CN111592938A

CN111592938A - Low-iron water-containing phospholipid

Info

Publication number: CN111592938A
Application number: CN202010455240.6A
Authority: CN
Inventors: 徐子谦
Original assignee: Inner Mongolia Boberman Technology Co ltd
Current assignee: Shanghai Beiman Technology Co ltd
Priority date: 2020-05-26
Filing date: 2020-05-26
Publication date: 2020-08-28
Anticipated expiration: 2040-05-26
Also published as: CN111592938B

Abstract

The invention belongs to the technical field of phospholipid processing, and particularly relates to low-iron water-containing phospholipid, which mainly comprises phospholipid, grease and water, wherein the water content is 70-80g/100 g; the content of acetone insoluble substances is 92.5-95.5g/100g on a dry basis; the iron content is less than or equal to 18mg/kg based on the acetone insoluble substance. The low-iron water-containing phospholipid is prepared from soybean oil residue by a hydration method, is used for solving the defects that the content of acetone insoluble substances of the existing water-containing phospholipid is not high, iron ions cannot be removed, and the industry depends on a solvent method for preparing powdered phospholipid for a long time, and solves the technical problem that the powdered phospholipid cannot be industrially produced by the hydration method. The low-iron water-containing phospholipid of the invention is used for preparing hydration method powdered phospholipid, the content of acetone insoluble substances reaches 92.5-95.5g/100g, the color is natural yellow, no bleaching and no solvent exist, the low-iron water-containing phospholipid can replace solvent method powdered phospholipid, the environmental pollution and food safety hidden trouble caused by solvent method powdered phospholipid are avoided, and the production cost of the hydration method powdered phospholipid is far lower than that of a solvent method.

Description

Low-iron water-containing phospholipid

Technical Field

The invention belongs to the technical field of phospholipid processing, and particularly relates to low-iron aqueous phospholipid.

Background

The raw material for processing the phospholipid is soybean oil residue, which is called hydrated oil residue for short, is a byproduct of a hydration degumming process in the soybean oil refining process in the field of oil processing, and is also called hydrated oil residue, wherein the main components comprise 30-45g/100g of phospholipid, 20-30g/100g of soybean oil and 30-50g/100g of water, and the trace components comprise metal ions, such as calcium, magnesium, iron and the like, and exist in the form of phospholipid metal salts, such as iron ion content, usually 50-100mg/kg calculated by acetone insoluble substances, and the content is up to more than 150mg/kg in individual cases.

The method for processing the industrial phospholipid mainly comprises two methods, one is that the concentrated phospholipid is prepared by a hydration method, namely the concentrated phospholipid is obtained by directly drying and dehydrating after soybean oil residue is extracted from crude soybean oil in a hydration manner, and the concentrated phospholipid is also called as fluid phospholipid due to the fluidity, and the content of dry acetone insoluble substances is 60-65g/100 g; and secondly, preparing the powdered phospholipid by a solvent method, namely taking soybean oil residue or concentrated phospholipid as a raw material, and extracting the raw material by using acetone to remove grease to obtain the powdered phospholipid, wherein the content of dry acetone insoluble substances is 95-98g/100 g. The mainstream product in the market is concentrated phospholipid, and the ratio of the powdered phospholipid in the market is less than 5%.

Although the soybean oil residue is mostly processed into concentrated phospholipids, the concentrated phospholipids have a great disadvantage. For example, documents "a process for producing concentrated phospholipids from soybean (Huxing. a process for producing concentrated phospholipids from soybean [ J ]. China fat, 2007,32(9):20-21) and" a process for preparing concentrated phospholipids (Houqing et al. a process for preparing concentrated phospholipids [ J ]. China fat, 2002,27(1):39-40) describe a method for producing concentrated phospholipids by dehydrating and oxidizing and bleaching hydrated oil residues as raw materials. The process has the disadvantages that the content of acetone insoluble substances in the concentrated phospholipid is too low (60-65g/100g), chemical bleaching is needed, the market price is only 0.4 ten thousand yuan/ton, and the price has a large difference with the price of 4 ten thousand yuan/ton of powder phospholipid.

