A low-reducing sugar high-stability SOD honeydew endogenous polysaccharide-protein complex extract, a preparation method thereof and a skin lightening application
Patent Information
- Application Number
- CN202611493902.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-23
- Publication Date
- 2026-11-03
AI Technical Summary
Existing melon SOD extracts have high reducing sugar content and are easily hygroscopic. They rely on gluten-soluble protein or fat-soluble coatings to improve stability, making them unsuitable for gluten-free, low-fat, and hard capsule applications. Furthermore, they lack multi-dimensional quality control indicators.
Melon pulp was crushed under low-oxygen conditions, extracted using food-grade buffer solution, and subjected to low-temperature centrifugation and microfiltration. Ultrafiltration concentration and dialysis were then performed to remove small molecule sugars and salts, forming a stable complex system of melon endogenous polysaccharides and SOD protein. Finally, low-temperature drying was used to obtain a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract.
It improves the stability and applicability of SOD extract, making it suitable for gluten-free, low-lipid, and hard-capsule powder products. It features multi-dimensional quality control and is suitable for oral nutritional products for non-therapeutic purposes such as improving dull skin and brightening skin tone.
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Figure CN123023725A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of plant extracts, food processing and oral nutritional products, and particularly relates to a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract, its preparation method and its application in brightening skin tone. Background Technology
[0002] Dull skin, uneven skin tone, and decreased radiance are related to factors such as oxidative stress, UV radiation, and free radical reactions induced by environmental stress, as well as the activation of melanin-related signaling pathways. Excessive production of reactive oxygen species (ROS) attacks lipids, proteins, and DNA in skin cells, leading to impaired cell function, collagen degradation, and abnormal melanin deposition. Oral nutritional products, by supplementing antioxidant-related nutrients, help maintain normal skin condition and have become an important development direction in the oral beauty product industry.
[0003] Superoxide dismutase (SOD) is an antioxidant enzyme that catalyzes the dismutation of superoxide anion free radicals, playing a crucial role in the scavenging of oxygen free radicals in organisms. SOD can be derived from animals, microorganisms, or plants. Honeydew melon (Cucumis melo L.) is an important source of plant-derived SOD, with certain varieties being particularly rich in SOD.
[0004] Existing technologies have disclosed SOD protein extracts derived from Cucumismelo. For example, GliSODin® is the world's first patented oral bioactive SOD product, which combines naturally SOD-rich melon extract with wheat gliadin to effectively exert the antioxidant activity of SOD in the body. In addition, there are technical solutions that combine melon extract with components such as vitamin E and selenium-enriched yeast for antioxidant purposes. While these technologies can improve the application stability or oral suitability of SOD to some extent, the following problems still exist: First, freeze-dried ordinary melon juice contains a relatively high amount of small-molecule sugars, organic acids, and free salts, resulting in high hygroscopicity, which is detrimental to the stability of hard capsule powder. Existing SOD plant extraction methods mostly involve direct pulping, pressing to extract juice, and then freeze-drying. The resulting products have a high reducing sugar content and are prone to hygroscopic clumping, making them unsuitable for preparing solid dosage forms such as hard capsules.
[0005] Second, lipid-soluble coating or fatty microencapsulation systems are not conducive to obtaining low-lipid, hydrophilically dispersed hard capsule powders, and the high lipid content limits their application in low-fat products.
[0006] Third, gliadin protection systems (such as those using wheat gliadin) are not suitable for consumers who are gluten-sensitive or require gliadin-free or plant-based pure labels.
[0007] Fourth, using SOD activity alone as a quality indicator makes it difficult to distinguish between ordinary honeydew melon SOD extract and stabilized extract suitable for oral hard capsules, and lacks systematic control over formulation-related indicators such as reducing sugar content, water activity, and stability in acidic media. Summary of the Invention
[0008] To overcome the aforementioned deficiencies of the prior art, this invention provides a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract, its preparation method, and its skin-brightening application. This solves the problems of existing melon SOD extracts having high reducing sugar content, being easily hygroscopic, relying on gluten-soluble protein or fat-soluble coating to improve stability, being unsuitable for gluten-free, low-fat, and hard capsule applications, and lacking multi-dimensional quality control indicators.
