Method for extracting pectin from seed melon rind

Abstract

The invention belongs to the technical field of pectin extraction, and discloses a method for extracting pectin from seed melon rind, which comprises the following steps: S1, pretreating the seed melon rind to obtain seed melon powder; s2, weighing seed melon powder, dissolving the seed melon powder in water, adding enzyme powder, and carrying out enzyme extraction; the enzyme extraction time is 3.5 to 4.5 hours; the enzyme powder comprises any one or more of hemicellulase, mixed enzyme, cellulase and pectinase; s3, mixing and stirring filtrate obtained by filtering and absolute ethyl alcohol, and performing alcohol precipitation; the alcohol precipitation time is 1.5-2.5 hours, and the volume ratio of the absolute ethyl alcohol to the filtrate obtained by filtering is (1-3): 1; and S4, performing centrifugal separation, and drying the lower-layer jelly to obtain crude pectin. The pectin in the seed melon rind is efficiently extracted through an enzyme extraction and alcohol precipitation method, the pectin is promoted to be dissolved out through enzyme extraction, the pectin is separated from a solution through alcohol precipitation, the seed melon rind is turned into wealth, and resource waste is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of pectin extraction, in particular to a method for extracting pectin from seed melon peel. Background Art

[0002] Seed melon is an annual herbaceous plant in the Cucurbitaceae family. A low-sugar melon, it's a uniquely regional agricultural product, similar in shape to, but smaller than, a watermelon. The fruit and seeds of seed melon are not only edible but also possess numerous therapeutic benefits, such as clearing the lungs and moistening the intestines, soothing the stomach and quenching thirst, lowering blood pressure, and preventing cardiovascular and cerebrovascular diseases. Seed melon rind, a byproduct of the watermelon industry, has long been neglected and discarded. However, with advances in technology and the in-depth development of resources, it has been discovered that seed melon rind is rich in a variety of valuable ingredients, pectin being a key one.

[0003] Pectin is a natural active ingredient with excellent physiological and pharmacological properties, including antioxidant, anti-inflammatory, anticoagulant, lipid-lowering, antibacterial, and immune-modulating properties. Pectin is a soluble dietary fiber that, when consumed, enhances intestinal motility, promotes nutrient absorption, lowers cholesterol, softens blood vessels, and prevents atherosclerosis. It also removes gastrointestinal toxins and promotes bowel movements. Studies have also shown that pectin can help prevent cancer. Pectin is also a commonly used natural food additive, providing thickening, solidifying, emulsifying, and stabilizing properties. It has irreplaceable functional properties in food, pharmaceuticals, and cosmetics. In recent years, to meet consumer demand for functional ingredients, a number of pectin products have entered the market, such as moisturizing lotions, moisturizing lotions, and facial masks. Pectin thickens the aqueous and oil phases in cosmetics, increasing their viscosity and improving their spreadability and moisturizing properties. Furthermore, relevant research has shown that pectin can be used to control pollution and is a good heavy metal adsorbent, playing an important role in the remediation of heavy metal pollution.

[0004] At present, the demand for pectin has increased significantly, and my country's seed melon planting area and output rank first in the world, and the planting area is still expanding. In addition, the seed melon rind contains 10% to 20% pectin, which is a high-quality pectin resource. Therefore, it is urgent to study a method that can efficiently extract pectin from seed melon rind, improve the utilization rate of seed melon rind, and realize the "waste to treasure" of seed melon rind. Summary of the Invention

[0005] The present invention aims to provide a method for extracting pectin from seed melon peel. Pectin in the seed melon peel is extracted by enzyme extraction and alcohol precipitation. The enzymatic extraction of pectin uses enzymes to act on cell cellulose according to the high selectivity of the enzyme itself to decompose it and promote the dissolution of pectin. Alcohol precipitation utilizes the insolubility of pectin in alcohol solution on the basis of enzyme extraction to separate the pectin from the solution, so as to realize the "waste-to-treasure" of the seed melon peel and reduce resource waste.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for extracting pectin from seed melon peel comprises the following steps:

