Ginkgo peptide zinc chelate with dietary fiber adsorption resisting effect and preparation method thereof

Abstract

The invention discloses a ginkgo peptide zinc chelate with a dietary fiber adsorption resisting effect and a preparation method of the ginkgo peptide zinc chelate, and belongs to the technical field of deep processing of forest products. The gingko peptide zinc chelate is prepared by carrying out coordination reaction on gingko peptide and zinc sulfate under specific conditions, and after the gingko peptide zinc chelate is chelated with the gingko peptide, the stability of zinc ions in a digestion environment is remarkably improved, and the precipitation phenomenon of the zinc ions in gastrointestinal tracts is effectively inhibited; the technical defects that a traditional inorganic zinc preparation is high in gastrointestinal irritation, low in bioavailability and the like are overcome. Meanwhile, the ginkgo peptide zinc chelate disclosed by the invention has excellent dietary fiber adsorption resistance, and the bioavailability of zinc can be remarkably enhanced. Therefore, the ginkgo peptide zinc chelate provided by the invention can be widely applied to the fields of special dietary foods, functional health foods, nutrition fortified foods and the like, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of deep processing of forest products, and particularly relates to a ginkgo biloba peptide zinc chelate with resistance to dietary fiber adsorption effect and a preparation method thereof. BACKGROUND

[0002] Zinc is an essential trace element for human health, playing a key role in maintaining cell structure integrity and ensuring the function of key biological processes. In the 21st century, zinc deficiency is still a global health problem. According to statistics, about 33% of the world's population has zinc deficiency, and the rate of zinc deficiency among Chinese children is as high as 60%. Zinc deficiency can lead to immune function loss, depression, easy aging, loss of appetite, poor development, metabolic disorders and other problems, seriously endangering human life and health. The adsorption of dietary fiber on zinc ions ingested into the human body is an important factor causing zinc deficiency in the human body. Using zinc supplements is an effective way to solve zinc deficiency in the human body, however, traditional inorganic and organic zinc supplements have low bioavailability and significant side effects, and there are safety hazards, so it is urgent to develop new safe and efficient zinc supplements.

[0003] At present, common zinc supplements can be divided into four categories: the first category is inorganic zinc supplement, represented by zinc sulfate and zinc chloride, which has low bioavailability (about 7%), poor taste and irritation to the gastrointestinal mucosa; the second category is organic zinc with organic acid as ligand, such as zinc lactate, zinc gluconate and zinc acetate, etc. The oral availability of organic zinc increases (about 14%), the synthesis process of this kind of organic zinc is complex, people are easy to be tired after taking zinc lactate, and zinc gluconate is not suitable for diabetics; the third category is zinc chelated with amino acid, which has good chemical stability and high bioavailability, but the reaction cost is extremely high, and may produce unwanted color reactions and lipid oxidation reactions, and has problems such as poor odor; the fourth category is peptide zinc chelate, which has the advantages of low reaction energy consumption, high transport efficiency and good stability.

[0004] Ginkgo biloba is a unique tree species in China, with a wide planting area, accounting for 3 / 4 of the total global cultivation area, and the ginkgo yield accounts for 70% of the global total. Ginkgo biloba is rich in protein, with a dry basis content of about 10%, and its amino acid composition is rich and reasonable, making it a high-quality plant protein resource. Literature shows that ginkgo biloba peptides have antibacterial, antioxidant, anti-aging and immunomodulatory activities, and show high edible and medicinal value, which is an advantageous peptide source for constructing peptide zinc chelate. However, there is no report on the use of ginkgo biloba peptides to coordinate with zinc sulfate to obtain peptide zinc chelate, especially the study of peptide zinc chelate with resistance to dietary fiber adsorption effect is less. SUMMARY

[0005] The purpose of the present application is to provide a ginkgo biloba peptide zinc chelate with resistance to dietary fiber adsorption effect and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following scheme: A ginkgo peptide zinc chelate with resistance to dietary fiber adsorption effect and a preparation method thereof, characterized in that the ginkgo peptide zinc chelate is obtained through the steps of ginkgo protein extraction, protease hydrolysis, ultrafiltration, chelation, purification and drying.

