking in clear water, and directly rinse, dehydrate and dry.

[0011] Further, the specific process of soaking and rinsing the debittered white pomelo peel layer is as follows: Soak the debittered white peel layer in clear water for a fixed time, then rinse and dehydrate. Rinse 3 times and dehydrate with a dehydrator 4 times, 20 seconds each time.

[0012] Further, microwave intermittent drying is carried out twice first, with a firepower of 90% for 2 minutes and 20 seconds each time, and then put it into a hot air drying oven and dry at 100 °C for 1.5 hours.

[0013] Further, the above scheme also includes the determination of the debittering rate, and the specific process is as follows:

[0014] Drawing of the standard curve: Take the standard naringin and dry it to constant weight at 110 °C, weigh 20.00 mg, add 20 mL of 0.1 mol / L NaOH to completely dissolve it, adjust the pH to 6 with citric acid, and make up the volume to 100 mL to obtain the naringin standard solution. At the same time, make a reagent blank solution for standard dilution. Respectively suck 0 mL, 1.0 mL, 2.0 mL, 3.0 mL, 4.0 mL, 5.0 mL of the standard solution into 6 test tubes, add 5.0 mL, 4.0 mL, 3.0 mL, 2.0 mL, 1.0 mL, 0 mL of the blank solution respectively, and then add 5.0 mL of 90% diethylene glycol and 0.1 mL of 4 mol / L NaOH to each. Place it in a constant temperature water bath at 40 °C for color development reaction for 10 minutes, then immediately inject it into a 1 cm colorimetric cell, and measure the absorbance at a wavelength of 420 nm. Draw a standard curve with the absorbance value as the ordinate and the milligram number of the standard product as the abscissa;

[0015] The dried white peel layer sample was crushed with a pulverizer. The powder was soaked and squeezed with pure water in a ratio of 1:10 to obtain the original juice. After obtaining the original juice, the naringin content was determined by the Davis spectrophotometry method. 10 mL of 0.1 mo1 / L NaOH was added to the original juice, and the pH was adjusted to 12 with 4 mol / L NaOH. After soaking for 30 min, the pH was then adjusted to 6 with 20% citric acid, and distilled water was added to make up the volume to 100 mL for standby measurement. Exactly 3 mL of the test solution was accurately pipetted into 4 portions and placed in 4 test tubes. The reagent blank solution was added to make up the volume to 5.0 mL. 5.0 mL of 90% diethylene glycol was added to each. Then, 0.0 mL of 4 mol / L NaOH was added to 3 test tubes and 0.1 mL of 4 mol / L NaOH was added to 1 test tube. After shaking well, color development and measurement were carried out in the same method as the standard curve. The absorbance of the tube with added alkali was subtracted from the absorbance value of the tube without added alkali, and the standard curve was checked to obtain the milligram number of the naringin content in the sampled solution;

[0016] The debittering rate was calculated according to the following formula:

[0017]

[0018] Among them, m1 is the mass of the white peel layer directly dried without any treatment, x1 is the naringin content of the white peel layer directly dried without any treatment, ω1 is the moisture content of the white peel layer directly dried without any treatment, m2 is the mass of the white peel layer after debittering and drying treatment, x2 is the naringin content of the white peel layer after debittering and drying treatment, and ω2 is the moisture content of the white peel layer after debittering and drying treatment.

[0019] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0020] The present invention takes the white peel layer of Shatian pomelo as the research object, and takes the debittering rate and sensory score as the index values to explore the effects of single debittering methods (hot blanching, brine, enzymatic hydrolysis) and composite debittering methods (hot blanching-brine composite, hot blanching-enzymatic hydrolysis composite) on the debittering effect of the white peel layer. The results show that the hot blanching-brine composite has the best debittering effect (hot water for 2 min, soaking in 4% brine for 4 h, soaking in clear water for 1 h). At this time, the debittering rate reaches as high as 80.1%, the sensory score is 90 points, and the treatment time is shortened by 29% compared with the single debittering method. Description of the Drawings