[0008] S1, separate the melon peel and melon pulp, blanch the melon peel to inactivate enzymes, drain the water and dry it in an oven, grind it with a grinder to obtain melon powder, and store it in a cool and dry place for later use;

[0009] S2. Weigh the seed melon powder and dissolve it in water, add enzyme powder, and place it in an electric constant temperature water bath for enzyme extraction; wherein the enzyme extraction time is 3.5 to 4.5 hours; the enzyme powder includes any one or more of hemicellulase, mixed enzyme, cellulase, and pectinase;

[0010] S3. After enzyme extraction, the filtrate is filtered, and the filtrate obtained by filtration is mixed with anhydrous ethanol and stirred, and then allowed to stand for alcohol precipitation; wherein the alcohol precipitation time is 1.5 to 2.5 hours, and the volume ratio of anhydrous ethanol to the filtrate obtained by filtration is 1 to 3:1;

[0011] S4. After standing and precipitating with alcohol, centrifuge to obtain a lower layer of colloid, which is then dried to obtain crude pectin.

[0012] Furthermore, in S1, the blanching of the melon peel to inactivate enzymes comprises immersing the seed melon peel in boiling water and blanching for 15 minutes.

[0013] Furthermore, in S2, the enzyme extraction time is 3.5 h; and the enzyme powder is hemicellulase.

[0014] Furthermore, in S2, the amount of enzyme powder is 0.5% of the mass of the seed melon powder; and the temperature of the electric constant temperature water bath is 40°C.

[0015] Furthermore, in S2, the ratio of seed melon powder to water is 1:20 (weight: volume).

[0016] Furthermore, in S3, the alcohol precipitation time is 2 h, and the volume ratio of anhydrous ethanol to the filtrate obtained by filtration is 3:1.

[0017] The beneficial effects of the technical solution are:

[0018] The present invention provides a method for extracting pectin from seed melon peel. The seed melon is pre-treated, and pectin in the seed melon peel is efficiently extracted by enzyme extraction and alcohol precipitation. The enzyme used for enzymatic extraction of pectin is selected according to the composition of the peel components. The most commonly used enzymes are cellulase, hemicellulase, and pectinase. The principle is to utilize the high selectivity of pectinase, hemicellulase, and cellulase itself to act on cell cellulose and then decompose it, thereby promoting pectin dissolution. Alcohol precipitation utilizes the insolubility of pectin in alcohol solution on the basis of enzyme extraction to separate pectin from the solution to achieve "turning waste into treasure" for the seed melon peel and reduce resource waste. In addition, the present invention optimizes the enzyme extraction time (3.5h), alcohol precipitation time (2h), alcohol dosage (3:1), and enzyme type (hemicellulase), and the pectin yield can reach 13.20%, further improving the extraction rate of pectin in the seed melon peel, further increasing the utilization rate of the seed melon peel, and reducing resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of a method for extracting pectin from seed melon peel according to the present invention;

[0020] Figure 2 This is a bar graph showing the effect of enzyme extraction time on pectin yield in the present invention, wherein, semi: hemicellulase; pectin: pectinase; cellulase: cellulase; mixed: mixed enzyme;

[0021] Figure 3 This is a bar graph showing the effect of alcohol precipitation time on pectin yield in the present invention, wherein, semi: hemicellulase; pectin: pectinase; cellulase: cellulase; mixed: mixed enzyme;

[0022] Figure 4 This is a bar graph showing the effect of different alcohol dosages on pectin yields in the present invention, wherein, semi: hemicellulase; pectin: pectinase; cellulase: cellulase; mixed: mixed enzyme;

[0023] Figure 5 This is a bar chart showing the effects of different types of enzymes on pectin yield in the present invention, wherein, semi: hemicellulase; pectin: pectinase; cellulase: cellulase; mixed: mixed enzyme. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0025] A method for extracting pectin from seed melon peel comprises the following steps:

[0026] S1, the seed melon peel and the melon pulp are separated, the melon peel is blanched and the enzyme is inactivated, and in actual application, the seed melon peel is immersed in boiling water, blanched for 15 minutes, drained and dried in an oven, and the seed melon powder is obtained after being crushed with a grinder, and stored in a cool and dry place for standby use;

[0027] S2. Weigh 5 g of melon seed powder and dissolve it in 100 ml of water. Add 0.5% hemicellulase powder by weight of melon seed powder and place it in an electric constant temperature water bath at 40°C for enzyme extraction; wherein, the enzyme extraction time is 3.5 h;

[0028] S3. After enzyme extraction, the filtrate is filtered, and the filtrate obtained by filtration is mixed with anhydrous ethanol and stirred, and then allowed to stand for alcohol precipitation; wherein the alcohol precipitation time is 2 hours, and the volume ratio of anhydrous ethanol to the filtrate obtained by filtration is 3:1, and the volume ratio of anhydrous ethanol to the filtrate obtained by filtration is defined as the alcohol dosage;

[0029] S4. After standing and settling with alcohol, centrifugation is performed to obtain a lower layer of colloid, which is then dried to obtain crude pectin. The mass of the crude pectin is weighed, and the crude pectin yield is calculated to be 13.20% according to the formula: pectin extraction rate = crude pectin mass ÷ melon powder mass × 100%.

[0030] The specific experimental process and conclusions are as follows:

[0031] 1. Materials and experimental instruments

[0032] Materials: Seed melon, purchased from the market; cellulase, food grade, from Guangdong Guangtai Food Technology; hemicellulase, food grade, from Guangdong Qianwei Food Business Department; pectinase, food grade, from Henan Fuda Biotechnology Co., Ltd.; anhydrous ethanol.

[0033] The experimental instruments are shown in Table 1 below:

[0034] Table 1 Experimental instruments

[0035] Instrument name model Manufacturer electronic balance AR124CN OHAUS Electric constant temperature water bath HWS-24 Shanghai Yiheng Scientific Instrument Co., Ltd. centrifuge Centrifuge5430 Eppendorf Digital display blast drying oven GZX-9140 Shanghai Boxun Industrial Co., Ltd. Medical Equipment Factory

[0036] 2. Research Methods

[0037] Using a single-factor sequential optimization method, we sequentially fixed the optimized factors, using the extraction rate as the measurement standard, and gradually explored the optimal conditions for enzyme extraction time, alcohol precipitation time, and alcohol dosage (the volume ratio of anhydrous ethanol to the filtrate after enzyme extraction). The experimental data were grouped by enzyme type (hemicellulase, pectinase, cellulase, and mixed enzyme), with three replicates per group. The experiment was mainly divided into:

[0038] (1) Optimization of pectin extraction process: The main research was on the effect of enzyme extraction time on pectin yield.

[0039] (2) Optimization of pectin alcohol precipitation scheme: By changing the alcohol precipitation time and the amount of ethanol used, the effect of alcohol precipitation time on pectin yield and the effect of alcohol dosage on pectin were studied, and the optimal pectin alcohol precipitation conditions were explored.

[0040] 3. Experiment on pectin extraction conditions

[0041] Using extraction rate as the standard, an extractant dosage of 0.5% (where the mixed enzyme ratio was hemicellulase:cellulase:pectinase = 2:2:1), and an extraction temperature of 40°C, the effects of different enzyme extraction times (3.5h, 4h, 4.5h), alcohol precipitation times (1.5h, 2h, 2.5h), and alcohol dosages (1:1, 2:1, 3:1) on pectin extraction rate were investigated. Several experimental designs, shown in Table 2 below, were developed and analyzed to determine the optimal extraction conditions for pectin.

[0042] Table 2 Factor levels of pectin extraction test

[0043]

[0044] Each set of data is plotted and analyzed to select the optimal item, and the optimized factors are fixed in turn:

[0045] (1) Effect of enzyme extraction time on pectin yield

[0046] The enzyme extraction time was 3.5h, 4h, and 4.5h respectively; the alcohol precipitation time was 2h; the alcohol dosage was 1:1; and the pectin yield was analyzed.