[0007] Preferably, the ginkgo protein extraction conditions are as follows: 1 part of defatted ginkgo powder is uniformly mixed with 10-20 parts of water, the pH of the mixed solution is adjusted to 10.0, and the solution is stirred and extracted at 40-80 DEG C for 2-4 hours; after centrifugation, the pH of the supernatant is adjusted to 4-4.5, and the solution is refrigerated (2-4 DEG C) for 5 hours; after the upper liquid is discarded, the pH of the system is adjusted to neutral, the precipitate is washed with distilled water for 3 times, and then the precipitate is treated with a dialysis bag with a molecular weight cut-off of 10000 Da for 72 hours; finally, the mixed solution in the bag is freeze-dried to obtain ginkgo protein.

[0008] Preferably, the protease hydrolysis conditions are as follows: 1 part of ginkgo protein is uniformly mixed with 10-20 parts of water, the pH of the system is adjusted to 8.0, and alkaline protease (Alcalase) is added at an enzyme-substrate ratio of 1:50-100; the solution is stirred and hydrolyzed at 50 DEG C for 4-6 hours, and the pH of the system is adjusted and maintained at 8.0 every 10 minutes during the hydrolysis; after the reaction is completed, the solution is heated at 95 DEG C for 5-10 minutes; and the supernatant is obtained by centrifugation.

[0009] Preferably, the ultrafiltration conditions are as follows: the supernatant is passed through an ultrafiltration membrane with a molecular weight cut-off of 1000 Da, and the filtrate is freeze-dried to obtain ginkgo peptide.

[0010] Preferably, the chelation uses ZnSO4·7H2SO4 as the zinc source.

[0011] Preferably, the chelation conditions are as follows: 1 part of ginkgo peptide is dissolved in 10 parts of water, ZnSO4·7H2SO4 is added at a ratio of ZnSO4·7H2SO4=1:2-4:1, the pH is adjusted to 4-8, and the solution is stirred and reacted at 30-70 DEG C for 15-75 minutes.

[0012] Preferably, the purification conditions are as follows: the chelation reaction solution is treated with a dialysis bag with a molecular weight cut-off of 100 Da for 24 hours.

[0013] Preferably, the drying conditions are as follows: the solution in the dialysis bag is freeze-dried or spray-dried to obtain ginkgo peptide zinc chelate.

[0014] Preferably, the ginkgo peptide zinc chelate prepared by any of the methods is used in a zinc supplement.

[0015] Beneficial effects The beneficial effects of the present application are: The application discloses a ginkgo biloba peptide zinc chelate with resistance to adsorption effect of dietary fiber and a preparation method thereof. The peptide zinc chelate prepared by the method has high zinc content, good solubility, small pH influence on solubility, strong stability in gastrointestinal environment and can effectively resist the adsorption effect of dietary fiber, and is an ideal zinc supplement. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Single factor experiment results of ginkgo biloba peptide and zinc ion chelation reaction in Example 3 Figure 2 Solubility of the peptide zinc chelate and zinc sulfate at different pH values Figure 3 Solubility of the peptide zinc chelate and zinc sulfate in a simulated digestion environment DETAILED DESCRIPTION

[0017] Example 1: Preparation of ginkgo biloba protein Take 1 part of defatted ginkgo biloba powder and mix with 10 parts of water, adjust the pH of the mixture to 10.0, extract at 60 DEG C for 4 hours, adjust the pH of the supernatant to 4.4 after centrifugation (2-4 DEG C) for 5 hours, discard the upper liquid, adjust the pH of the system to neutral, wash the precipitate with distilled water for 3 times, then use a molecular weight cut-off of 10000 Da dialysis bag to treat for 72 hours, and finally freeze-dry the mixture in the bag to obtain ginkgo biloba protein.

[0018] Example 2: Enzymatic hydrolysis and ultrafiltration of ginkgo biloba protein Take 1 part of ginkgo biloba protein and mix with 10 parts of water, adjust the pH of the system to 8.0, add alkaline protease (Alcalase) according to an enzyme-substrate ratio of 1:50, stir and hydrolyze at 50 DEG C for 6 hours, adjust and maintain the pH of the system to 8.0 every 10 minutes during the hydrolysis, heat treat at 95 DEG C for 10 minutes after the reaction is completed, and obtain the supernatant by centrifugation. The supernatant is filtered through an ultrafiltration membrane with a molecular weight cut-off of 1000 Da, and the filtrate is freeze-dried to obtain ginkgo biloba peptide.

