CN111690462A - Method for demulsifying and extracting oil from oil-containing algae or fungus cell wall-broken liquid - Google Patents

Abstract

The invention discloses a method for demulsifying and extracting grease from oil-containing algae or fungus cell wall-broken liquid. According to the invention, the wall-breaking liquid is subjected to pH adjustment under a vacuum condition, a proper amount of inorganic salt is added, and stirring speed and temperature in different time periods are regulated and controlled, so that complete separation of medium oil, water, protein and fermentation extracellular products of the wall-breaking liquid is realized, and the extraction yield of intracellular grease of algae and fungi cells is increased to 90-96% by 85-90%. The method for demulsifying the oil-containing emulsion can effectively avoid solvent residue caused by leaching and demulsifying by using an organic solvent and oxidation of unsaturated fatty acid caused by recovering the solvent at high temperature, and simultaneously, the extracted crude oil has lower physical and chemical indexes, better quality and no toxicity and no residue in the process of extracting the product.

Description

Method for demulsifying and extracting oil from oil-containing algae or fungus cell wall-broken liquid

Technical Field

The invention relates to the field of industrial microbial fermentation and food and feed, in particular to a method for demulsifying and extracting oil from oil-containing algae or fungus cell wall-broken liquid.

Background

DHA belongs to omega-3 series polyunsaturated fatty acids (omega-3 PUFAs), is a main substance for the growth and maintenance of nervous system cells, is also an important constituent of brain and retina, is a nutrient substance necessary for brain cell proliferation, formation of sulcus and retinal development, is beneficial to the extension and regeneration of brain cell processes, can enhance memory and thinking and improve intelligence, and is called 'brain gold' in the art. DHA is an essential fatty acid which is difficult to synthesize by human body, the content of DHA in cerebral cortex is up to 20%, the content of DHA in retina is about 50%, DHA is important for intelligence and visual development of infants, and deficiency can cause symptoms such as growth retardation, visual dysplasia, skin abnormal scale and the like, and even can cause infertility and intelligence disorder. DHA also has important physiological regulation function and health care function, can protect retina, prevent myopia, improve eyesight, reduce activity of inflammatory factors, inhibit inflammation, resist oxidation and aging, improve immunity of organism, slow down apoptosis, reduce incidence of cancer, inhibit platelet aggregation, reduce blood lipid concentration, prevent and improve cardiovascular function, etc.

DHA is predominantly morphologically of the Triglyceride (TG), Ethyl Ester (EE) and lecithin (PC-DHA) types, whereas fish oil and algae oil derived DHA is the triglyceride type, which is a light yellow transparent liquid insoluble in water and alcohol and readily soluble in ethers and alkanes at room temperature. Marine algae are the main producers of fatty acids in the marine food chain, and DHA of marine fish comes primarily from marine algae at the root. While marine fungi and bacteria are also capable of synthesizing DHA, such as Thaustochytrium, Schizochytrium, Entomophthora obscurura, etc., the DHA in Thraustochytrium (Thraustochytrium aureum) is rather abundant, accounting for 34% of its total fatty acid content. At present, DHA algae oil mainly comes from Schizochytrium sp, Ulkenia amoeboida and Crypthecodinium cohnii, and DHA is produced by fermenting, separating and purifying the raw materials of Schizochytrium sp. The ministry of health in China reached in 2010 an announcement (No. 3 in 2010) about approval of seven items such as DHA algal oil and ARA grease as new resource food.

DHA oil is an intracellular product of algae cells, and the existing industrialized wall breaking technology adopts mechanical wall breaking (such as a homogenizer, a sand mill, ultrasonic waves, a grinding mill, a crushing machine or a high-pressure wall breaking machine) and chemical methods (acid-base wall breaking and the like) or biological enzyme methods (alkaline protease, acid protease or neutral protease) and the like. In the prior patent technology, organic solvents are mainly adopted to directly carry out demulsification (such as CN201210030370.0, CN201110111271.0, CN201110313815.1 and CN 201010136309.5); performing emulsion breaking extraction by using other technologies and organic solvent (such as CN 201210491610.7 extracted by using chitosan flocculation organic solvent, CN201110313815.1 extracted by using short-chain alcohol solvent and organic solvent, CN 201310618440.9 extracted by using ultrasonic assistance and organic solvent and CN 201410273112.4 extracted by using enzymolysis and organic solvent); and demulsification adjusted by acid and surfactant (such as CN 200810240949.3 demulsified by pH adjustment with acid, CN 201710895535.3 demulsified by synergistic action of alkali, salt and microwave, and CN201110433429.6 demulsified by surfactant). When the organic solvent is adopted for demulsification, the using amount of the organic solvent is large, the components of the crude oil are complex, and meanwhile, the crude oil is heated in the process of desolventizing, so that the quality of the crude oil is easily deteriorated, particularly the peroxide value and anisidine value in the oil are increased, and the organic solvent residue is caused, thereby influencing the production and edible safety; when the microwave is adopted to cooperate with demulsification, the energy consumption is high, the process is complex, the production time is long, and the quality of the product is poor; when the surfactant is used for demulsification, the crude oil has complex components and narrow application range.