[0047] (2) Effect of alcohol precipitation time on pectin yield

[0048] The experiments were conducted with alcohol precipitation time of 1.5h, 2h, and 2.5h, enzyme extraction time of the optimal step, and alcohol dosage of 1:1.

[0049] (3) Effect of alcohol dosage on pectin yield

[0050] The alcohol dosages were 1:1, 1:2, and 1:3 respectively; the enzyme extraction time and alcohol precipitation time were the optimal ones mentioned above, and the effects of different alcohol dosages on pectin yield were compared.

[0051] IV. Experimental Procedure

[0052] The process is as follows Figure 1 As shown, the seed melon was first washed with clean water to remove surface sediment, then cut open to remove the seeds, separating the rind and pulp. The rind was then blanched to inactivate enzymes. The rind was immersed in boiling water and blanched for 15 minutes, then drained and oven-dried. After pulverizing with a grinder, it was stored in a cool, dry place until ready for use. 5g of pretreated seed melon powder was dissolved in 100ml of water, 0.5% enzyme powder was added, and the mixture was placed in an electric constant-temperature waterbath at 40°C for enzyme extraction. After enzyme extraction, the resulting filtrate was filtered and then mixed with anhydrous ethanol in a certain proportion and stirred for 20 minutes, followed by ethanol precipitation. Finally, the mixture was centrifuged to obtain a lower gelatinous material, which was dried, weighed, and the data recorded.

[0053] 5. Experimental Results

[0054] Pectin extraction rate = crude pectin mass ÷ melon powder mass × 100%

[0055] The results are expressed as mean ± standard deviation. IBM SPSS Statistics software was used to analyze the pectin extraction experimental data based on one-way analysis of variance to determine the significant differences among the factors.

[0056] (1) Effect of enzyme extraction time on pectin yield

[0057] The effect of enzyme extraction time on pectin yield is shown in Table 3:

[0058] Table 3 Effect of enzyme extraction time on pectin yield

[0059]

[0060] As shown in Table 3, different enzyme extraction times have an impact on the pectin yield. The average pectin extraction rate reached 3.98% when the enzyme extraction time was 3.5 h and the cellulase was used, while the yield was the lowest when the pectinase was used for 4 h. Figure 2 The average pectin extraction rates for hemicellulase, pectinase, cellulase, and mixed enzymes at 3.5, 4, and 4.5 hours are displayed. The yields for different enzyme types at each extraction time are clearly visible. Regardless of the enzyme used, the pectin extraction rate for 3.5 hours of extraction is significantly superior to that for other extraction conditions. The yield fluctuations for different enzyme types at different time points do not show a significant pattern over time, decreasing slightly with time, with no significant monotonic trend, and the data are generally quite dispersed.

[0061] The extraction rate data of different enzyme types at different extraction times (3.5 h, 4 h, 4.5 h) were sorted out, and the data obtained by variance analysis statistical analysis using software are shown in Table 4:

[0062] Table 4 Variance analysis table of the effect of enzyme extraction time on pectin yield

[0063]

[0064] As can be seen in the table, the mean for 3.5 hours of extraction is slightly higher, but the standard deviation is smaller, indicating more concentrated data. The mean for 4 hours of extraction is the lowest, the standard deviation is the largest, and the data is more dispersed. The mean for 4.5 hours of extraction is in the middle, with a moderate standard deviation. The F value is 1.49, reflecting the ratio of between-group variation to within-group variation. A P value greater than 0.05 indicates that the differences in pectin yield between the different extraction times are not statistically significant, indicating that the three extraction times have no significant effect on pectin yield.

[0065] Because different enzyme extraction times had no significant effect on the pectin yield, no further multiple comparisons were performed. Based on the existing analysis results, the yield was highest at 3.5h, so an enzyme extraction time of 3.5h was selected as the optimal extraction condition.

