CN111528480A

CN111528480A - Calcium nutritional supplement and preparation method thereof

Info

Publication number: CN111528480A
Application number: CN202010435331.3A
Authority: CN
Inventors: 汤佳鹏; 陆亚鹏; 葛彦; 朱俐; 李梦雪
Original assignee: Nantong University
Current assignee: Nantong University
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2020-08-14
Anticipated expiration: 2040-05-21
Also published as: CN111528480B

Abstract

The invention belongs to the field of biomedical engineering, and discloses a calcium nutritional supplement and a preparation method thereof. The preparation method provided by the invention comprises the following steps: (1) boiling silkworm cocoon or waste raw silk with sodium carbonate solution to degum to obtain sericin solution; (2) adding alkaline protease into sericin solution for reaction, adjusting the pH to 7.5 with hydrochloric acid, adding elastase for reaction, performing ultrafiltration, and spray-drying the filtrate to obtain sericin peptide; (3) and (3) dropwise adding polyphosphoric acid on sericin peptide, adding soybean lecithin for reaction, then adding a saturated calcium hydroxide solution to precipitate redundant phosphate radicals, centrifuging, taking supernate, and performing spray drying to obtain the calcium nutritional supplement. The calcium nutritional supplement prepared by the invention is rich in absorbable calcium and has the effect of promoting calcium absorption.

Description

Calcium nutritional supplement and preparation method thereof

Technical Field

The invention relates to the field of biomedical engineering, in particular to a calcium nutritional supplement and a preparation method thereof.

Background

At present, the raw materials of calcium supplement products on the market mainly comprise:

firstly, organic calcium: such as calcium gluconate, calcium lactate, calcium acetate, calcium citrate, calcium levulinate, etc. The organic calcium has high solubility and less irritation to stomach and intestine, but the content of calcium is less, and the absorption rate is about 10-15%.

II, inorganic calcium: such as calcium carbonate, calcium phosphate, calcium oxide, calcium hydrogen phosphate, etc., with an absorption rate of 30-40%. Inorganic calcium has low solubility and is more irritating to the stomach and intestine, but the content of calcium is relatively high.

Thirdly, active calcium: the active calcium is prepared from animal bone and shell by calcining at high temperature and electrolyzing, and mainly comprises calcium hydroxide and calcium chloride. Although the active calcium has high ionization degree and solubility, the bioavailability is not high, the calcium content is low, small-time liquid of the active calcium is strong alkaline (pH is more than 12), the acute toxicity is high, the stimulation to intestines and stomach is large, nausea, vomiting and the like are easily caused, and the content of heavy metals (lead, arsenic, cadmium and the like) in a calcium product is high.

Fourthly, biological calcium: the natural biological calcium is mainly prepared from oyster shells, shells and the like in the current market, and is sourced from lakes, offshore waters and other water areas. Due to the pollution problem of oceans and lakes, the pollution of elements such as lead, cadmium and the like in the calcium agent is reported. Oyster shell often contains various heavy metal elements, and long-term administration can cause the heavy metals to deposit in vivo to cause chronic poisoning.

In conclusion, the main sources of raw materials of the safer calcium supplement products in the market are organic calcium and inorganic calcium, but the organic calcium and the inorganic calcium generally have the problem of low calcium absorption rate, and the common solution is to promote the absorption and utilization of calcium by adding a calcium nutritional supplement. A commonly used calcium nutritional supplement is casein phosphopeptide (CPP), the core structure of which is: -Ser (P) -Glu-Glu- (Ser: serine, Glu: glutamic acid, P: phosphate). Phosphoserine residues (-Ser (P)) in the structure of the CPP exist in clusters, and are negatively charged in the intestinal tract pH weakly alkaline environment, so that the further action of digestive enzymes can be prevented, and the CPP can not be further hydrolyzed and stably exists in the intestine. Domestic researches find that the smaller the molar ratio of nitrogen to phosphorus in the CPP, the shorter the peptide chain of the CPP, and the higher the density of phosphate group, the higher the purity of the CPP, and the stronger the effect of promoting the absorption and utilization of calcium. However, CPP has limited phosphate groups bound to casein, especially beta-casein, contains a large amount of glutamine, forms a major phosphorylation site near the N-terminus, and has a smaller number of beta-casein phosphorylation sites and a smaller level of phosphorylation than alpha-casein, which greatly limits its calcium-holding ability.

Therefore, there is a need for a calcium supplement having a high calcium carrying capacity, which is effective in improving calcium absorption.