Disclosure of Invention

The invention aims to provide a cell wall breaking liquid demulsification oil extraction method which has high comprehensive utilization efficiency, zero residue and zero pollution and is suitable for industrial popularization for extracting intracellular grease from algae or fungal cells.

The invention provides a method for demulsifying and extracting oil from oil-containing algae or fungus cell wall-broken liquid, which comprises the following steps:

1) diluting the algae or fungus cell wall-breaking emulsion to a solid content of 12-22%, adding an antioxidant, heating the wall-breaking tank to 70-90 ℃, and maintaining the temperature for 1-3 hours;

2) vacuumizing the wall breaking tank to-0.05 to-0.1 MPa, adding an inorganic salt solution, stirring while rolling nitrogen, and uniformly mixing;

3) and (3) after the reaction is completed, adding organic acid, uniformly mixing, stopping stirring, standing, centrifuging by using a three-phase centrifuge, and collecting the upper-layer crude oil phase to obtain the hair oil.

In the step 1), the algae or fungus cell wall-broken emulsion is a wall-broken emulsion formed by breaking walls of algae or fungus cells by an enzymatic method, a mechanical method, a chemical method (such as acid or alkali) or an organic solvent;

diluting with deionized water;

the solid content after dilution can be specifically as follows: 15%, 12% or 22%;

the antioxidant can be D-sodium erythorbate and/or ascorbyl palmitate;

the ratio of the antioxidant to the wall-broken emulsion before dilution can be as follows: 0.1-0.3 g/kg;

in the step 2), the vacuum degree can be-0.08 MPa, -0.06MPa or-0.1 MPa;

the inorganic salt in the inorganic salt solution may be: one or a mixture of more of potassium chloride, sodium sulfate, magnesium sulfate, calcium chloride, EDTA-2Na, sodium chloride, magnesium chloride and potassium sulfate;

specifically, the inorganic salt can be a mixture of any two of potassium chloride, sodium sulfate, magnesium sulfate, calcium chloride, EDTA-2Na, sodium chloride, magnesium chloride and potassium sulfate in a mass ratio of 1: 1;

the mass concentration of the inorganic salt solution in the inorganic salt solution can be 20-60%;

the inorganic salt solution is added in a proportion of 0.3-3.0% of the volume of the algae or fungus cell wall breaking emulsion before dilution, and specifically can be 0.5% or 2.0%;

the rotation speed of the stirring can be as follows: 20-100 rpm, specifically 30 rpm;

the stirring and nitrogen tumbling time can be 1-2 h, specifically 1 h;

in step 3), the organic acid may be: one or more of malic acid, citric acid, oxalic acid and glacial acetic acid;

the organic acid is added in the form of an organic acid solution, and the mass concentration of the organic acid solution can be 10-60%;

the organic acid solution is added in a proportion of 0.2-2.0% of the volume of the algae or fungus cell wall breaking emulsion before dilution, and specifically can be 0.2%, 0.5% or 2.0%;

the standing time can be 0.5-2.0 h, specifically 1 h;

and centrifuging the three-phase centrifuge at the centrifugal rotating speed of 2000-10000 rpm to collect the oil phase.

The yield of the oil demulsification extraction from the oil-containing algae or fungal cell wall-broken liquid by the method is 90-96%.

Under the vacuum condition, the invention realizes the demulsification of the feed liquid, improves the extraction yield of the oil, avoids the problems of residue caused by using an organic solvent or a surfactant, oxidation of the oil caused by distillation and the like, simultaneously recycles cell walls, improves the product benefit, and realizes the aims of no toxicity, no residue, environmental protection and high comprehensive utilization rate of the product by controlling the concentration of the feed liquid, adjusting the temperature of the wall-breaking liquid, adding quantitative inorganic salt, adjusting the pH of the feed liquid, stirring the feed liquid and the like.

Detailed Description

The present invention will be described below with reference to specific examples, but the present invention is not limited thereto.

The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.

The invention aims to provide a cell wall breaking liquid demulsification oil extraction method which has high comprehensive utilization efficiency, zero residue and zero pollution and is suitable for industrial popularization for extracting intracellular grease from algae or fungal cells.