[0066] (2) Effect of alcohol precipitation time on pectin yield

[0067] The enzyme extraction time was fixed at 3.5 h. The effects of three different alcohol precipitation times on the pectin extraction rate are shown in Tables 5, 6 and Figure 3 As shown:

[0068] Table 5 Effect of alcohol precipitation time on pectin yield

[0069]

[0070] Table 6 Variance analysis table of the effect of alcohol precipitation time on pectin yield

[0071]

[0072] As shown in Table 5, the highest extraction yield reached 4.44% after 1.5 hours of alcohol precipitation with cellulase; the lowest extraction yield reached 2.69% after 2.5 hours of alcohol precipitation with the enzyme mixture. Data from three parallel experiments using different enzyme types and different alcohol precipitation times were analyzed using a variance analysis software to produce Table 6. This table shows the average pectin yield and data stability at different alcohol precipitation times, using means and standard deviations. The differences between these time points were statistically insignificant, as determined by F and P values. For alcohol precipitation times of 1.5, 2, and 2.5 hours, the corresponding pectin yields had mean ± standard deviations of 3.33 ± 1.21, 3.83 ± 0.34, and 3.18 ± 1.03, respectively, indicating relatively small differences. However, the standard deviations were larger for 1.5 and 2.5 hours, indicating a high degree of data dispersion. The standard deviation for 2 hours was smaller, indicating a more concentrated data set. It is known that the F value of different alcohol precipitation times on pectin yield is 1.56, and the P value is > 0.05, so alcohol precipitation time has no significant effect on pectin extraction rate.

[0073] Combine Figure 3 (showing the average pectin extraction rate of hemicellulase, pectinase, cellulase, mixed enzyme at 1.5h, 2h, 2.5h respectively) look at each enzyme yield under different alcohol precipitation time though there is fluctuation, but in conjunction with the P value of Table 6, these fluctuations do not reach statistically significant level, namely not caused by the alcohol precipitation time change, what embodies more is the difference of different enzyme types themselves.For example hemicellulase yield is higher when 2h, but this fluctuation is not attributed to the alcohol precipitation time statistically.Look at the comprehensive situation alcohol precipitation time is not the key factor affecting pectin yield, from the performance of four different types of enzymes under different alcohol precipitation times, the performance of 2h alcohol precipitation time is relatively excellent, therefore selecting optimal alcohol precipitation time is 2h.

[0074] (3) Effect of different alcohol dosages on pectin yield

[0075] The enzyme extraction time was fixed at 3.5 h and the alcohol precipitation time was 2 h. The effects of three different alcohol dosages on the pectin extraction rate are shown in Tables 7, 8, and 9. Figure 4 As shown:

[0076] Table 7 Effect of different alcohol dosages on pectin yield

[0077]

[0078] Table 8 Effect of different alcohol dosages on pectin yield

[0079]

[0080] Table 9 Multiple comparison of different alcohol dosages (LSD method)

[0081]

[0082] As shown in Table 7, under different conditions, the average extraction yield reached a maximum of 13.20% when hemicellulase was used for extraction at an alcohol ratio of 3:1. The lowest extraction yield was 3.35% when pectinase was used at an alcohol ratio of 1:1. Software was used to analyze the parallel data of pectin extraction yields at different alcohol ratios and different enzymes. The results, as shown in Table 8, show that the F value for the effect of alcohol ratio on pectin extraction yield was 51.70, with a P value of < 0.01, indicating that alcohol ratio had a highly significant effect on pectin yield. Furthermore, the yield increased significantly with increasing alcohol ratio, with the average value at a 3:1 ratio being 2.64 times that of a 1:1 ratio.

[0083] Because the variance analysis showed P < 0.01, it was necessary to use the LSD method to perform multiple comparisons on the parallel usage data of different alcohol dosages, so Table 9 was obtained. It can be seen from Table 9 that when the alcohol dosage is 3:1, compared with 1:1, the difference in average values ​​is 6.29, and the significance is 0.000, indicating that the index value of 3:1 is extremely significantly higher than 1:1. Compared with 2:1, the difference in average values ​​is 2.37, and the significance is 0.001, indicating that the index value of 3:1 is significantly higher than 2:1. It can be determined that there are extremely significant differences between all alcohol dosage levels, and high alcohol dosage significantly improves pectin yield. Combined with Figure 4 It can be determined that the optimal alcohol dosage based on this experiment is 3:1.