[0009] To achieve the above objectives, the present invention provides the following technical solution: A low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract, its preparation method, and its skin-brightening application, comprising the following steps: (1) Take the pulp, placenta or mixture of Cucumismelo L. melon, crush and homogenize it under low oxygen conditions at 2-10℃ to obtain melon pulp; (2) Add food-grade buffer solution with pH 6.4 to 7.6 to the melon pulp and extract for 0.5 to 3 hours at 2 to 15°C to obtain crude extract; (3) The crude extract is subjected to low-temperature centrifugation and microfiltration to remove insoluble impurities and obtain a clear extract; (4) The clarified extract is concentrated by ultrafiltration and dialysis to retain components with a molecular weight greater than 10 kDa, and to remove small molecule sugars, organic acids and free salts to obtain SOD enriched solution. (5) Adjust the pH and ionic strength of the SOD enrichment solution and let it stand at 2-15℃ to allow the SOD protein in it to form a complex stable system with the endogenous soluble polysaccharide of honeydew melon, and obtain a complex stable solution. (6) The composite stabilized liquid is dried at low temperature, pulverized and sieved to obtain the extract.
[0010] Preferably, the low-oxygen conditions in step (1) are nitrogen protection, vacuum deoxygenation, or control of dissolved oxygen in the material system to be no higher than 3 mg / L.
[0011] Preferably, the food-grade buffer solution in step (2) is a phosphate buffer, a citrate buffer or a combination thereof, and the food-grade buffer solution does not contain wheat gliadin, zein, barley gliadin, rye gliadin or other exogenous gliadin.
[0012] Preferably, the ultrafiltration concentration and dialysis filtration in step (4) use an ultrafiltration membrane with a molecular weight cutoff of 10 to 30 kDa, the amount of water used for dialysis filtration is 2 to 8 times the volume of the SOD enrichment liquid, and the endpoint of dialysis filtration is that the soluble solids in the permeate are not higher than 0.5°Brix or the conductivity of the permeate is not higher than 3.0 mS / cm.
[0013] Preferably, in step (5), the pH is adjusted to 6.2-7.2, the ionic strength is adjusted to 10-80 mmol / L, and the standing time is 0.5-6 hours; the mass ratio of melon endogenous soluble polysaccharides to total protein in the composite stabilized solution is 0.2-3.0:1.
[0014] Preferably, the low-temperature drying in step (6) is freeze drying or low-temperature vacuum drying; the freeze drying includes pre-freezing at -20 to -60°C for 2 to 12 hours and drying under vacuum conditions for 12 to 48 hours; the material temperature during the low-temperature vacuum drying process is not higher than 45°C.
[0015] Preferably, the low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract, based on the total dry weight of the extract, contains: (1) The SOD activity is 10,000 to 80,000 U / g, and the SOD activity is determined by the WST-1 method; (2) The total protein content is 8%–35%; (3) The content of endogenous soluble polysaccharides in honeydew melon is 5% to 30%; (4) The reducing sugar content is not higher than 8%; (5) Moisture content not exceeding 8%; (6) The water activity (aw) is not higher than 0.45; (7) The lipid content is not higher than 2%; (8) After treatment at 37°C for 60 minutes in an acidic medium with pH 1.2 and followed by neutralization, the SOD activity retention rate is not less than 35%; The extract does not contain exogenously added glutenin, nor does it contain a lipophilic coating layer, microencapsulated wall material, or glutenin embedding layer.
[0016] Preferably, the extract contains: (1) The SOD activity is 20,000 to 60,000 U / g; (2) The total protein content is 10%–28%; (3) The content of endogenous soluble polysaccharides in honeydew melon is 8% to 25%; (4) The reducing sugar content is not higher than 6%; (5) The water activity (aw) is not higher than 0.35; (6) The SOD activity retention rate is not less than 45% after treatment in an acidic medium of pH 1.2 for 60 minutes; (7) After being placed at 40℃ and 75%RH for 30 days, the SOD activity retention rate is not less than 65%.
[0017] Preferably, an oral nutritional composition comprises the extract and food-acceptable excipients.
[0018] Preferably, the oral product is used for non-therapeutic purposes to scavenge free radicals, improve dull skin, brighten skin tone, improve skin tone evenness, increase skin L* value, improve ITA°, or reduce melanin index; the oral product is a hard capsule, tablet, granule, powder, solid beverage, or compressed candy.
[0019] This invention relates to a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract, its preparation method, and its technical effects and advantages in brightening skin tone: 1. This invention reduces the risk of oxidative inactivation of SOD during the crushing, extraction and concentration process by using low oxygen and low temperature conditions, which is beneficial to maintaining the enzyme activity of plant-derived SOD.