The specific contents are as follows:

1) the cell wall breaking liquid provided by the invention is a wall breaking emulsion formed by breaking walls of algae or fungal cells by an enzymatic method, a mechanical method, a chemical method (such as acid or alkali) or an organic solvent;

2) the production conditions provided by the invention are as follows:

a. the solid content of the wall-broken emulsion is controlled to be 12-22%;

b. the temperature is maintained to be 70-90 ℃ in the whole demulsification extraction process;

c. the whole demulsification and extraction process is carried out under the vacuum condition, and the vacuum degree is-0.05 to-0.1 MPa;

d. uniformly mixing the wall breaking process by using nitrogen and stirring at the stirring speed of 20-100 rpm;

3) the inorganic salt provided by the invention is as follows: potassium chloride, sodium sulfate, magnesium sulfate, calcium chloride, EDTA-2Na, sodium chloride, magnesium chloride and potassium sulfate; the concentration of the use is 0.3-3.0%, and the use is single or composite;

4) the organic acids provided by the invention are as follows: malic acid, citric acid, oxalic acid, glacial acetic acid; the concentration of the use is 0.2-2.0%, and the use is single or composite;

5) the yield of the oil-containing algae or fungus cell wall breaking liquid demulsification extraction oil produced by the invention is 90-96%.

Example 1:

1. the wall-breaking liquid is wall-breaking liquid obtained in the fourth step of the invention content of the patent ' method ZL200910225296.6 for extracting DHA from algae and fungus cell by breaking wall ' method of breaking wall ' and ' bacterial sludge is homogenized and broken wall under high pressure by a high pressure homogenizer ';

2. 70000kg of wall-broken emulsion is diluted by deionized water according to the solid content requirement until the solid content reaches 15%, 21kg of antioxidant D-sodium erythorbate and ascorbyl palmitate (the mass ratio of the two antioxidants is 5:1) are added, the temperature of the wall-broken tank is raised to 70 ℃, and the temperature is maintained for 2 hours;

3. vacuumizing the wall breaking tank to-0.08 MPa, adding 0.5% of magnesium chloride and calcium chloride (the mass concentration of the magnesium chloride and calcium chloride solution is 30% according to the proportion of 1: 1) in the volume of the wall breaking emulsion before dilution, controlling the temperature at 68-70 ℃, stirring at the rotating speed of 30rpm and rolling for 2 hours by nitrogen;

4. after the reaction is completed, adding 0.2% citric acid (the mass concentration of the citric acid solution is 50%) of the volume of the wall-broken emulsion before dilution, mixing uniformly, stopping stirring immediately, standing for 1 hour, and centrifuging by using a three-phase centrifuge to obtain crude oil.

The yield of the oil extracted by breaking the cell wall and the emulsion of the cell wall breaking liquid is 94 percent, and the indexes of the crude oil after being extracted and dried are

Item	Index (I)
		Water content%	0.5
Impurities%	0.3
		Acid value mgKOH/g	2.5
Peroxide number mmol/kg	0.2
		Anisidine number	3.5
DHA ％	55.6

Meanwhile, if the mass concentration of the magnesium chloride and calcium chloride solution is increased to 40% in the step 3, and other conditions are not changed, the yield of the oil extracted by demulsification of the cell wall breaking solution is 96%, and the indexes after the crude oil is extracted and dried are as follows:

item	Index (I)
		Water content%	0.2
Impurities%	0.2
		Acid value mgKOH/g	2.0
Peroxide number mmol/kg	0.1
		Anisidine number	2.0
DHA ％	57.9

Example 2:

1. 60000kg of wall-breaking emulsion is diluted by deionized water according to the solid content requirement until the solid content is 22%, 12kg of antioxidant D-sodium erythorbate and ascorbyl palmitate (the mass ratio of the two antioxidants is 5:1) are added, the temperature of a wall-breaking tank is raised to 80 ℃, and the temperature is maintained for 2 hours;

2. vacuumizing the wall breaking tank to-0.06 MPa, adding 2.0% of sodium sulfate and magnesium sulfate (mass concentration of sodium sulfate and magnesium sulfate solution is 50% according to a ratio of 1: 1) in the volume of the wall breaking emulsion before dilution, controlling the temperature at 78-80 ℃, stirring at a rotating speed of 30rpm, and rolling for 1h by nitrogen;

3. after the reaction is completed, 0.5% of malic acid (the mass concentration of the malic acid is 50%) in the volume of the wall-broken emulsion before dilution is added, the stirring is stopped immediately after the mixing, the mixture is stood for 1 hour and then centrifuged, and a three-phase centrifuge is used for centrifuging after the standing for 1 hour to obtain crude oil.