[0084] (4) Effect of different enzymes on yield

[0085] Three enzymes (hemicellulase, pectinase, and cellulase) and their mixed combinations (the ratio of each enzyme was 2:2:1) were used in the experimental design. Under the optimal conditions of this experiment (enzyme extraction for 3.5 hours, alcohol precipitation for 2 hours, and alcohol dosage of 3:1), the effects of different enzymes on the yield are shown in Tables 10, 11, and Figure 5 As shown:

[0086] Table 10 Effects of different types of enzymes on pectin yield

[0087]

[0088] Table 11 Multiple comparison of the effects of different enzymes on pectin yield (LSD method)

[0089]

[0090] Table 10 shows that the yields of the three single enzymes and the mixed enzymes significantly affect the pectin extraction rate. The mean of hemicellulase was 13.20 ± 1.75, the highest of the four enzymes, indicating that it has the best overall effect on improving pectin yield. The standard deviation of 1.75 indicates that the data have some dispersion, but the overall mean is significantly superior. The mean of pectinase was 7.89 ± 0.64, the lowest, and the standard deviation of 0.64 indicates that its data is highly stable, but its ability to improve pectin yield is weaker. The mean of cellulase was 9.50 ± 1.70, and the mean of the mixed enzyme was 9.87 ± 1.23. The two means are similar and both are lower than that of hemicellulase. The data obtained from pectin extraction by different enzyme types were further compared multiple times, and the different enzyme types were compared pairwise.

[0091] From Table 11, we can see that it shows the average difference and significance analysis between different enzyme types, so we can judge whether the enzymes are statistically significant (usually significant with P < 0.05). Whether hemicellulase is compared with pectinase, cellulase, or mixed enzyme, the P value is less than 0.05, indicating significant differences; pectinase, cellulase, and mixed enzyme only have significant differences when compared with cellulase, and most of them are not significant with each other. Hemicellulase performs better than the other three enzymes under this experimental condition. By plotting the data, Figure 5 The mean and error range of the yield of different enzyme types under each factor level are shown. Combined with the previous analysis, we can finally determine the performance of the four enzymes in pectin extraction: hemicellulase > mixed enzyme > cellulase > pectinase.

[0092] Based on the above experimental process and results, it can be concluded that the enzyme extraction time (3.5-4.5 hours) and alcohol precipitation time (1.5-2.5 hours) have no significant effect on pectin yield, which differs from the traditional belief that "extending the enzymatic hydrolysis time can improve substrate conversion rate." The reasons include: a. Enzyme extraction stage: Pectin in the cell walls of seed melon peel is basically released within 3.5 hours. Prolonging the time leads to decreased enzyme activity or pectin degradation, forming a dynamic "enzymatic hydrolysis-degradation" equilibrium, and the yield tends to stabilize; b. Alcohol precipitation stage: The final ethanol concentration (≥70%) is the key factor for precipitation. When the concentration reaches the standard, pectin can be completely precipitated within 1.5 hours. Further extension of the time may introduce impurities or cause solvent volatilization, which in turn reduces purity. This suggests that in actual production, the enzyme extraction time can be fixed at 3.5 hours and the alcohol precipitation time at 2 hours to improve production efficiency while ensuring yield.

[0093] The highly significant effect of alcohol dosage on yield (P < 0.01) indicates that high ethanol concentration is crucial for efficient pectin precipitation. The yield increased 2.64-fold at a 3:1 alcohol ratio compared to a 1:1 ratio, validating the theory that "ethanol concentration dominates pectin precipitation." However, high alcohol dosages increase ethanol usage and thus costs. Industrial production can be optimized through the following methods: a) using a gradient alcohol precipitation method, first removing small molecular weight impurities with low-concentration ethanol, then precipitating pectin with high-concentration ethanol; b) recovering ethanol to reduce unit consumption; c) combining membrane concentration technology to reduce supernatant volume and indirectly reduce ethanol usage. Furthermore, the excellent performance of hemicellulase at high alcohol dosages suggests that it may be the preferred enzyme for seed melon peel pectin extraction. Further research is needed to investigate its synergistic effect with pectinase to balance yield and cost.