[0019] Example 3: Preparation and purification of ginkgo biloba peptide zinc chelate The single factor method is adopted to optimize the preferred preparation process of the peptide zinc chelate by taking the zinc chelation capacity as an index.

[0020] (1) Effect of reaction pH value on ginkgo biloba peptide chelating zinc: take 1 part of ginkgo biloba peptide and dissolve in 10 parts of water, GPIH / ZnSO4·7H2O = 1:1, the reaction temperature is 40 DEG C, the reaction time is 1 hour, the reaction pH is controlled at 4.0, 5.0, 6.0, 7.0 and 8.0, and the effects of different reaction pH values on ginkgo biloba peptide chelating zinc are compared.

[0021] (2) The effect of GPIH / ZnSO4·7H2O ratio on the chelation of zinc by ginkgo biloba peptide: 1 part of ginkgo biloba peptide was dissolved in 10 parts of water, the pH of the system was adjusted to 6.0, the reaction temperature was 40 degrees Celsius, the reaction time was 1 hour, and the GPIH / ZnSO4·7H2O ratio was controlled at 1:2-4:1. The effect of different peptide / zinc ratios on the chelation of zinc by ginkgo biloba peptide was compared.

[0022] (3) The effect of reaction temperature on the chelation of zinc by ginkgo biloba peptide: 1 part of ginkgo biloba peptide was dissolved in 10 parts of water, the pH of the system was adjusted to 6.0, the GPIH / ZnSO4·7H2O ratio was 1:1, the reaction time was 1 hour, and the reaction temperature was controlled at 30, 40, 50, 60, and 70 degrees Celsius. The effect of different reaction temperatures on the chelation of zinc by ginkgo biloba peptide was compared.

[0023] (4) The effect of reaction time on the chelation of zinc by ginkgo biloba peptide: 1 part of ginkgo biloba peptide was dissolved in 10 parts of water, the pH of the system was adjusted to 6.0, the GPIH / ZnSO4·7H2O ratio was 1:1, the reaction temperature was 50 degrees Celsius, and the reaction time was controlled at 15, 30, 45, 60, and 75 minutes. The effect of different reaction times on the chelation of zinc by ginkgo biloba peptide was compared.

[0024] After the chelation was completed, the reaction system was placed in a 100 Da dialysis bag and dialyzed for 24 hours. The solution in the bag was freeze-dried to obtain the ginkgo biloba peptide zinc chelate.

[0025] Chelation of zinc by ginkgo biloba peptide: A certain amount of chelate was weighed into a digestion tank, 10 mL of concentrated nitric acid was added, mixed well, and left overnight. Then, the tank was heated at 300 degrees Celsius for 4 hours. During the digestion, nitric acid solution was continuously added until the solution turned from yellow-brown to transparent. After cooling, the solution was diluted with distilled water. The content of zinc was quantitatively analyzed using an inductively coupled plasma emission spectrometer. The chelation capacity was calculated using the following formula: Chelation capacity (mg / g) = m / M, where M is the mass of the chelate (g) and m is the mass of zinc in the chelate (mg).

[0026] The results of the single-factor experiment are shown in Figure 1 , and the optimal process conditions for the chelation of zinc by ginkgo biloba peptide were determined as follows: the reaction pH was 6.0, the GPIH / ZnSO4·7H2O ratio was 1:1, the reaction temperature was 50 degrees Celsius, and the reaction time was 30 minutes. Under these conditions, the chelation capacity of ginkgo biloba peptide for zinc reached 135 mg / g.

[0027] Example 4: The effect of pH on the solubility of zinc in the chelate Ginkgo biloba extract or zinc sulfate was dissolved in distilled water, and the pH of the solutions was adjusted to 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, and 8.0, respectively. After shaking at 37°C for 30 minutes, the solutions were centrifuged at 8000 rpm for 10 minutes. The supernatant was collected and completely digested using wet digestion. The zinc content was then quantitatively analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES). The solubility of zinc was calculated using the following formula: Solubility (%) = s / S × 100%, where s is the amount of zinc in the supernatant and S is the amount of zinc in the chelate.