[0020] 2. This invention removes small molecule sugars, organic acids and free salts through ultrafiltration concentration and dialysis filtration, reduces the reducing sugar content and hygroscopic tendency of the extract, and improves the storage stability of the powder in hard capsules, powders and tablets.
[0021] 3. This invention utilizes the soluble polysaccharides contained in the melon raw material itself to form an endogenous polysaccharide-protein complex stable system with SOD protein. It does not use fat-soluble coating materials, hydrogenated oil, wax or fatty microencapsulation, or wheat gliadin or other glutenin, making it suitable for the development of gliadin-free, low-lipid and hard capsule powder products.
[0022] 4. The extract of this invention uses SOD activity, total protein, endogenous soluble polysaccharides, reducing sugar, water activity, lipid content, activity retention rate in acidic media, and accelerated stability as quality control indicators, which can distinguish it from ordinary freeze-dried melon juice, fat-soluble coated SOD melon powder, and phytol-protected SOD products.
[0023] 5. The extract of this invention can be used in the development of oral nutritional products for non-therapeutic purposes to scavenge free radicals and brighten skin tone. Its applications include improving dull skin, improving skin tone evenness, increasing skin L* value, improving ITA°, and reducing melanin-related indicators. Attached Figure Description
[0024] Figure 1This is a flowchart illustrating a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract, its preparation method, and its application in brightening skin tone, as proposed in this invention. Detailed Implementation
[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "includes..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.
[0027] refer to Figure 1This invention provides a low-reducing-sugar, high-stability SOD (superoxide dismutase) melon endogenous polysaccharide-protein complex extract, its preparation method, and its application for brightening skin tone, belonging to the technical field of plant extracts and oral nutritional products. The preparation method includes: taking Cucumis melo L. melon pulp and / or placenta, crushing and homogenizing under low-oxygen conditions at 2–10℃, adding a food-grade buffer solution of pH 6.4–7.6, and extracting at 2–15℃. Then, the extract is subjected to low-temperature centrifugation, microfiltration, ultrafiltration concentration with a molecular weight cutoff greater than 10 kDa, and dialysis filtration to remove small molecule sugars, organic acids, and free salts to obtain an SOD-enriched solution. The pH is adjusted to 6.2–7.2 and the ionic strength to 10–80 mmol / L, and the solution is allowed to stand at 2–15℃ to allow the SOD protein to form a stable complex system with the melon's endogenous soluble polysaccharides. Finally, the extract is obtained by low-temperature drying. The extract has an SOD activity of 10,000–80,000 U / g, total protein of 8%–35%, endogenous polysaccharides of 5%–30%, reducing sugar ≤8%, moisture ≤8%, water activity ≤0.45, lipids ≤2%, and an SOD activity retention rate ≥35% after treatment at pH 1.2 for 60 minutes. It also does not contain exogenous glutenin or a lipid-soluble coating layer. This invention also provides oral nutritional compositions containing this extract and their application in the preparation of non-therapeutic oral products for scavenging free radicals, improving dull skin, brightening skin tone, improving skin tone evenness, increasing skin L* value, improving ITA°, or reducing melanin index.
[0028] Example 1 Preparation of a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract.
[0029] Select Cucumismelo L. melons of uniform ripeness, free from rot and mechanical damage, and remove the flesh and placenta. After removing surface impurities, cut the melons into pieces. Pre-cool the raw materials to 4–8°C, and then crush and homogenize them under nitrogen protection to obtain melon pulp.
[0030] Add food-grade phosphate buffer solution with pH 7.0 to the melon pulp, control the solid-liquid ratio at 1:6, and stir and extract for 1.5 hours at 6-10℃ to obtain crude extract.
[0031] The crude extract was centrifuged at 4–8°C with a centrifugal force of 8,000 g for 20 minutes, and the supernatant was collected. The supernatant was then filtered through a 0.45 μm microfiltration membrane to obtain a clear extract.
[0032] The clarified extract was concentrated using an ultrafiltration membrane with a molecular weight cutoff of 10 kDa, and then dialyzed with purified water at a volume five times that of the concentrated extract. The endpoint of the dialysis was controlled when the soluble solids in the permeate did not exceed 0.5°Brix. This yielded an SOD-enriched solution.