[0021] Figure 1 is the drawing of the white peel layer of the pomelo of the present invention;

[0022] Figure 2 is the drawing of the debittering rate and sensory score of the white peel layer under different hot blanching times of the present invention;

[0023] Figure 3 is the drawing of the debittering rate and sensory score of the white peel layer under different salt concentrations of the present invention;

[0024] Figure 4It is the graph of the debittering rate and sensory score of the white peel layer under different enzyme concentrations of the present invention;

[0025] Figure 5 It is the graph of the influence of the composite debittering method (blanching + brine) of the present invention on the debittering effect of the white peel layer;

[0026] Figure 6 It is the graph of the influence of the composite debittering method of the present invention on the debittering effect of the white peel layer. Specific Embodiments

[0027] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following preferred embodiments are cited with reference to the accompanying drawings, and the present invention is further described in detail. However, it should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0028] 1.1 Materials and Reagents

[0029] Shatian pomelo, purchased from Guangxi Citrus Fresh Fruit Co., Ltd.; table salt: Xiaogan Guangyan Huayuan Salt Industry Co., Ltd.; naringin standard: Xi'an Kailai Bio-Engineering Co., Ltd.; diethylene glycol (diglycol): Tianjin Huasheng Chemical Reagent Co., Ltd.; naringinase: Qingdao Youshunfa Biotechnology Co., Ltd.; anhydrous citric acid: Shandong Yingxuan Industrial Co., Ltd.; sodium hydroxide (granular): Tianjin Zhiyuan Chemical Reagent Co., Ltd.

[0030] 1.2 Main Instruments

[0031] Ultraviolet spectrophotometer (UV-1600PC), Mepada Instruments Co., Ltd.; Aike laboratory ultrapure water machine (Advanced-Ⅱ-40), Corning Laboratory Special Pure Water Equipment Factory; electronic balance (JJ1000), Changshu Shuangjie Testing Instrument Factory; electrothermal constant temperature forced air drying oven (DHG-9145A), Shanghai Qixin Scientific Instruments Co., Ltd.; microwave oven (G80F20CN2L-B8(R0)), Galanz Microwave Living Appliance Co., Ltd.; induction cooker (C21-ST2106), Midea Living Appliance Manufacturing Co., Ltd.; grinder (JJ-668), Yongkang Jinweilai Electric Appliance Co., Ltd.; digital display constant temperature water bath (HH-8), Jiangsu Jintan Huanyu Scientific Instruments Factory; desktop pH meter (FE-28Standard), Mettler-Toledo Instruments (Shanghai) Co., Ltd.; moisture analyzer (YN-610A), Dongguan Nanyue Experimental Equipment Co., Ltd.

[0032] 1.3 Test Methods

[0033] 1.3.1 Process Flow

[0034] Shatian pomelo → Peel and cut into pieces → Debitter → Soak and rinse → Dry → Finished product

[0035] (1) Peel and cut into pieces: Separate the pomelo pulp from the pomelo peel, take the pomelo peel, remove the yellow outer skin of the pomelo peel to obtain the white pomelo peel layer. Cut 20 g of the white pomelo peel layer into triangular openings with dimensions of 8 cm × 8 cm × 8 cm, as Figure 1 shown.

[0036] (2) Debitter

[0037] Use single treatments (blanching, brine, enzymatic hydrolysis) and combined methods (blanching + brine combination, blanching + enzymatic hydrolysis combination) to debitter the triangular-opening white peel layer respectively.

[0038] (3) Soak and rinse

[0039] Soak the debittered white peel layer in water for a certain period of time, and then rinse and dehydrate (rinse 3 times, dehydrate with a dehydrator 4 times, 20 s each time).

[0040] (4) Dry

[0041] First, perform microwave intermittent drying twice, with a power of 90% for 2 min 20 s each time, and then place it in a hot air drying oven and dry at 100 °C for 1.5 h.

[0042] 1.3.2 Determination of moisture

[0043] Use a pulverizer to pulverize the dried sample, and take a certain amount of powder to measure the moisture.