Chinese patent CN103665029A discloses a method for preparing soybean powder phospholipid, which adopts acetone as solvent to extract hydrated oil residue, separates out acetone insoluble substances, and then carries out low-temperature vacuum drying on the acetone insoluble substances to remove the solvent, thus obtaining the powder phospholipid. The method has the defects that an acetone solvent is used, the production cost is high, the potential safety hazard of environmental pollution and solvent residue exists, and the method is difficult to popularize generally, so that the structure upgrade of a product converted from concentrated phospholipid to powdered phospholipid in the field of oil processing cannot be promoted, and the current situation of high oil refining loss cannot be improved.

For example, chinese patent CN107325125A discloses a method for preparing a phospholipid hydrate from soybean oil residue and a phospholipid hydrate (hereinafter referred to as phospholipid hydrate) prepared by the method, and the method includes the following steps: adding softened water into soybean oil residue, mixing, standing, and performing chromatography; after the chromatography is finished, controlling the temperature to be 85-95 ℃, and carrying out centrifugal separation to obtain the hydrated phospholipid, wherein the acetone insoluble matter can reach 90-92%. This patent has the following drawbacks:

(1) the dry acetone insoluble content of the hydrated phospholipids is low: the patent is a homogeneous hydration method, namely oil residue and water are mixed uniformly, emulsification inevitably occurs when the mixing is uniform, and phospholipid and oil are difficult to re-separate if the emulsification is serious. In order to avoid serious emulsification, the patent adopts two measures, namely strictly controlling the water adding amount which is 0.25-0.74 times of the weight of oil residue; second, sodium hydroxide or sulfuric acid is added, acting as a demulsifier. The problem brought by the measures is that the main components of phospholipid, grease and phospholipid metal salt in the soybean oil residue are not effectively separated, the content of dry acetone insoluble substances of the hydrated phospholipid reaches only 92 percent at most, and has a certain difference compared with 95-98 percent of acetone insoluble substances in a solvent method;

(2) lack of industrial use: the hydrated phospholipid is subjected to concentration dehydration, preservative addition, pasteurization and packaging to obtain an aqueous phospholipid product with the water content of 22.5-41.2 percent, but the aqueous phospholipid product does not meet the regulation of national standard GB28401 food additive phospholipid on that the water content cannot exceed 2 percent and cannot be sold; if the drying is performed according to the existing method for preparing powdered phospholipids, the time is too long, the productivity is too low, and the industrial production is not feasible, and the powdered phospholipids can not be sold or further processed, so that the powdered phospholipids are not industrially used.

Another prior art for extracting phospholipid by hydration method is disclosed in the document "research on liquid crystal separation and purification of soybean phospholipid" (Leziming et al. research on liquid crystal separation and purification of soybean phospholipid [ J ]. Chinese food and oil institute, 2007,22(1):31-32), hereinafter referred to as liquid crystal phospholipid. The method of the document has the following technical defects: (1) the content of insoluble acetone on dry basis of the liquid crystal state phospholipid is low: the homogeneous hydration method is adopted, the water adding amount is 0.67 times of oil residue, and the content of the obtained liquid crystal state phospholipid in dry acetone insoluble matters is only 86.05 percent, which is the same as the defect of the hydrated phospholipid; (2) lack of industrial use: the drying problem of the liquid crystal phospholipid is the same as that of the hydrated phospholipid, although the liquid crystal phospholipid is obtained into powder phospholipid by a batch vacuum drying mode, the drying time is too long, and the color of the phospholipid product is dark (brown), so that the liquid crystal phospholipid cannot be applied to industrial production.