[0094] Single hemicellulase is more effective, which is contrary to the traditional view that compound enzymes perform better during the extraction process. This may be due to the small experimental range and the need to expand the range, or it may be due to the structural composition of the seed melon peel itself. Among the cell wall components of the seed melon peel, hemicellulose (such as xylan and mannan) accounts for about 30% to 40%, which is higher than cellulose (20% to 25%). Therefore, degrading hemicellulose can more effectively destroy the cell wall structure and release the encapsulated pectin. The inefficiency of pectinase may be due to its action on the pectin molecule itself, resulting in a decrease in molecular weight, while the effect of cellulase is limited by the cellulose content in the substrate. In actual production, if yield is the primary goal, hemicellulase is preferred.

[0095] Therefore, the present invention, through single-factor experiments and variance analysis, clarifies the key influencing factors of the enzyme extraction and alcohol precipitation method for extracting seed melon peel pectin: enzyme extraction time: 3.5h is the optimal, and there is no significant gain in extending the time; alcohol precipitation time: 2h is the best, balancing precipitation efficiency and data stability; alcohol dosage: 3:1 when the yield is the highest (13.20%, hemicellulase), is the most critical factor affecting the yield; enzyme type: hemicellulase has the best effect, significantly better than pectinase, cellulase and mixed enzymes. It provides clear process parameters for the efficient extraction of seed melon peel pectin, especially reveals the unique advantages of hemicellulase and the key role of alcohol dosage, laying a theoretical foundation for subsequent industrial production and efficient resource utilization. In the future, it is necessary to further optimize the enzyme system and integrated purification technology to promote the transformation of seed melon peel pectin from laboratory to industry, which can greatly improve the production efficiency of pectin and promote economic and social development.

[0096] The above is only an embodiment of the present invention, and common knowledge such as the specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A method for extracting pectin from seed melon peel, characterized in that: The following steps are involved: S1, separate the melon peel and melon pulp, blanch the melon peel to inactivate enzymes, drain the water and dry it in an oven, grind it with a grinder to obtain melon powder, and store it in a cool and dry place for later use; S2. Weigh the seed melon powder and dissolve it in water, add enzyme powder, and place it in an electric constant temperature water bath for enzyme extraction; wherein the enzyme extraction time is 3.5 to 4.5 hours; the enzyme powder includes any one or more of hemicellulase, mixed enzyme, cellulase, and pectinase; S3. After enzyme extraction, the filtrate is filtered, and the filtrate obtained by filtration is mixed with anhydrous ethanol and stirred, and then allowed to stand for alcohol precipitation; wherein the alcohol precipitation time is 1.5 to 2.5 hours, and the volume ratio of anhydrous ethanol to the filtrate obtained by filtration is 1 to 3:1; S4. After standing and precipitating with alcohol, centrifuge to obtain a lower layer of colloid, which is then dried to obtain crude pectin.

2. The method for extracting pectin from seed melon peel according to claim 1, wherein: In S1, the process of blanching the melon peel to inactivate enzymes comprises immersing the melon peel in boiling water for 15 minutes.

3. The method for extracting pectin from seed melon peel according to claim 1, wherein: In S2, the enzyme extraction time is 3.5 h; the enzyme powder is hemicellulase.

4. The method for extracting pectin from seed melon peel according to claim 1, wherein: In S2, the amount of enzyme powder used is 0.5% of the mass of the seed melon powder; and the temperature of the electric constant temperature water bath is 40°C.

5. The method for extracting pectin from seed melon peel according to claim 1, wherein: In S2, the ratio of seed melon powder to water is 1:20 (weight:volume).

6. The method for extracting pectin from seed melon peel according to claim 1, wherein: In S3, the alcohol precipitation time is 2 h, and the volume ratio of anhydrous ethanol to the filtrate obtained by filtration is 3:1.

Images