[0044] 1.3.3 Determination of debittering rate

[0045] Drawing of the standard curve: Take standard naringin and dry it to constant weight at 110 °C. Weigh 20.00 mg, add 20 mL of 0.1 mol / L NaOH to completely dissolve it, adjust the pH to 6 with citric acid, and make up the volume to 100 mL to obtain the naringin standard solution. At the same time, prepare a reagent blank solution for standard dilution. Respectively pipette 0 mL, 1.0 mL, 2.0 mL, 3.0 mL, 4.0 mL, 5.0 mL of the standard solution into 6 test tubes, and add 5.0 mL, 4.0 mL, 3.0 mL, 2.0 mL, 1.0 mL, 0 mL of the blank solution respectively. Then add 5.0 mL of 90% diethylene glycol and 0.1 mL of 4 mol / L NaOH to each test tube. Place them in a constant temperature water bath at 40 °C for color development reaction for 10 min, and then immediately inject them into a 1 cm cuvette and measure the absorbance at a wavelength of 420 nm. Draw the standard curve with the absorbance value as the ordinate and the milligram number of the standard product as the abscissa.

[0046] The dried white peel layer sample was crushed with a pulverizer. The powder was soaked and squeezed with pure water at a ratio of 1:10 to obtain the original juice. After obtaining the original juice, the naringin content was determined by the Davis spectrophotometry method. 10 mL of 0.1 mo1 / L NaOH was added to the original juice, and the pH was adjusted to 12 with 4 mol / L NaOH. After soaking for 30 min, the pH was adjusted to 6 with 20% citric acid, and distilled water was added to make up the volume to 100 mL for standby measurement. 3 mL of the test solution was accurately pipetted into 4 test tubes, and the reagent blank solution was added to 5.0 mL. 5.0 mL of 90% diethylene glycol was added to each. Then, 0.0 mL of 4 mol / L NaOH was added to 3 test tubes and 0.1 mL of 4 mol / L NaOH was added to 1 test tube. After shaking well, color development and determination were carried out in the same way as the standard curve. The absorbance value of the tube with added alkali was subtracted from the absorbance value of the tube without added alkali, and the standard curve was consulted to obtain the milligram number of naringin content in the sampled solution.

[0047] The debittering rate was calculated according to the following formula.

[0048]

[0049] Among them: m1—the mass of the white peel layer directly dried without any treatment, g;

[0050] x1—the naringin content of m1 g of the white peel layer directly dried without any treatment, mg;

[0051] ω1—the moisture content of the white peel layer directly dried without any treatment, %;

[0052] m2—the mass of the white peel layer after debittering and drying treatment, g;

[0053] x2—the naringin content of m2 g of the white peel layer after debittering and drying treatment, mg;

[0054] ω2—the moisture content of the white peel layer after debittering and drying treatment, %;

[0055] 1.3.4 Sensory evaluation criteria

[0056] The white peel layer after debittering and drying was immersed in water and rehydrated to saturation at room temperature, and sensory evaluation was carried out by food professionals according to Table 1.

[0057] Table 1 Sensory evaluation form

[0058]

[0059] 2 Results and analysis

[0060] 2.1 Influence of blanching time on the debittering effect of white peel layer

[0061] Single blanching treatment: Immerse the white peel layer in the shape of a triangular opening in boiling water and blanch for 0 min, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, and then cool it to room temperature. After debittering, the white peel layer is soaked in water for 3 h, then rinsed, dehydrated, and dried, and the debittering rate and sensory score can be measured.