Chinese patent CN102517148A discloses a two-step decolorization method of phospholipid, which adopts two-step decolorization methods of hydrogen peroxide bleaching and silica gel adsorption, and has the following defects: (1) chemical bleaching and decoloring, so that phospholipid generates oxidation byproducts, the naturalness of the phospholipid is damaged, and meanwhile, food safety risks exist and the method does not conform to the large trend of green development; (2) the adsorption and decoloration effects of silica gel are poor, and the invalid silica gel becomes waste residue, which is not beneficial to environmental protection; (3) bleaching destroys the beneficial antioxidant components in the phospholipid, reduces the antioxidant and nutritive values of the phospholipid, and shortens the shelf life of the phospholipid.

At present, the research of metal ions in phospholipid is limited to content detection, and soybean oil residue contains a certain amount of metal ions such as calcium, magnesium, iron and the like, and exists in the form of phospholipid metal salt, which is referred to as phospholipid salt for short. Among the phosphatidic salts, phosphatidic iron salt is most representative. In the literature "phospholipid composition and properties of soybean oil" (rich nations. phospholipid composition and properties of soybean oil [ J ] grain processing, 1982, 2:62) it is reported that in soyabean crude oil hydratable phospholipids contain 150mg/kg of iron ions which are eventually transferred to hydrated oil foots; the content of metal ions in soybean crude oil is reported in the literature, comparison of nuclear magnetic detection and phosphatidic acid content of soybean crude oil phospholipids from different sources (Shule et al, comparison of nuclear magnetic detection and phosphatidic acid content of soybean crude oil phospholipids from different sources [ J ]. China fat, 2017,42(1): 132). However, no studies have been reported on how to remove iron phosphatidate salts from soybean oil bottoms.

In the phospholipid processing field, the substitution of the powdered phospholipid for the concentrated phospholipid is the future direction from the product perspective, the substitution of the hydration method for the solvent method is the future direction from the method perspective, and although some researches on the hydration method exist at present, the purity of the phospholipid prepared by the hydration method is not high enough, the color improvement is not separated from the chemical bleaching method, the dehydration efficiency of the hydration method does not reach the industrial level, and the process technology is not enough in the aspects of integrity and continuity.

Therefore, it is necessary to develop a low-iron aqueous phospholipid which can solve the above-mentioned problems.

Disclosure of Invention

The first object of the present invention is to provide a low-iron aqueous phospholipid. The low-iron water-containing phospholipid is prepared from soybean oil residue by a hydration method, is used for solving the defects that the content of acetone insoluble substances of the existing water-containing phospholipid is not high, iron ions cannot be removed, and the industry depends on a solvent method for preparing powdered phospholipid for a long time, and also solves the technical problem that the powdered phospholipid cannot be industrially produced by the hydration method. The low-iron water-containing phospholipid of the invention is used for preparing hydration method powdered phospholipid, the content of acetone insoluble substances reaches 92.5-95.5g/100g, the color is natural yellow, no bleaching and no solvent exist, the low-iron water-containing phospholipid can replace solvent method powdered phospholipid, the environmental pollution and food safety hidden trouble caused by solvent method powdered phospholipid are avoided, and the production cost of the hydration method powdered phospholipid is far lower than that of a solvent method. The low-iron aqueous phospholipid is not reported in the phospholipid processing field and related researches.

The second purpose of the invention is to provide the application of the low-iron aqueous phospholipid in preparing low-iron powder phospholipid.

In order to achieve the above purpose, the technical scheme provided by the invention is as follows:

a low-iron aqueous phospholipid comprises phospholipid, oil and water as main ingredients, and has a water content of 70-80g/100 g; the content of acetone insoluble substances is 92.5-95.5g/100g on a dry basis; the iron content is less than or equal to 18mg/kg based on the acetone insoluble substance.

Preferably, the sensory index of the low-iron aqueous phospholipid is a brown translucent fluid.

Preferably, the low-iron water-containing phospholipid is prepared from soybean oil residue by a hydration method, and comprises the following steps:

(1) adding soybean oil residue into water, and soaking to obtain saturated water-absorbing oil residue;

(2) carrying out centrifugal sedimentation on the saturated water absorption oil residue to remove phospholipid metal salt to obtain a fluid substance;

(3) standing and layering the fluid to obtain the low-iron water-containing phospholipid on the bottom layer.