[0033] The SOD enrichment solution was adjusted to pH 6.8 and the ionic strength was controlled at 30–60 mmol / L. It was then allowed to stand at 4–8 °C for 2 hours to allow the SOD protein to form a complex stable system with the endogenous soluble polysaccharides of cantaloupe, thus obtaining the complex stable solution.
[0034] The composite stabilized liquid was pre-frozen at -40℃ for 6 hours, then vacuum freeze-dried for 24–36 hours. After drying, it was pulverized and passed through a 60-mesh sieve to obtain a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein composite extract.
[0035] Example 2 Extraction under different pH conditions.
[0036] SOD melon extract was prepared according to the method in Example 1, except that the pH of the extraction buffer was controlled at 6.4, 6.8, 7.2, and 7.6, respectively. The resulting extracts were subjected to the same centrifugation, microfiltration, ultrafiltration, dialysis filtration, compound stabilization, and freeze-drying steps.
[0037] Using SOD activity, total protein content, reducing sugar content, water activity, and activity retention rate in acidic media as evaluation indicators, suitable process conditions for maintaining SOD activity and reducing reducing sugar content were screened.
[0038] Example 3 Preparation under different membrane separation conditions.
[0039] SOD melon extract was prepared according to the method in Example 1, except that the molecular weight cutoff of the ultrafiltration membrane was 10kDa, 20kDa and 30kDa, respectively, and dialysis was performed using purified water at volumes of 2, 5 and 8 times that of the SOD enrichment solution, respectively.
[0040] The effects of membrane separation conditions on the quality of the final extract were evaluated by considering reducing sugar content, SOD activity retention rate, total protein content, soluble polysaccharide content, and powder hygroscopicity.
[0041] Example 4 Preparation by low-temperature vacuum drying.
[0042] The composite stabilized liquid was obtained according to the method in Example 1, except that the composite stabilized liquid was subjected to low-temperature vacuum drying, with the material temperature controlled not to exceed 45°C, and dried until the moisture content was not higher than 8%. After drying, it was pulverized and passed through a 60-mesh sieve to obtain a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein composite extract.
[0043] Comparative Example 1 Freeze-dried regular honeydew melon juice.
[0044] Take the same melon raw material as in Example 1, crush and homogenize it, centrifuge to obtain the supernatant, do not perform ultrafiltration desugaring and endogenous polysaccharide-protein complex stabilization, directly freeze-dry to obtain ordinary melon juice freeze-dried product.
[0045] Comparative Example 2 SOD melon extract that has not undergone dialysis filtration.
[0046] Prepared according to the method of Example 1, except that the clarified extract is only concentrated by ultrafiltration and not by dialysis filtration, while the other steps are the same.
[0047] Comparative Example 3 SOD melon extract that has not undergone endogenous polysaccharide-protein complex stabilization.
[0048] The SOD enrichment solution was prepared according to the method in Example 1, except that it was not subjected to pH, ionic strength and static stabilization treatment, but was directly freeze-dried.
[0049] Detection method: SOD activity assay: The WST-1 method was used as the primary detection method, and the NBT reduction method or the pyrogallol autoxidation method could be used for methodological comparison. The activity unit is defined as the amount of enzyme required to achieve a 50% inhibition rate of the colorimetric reaction under specified assay conditions.
[0050] Total protein content determination: can be performed using the Kjeldahl method, Bradford method, or BCA method.
[0051] Determination of endogenous soluble polysaccharide content in cantaloupe: The phenol-sulfuric acid method can be used, with glucose as the standard.
[0052] Characterization of the composite stable system: The stable state of the composite can be characterized by dynamic light scattering, SEC-HPLC, Zeta potential, FT-IR or endogenous soluble polysaccharide / total protein ratio, and compared with the control group that has not undergone composite stabilization treatment.
[0053] Reducing sugar content determination: can be performed using the DNS method or high performance liquid chromatography.
[0054] Moisture content determination: can be performed using the direct drying method or the Karl Fischer method. Water activity is determined using a water activity meter.
[0055] Lipid content determination: Soxhlet extraction or acid hydrolysis can be used for determination.
[0056] pH 1.2 acidic medium stability test: Take the extract of the present invention and the comparative sample, respectively place them in an acidic medium of pH 1.2 and treat them at 37°C for 60 minutes. After treatment, adjust to a pH suitable for SOD activity determination, and determine the residual SOD activity according to the WST-1 method and calculate the SOD activity retention rate.
