CN104232717A - Method for reducing fluorine content in water soluble active peptides from Antarctic krill - Google Patents

Abstract

The purpose of the present invention is to provide a method for reducing the fluorine content in the water-soluble Antarctic krill active peptide, which is to hydrolyze the Antarctic krill meal with protease to obtain an aqueous solution of krill active peptide; add a defluorination agent to the active peptide aqueous solution in turn Mix Ⅰ and defluorinating agent II; the active peptide aqueous solution is centrifuged to obtain a defluorinated supernatant; the defluorinated supernatant is spray-dried to obtain a water-soluble Antarctic krill active peptide powder product with low fluorine content. The method of the present invention has the advantages of simple operation, low equipment investment, no environmental pollution, high product recovery rate, and is suitable for industrial operation; the obtained krill active peptide powder with low fluorine content has the following characteristics: the fluorine content is reduced from 350-450ppm to 2-5ppm, The protein content is higher than 85%, there is no harmful substance residue, and the product safety is high; the essential amino acid content is high, and it conforms to the amino acid composition mode stipulated by FAO/WHO.

Description

A method for reducing fluorine content in water-soluble Antarctic krill active peptide

technical field

The invention belongs to the technical field of aquatic product purification, and in particular relates to a method for reducing the fluorine content in water-soluble Antarctic krill active peptide.

Background technique

Fluorine has a high degree of biological activity and cannot be automatically degraded in animals and plants. Therefore, excessive intake of fluorine will lead to fluorosis, which will have very adverse effects on health. Excessive fluoride intake can lead to symptoms such as dental fluorosis, skeletal fluorosis, joint pain, ligament calcification, bone hyperplasia, and inconvenient movement. In severe cases, it can also cause curvature of the spine and even paralysis. In view of the potential harm of fluorine to the human body, the Ministry of Health of my country stipulates that the allowable daily intake of fluorine for adults is 3.5 mg.

Antarctic krill is a class of marine invertebrates distributed in Antarctic waters. According to statistics, the reserves of Antarctic krill are 650-100 million tons, which is a huge treasure house of human protein resources. The protein content of krill dry weight is about 65-75%. Its amino acid composition is reasonable and its essential amino acid content is high. It is an important raw material for high-value protein utilization. However, the high fluoride in Antarctic krill restricts the development of krill-related functional foods. The average fluorine content in krill meal processed from whole shrimp is 1800-2500ppm. The fluorine content in water-soluble krill active peptide powder prepared by protease hydrolysis using krill powder as raw material is about 350-450ppm, which seriously affects the development and application prospects of active peptide as a functional protein food.

The foreign patent UK2240786A discloses a method for reducing the fluorine content of Antarctic krill by enriching with aluminum electrodes, but this method has the problem of aluminum residue; the domestic patent CN101690538B discloses a method for preparing low-fluorine protein base material by pickling method. The method uses the low solubility of protein at the isoelectric point (weak acid condition) to recover the protein, which is not suitable for low molecular weight polypeptides with good water solubility; domestic patent CN102524510B discloses a method for preparing a low-fluorine protein base material. Solution pH or heating to recover protein is not suitable for low-molecular-weight polypeptides with good water solubility; domestic patent CN102532255A discloses a method for preparing low-fluorine Antarctic krill shrimp meat protein using ion-exchange membrane electrolysis and electroosmosis. The recovery of shrimp meat protein by solid-liquid separation is not suitable for low-molecular-weight polypeptides with good water solubility; domestic patent CN102106493B discloses a method for preparing low-fluorine Antarctic krill meal by adjusting acid and reducing and evaporating cycle defluorination. The equipment used in this method is complex and expensive. Therefore, it is necessary to provide a more effective method for reducing the fluorine content in Antarctic krill polypeptides.

Contents of the invention

The purpose of the present invention is to provide a method for reducing the fluorine content in water-soluble Antarctic krill active peptides, that is, to provide a method for reducing fluorine in water-soluble krill active peptides with simple operation, low cost, high safety, and high product recovery rate. The method of content, thereby makes up for the deficiency of prior art.

The method of the present invention comprises the following steps:

1) Add distilled water to Antarctic krill powder, the mass ratio of solid to liquid is 1:6-15, adjust the pH value of the mixed solution, and then add protease to the mixed solution for hydrolysis, the hydrolysis temperature is 40-60°C, and the hydrolysis time is 2 ~12 hours; after the hydrolysis, heat to terminate the enzymolysis reaction, centrifuge to obtain the supernatant, which is the krill active peptide aqueous solution;

2) Adjust the krill active peptide aqueous solution to a solid content of 5-30%, then add defluorinating agent I and mix to obtain a mixed solution;

3) Add defluorinating agent II to the mixed solution in step 2), and stir evenly for defluorinating treatment;

4) After step 3) the defluorinated mixed solution is centrifuged to obtain a supernatant;

5) The supernatant E was spray-dried to obtain a krill active peptide powder product with low fluorine content.