More preferably, the mass ratio of the soybean oil foot to the water in the step (1) is 1: 1-3.5.

When the weight of the water is less than 1.0 time of that of the oil residue, the soybean oil residue can not be effectively soaked in the water, and the combination of the phospholipid and the water is further influenced. When the water is more than 3.5 times of the mass of the oil residue, although the soaking of the soybean oil residue is facilitated, the cost of water, the energy consumption and the volume of the equipment are increased.

More preferably, the temperature of the soaking is 60-95 ℃.

During the soaking process, the combination of phospholipid and water can be carried out in water at 0-100 ℃, and the combination efficiency is higher when the temperature is higher. Therefore, the water temperature is increased, and the soaking time can be shortened. However, in boiling water, the stabilization of low-iron aqueous phospholipids is not facilitated, and the boiling evaporation of water wastes energy. The temperature of the soaking is therefore preferably 60-95 ℃. When the temperature is above 60 deg.C, the sterilization temperature can prevent oil residue from deteriorating during soaking, and when the temperature is below 95 deg.C, water can be prevented from boiling.

More preferably, the soaking time is 1-3 h.

The soaking means that the soybean oil residue is a dispersed phase in water, and the water is a continuous phase, so that a soaking system is formed.

As a result of the soaking, a saturated water-absorbing oil foot was obtained. And after soaking, the water absorption capacity of the phospholipid in the saturated water absorption oil residue reaches saturation, namely the water content of the phospholipid reaches 70-80g/100 g.

The soaking time refers to the time required for obtaining the saturated water-absorbing oil foot, and the soaking time is from the time when the soybean oil foot is in a granular shape and stands still in water for soaking until brown low-iron water-containing phospholipid begins to appear in the soybean oil foot. The soybean oil residue in the soaking was yellow, and the low-iron hydrous phospholipid appeared brown, so that it was possible to visually judge whether the end time of the soaking was reached.

During the soaking period, stirring operation is not suitable to prevent emulsification.

More preferably, the soybean oil foot is broken up into particles in water with stirring before soaking.

More preferably, the particle size of the soybean oil foot is less than or equal to 5 mm.

More preferably, the particle size of the soybean oil foot is 0.3-3 mm.

The smaller the grain size of the oil residue is, the larger the contact area of the oil residue and water is, and the mass transfer and heat transfer efficiency of phospholipid and water in the oil residue is improved. However, the size of the oil residue is too small, and there is a risk that the oil residue and water are uniformly mixed and homogenized, and the soaking system is damaged.

More preferably, the method for preparing the low-iron aqueous phospholipid in step (1) further comprises adding an electrolyte into the soaking system.

More preferably, the electrolyte has a mass fraction in water of 0.01 to 0.3%.

The proper amount of electrolyte is beneficial to the combination of the phospholipid and water in the soybean oil residue, the combination of the phospholipid and the water can be inhibited when the electrolyte is excessive, and the water content of the low-iron water-containing phospholipid is higher when the electrolyte is too little or not added, so that the energy waste during dehydration is caused.

More preferably, the electrolyte includes at least one of an acid, a base, and a salt.

More preferably, the electrolyte is at least one of DL-sodium malate, L-malic acid, DL-malic acid, glacial acetic acid, citric acid, potassium citrate, sodium citrate, monosodium citrate, sodium gluconate, lactic acid, potassium lactate, sodium carbonate, potassium bicarbonate, sodium sulfate, potassium chloride, potassium hydroxide, sodium hydroxide, hydrochloric acid, phosphoric acid, and sodium chloride.

More preferably, the centrifugal sedimentation of step (2) is batch centrifugal sedimentation.

The intermittent centrifugal sedimentation means that the loading and unloading are necessarily carried out at the shutdown. Continuous centrifuges cannot be used here because they cause severe emulsification of the material during the feeding and discharge and do not achieve the desired separation effect. Because the saturated water absorption oil foot and the fluid obtained by centrifugal sedimentation are all fluids with excellent fluidity and can be automatically loaded and unloaded, the operation of the batch centrifuge can be automated through program design so as to meet the requirement of large-scale industrial production.