Disclosure of Invention

In view of the above, the present invention aims to provide a calcium supplement and a preparation method thereof, and the prepared calcium supplement has a low nitrogen-phosphorus ratio, a short peptide chain and a strong calcium carrying capacity.

In order to solve the technical problems, the invention provides a preparation method of a calcium nutritional supplement, which comprises the following steps:

s1, boiling silkworm cocoons or waste raw silks with sodium carbonate solution to obtain a sericin solution;

s2, adding alkaline protease into the sericin solution to perform a first-step hydrolysis reaction to obtain a first reaction solution, adjusting the pH of the first reaction solution to 7.5 by using 6mol/L hydrochloric acid, adding elastase to perform a second-step hydrolysis reaction, performing ultrafiltration, and performing spray drying on a permeate obtained by ultrafiltration to obtain sericin;

s3, dripping polyphosphoric acid on the sericin peptide, adding soybean lecithin, reacting for 5-8h at 20-50 ℃, adding water after the reaction is finished, cooling to room temperature after 20-30min of boiling water bath, slowly dripping saturated calcium hydroxide solution, fully stirring to determine the pH value, stopping adding the saturated calcium hydroxide solution when the pH value is increased and then reduced to 7.5, cooling to 4-8 ℃, centrifuging, taking supernate, and spray drying to obtain the calcium nutritional supplement.

Preferably, in step S1, the concentration of the sodium carbonate solution is 50-100g/L, the bath ratio of the water boiling is 1:40-1:60, and the time of the water boiling is 30-60 min.

Preferably, in step S2, the specific activity of the alkaline protease is 100000-200000U/g, and the dosage ratio of the alkaline protease to the sericin solution is (10-20) g: 1L.

Preferably, in step S2, the temperature of the first hydrolysis reaction is 40 to 50 ℃ and the reaction time is 2 to 4 hours.

Preferably, in step S2, the specific activity of the elastase is 3000-8000U/g, and the dosage ratio of the elastase to the first reaction solution is (0.5-2) g: 1L.

Preferably, in step S2, the temperature of the second hydrolysis reaction is 35-40 ℃ and the reaction time is 24-48 h.

Preferably, in step S3, the polyphosphoric acid, sericin, soybean lecithin and water are added in a ratio of (10-20) mL (0.5-0.8) g (5-20) mg (90-180) mL.

The invention also provides a calcium nutritional supplement prepared by the preparation method.

Compared with the prior art, the invention has the following beneficial effects:

the mol nitrogen-phosphorus ratio of the calcium nutritional supplement is as low as 5.21mol/mol, the calcium holding amount is as high as 0.0136g/g, and experimental results show that the calcium absorption rate and the calcium retention rate of a mouse eating the calcium nutritional supplement are obviously improved, which shows that the calcium nutritional supplement has stronger calcium carrying capacity and calcium absorption promoting capacity.

Detailed Description

The invention will be better understood from the following examples. However, those skilled in the art will readily appreciate that the description of the embodiments is only for illustrating the present invention and should not be taken as limiting the invention as detailed in the claims.

The invention provides a preparation method of a calcium nutritional supplement, which comprises the following specific steps:

firstly, boiling silkworm cocoons or waste raw silks with sodium carbonate solution in water to obtain sericin solution, wherein the concentration of the adopted sodium carbonate solution is preferably 50-100g/L, the bath ratio of water boiling is preferably 1:40-1:60, and the time of water boiling is preferably 30-60 min.

And then adding alkaline protease into the obtained sericin solution to perform a first-step hydrolysis reaction to obtain a first reaction solution, adjusting the pH of the first reaction solution to 7.5 by using 6mol/L hydrochloric acid, adding elastase to perform a second-step hydrolysis reaction, performing ultrafiltration, and performing spray drying on the ultrafiltration-obtained permeate to obtain sericin peptide. In this step, the specific activity of the alkaline protease is preferably 100000-; the specific activity of the adopted elastase is preferably 3000-8000U/g, and the adding amount of the elastase is preferably 0.5-2g added into 1L of the first reaction liquid. The temperature of the hydrolysis reaction is preferably 40-50 ℃ and the time of the hydrolysis reaction is preferably 2-4 hours during the first hydrolysis reaction, and the temperature of the hydrolysis reaction is preferably 35-40 ℃ and the time of the hydrolysis reaction is preferably 24-48 hours during the second hydrolysis reaction.

The sericin prepared by the method has a large amount of serine residues, wherein the mass fraction of serine in the total sericin is more than 20%, which is far higher than that of other proteins such as casein, and the serine residues can be combined with calcium after phosphorylation, so that the sericin with high serine content has a low nitrogen-phosphorus ratio, and the calcium combining capability is greatly improved. In addition, the sericin peptide also contains a large amount of aspartic acid, the content of which reaches 14 percent, which is beneficial to improving the water solubility and is easier to be absorbed by organisms.