[0057] Accelerated stability test: The extract of the present invention was sealed and placed at 40°C and 75%RH for 30 days. SOD activity was measured and compared with the initial SOD activity to calculate the activity retention rate.
[0058] Determination of melanin-related indicators: A B16-F10 melanocyte model induced by α-MSH was used. Cells were divided into a blank control group, an α-MSH model group, a low-dose extract group, a medium-dose extract group, a high-dose extract group, and a control group. Each group was treated at a non-cytotoxic concentration for 48–72 hours, and cell viability, melanin production, and tyrosinase activity were measured. The expression levels of MITF, TYR, TRP-1, or TRP-2 could also be further detected.
[0059] Skin color evaluation: When used for human trial evaluation, a randomized, double-blind, placebo-controlled design can be adopted, with continuous intake for 8 to 12 weeks, and skin L* value, ITA°, melanin index, erythma index, VISIA image index, skin color evenness and dullness self-evaluation score can be detected.
[0060] Experimental data: Experimental Example 1 Comparison of quality indicators of extracts obtained by different processes: SOD activity was determined using the WST-1 method, total protein using the BCA method, soluble polysaccharides using the phenol-sulfuric acid method, reducing sugars using the DNS method, moisture content was determined by drying at 105℃, water activity was measured using a water activity meter, and lipid content was determined by Soxhlet extraction. Each group was measured in triplicate, and the results are expressed as mean ± standard deviation.
[0061] The results showed that, compared with ordinary freeze-dried melon juice, Examples 1-3 had higher SOD activity, lower reducing sugar content, lower water activity, and lower lipid content, indicating that the process of the present invention can obtain a low-reducing-sugar, high-stability SOD melon extract that is more suitable for oral hard capsule applications.
[0062] Experiment Example 2 pH 1.2 acidic medium stability test: Each sample was prepared into a 1 mg / mL suspension and placed in an acidic medium at pH 1.2. The suspension was then treated at 37°C for 30, 60, and 120 minutes. After sampling, the suspension was neutralized to pH 7.0, and the SOD activity was determined using the WST-1 method. Each group was measured in triplicate, and the retention rate was calculated with 0 minutes of activity as 100%.
[0063] The results showed that the SOD activity retention rate of Examples 1-3 after treatment in an acidic medium at pH 1.2 for 60 minutes was 41.7%-47.8%, which was higher than that of the comparative examples. This indicates that ultrafiltration / dialysis desaccharification and endogenous polysaccharide-protein complex stabilization can improve the activity retention rate of SOD melon extract in an acidic environment.
[0064] Experimental Example 3 Accelerated stability test: Each sample was sealed in an aluminum foil bag and placed at 40℃ and 75%RH. SOD activity was measured at 0, 30, 60, and 90 days. Each group was measured in triplicate, and the retention rate was calculated with the activity at day 0 as 100%.
[0065] The results showed that after being placed at 40°C and 75%RH for 30 days, the SOD activity retention rate of Examples 1-3 was still 66.5%-72.6%, which was higher than that of the comparative examples, indicating that the extract of the present invention has good storage stability.
[0066] Experiment Example 4 Hygroscopicity and powder flowability test: Each sample was placed in an open environment at 25℃ and 75%RH for 24 hours. The moisture absorption weight gain rate and angle of repose were measured, and the appearance of the powder was observed.
[0067] The results showed that Examples 1-3 had lower moisture absorption and weight gain rates and smaller angles of repose, and the powder flowability was better than that of the comparative examples, making them more suitable for preparation as hard capsules, tablets, granules or powders.
[0068] Experimental Example 5 In vitro antioxidant capacity experiment: The in vitro antioxidant capacity of each sample was evaluated using DPPH, ABTS, and ORAC methods. DPPH and ABTS scavenging rates were determined at a sample concentration of 1 mg / mL, and ORAC results were expressed as μmol TE / g.
[0069] The results showed that the DPPH, ABTS scavenging ability and ORAC value of Examples 1-3 were all higher than those of the comparative example, indicating that the SOD melon extract obtained by the process of the present invention has better in vitro antioxidant capacity.
[0070] Experimental Example 6 HaCaT cell ROS inhibition experiment: A human keratinocyte (HaCaT) cell line was used to establish an H2O2-induced oxidative stress model. Sample concentrations were 25, 50, and 100 μg / mL. Cell viability was assessed using the CCK-8 assay, and intracellular ROS levels were detected using the DCFH-DA fluorescent probe. ROS levels were set at 100% for the model group.