[0062] It can be seen from Figure 2 that compared with non-blanching, the debittering rate of the white peel layer of Shatian pomelo after blanching increased significantly. This is because the solubility of naringin in the white peel layer in water is related to the temperature. As the temperature increases, the dissolution degree of naringin increases [8] . At the same time, as the temperature increases, the molecular diffusion movement increases, and the exchange between substances speeds up, so the debittering rate naturally becomes larger. It can be seen from Figure 1 that as the blanching time increases, the debittering rate of the white peel layer shows an upward trend, and the sensory score first increases and then levels off. This is because long-term soaking at high temperature is beneficial to debittering, but it will also damage the tissue structure of the white peel layer, thus reducing the tissue form score in the sensory score. Considering the debittering rate and sensory score comprehensively, the blanching time is finally determined to be 2 min. At this time, the debittering rate of the white peel layer can reach 62.4%, and the bitterness is not obvious and the tissue form is good in terms of sensory evaluation.

[0063] 2.2 Effect of salt concentration on the debittering effect of white peel layer

[0064] Single brine treatment: Immerse the white peel layer in the shape of a triangular opening in brine with concentrations of 0%, 1%, 4%, 7%, 10%, and 13% for 4 h, then soak it in water for 3 h, then rinse, dehydrate, and dry, and the debittering rate and sensory score can be measured.

[0065] It can be seen from Figure 3 that compared with no salt addition, the debittering rate of the white peel layer of Shatian pomelo after adding salt increased significantly. This is because adding salt can increase the osmotic pressure in the solution and promote the entry of substances such as naringin into the solution, thus enhancing the debittering effect. As the salt solution concentration increases, both the debittering rate and the sensory score first increase and then level off. The sensory score no longer increases significantly when the salt concentration reaches 4%. This is because the high-concentration salt solution will damage the tissue structure of the oil-in-water layer, making the tissue state of the white peel layer too soft and the residual salty taste obvious, resulting in an increase in the bitterness score and a decrease in the tissue form score in the sensory score. After the two offset each other, the total sensory evaluation score does not increase significantly. Considering the debittering rate and sensory score comprehensively, when the salt concentration is 4%, the overall effect is relatively good, which is similar to the research results of Tengfei [9] .

[0066] 2.3 Effect of enzyme concentration on the debittering effect of white peel layer

[0067] Single enzyme treatment: Pour 200 ml of water into a beaker, adjust its pH to 5 with citric acid and sodium hydroxide, and then place the beaker in a water bath and heat it to 60 °C. Add naringinase by weight percentage to prepare enzyme solutions with 0%, 1.5%, 2%, 2.5%, 3%, and 3.5%. Immerse the white peel in the shape of a triangular opening into enzyme solutions of different concentrations, keep it at 60 °C for enzymatic hydrolysis for 4 h, then soak it in water for 3 h, and then rinse, dehydrate, and dry it to measure the debittering rate and sensory score.

[0068] As Figure 4 shown, naringin can be enzymatically hydrolyzed by naringinase. Most studies believe that naringinase is a complex enzyme composed of α-L-rhamnosidase and β-D-glucosidase. During enzymatic hydrolysis, naringin will first be hydrolyzed by α-L-rhamnosidase into rhamnose and prunin. The bitterness of prunin is lower than that of naringin, so the bitterness will be reduced. Then, the generated prunin will be hydrolyzed by β-D-glucosidase into non-bitter glucose and naringenin, further achieving the effect of debittering.

[0069] From Figure 3 it can be seen that with the increase of enzyme concentration, the debittering rate and sensory score first increase and then tend to be stable. When the enzyme concentration is 3%, the debittering rate is basically stable, the debittering rate is as high as 86.5%, and the sensory score reaches 89 points. Comparing the above three debittering methods, it is found that enzymatic debittering has the best debittering effect and the highest sensory score, but the debittering time is long (7 h); hot blanching debittering has the shortest treatment time, but the debittering efficiency is average.

[0070] 2.4 Effect of combined debittering methods on the debittering effect of white peel

[0071] To find a method with a higher debittering rate and a shorter debittering time, we tried to combine hot blanching debittering, which takes a shorter time, with brine debittering and enzymatic debittering.

[0072] 2.4.1 Hot blanching-brine combined debittering method

[0073] First, blanch the white peel for 2 min, then immerse it in 4% brine for 1 h and 4 h respectively, soak it in water for 3 h, and finally rinse, dehydrate, and dry it; blanch the white peel for 2 min first, then immerse it in 4% brine for 1 h, 2 h, 3 h, and 4 h respectively, without soaking in water, and directly rinse, dehydrate, and dry it.