After sericin is obtained, dropwisely adding polyphosphoric acid onto the sericin, adding soybean lecithin, reacting for 5-8h at 20-50 ℃, adding water after the reaction is finished, cooling to room temperature after 20-30min in a boiling water bath, slowly dropwisely adding a saturated calcium hydroxide solution, fully stirring to determine the pH value, stopping adding the saturated calcium hydroxide solution when the pH value is increased and then reduced to 7.5, cooling to 4-8 ℃, centrifuging, taking a supernatant, and spray drying to obtain the calcium nutritional supplement. In the process, the ratio of the added amount of the polyphosphoric acid, the sericin peptide, the soybean lecithin and the water is preferably (10-20) mL, (0.5-0.8) g, (5-20) mg, (90-180) mL.

In the invention, unreacted polyphosphoric acid can be decomposed into orthophosphoric acid in the boiling water bath process, the added saturated calcium hydroxide solution can be used as a calcium donor, and the orthophosphoric acid in the solution can be converted into calcium phosphate precipitate to be removed, so that excessive phosphoric acid in the system is prevented from antagonizing calcium absorption.

To further illustrate the present invention, a calcium supplement and a method for preparing the same are described in detail below with reference to examples.

Example 1

(1) Boiling silkworm cocoon with 75g/L sodium carbonate solution in water at a bath ratio of 1:50 for 50min to obtain sericin solution.

(2) Taking 100mL of the sericin solution prepared in the step (1), adding 1.5g of alkaline protease with the specific activity of 150000U/g, and reacting at 45 ℃ for 3h to obtain a first reaction solution. Adjusting pH of the first reaction solution to 7.5 with 6mol/L hydrochloric acid, adding 0.12g of elastase with specific activity of 6000U/g, reacting at 38 deg.C for 36h, ultrafiltering, and spray drying the filtrate obtained by ultrafiltration to obtain sericin peptide.

(3) And (3) dropwise adding 15mL of polyphosphoric acid onto 0.6g of sericin peptide prepared in the step (2), adding 12mg of soybean lecithin, reacting at 37 ℃ for 6h, adding 130mL of water after the reaction is finished, cooling to room temperature after 25min in a boiling water bath, adding a saturated calcium hydroxide solution, slowly dropwise adding a saturated calcium hydroxide solution, fully stirring to determine the pH value, stopping adding the saturated calcium hydroxide solution when the pH value is increased and then reduced to 7.5, cooling to 6 ℃, centrifuging, taking a supernatant, and performing spray drying to obtain the calcium nutritional supplement.

Example 2

(1) Boiling waste raw silk with 50g/L sodium carbonate solution for 30min at a bath ratio of 1:40 to obtain sericin solution.

(2) And (2) taking 100mL of the sericin solution prepared in the step (1), adding 1g of alkaline protease with specific activity of 100000U/g, and reacting at 50 ℃ for 4 hours to obtain a first reaction solution. Adjusting pH of the first reaction solution to 7.5 with 6mol/L hydrochloric acid, adding 0.05g of elastase with specific activity of 3000U/g, reacting at 35 deg.C for 24h, ultrafiltering, and spray drying the filtrate obtained by ultrafiltration to obtain sericin peptide.

(3) And (3) dropwise adding 10mL of polyphosphoric acid onto 0.5g of sericin peptide prepared in the step (2), adding 5mg of soybean lecithin, reacting for 5 hours at 20 ℃, adding 90mL of water after the reaction is finished, cooling to room temperature after 20min of boiling water bath, slowly dropwise adding a saturated calcium hydroxide solution, fully stirring to measure the pH value, stopping adding the saturated calcium hydroxide solution when the pH value is increased and then reduced to 7.5, cooling to 4 ℃, centrifuging, taking a supernatant, and performing spray drying to obtain the calcium nutritional supplement.

Example 3

(1) Boiling waste raw silk with 100g/L sodium carbonate solution for 60min at bath ratio of 1:60 to obtain sericin solution.

(2) Taking 100mL of the sericin solution prepared in the step (1), adding 2g of alkaline protease with the specific activity of 200000U/g, and reacting for 2h at 40 ℃ to obtain a first reaction solution. Adjusting pH of the first reaction solution to 7.5 with 6mol/L hydrochloric acid, adding 0.2g of elastase with specific activity of 8000U/g, reacting at 40 deg.C for 48 hr, ultrafiltering, and spray drying the filtrate to obtain sericin peptide.