[0028] like Figure 2 As shown, the zinc solubility of both ginkgo peptide zinc chelate and zinc sulfate is relatively high in the pH range of 2-6. When the pH rises to 7, the solubility of zinc sulfate decreases rapidly, while the solubility of peptide zinc chelate is 89.44%, which is 3.78 times that of zinc sulfate.

[0029] Example 5: Effect of gastrointestinal digestion on zinc solubility in chelates Zinc sulfate or zinc peptide chelate was dissolved in 10 mM hydrochloric acid solution (pH 2.0) to a concentration of 5 mg / mL. After thorough mixing, pepsin was added at an enzyme-to-solvent ratio of 1:100, and the mixture was incubated at 37°C with shaking for 1.5 h. Subsequently, the pH of the system was adjusted to 7.5, and trypsin was added at an enzyme-to-solvent ratio of 1:50, and the mixture was incubated at 37°C with shaking for 2.5 h. During incubation, samples were taken at 0, 15, 30, 60, 90, 95, 100, 120, 150, 180, and 240 minutes. The solution was centrifuged at 8000 rpm for 10 minutes, and the supernatant was completely digested using wet digestion. The zinc content was quantitatively analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES). The solubility of zinc was calculated using the following formula: Solubility (%) = s / S × 100%, where s is the amount of zinc in the supernatant and S is the amount of zinc in the chelate.

[0030] like Figure 3 As shown, the solubility of ginkgo peptide zinc chelate and zinc sulfate differs significantly during simulated gastrointestinal digestion. In the simulated gastric digestion stage, zinc sulfate has better solubility than ginkgo peptide zinc chelate. However, in the simulated intestinal digestion stage, the solubility of zinc sulfate is close to 0, while the solubility of ginkgo peptide zinc chelate is still high (greater than 50%), which is better than zinc absorption, which mainly occurs in the small intestine. Therefore, ginkgo peptide zinc chelate can effectively promote zinc absorption.

[0031] Example 6: Preparation of insoluble dietary fiber from carrots After the carrot was treated into paste by grinder, the paste was washed repeatedly 5 times by distilled water to remove soluble impurities. Then, the washed mixture was hydrolyzed under catalysis of amylase, glucoamylase and protease. After hydrolysis, the mixture was centrifuged at 8000 rpm for 10 minutes to separate the hydrolysate from the residue, and the obtained residue was carrot insoluble dietary fiber. After freeze-drying, the carrot insoluble dietary fiber powder with uniform particle size was obtained by crushing through a 60-mesh sieve.

[0032] Example 7: Adsorption capacity of peptide zinc chelate on carrot insoluble dietary fiber powder The maximum adsorption capacity (BCmax) was determined as follows: 0.2 g of carrot insoluble dietary fiber was mixed with 20 mL of distilled water, and a certain amount of ginkgo peptide or zinc sulfate was added to make the zinc concentration in the solution 10 mM. At the same time, the pH value of the system was adjusted to 2.0 or 7.0. The reaction system was incubated at 37°C for 6 hours, and then centrifuged at 8000 rpm for 10 minutes. After complete wet digestion of the supernatant, the zinc content was quantitatively analyzed by inductively coupled plasma emission spectrometer. The minimum adsorption capacity (BCmin) was determined as follows: the amount of dietary fiber was increased to 0.5 g, and the zinc concentration was reduced to 500 μM. The rest of the monitoring method was the same as that for the maximum adsorption capacity. The adsorption capacity of zinc on the dietary fiber can be calculated by the following formula: q e =( C 0- C e ) V / m , wherein q e is the adsorption capacity of zinc on the dietary fiber (mg / g); C 0 is the initial concentration of zinc (mg / L); C e is the concentration of zinc in the supernatant after adsorption by the dietary fiber (mg / L); m is the mass of carrot insoluble dietary fiber.

[0033] The maximum and minimum adsorption capacities of zinc sulfate and ginkgo peptide zinc chelate on carrot insoluble dietary fiber are shown in Table 1. As shown in the table, when the pH was 7.0, the adsorption capacity of zinc sulfate on carrot insoluble dietary fiber was 16.36 mg / g, and that of the peptide zinc chelate was 14.49 mg / g, which was more than 10% lower than that of zinc sulfate; similarly, when the pH was 7.0, the adsorption capacity of zinc sulfate on carrot was 1.13 mg / g, which was also higher than that of the peptide zinc chelate.