In the centrifugal sedimentation process, the saturated water absorption oil foot is divided into two components of slag and fluid in a batch centrifuge, wherein the slag is mainly phospholipid metal salt and is tightly attached to the rotary drum wall of the centrifuge in the form of slag, and the slag is taken out from the upper part of the centrifuge in a slag discharging mode. The fluid is primarily grease, water and low iron aqueous phospholipids, and is referred to as a fluid because it can flow. After the machine is stopped, the fluid can automatically flow into the standing layering tank from the bottom of the centrifuge, and grease, water and low-iron water-containing phospholipid in the fluid are automatically divided into three layers due to different specific gravities.

More preferably, the temperature of the centrifugal sedimentation is 60 to 95 ℃.

More preferably, the rotational speed of the centrifugal sedimentation is 500-2000 rpm.

More preferably, the time of the centrifugal sedimentation is 5-15 min.

More preferably, the temperature of the standing and layering in the step (3) is 60-95 ℃.

The invention also relates to application of the low-iron water-containing phospholipid in preparation of low-iron powder phospholipid.

Preferably, the low-iron powder phospholipid is prepared by using the low-iron aqueous phospholipid, and comprises the following steps:

(1) preparation of concentrated aqueous phospholipids: concentrating the low-iron water-containing phospholipid at 90-110 deg.C under vacuum condition to water content of 25-65g/100g to obtain concentrated water-containing phospholipid, wherein the dry acetone insoluble content is 92.5-95.5g/100g, the iron content is not more than 18mg/kg based on acetone insoluble, and the sensory index is brown semitransparent fluid.

(2) Preparation of aqueous phospholipid elastomer: and pushing the concentrated aqueous phospholipid into a stirrer at the speed of 10-100cm/min, wherein the stirring rotation number is 800-1200rpm, and the stirring time is 5-30s, so as to obtain the continuously output aqueous phospholipid elastomer, wherein the water content and the acetone insoluble content of the aqueous phospholipid elastomer are the same as those of the concentrated aqueous phospholipid, but the sensory index is changed into yellow opaque semisolid.

(3) Preparing solid phospholipid: and (2) feeding the continuously output water-containing phospholipid elastomer into a normal-pressure or vacuum continuous dryer through a feed inlet with the aperture of 2-6mm, and drying at the temperature of 120-160 ℃ for 6-20min to obtain continuously output strip-shaped solid phospholipid, wherein the water content of the strip-shaped solid phospholipid is 3-10g/100g, the content of the dry acetone insoluble substances is 92.5-95.5g/100g, and the sensory index of the strip-shaped solid is yellow strip-shaped solid.

(4) Preparing low-iron powder phospholipid: and (2) crushing and sieving the strip-shaped solid phospholipid, and performing vacuum drying at 60 ℃ for 30-60min to obtain the low-iron powder phospholipid, wherein the water content of the low-iron powder phospholipid is less than or equal to 2g/100g, the content of dry acetone insoluble substances is 92.5-95.5g/100g, the iron content is less than or equal to 18mg/kg based on the acetone insoluble substances, the sensory index is yellow powder, and the product meets the national standard GB28401 food additive phospholipid.

The water content of the powder phospholipid in the step (4) is equal to the drying decrement described in the national standard GB28401 food additive phospholipid.

The vacuum is 0.01-0.004 MPa.

The significance of removing phospholipid metal salts:

first, the phospholipid metal salts result in a reduction in the acetone insoluble content of the aqueous phospholipid: the oil content of the phospholipid metal salt separated from the oil residue by the hydration method reaches 40 percent on a dry basis. If the metal salt of phospholipid remains in the aqueous phospholipid, the content of acetone-insoluble substances in the aqueous phospholipid is reduced, which is a reason for the low content of acetone-insoluble substances in the liquid crystalline phospholipid in patent CN107325125A hydrated phospholipid and the research on liquid crystalline separation and purification of soybean phospholipid;

secondly, phospholipid metal salts lead to a decrease in the shelf life of phospholipid products: the metal ions play a catalytic role in the oxidation of the phospholipid, and the phospholipid metal salt separated from the oil residue is oxidized and deteriorated within 30 days. Phospholipid products contain metal salts of phospholipids, which can reduce the shelf life of the phospholipid product.