(3) And (3) dropwise adding 20mL of polyphosphoric acid onto 0.8g of sericin peptide prepared in the step (2), adding 20mg of soybean lecithin, reacting for 8 hours at 50 ℃, adding 180mL of water after the reaction is finished, cooling to room temperature after 30min of boiling water bath, slowly dropwise adding a saturated calcium hydroxide solution, fully stirring to measure the pH value, stopping adding the saturated calcium hydroxide solution when the pH value is increased and then reduced to 7.5, cooling to 8 ℃, centrifuging, taking a supernatant, and performing spray drying to obtain the calcium nutritional supplement.

Comparative example 1 (phosphorus oxychloride instead of polyphosphoric acid)

(3) And (3) dropwise adding 15mL of phosphorus oxychloride on 0.6g of sericin peptide prepared in the step (2), adding 12mg of soybean lecithin, reacting at 37 ℃ for 6h, adding 130mL of water after the reaction is finished, cooling to room temperature after 25min in a boiling water bath, slowly dropwise adding a saturated calcium hydroxide solution, fully stirring to measure the pH value, stopping adding the saturated calcium hydroxide solution when the pH value is increased and then reduced to 7.5, cooling to 6 ℃, centrifuging, taking a supernatant, and performing spray drying to obtain the calcium nutritional supplement.

Comparative example 2 (without alkaline protease treatment)

(1) Boiling waste raw silk with 75g/L sodium carbonate solution for 50min at a bath ratio of 1:50 to obtain sericin solution.

(2) And (2) taking 100mL of the sericin solution prepared in the step (1), adjusting the pH to 7.5 by using 6mol/L hydrochloric acid, adding 0.12g of elastase with the specific activity of 6000U/g, reacting for 36h at 38 ℃, performing ultrafiltration, and performing spray drying on the filtrate obtained by ultrafiltration to obtain sericin peptide.

(3) And (3) dropwise adding 15mL of polyphosphoric acid onto 0.6g of sericin peptide prepared in the step (2), adding 12mg of soybean lecithin, reacting at 37 ℃ for 6h, adding 130mL of water after the reaction is finished, cooling to room temperature after 25min in a boiling water bath, slowly dropwise adding a saturated calcium hydroxide solution, fully stirring to measure the pH value, stopping adding the saturated calcium hydroxide solution when the pH value is increased and then reduced to 7.5, cooling to 6 ℃, centrifuging, taking a supernatant, and performing spray drying to obtain the calcium nutritional supplement.

Comparative example 3 (without Elastase treatment)

(2) And (2) taking 100mL of the sericin solution prepared in the step (1), adding 1.5g of alkaline protease with the specific activity of 150000U/g, reacting at 45 ℃ for 3 hours, then carrying out ultrafiltration, and carrying out spray drying on the filtrate obtained by ultrafiltration to obtain the sericin peptide.

Experimental example 1

Measuring the nitrogen content in the calcium nutritional supplement obtained in the examples 1-3 and the comparative examples 1-3 by using a Kjeldahl method, measuring the total phosphorus and inorganic phosphorus content in the calcium nutritional supplement by using a Fiske-Subbarow phosphorus determination method, and calculating the organic phosphorus content; measuring relative molecular mass (Sephadex G-25, column specification of 100cm × 5.0cm) by gel filtration, and eluting with 0.025mol/L KCl-0.2mol/L HAc solution at 0.2 mL/min; and measuring the in-vitro calcium holding capacity of the calcium nutritional supplement by using an inductively coupled plasma emission spectrometer. The results of the measurements of nitrogen content, organic phosphorus content, molar nitrogen-phosphorus ratio, relative molecular mass, and calcium holding amount of the calcium supplement are shown in table 1.

TABLE 1 determination of calcium nutritional supplements

As can be seen from table 1, as the molar nitrogen-phosphorus ratio of the calcium supplement decreases, its calcium-holding capacity gradually increases. The calcium holding amount of the calcium nutritional supplements prepared in the examples 1-3 is obviously higher than that of the calcium nutritional supplements prepared in the comparative examples 1-3. Due to the lack of a protease in the preparation methods of comparative example 2 and comparative example 3, the sericin is not hydrolyzed completely, and the molecular weight of the calcium nutritional supplement is obviously larger.

Experimental example 2

The effect of the calcium nutritional supplement of the invention on calcium absorption in mice:

1) test samples: the calcium nutritional supplements prepared in examples 1-3 of the present invention, the calcium nutritional supplements prepared in comparative examples 1-3, and commercially available casein phosphopeptides.