[0071] The results showed that Example 1 did not exhibit significant cytotoxicity in the range of 25–100 μg / mL, and could reduce the intracellular ROS level of H2O2-induced HaCaT cells, indicating that it has the potential for antioxidant protection of skin cells.
[0072] Experimental Example 7 B16-F10 melanin production experiment: B16-F10 mouse melanoma cells were used to induce melanin production with α-MSH. Sample concentrations of 25, 50, and 100 μg / mL were used. Cell viability, melanin content, and tyrosinase activity were measured after 72 hours of treatment. Melanin content and tyrosinase activity were calculated as 100% for the α-MSH model group.
[0073] The results showed that Example 1 did not significantly affect the viability of B16-F10 cells in the range of 25–100 μg / mL, and reduced α-MSH-induced melanin production and tyrosinase activity in a dose-related manner, indicating that it can be used for the development of oral nutritional products for non-therapeutic purposes to brighten skin tone, improve dullness, and improve skin tone evenness.
[0074] Quality control requirements: The low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract prepared by the method of this invention should meet the following quality control requirements: SOD activity measured by the WST-1 method is 10,000–80,000 U / g; total protein content is 8%–35%; melon endogenous soluble polysaccharide content is 5%–30%; reducing sugar content is not higher than 8%; moisture content is not higher than 8%; water activity (aw) is not higher than 0.45; lipid content is not higher than 2%; after treatment at 37°C for 60 minutes in an acidic medium of pH 1.2 and neutralization, the SOD activity retention rate is not less than 35%. The extract does not contain exogenously added glutenin, nor does it contain a lipophilic coating layer, microencapsulated wall material, or glutenin embedding layer.
[0075] Preferably, the extract meets the following quality control requirements: the SOD activity measured by the WST-1 method is 20,000–60,000 U / g; the total protein content is 10%–28%; the content of endogenous soluble polysaccharides from honeydew melon is 8%–25%; the reducing sugar content is not higher than 6%; the water activity (aw) is not higher than 0.35; after treatment at 37°C for 60 minutes in an acidic medium of pH 1.2 and then neutralization, the SOD activity retention rate is not less than 45%; after being placed at 40°C and 75% RH for 30 days, the SOD activity retention rate is not less than 65%.
[0076] Application method: The low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract of the present invention can be used as an active plant extract raw material for oral nutritional products, and can be used in hard capsules, tablets, granules, powders, solid beverages or compressed candies.
[0077] The present invention also provides an oral nutritional composition comprising the above-mentioned extract and food-grade acceptable excipients. The food-grade acceptable excipients include, but are not limited to, fillers (such as microcrystalline cellulose, starch, lactose), flow aids (such as silica, magnesium stearate), or anti-caking agents.
[0078] When used in hard capsules, the extract can be mixed with food-acceptable fillers, flow aids, or anti-caking agents and then filled into HPMC hard capsules or gelatin hard capsules. The daily intake of the SOD melon endogenous polysaccharide-protein complex extract in the hard capsules can be 5–100 mg, preferably 10–50 mg.
[0079] The oral products described herein are not intended for therapeutic purposes and are not intended for the diagnosis, treatment, or prevention of any disease. Their uses include scavenging free radicals, improving dull skin, brightening skin tone, improving skin tone evenness, increasing skin L* value, improving ITA°, or reducing melanin index.
[0080] Industrial applicability: The preparation method described in this invention utilizes equipment available in the food processing field, including low-temperature crushing, centrifugation, microfiltration, ultrafiltration, dialysis filtration, and low-temperature drying. The process path is clearly defined, enabling large-scale production. The resulting low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract has clear quality control indicators and is suitable for oral nutritional product applications. It is applicable to the development of products such as hard capsules, tablets, granules, powders, and solid beverages, demonstrating good industrial applicability.
[0081] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.