The yield of the oil extracted by demulsification of the cell wall breaking liquid is 93%, and the indexes after crude oil extraction and drying are as follows:

item	Index (I)
		Water content%	0.8
Impurities%	0.5
		Acid value mgKOH/g	2.5
Peroxide number mmol/kg	0.4
		Anisidine number	4.0
DHA ％	53.2

Example 3:

1. 50000kg of wall-broken emulsion is diluted by deionized water according to the solid content requirement until the solid content is 12%, and antioxidant D-sodium erythorbate and ascorbyl palmitate (the mass ratio of the two antioxidants is 5:1) are added

10kg, heating the wall breaking tank to 90 ℃, and maintaining for 1 hour;

2. vacuumizing the wall breaking tank to-0.1 MPa, adding a solution of sodium sulfate and EDTA-2Na (the mass concentration of the solution of sodium sulfate and EDTA-2Na is 40% according to the ratio of 1: 1) with the volume of 2.0% of the wall breaking emulsion before dilution, controlling the temperature at 88-90 ℃, stirring at the rotating speed of 30rpm and nitrogen tumbling for 1 h;

3. after the reaction is completed, 2.0% of malic acid (the mass concentration of the malic acid is 50%) in the volume of the wall-broken emulsion before dilution is added, the stirring is stopped immediately after the mixing, the mixture is stood for 1 hour and then centrifuged, and a three-phase centrifuge is used for centrifuging after the standing for 1 hour to obtain crude oil.

The yield of the oil extracted by demulsification of the cell wall breaking liquid is 90%, and the indexes after crude oil extraction and drying are as follows:

item	Index (I)
		Water content%	1.0
Impurities%	0.7
		Acid value mgKOH/g	2.7
Peroxide number mmol/kg	0.8
		Anisidine number	5.0
DHA ％	51.0

The DHA grease obtained by adopting the method in the ZL200910225296.6 patent has the following drying indexes:

item	Index (I)
		Water content%	1.0
Impurities%	2.0～4.0
		Acid value mgKOH/g	3.5～4.5
Peroxide number mmol/kg	5.0～10.0
		Anisidine number	7.8～12.0
DHA ％	45～47

The method has the advantages that DHA algae oil is collected by centrifugation of the three-phase centrifuge after the wall breaking liquid is demulsified, so that impurities in the oil can be effectively removed, meanwhile, because the impurities and the moisture in the oil are reduced, the cleanliness of the oil is kept, the contact time of the oil with the impurities and the moisture is reduced, the stability of the oil can be effectively improved, and the peroxide value and the anisidine value of the oil are reduced. Partial phospholipid, monoester oil and diester oil are removed in the demulsification process, so that the DHA content can be effectively improved.

Claims (5)

1. A method for demulsifying and extracting oil from oil-containing algae or fungus cell wall-broken liquid comprises the following steps:

1) diluting the algae or fungus cell wall-breaking emulsion to a solid content of 12-22%, adding an antioxidant, heating the wall-breaking tank to 70-90 ℃, and maintaining the temperature for 1-3 hours;

2) vacuumizing the wall breaking tank to-0.05 to-0.1 MPa, adding an inorganic salt solution, stirring while rolling nitrogen, and uniformly mixing;

3) and (3) after the reaction is completed, adding organic acid, mixing uniformly, stopping stirring, standing, centrifuging, and collecting the upper-layer crude oil phase to obtain the hair oil.

2. The method of claim 1, wherein: in the step 1), the algae or fungus cell wall-broken emulsion is a wall-broken emulsion formed by breaking walls of algae or fungus cells by an enzymatic method, a mechanical method, a chemical method or an organic solvent;

diluting with deionized water;

the antioxidant is D-sodium erythorbate and/or ascorbyl palmitate;

the ratio of the antioxidant to the wall-broken emulsion before dilution is as follows: 0.1 to 0.3 g/kg.

3. The method according to claim 1 or 2, characterized in that: in the step 2), the inorganic salt in the inorganic salt solution is: one or a mixture of more of potassium chloride, sodium sulfate, magnesium sulfate, calcium chloride, EDTA-2Na, sodium chloride, magnesium chloride and potassium sulfate;

the mass concentration of the inorganic salt solution in the inorganic salt solution is 20-60%;

the inorganic salt solution is added according to the proportion of 0.3-3.0% of the volume of the algae or fungus cell wall breaking emulsion before dilution;

the rotating speed of the stirring is as follows: 20-100 rpm;

the stirring time and the nitrogen tumbling time can be 1-2 hours.

4. The method according to any one of claims 1-3, wherein: in the step 3), the organic acid is: one or more of malic acid, citric acid, oxalic acid and glacial acetic acid;

the organic acid is added in the form of an organic acid solution, and the mass concentration of the organic acid solution is 10-60%;

the organic acid solution is added according to the proportion of 0.2-2.0% of the volume of the algae or fungus cell wall breaking emulsion before dilution;

the standing time is 0.5-2.0 h;

and centrifuging the three-phase centrifuge at the centrifugal rotating speed of 2000-10000 rpm to collect the oil phase.

5. The method according to any one of claims 1-4, wherein: the method has the advantage that the yield of demulsification and extraction of the grease from the oil-containing algae or fungal cell wall-broken liquid is 90-96%.