[0074] As Figure 5As shown in the figure, by comparing single blanching, single salt treatment, and the treatment of "2-minute blanching + 4-hour salt + 3-hour water", it was found that the combination of blanching and brine can increase the debittering rate from about 60% to 84.3%. This indicates that the combination of blanching and brine has a synergistic enhancement effect. To shorten the debittering time and increase production efficiency, we tried to reduce the soaking time in water and brine. The results showed that the best conditions for debittering by the combination of blanching and brine are 2-minute blanching, soaking in 4% salt for 4 hours, and soaking in water for 1 hour. At this time, the debittering rate of the white peel layer reached 80.1%, the sensory score was 90 points, and the treatment time was shortened by 29%.

[0075] 2.4.2 Blanching and enzymatic hydrolysis combined debittering method

[0076] Blanching and enzymatic hydrolysis combined treatment: First, blanch the white peel layer of the first group for 2 minutes, then soak it in 3% enzyme for 4 hours, soak it in water for 3 hours, and finally rinse, dehydrate, and dry.

[0077] Blanch the white peel layer of each group for 2 minutes first, then soak it in 3% enzyme for 4 hours, soak it in water for 1 hour, and finally rinse, dehydrate, and dry; Blanch the white peel layer of the other three groups for 2 minutes first, then soak it in 3% enzyme for 2 hours, 3 hours, and 4 hours respectively, without soaking in water, and directly rinse, dehydrate, and dry.

[0078] From Figure 6 it can be seen that compared with single blanching debittering treatment, the blanching and enzymatic hydrolysis combined treatment can increase the debittering rate from about 60% to 82.6%; compared with single enzyme treatment, the debittering rate of the blanching and enzymatic hydrolysis combined treatment has no significant change, and the values are all in the eighties. This indicates that when blanching and enzyme are combined, the main debittering effect is from the enzyme treatment. To shorten the debittering time and increase production efficiency, we reduced the soaking time in water and the enzymatic hydrolysis time. The results showed that as the soaking time in water decreased, the debittering rate decreased significantly because the soaking time in water directly affects the residual amount of naringin in the white peel layer. As the enzymatic hydrolysis time decreased, the debittering rate decreased significantly, but the sensory score remained stable because the scores for tissue morphology and appearance structure in the sensory score increased. Considering the debittering rate, debittering time, and sensory score comprehensively, the final combined debittering conditions were determined as: 2-minute blanching, soaking in 3% enzyme for 4 hours. The debittering effect under this condition is worse than that of the blanching and brine combination method.

[0079] 3 Conclusions

[0080] In this experiment, with the debittering rate and sensory score as the index values, the effects of different debittering methods on the debittering of the white peel layer of Shatian pomelo were explored. The results showed that compared with single debittering methods, the combined debittering has a higher debittering rate and a shorter debittering time. The best combined debittering conditions are 2-minute blanching, soaking in 4% salt for 4 hours, and soaking in water for 1 hour. At this time, the debittering rate of the white peel layer of Shatian pomelo reached 80.1%, the sensory score was 90 points, and the treatment time was shortened by 29%.

[0081] Matters not described in detail in this invention are well-known techniques.

[0082] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. The debittering process of the white peel layer of Shatian pomelo, characterized in that: The process includes the following steps: peeling and cutting Shatian pomelos to obtain the white pomelo peel layer, debittering the white pomelo peel layer, soaking and rinsing the debittered white pomelo peel layer, and then drying to obtain the finished product.

2. The debittering process of the white peel layer of Shatian pomelo according to claim 1, characterized in that: The specific process of peeling and cutting Shatian pomelos to obtain the white pomelo peel layer is as follows: separating the pomelo pulp from the pomelo peel, taking the pomelo peel, peeling off the yellow outer skin of the pomelo peel to obtain the white pomelo peel layer, and cutting it into a triangular opening shape of 8 cm × 8 cm × 8 cm.