[0034] Table 1: Adsorption capacity of ginkgo peptide zinc chelate on carrot insoluble dietary fiber The white ginkgo peptide zinc chelate obtained by the preparation method disclosed by the application has high zinc content, good stability, strong resistance to dietary fiber adsorption, and can be used for functional food, especially dietary zinc supplement.

[0035] Although the above embodiment has made a detailed description of the application, it is only a part of the embodiments of the application, not all the embodiments, and other embodiments can be obtained without creativity on the basis of the embodiment, which all belong to the protection scope of the application.

Claims

1. A ginkgo biloba peptide zinc chelate having a dietary fiber adsorption effect resistance and a preparation method thereof, characterized by, The white ginkgo peptide zinc chelate is obtained through the steps of white ginkgo protein extraction, proteolysis, ultrafiltration, chelation, purification and drying.

2. The ginkgo peptide zinc chelate having resistance to the adsorption effect of dietary fiber according to claim 1, and a preparation method thereof, characterized in that, The white ginkgo protein extraction condition is that 1 part of defatted white ginkgo powder is uniformly mixed with 10-20 parts of water, the pH of the mixed solution is adjusted to 10.0, and the solution is stirred and extracted at 40-80 ℃ for 2-4 hours; after centrifugation, the pH of the supernatant is adjusted to 4-4.5, and the solution is refrigerated (2-4 ℃) for 5 hours; after the upper liquid is discarded, the pH of the system is adjusted to neutral, the precipitate is washed with distilled water for 3 times, and then the solution is treated with a dialysis bag with a molecular weight cut-off of 10000 Da for 72 hours; finally, the mixed solution in the bag is freeze-dried to obtain white ginkgo protein.

3. The ginkgo peptide zinc chelate having resistance to the adsorption effect of dietary fiber according to claim 1, and a preparation method thereof, characterized by, The proteolysis condition is that 1 part of white ginkgo protein is uniformly mixed with 10-20 parts of water, the pH of the system is adjusted to 8.0, and alkaline protease (Alcalase) is added at an enzyme-substrate ratio of 1:50-100; the solution is stirred and enzymolyzed at 50 ℃ for 4-6 hours, and the pH of the system is adjusted and maintained at 8.0 every 10 minutes during the enzymolysis; after the reaction is completed, the solution is heated at 95 ℃ for 5-10 minutes, and the supernatant is obtained by centrifugation.

4. The ginkgo peptide zinc chelate having resistance to the adsorption effect of dietary fiber according to claim 1, and a preparation method thereof, characterized by, The ultrafiltration condition is that the supernatant is passed through an ultrafiltration membrane with a molecular weight cut-off of 1000 Da, and the filtrate is freeze-dried to obtain white ginkgo peptide.

5. The ginkgo peptide zinc chelate having resistance to the adsorption effect of dietary fiber according to claim 1, and a preparation method thereof, characterized by, The zinc source used in the chelation is ZnSO4·7H2O.

6. The ginkgo peptide zinc chelate having resistance to the adsorption effect of dietary fiber according to claim 1, and a preparation method thereof, characterized by, The chelation condition is that 1 part of white ginkgo peptide is dissolved in 10 parts of water, ZnSO4·7H2O is added at a GPIH / ZnSO4·7H2O ratio of 1:2-4:1, the pH is adjusted to 4-8, and the solution is stirred and reacted at 30-70 ℃ for 15-75 minutes.

7. The ginkgo peptide zinc chelate having resistance to the adsorption effect of dietary fiber according to claim 1, and a preparation method thereof, characterized by, The purification condition is that the chelation reaction solution is treated with a dialysis bag with a molecular weight cut-off of 100 Da for 24 hours.

8. The ginkgo peptide zinc chelate having resistance to the adsorption effect of dietary fiber according to claim 1, and a preparation method thereof, characterized by, The drying condition is that the solution in the dialysis bag is freeze-dried or spray-dried to obtain white ginkgo peptide zinc chelate.

9. The white ginkgo peptide zinc chelate prepared by the method of any one of claims 1-8 is used in a zinc supplement.

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