[0082] In conclusion, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract, characterized in that, Includes the following steps: (1) Take the pulp, placenta or mixture of Cucumismelo L. melon, crush and homogenize it under low oxygen conditions at 2-10℃ to obtain melon pulp; (2) Add food-grade buffer solution with pH 6.4 to 7.6 to the melon pulp and extract for 0.5 to 3 hours at 2 to 15°C to obtain crude extract; (3) The crude extract is subjected to low-temperature centrifugation and microfiltration to remove insoluble impurities and obtain a clear extract; (4) The clarified extract is concentrated by ultrafiltration and dialysis to retain components with a molecular weight greater than 10 kDa, and to remove small molecule sugars, organic acids and free salts to obtain SOD enriched solution. (5) Adjust the pH and ionic strength of the SOD enrichment solution and let it stand at 2-15℃ to allow the SOD protein in it to form a complex stable system with the endogenous soluble polysaccharide of honeydew melon, and obtain a complex stable solution. (6) The composite stabilized liquid is dried at low temperature, pulverized and sieved to obtain the extract.
2. The preparation method of the low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract as described in claim 1, characterized in that, The low-oxygen conditions described in step (1) are nitrogen protection, vacuum deoxygenation, or control of dissolved oxygen in the material system to be no higher than 3 mg / L.
3. The preparation method of the low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract as described in claim 1, characterized in that, The food-grade buffer solution in step (2) is a phosphate buffer, a citrate buffer or a combination thereof, and the food-grade buffer solution does not contain wheat gliadin, zein, barley gliadin, rye gliadin or other exogenous gliadin.
4. The preparation method of the low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract as described in claim 1, characterized in that, The ultrafiltration concentration and dialysis filtration in step (4) use an ultrafiltration membrane with a molecular weight cutoff of 10 to 30 kDa. The amount of water used for dialysis filtration is 2 to 8 times the volume of the SOD enrichment liquid. The endpoint of dialysis filtration is when the soluble solids in the permeate are not higher than 0.5°Brix or the conductivity of the permeate is not higher than 3.0 mS / cm.
5. The method for preparing a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract as described in claim 1, characterized in that, In step (5), the pH is adjusted to 6.2-7.2, the ionic strength is adjusted to 10-80 mmol / L, and the standing time is 0.5-6 hours; the mass ratio of melon endogenous soluble polysaccharides to total protein in the composite stabilized solution is 0.2-3.0:
1.
6. The method for preparing a low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract as described in claim 1, characterized in that, The low-temperature drying in step (6) is freeze drying or low-temperature vacuum drying; the freeze drying includes pre-freezing at -20 to -60°C for 2 to 12 hours and drying under vacuum for 12 to 48 hours; the material temperature during the low-temperature vacuum drying process does not exceed 45°C.
7. The low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract prepared by the method according to any one of claims 1 to 6, characterized in that, Based on the total dry weight of the extract, the extract contains: (1) The SOD activity is 10,000 to 80,000 U / g, and the SOD activity is determined by the WST-1 method; (2) The total protein content is 8%–35%; (3) The content of endogenous soluble polysaccharides in honeydew melon is 5% to 30%; (4) The reducing sugar content is not higher than 8%; (5) Moisture content not exceeding 8%; (6) The water activity (aw) is not higher than 0.45; (7) The lipid content is not higher than 2%; (8) After treatment at 37°C for 60 minutes in an acidic medium with pH 1.2 and followed by neutralization, the SOD activity retention rate is not less than 35%; The extract does not contain exogenously added glutenin, nor does it contain a lipophilic coating layer, microencapsulated wall material, or glutenin embedding layer.
8. The low-reducing-sugar, high-stability SOD melon endogenous polysaccharide-protein complex extract as described in claim 7, characterized in that, The extract contains: (1) The SOD activity is 20,000 to 60,000 U / g; (2) The total protein content is 10%–28%; (3) The content of endogenous soluble polysaccharides in honeydew melon is 8% to 25%; (4) The reducing sugar content is not higher than 6%; (5) The water activity (aw) is not higher than 0.35; (6) The SOD activity retention rate is not less than 45% after treatment in an acidic medium of pH 1.2 for 60 minutes; (7) After being placed at 40℃ and 75%RH for 30 days, the SOD activity retention rate is not less than 65%.
9. An oral nutritional composition, characterized in that, It contains the extract as described in claim 7 or 8 and food-grade excipients.
10. The use of the extract as described in claim 7 or 8 in the preparation of an oral product, characterized in that, The oral product is used for non-therapeutic purposes to scavenge free radicals, improve dull skin, brighten skin tone, improve skin tone evenness, increase skin L* value, improve ITA°, or reduce melanin index; the oral product is in the form of hard capsules, tablets, granules, powders, solid beverages, or compressed candies.