Third, the phospholipid metal salts are not emulsifying: the phospholipid is mainly used as an emulsifier for preparing products such as medicines, foods and the like, and the phospholipid metal salt has no emulsibility and interferes with the emulsibility of normal phospholipid so that the normal phospholipid is coagulated and loses the emulsibility.

Fourth, phosphosiderite is a dark red substance: if the phospholipid product contains more phospholipid iron salts, the color of the product can become dark and dark, and the traditional method relies on chemical bleaching for decolorization, so that the food safety is reduced, the shelf life is reduced, the nature of phospholipid is damaged, and other adverse effects are caused.

Compared with the hydration-method low-iron powder phospholipid, the solvent-method powder phospholipid has the following main defects:

firstly, the organic solvent acetone is used, so that the potential safety hazard of food caused by environmental pollution and solvent residue exists, and the production cost is high;

secondly, when the oil is removed by extraction, the color of natural plants such as lutein in the phospholipid are removed by a solvent method, so that the nutritional value of the phospholipid is reduced, the antioxidant protection of natural plant pigments is lost, and the quality guarantee period of the phospholipid is shortened;

thirdly, the solvent method cannot reduce the content of iron ions in the phospholipid, cannot improve the color of the phospholipid (the iron salt of the phospholipid is dark red), and cannot improve the antioxidant performance of the phospholipid (the iron ions have a catalytic effect on the oxidation of the phospholipid).

The invention has the beneficial effects that:

first, the acetone insoluble content of the low iron aqueous phospholipids of the present invention is highest in all current hydration processes: the content of dry acetone insoluble matters of the low-iron water-containing phospholipid is 92.5-95.5g/100g, the content of the patent-disclosed hydrated phospholipid is 90-92g/100g, and the content of liquid crystal state phospholipid reported in the literature is 86.05g/100 g. The water content of the low-iron water-containing phospholipid reaches 70-80g/100g, the water absorption capacity of the phospholipid reaches saturation: when the water absorption capacity of the phospholipid reaches saturation, the lipophilicity of the phospholipid is reduced to the minimum, namely the oil content of the low-iron water-containing phospholipid is the minimum, the purity of the phospholipid is the highest, and the content of dry acetone insoluble matters reaches 92.5-95.5g/100 g.

Secondly, the acetone insoluble content of the low-iron aqueous phospholipid of the invention is most similar to that of the solvent method: the dry acetone insoluble content of the low-iron aqueous phospholipid of the invention is 92.5-95.5g/100g, which is close to or even reaches the level of 95-98g/100g of solvent method powder phospholipid. From the perspective of industrial development, a hydration method is a mainstream product to replace a solvent method finally so as to eliminate environmental pollution caused by organic solvents and food safety hidden dangers caused by solvent residues and reduce production cost.

Thirdly, the low-iron aqueous phospholipid of the invention is the only product capable of removing phospholipid metal salts in all hydration methods and solvent methods, including phosphatide iron salt: both the patent-published hydrated phospholipids and the liquid crystal phospholipids reported in the literature and the prior art powdered phospholipids extracted by solvent cannot remove the metal salts of the phospholipids, so that the products have defects in color, shelf life, emulsibility and the like. Clearly, the low iron aqueous phospholipids of the present invention eliminate these drawbacks.

Fourthly, the low-iron aqueous phospholipid and the low-iron powder phospholipid prepared by the low-iron aqueous phospholipid have complete process technology from soybean oil residue to powder phospholipid, have great advantages in the aspects of quality, quality guarantee period, production cost, environmental protection and food safety, and are suitable for industrial production.