2) Test animals: 80 weaned mice born at 14d have half of the male and female bodies and good health condition.

3) The test method comprises the following steps: after experimental mice are fed for 4 days in an adaptive mode, the experimental mice are randomly divided into 8 groups, 10 mice in each group are half female and half male, the 8 groups of mice are respectively fed into polyethylene plastic boxes according to the group and the sex, the mice freely eat 2-week basic low-calcium feed, and the mice freely drink deionized water to serve as a dead-time period. After the depletion period, 4 weeks of growth experiments were performed during which the groups were fed as follows:

experiment group I: feeding the mice with basal low-calcium feed;

experiment II group: feeding the mice with a basal low-calcium feed mixed with 20% by mass of the calcium nutritional supplement prepared in example 1;

experiment group III: feeding the mice with a basal low-calcium feed mixed with 20% by mass of the calcium nutritional supplement prepared in example 2;

experiment group IV: feeding the mice with a basal low-calcium feed mixed with 20% by mass of the calcium nutritional supplement prepared in example 3;

experiment group V: feeding mice with a basal low-calcium feed mixed with 20% by mass of a commercially available casein phosphopeptide;

experiment group VI: feeding the mice with a basic low-calcium feed mixed with 20% by mass of the calcium supplement prepared in comparative example 1;

experiment group VII: feeding the mice with a basic low-calcium feed mixed with 20% by mass of the calcium supplement prepared in comparative example 2;

experiment group VIII: the mice were fed a basal low-calcium feed mixed with 20% by mass of the calcium nutritional supplement prepared in comparative example 3.

And (3) carrying out a metabolism experiment in the last 3d of the growth experiment, measuring feed calcium, fecal calcium and urinary calcium, and calculating the absorption rate and the retention rate of calcium according to a formula:

the content of the fecal calcium, the urine calcium and the feed calcium is measured according to the GB12398-90 method by adopting an atomic absorption spectrophotometer, and the result is shown in table 2.

TABLE 2 Effect of the calcium supplement of the present invention on calcium absorption in mice

Experimental group	Sample (I)	Calcium absorption rate (%)	Calcium retention rate (%)
				Experiment group I	Low calcium feeding control	20.1±4.3	22.5±4.2
Experiment II group	Example 1	93.4±2.5	92.4±2.1
				Experiment group III	Example 2	89.7±2.0	94.0±0.9
Experiment group IV	Example 3	91.8±1.4	90.3±3.3
				Experiment group V	Casein phosphopeptides commercially available	69.3±3.4	82.4±2.7
Experiment group VI	Comparative example 1	49.0±4.6	57.1±1.9
				Experiment group VII	Comparative example 2	42.1±2.7	56.3±5.3
Experiment group VIII	Comparative example 3	52.7±5.2	44.0±3.7

As shown in the results of Table 2, the calcium supplement prepared in examples 1 to 3 of the present invention can enhance the absorption and retention of calcium in vivo, and has better effect than the calcium supplement prepared in the commercial casein phosphopeptide and comparative examples 1 to 3.

The present invention provides a calcium supplement and a method for preparing the same, and a plurality of methods and ways for implementing the technical scheme, and the above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention. All the components not specified in the present embodiment can be realized by the prior art.

Claims

1. A method for preparing a calcium nutritional supplement, comprising the steps of:

2. The method for preparing a calcium supplement, according to claim 1, wherein in step S1, the concentration of the sodium carbonate solution is 50-100g/L, the bath ratio of water boiling is 1:40-1:60, and the time of water boiling is 30-60 min.

3. The method as claimed in claim 1, wherein in step S2, the specific activity of the alkaline protease is 100000-200000U/g, and the ratio of the alkaline protease to the sericin solution is (10-20) g: 1L.

4. The method for preparing calcium supplement of claim 1, wherein the first hydrolysis reaction is performed at a temperature of 40-50 ℃ for 2-4h in step S2.

5. The method as claimed in claim 1, wherein in step S2, the specific activity of elastase is 3000-8000U/g, and the ratio of the elastase to the first reaction solution is (0.5-2) g: 1L.

6. The method for preparing calcium supplement of claim 1, wherein the second hydrolysis reaction is performed at 35-40 ℃ for 24-48h in step S2.

7. The method of claim 1, wherein the polyphosphoric acid, the sericin, the soybean lecithin and the water are added in a ratio of (10-20) mL (0.5-0.8) g (5-20) mg (90-180) mL in step S3.

8. A calcium nutritional supplement prepared by the preparation method according to any one of claims 1 to 7.