3. The debittering process of the white peel layer of Shatian pomelo according to claim 1, characterized in that: The specific process of debittering the white pomelo peel layer is as follows: first blanching the white peel layer for 2 minutes, then soaking it in 4% saline for 1 hour and 4 hours respectively, soaking it in water for 3 hours, and finally rinsing, dehydrating and drying; first blanching the white peel layer for 2 minutes, then soaking it in 4% saline for 1 hour, 2 hours, 3 hours and 4 hours respectively, without soaking it in water, and directly rinsing, dehydrating and drying.

4. The debittering process of the white peel layer of Shatian pomelo according to claim 1, characterized in that: The specific process of soaking and rinsing the debittered white pomelo peel layer is as follows: soaking the debittered white peel layer in water for a fixed time, then rinsing and dehydrating, rinsing 3 times, and dehydrating with a dehydrator 4 times, 20 seconds each time.

5. The debittering process of the white peel layer of Shatian pomelo according to claim 1, characterized in that: The specific process of drying is as follows: first drying intermittently by microwave twice, with a power of 90% each time for 2 minutes and 20 seconds, and then putting it into a hot air drying oven and drying at 100 °C for 1.5 hours.

6. The debittering process of the white peel layer of Shatian pomelo according to claim 1, characterized in that: The specific process of drying also includes the determination of the debittering rate, and the specific process is as follows: Drawing of the standard curve: Taking standard naringin and drying it to constant weight at 110 °C, weighing 20.00 mg, adding 20 mL of 0.1 mol / L NaOH to completely dissolve it, adjusting the pH to 6 with citric acid, and making up the volume to 100 mL to obtain the naringin standard solution. At the same time, making a reagent blank solution for standard dilution. Respectively sucking 0 mL, 1.0 mL, 2.0 mL, 3.0 mL, 4.0 mL, 5.0 mL of the standard solution into 6 test tubes, adding 5.0 mL, 4.0 mL, 3.0 mL, 2.0 mL, 1.0 mL, 0 mL of the blank solution respectively, then adding 5.0 mL of 90% diethylene glycol and 0.1 mL of 4 mol / L NaOH to each, placing them in a 40 °C constant temperature water bath for color development reaction for 10 minutes, then immediately injecting them into a 1 cm cuvette, measuring the absorbance at a wavelength of 420 nm, and drawing the standard curve with the absorbance value as the ordinate and the milligram number of the standard product as the abscissa; Using a pulverizer to pulverize the dried white peel layer sample, taking the powder and soaking and squeezing juice with pure water in a ratio of 1:10 to obtain the original juice. After that, using the Davis spectrophotometry method to measure the naringin content. Adding 10 mL of 0.1 mo1 / L NaOH to the original juice, adjusting the pH to 12 with 4 mol / L NaOH, soaking for 30 minutes, then adjusting the pH to 6 with 20% citric acid, adding distilled water to make up the volume to 100 mL for standby measurement. Accurately sucking 3 mL of the test solution in 4 portions into 4 test tubes, adding the reagent blank solution to 5.0 mL, adding 5.0 mL of 90% diethylene glycol to each, and then adding 0.0 mL of 4 mol / L NaOH to 3 test tubes and 0.1 mL to 1 test tube respectively, shaking well, and performing color development and measurement in the same way as the standard curve. Subtracting the absorbance of the non-alkali-added tube from the absorbance of the alkali-added tube, and checking the standard curve to obtain the milligram number of the naringin content in the sampled solution; The debittering rate is calculated according to the following formula: Where, m1 is the mass of the white peel layer directly dried without any treatment, x1 is the naringin content of the white peel layer directly dried without any treatment, ω1 is the moisture content of the white peel layer directly dried without any treatment, m2 is the mass of the white peel layer after debittering and drying treatment, x2 is the naringin content of the white peel layer after debittering and drying treatment, and ω2 is the moisture content of the white peel layer after debittering and drying treatment.

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