Wherein, the protease in step 1) is one or more in papain, bromelain, trypsin, neutral protease or alkaline protease;

In step 2), the defluorinating agent I is one or more of calcium oxide, calcium hydroxide, and calcium carbonate, and the added mass is 0.5-4.0% (w/v) of the solution volume;

In step 3), the defluorinating agent II is one or more of calcium phosphate, calcium monohydrogen phosphate, and calcium dihydrogen phosphate;

In step 3), the molar ratio of defluorinating agent I to defluorinating agent II is 0.5-2.0;

The spray drying condition in step 5) is that the inlet air temperature is 120-160°C, and the outlet air temperature is 80-120°C.

The method of the present invention has the advantages of simple operation, low equipment investment, no environmental pollution, high product recovery rate, and is suitable for industrial operation; the obtained krill active peptide powder with low fluorine content has the following characteristics: the fluorine content is reduced from 350-450ppm to 2-5ppm, The protein content is higher than 85%, the ash content is 7-15%, and the product safety is high; the essential amino acid content is high, which conforms to the amino acid composition mode stipulated by FAO/WHO.

Detailed ways

In the present invention, the purpose of removing most of the fluoride in the krill peptide solution is achieved by adding a defluorination agent twice to the Antarctic krill active peptide aqueous solution. And the precipitated product is calcium phosphate salt, which can further adsorb a small amount of fluoride remaining in the krill peptide solution, thereby achieving the purpose of significantly reducing the fluorine content in the product krill peptide powder. The defluoridation agent used in the present invention is a commonly used calcium salt, which is cheap and has a wide range of sources. The added calcium salt finally exists in the form of insoluble precipitates such as calcium phosphate salts, which can be quickly removed by solid-liquid separation, avoiding krill active peptides. With the introduction of medium soluble inorganic salts, the protein loss rate before and after defluorination is less than 10%.

The detection method adopted to Antarctic krill active peptide in the present invention is as follows:

The determination method of protein content refers to the Kjeldahl method in GB5009.5-2010 "National Standard - Determination of Protein in Food"; the determination method of ash content refers to GB5009.4-2010 "National Standard - Determination of Ash Content in Food"; The determination method of the content refers to the fluoride ion selective electrode method in GB/T5009.18-2003 "National Standard - Determination of Fluorine in Food"

Example 1

1) Take 5kg of Antarctic krill powder, add 60L of distilled water to the krill powder, add 2M HCl to the mixed solution, adjust the pH value of the mixed solution to 7.5, raise the temperature to 45°C, add 75g of neutral protease to the mixed solution, and Stir in the reaction kettle at constant temperature for 10 hours, heat to 100°C to terminate the enzyme reaction, and centrifuge to obtain supernatant A;

2) Make the solid content of the supernatant A reach 15% by vacuum concentration, the vacuum degree is 0.08MPa, and the temperature is 40-80°C to obtain solution B;

3) Take 10L of solution B, add 100g of calcium hydroxide to it, mix well, and cool to obtain mixed solution C;

4) Add 184 g of monobasic calcium phosphate (calcium hydrogen phosphate) to the mixed solution C, and stir while adding to obtain the mixed solution D;

5) After the mixture D is centrifuged at 5000r/min, the supernatant E is obtained;

6) The supernatant E was spray-dried (inlet air temperature 140°C, outlet air temperature 100°C) to obtain low-fluorine water-soluble Antarctic krill active peptide powder.

The protein content of the Antarctic krill active peptide powder prepared after defluorination in the present invention is higher than 85%, the fluorine content is 2-5mg/kg, and the ash content is 7-12%; while the Antarctic krill active peptide powder without defluorination treatment The fluorine content in the peptide powder is 350-450mg/kg, and the ash content is 7-12%. During the defluorination process, the loss rate of protein is less than 10%, the amino acid composition and content of krill peptides before and after defluorination have no significant changes, and the essential amino acid content is higher than the regulations of FAO/WHO/UNU (2007), meeting the requirements of adults/infants Requirements for essential amino acids (Table 1).

Table 1: Analysis results of amino acid composition before and after defluorination of Antarctic krill active peptide powder prepared by the present invention

Example 2

1) Take 10 kg of Antarctic krill powder, add 100 L of 95% ethanol to the krill powder, stir in the reaction kettle for 6 hours, centrifuge to take the precipitate, and dry it in vacuum to obtain defatted krill powder;

2) Take 5kg of defatted shrimp powder, add 50L of distilled water to the defatted shrimp powder, add 2M HCl to the mixture, adjust the pH value of the mixture to 8.0, raise the temperature to 50°C, add 80g of alkaline protease to the mixture, and hydrolyze at constant temperature 8h, heat to 100°C to stop the enzyme reaction, centrifuge to get the supernatant A;

3) Make the solid content of the supernatant A reach 10% by vacuum concentration, the vacuum degree is 0.08MPa, and the temperature is 40-80°C to obtain solution B;

4) Take 10L of solution B, add 80g of calcium oxide to it, mix well, and cool to obtain mixed solution C;

5) Add 334 g of calcium dihydrogen phosphate to the mixed solution C, and stir while adding, to obtain the mixed solution D;

6) After the mixture D is centrifuged at 4500r/min, the supernatant E is obtained;

7) The supernatant E was spray-dried (inlet air temperature 130°C, outlet air temperature 85°C) to obtain low-fluorine water-soluble Antarctic krill active peptide powder.

The protein content of the Antarctic krill active peptide powder prepared after defluorination treatment in the present invention is higher than 85%, the fluorine content is 2-5mg/kg, and the ash content is 8-12%; the activity of the Antarctic krill active peptide powder without defluorination treatment The fluorine content in the peptide powder is 350-450mg/kg, and the ash content is 8-12%. During the defluorination process, the loss rate of protein is less than 10%, the amino acid composition and content of krill peptides before and after defluorination have no significant changes, and the essential amino acid content is higher than the regulations of FAO/WHO/UNU (2007), meeting the requirements of adults/infants Requirements for essential amino acids

Example 3

1) Take 10 kg of Antarctic krill powder, add 100 L of 95% ethanol to the krill powder, stir in the reaction kettle for 6 hours, centrifuge to take the precipitate, and dry it in vacuum to obtain defatted krill powder;

2) Take 5kg of defatted shrimp powder, add 50L of distilled water to the defatted shrimp powder, raise the temperature to 50°C, add 2M HCl to the mixture to adjust the pH value of the mixture to 8.0, add 80g of alkaline protease to the mixture, and hydrolyze for 8 hours at constant temperature , heated to 100°C to terminate the enzyme reaction, and centrifuged to get the supernatant A;

3) Make the solid content of the supernatant A reach 10% by vacuum concentration, the vacuum degree is 0.08MPa, and the temperature is 40-80°C to obtain solution B;

4) Take 10L of solution B, add 150g of calcium chloride to it, mix well, and cool to obtain mixed solution C;

5) After the mixture C is centrifuged at 4500r/min, the supernatant D is obtained;

7) The supernatant D was spray-dried (inlet air temperature 130°C, outlet air temperature 85°C) to obtain low-fluorine water-soluble Antarctic krill active peptide powder.

The fluorine content in the Antarctic krill active peptide powder prepared by the invention is higher than 10 mg/kg, and the ash content is 12-20%; the fluorine content in the Antarctic krill active peptide powder without defluorination treatment is 350-450 mg/kg, The ash content is 8-12%. The ash content of krill peptide powder increased by about 50% after defluorination, indicating that this method introduced more ash to krill peptide powder.

Claims (7)

1. reduce a method for Oil repellent in water-soluble krill bioactive peptide, it is characterized in that, described method includes following steps:

1) in euphausia superba powder, add distilled water, feed liquid mass ratio is 1:6 ~ 15, regulates mixed solution pH value, then in mixed solution, adds proteolytic enzyme be hydrolyzed, and hydrolysis temperature is 40 ~ 60 DEG C, and hydrolysis time is 2 ~ 12h; Hydrolysis terminates post-heating enzymolysis reaction, centrifugal, obtains the krill bioactive peptide aqueous solution;

2) adjusting the krill bioactive peptide aqueous solution is 5 ~ 30% to solid content, then adds defluorinating agent I mixing and obtain mixed solution;

3) to step 2) mixed solution in add defluorinating agent II again, and stir and carry out defluorinate process;

4) step 3) mixed solution after defluorinate process after centrifugation, obtain supernatant liquor;

5) supernatant liquor E spray-dried after obtain the krill bioactive peptide powder-product of low fluorine content.

2. the method for claim 1, is characterized in that described step 1) in proteolytic enzyme be one or more in papoid, bromeline, trypsinase, neutral protease or Sumizyme MP.

3. the method for claim 1, is characterized in that described step 2) in defluorinating agent I be calcium oxide, one or more in calcium hydroxide, calcium carbonate.

4. the method for claim 1, is characterized in that described step 2) in defluorinating agent I add quality concentration of volume percent be 0.5 ~ 4.0%.

5. the method for claim 1, is characterized in that described step 3) in defluorinating agent II be calcium phosphate, one or more in calcium monohydrogenphosphate, monocalcium phosphate.

6. the method for claim 1, is characterized in that described step 3) in defluorinating agent I be 0.5 ~ 2.0 with the mol ratio of defluorinating agent II.

7. the method for claim 1, is characterized in that described step 5) in spray drying condition be inlet temperature be 120 ~ 160 DEG C, air outlet temperature is 80 ~ 120 DEG C.