Drawings

FIG. 1 is a process flow diagram of the low-iron aqueous phospholipid obtained by soaking, centrifugal sedimentation and standing layering of soybean oil residue.

FIG. 2 is a schematic diagram of a process for obtaining low-iron aqueous phospholipid by soaking, centrifugal sedimentation and standing layering of soybean oil residue; wherein:

(a) is a schematic diagram of soybean oil foot in water;

(b) the soaking system is a schematic diagram of a soaking system with soybean oil residue particles as a dispersed phase and water as a continuous phase;

(c) is a schematic diagram of saturated water absorption oil foot;

(d) a schematic diagram of a batch centrifuge shutdown charging;

(e) is a schematic diagram in the operation of a batch centrifuge;

(f) the schematic diagram of the shutdown discharge of the batch centrifuge is shown;

(g) the schematic diagram of the low-iron aqueous phospholipid and the grease obtained by standing and layering the fluid in the standing and layering tank is shown.

FIG. 3 is a process flow diagram for preparing low-iron solid phospholipid from low-iron aqueous phospholipid.

FIG. 4 is a schematic diagram of a process for concentrating aqueous phospholipids to prepare low-iron solid phospholipids.

Wherein: (1) is a continuous phase of water; (2) is soybean oil residue; (3) is dispersed phase soybean oil foot particles; (4) is saturated water absorption oil residue; (5) is a residue, i.e. a metal salt of a phospholipid; (6) is a fluid substance, namely a mixture of grease, low-iron water-containing phospholipid and water; (7) is a low iron aqueous phospholipid; (8) is grease; (9) is a concentrated aqueous phospholipid; (10) is an aqueous phospholipid elastomer; (11) is low-iron solid phospholipid. A is a soaking tank; b is a batch centrifuge; c, standing and layering the tank; d is a speed-regulating gear pump; e is a pipeline stirrer; f is a continuous dryer.

Detailed Description

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention. The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials, unless otherwise indicated, are commercially available; the vacuum is 0.01-0.004 MPa.

Definition of dry acetone insoluble yield of low iron aqueous phospholipids: yield of dry acetone insoluble matter of low iron hydrous phospholipid/weight of dry acetone insoluble matter in soybean oil residue.

Definition of iron removal rate in low-iron aqueous phospholipid: the iron removal rate of the low-iron hydrous phospholipid (weight of iron in soybean oil residue-weight of iron in low-iron hydrous phospholipid)/weight of iron in soybean oil residue.

Example 1

A low-iron aqueous phospholipid is prepared by the following steps with reference to fig. 1 and 2:

(1) soaking: adding soybean oil residue into water, and stirring to break the oil residue into granules in water to form a soaking system with oil residue granules as disperse phase and water as continuous phase, wherein the soaking temperature is 60 deg.C, and the soaking time is 3 hr to obtain saturated water-absorbing oil residue. The saturated water-absorbing oil foot obtained is marked by the beginning of the appearance of brown low-iron water-containing phospholipids.

The oil residue is from the grain and oil industry of China food, east China sea (Zhang hong) GmbH, and the material composition is as follows: the water content was 38.12g/100g, the content of acetone-insoluble matter on a dry basis was 61.47g/100g, and the iron content was 50.13mg/kg in terms of acetone-insoluble matter; the water is drinking water; the mass ratio of oil residue to water is 1: 1; the grain diameter of the oil residue particles is 0.3-3 mm.

(2) Centrifugal sedimentation: and (3) centrifugally settling the saturated water absorption oil residue, separating out phospholipid metal salt in the form of slag to obtain a fluid substance, wherein the centrifugal rotation speed is 500rpm, the time is 15min, and the temperature of centrifugal settling is the same as the soaking temperature.

(3) Standing and layering: standing and layering the obtained fluid to obtain the low-iron water-containing phospholipid, wherein the standing and layering temperature is the same as the soaking temperature.

The obtained low-iron hydrous phospholipid had a water content of 78.12g/100g, a dry acetone insoluble content of 94.48g/100g, an iron content of 5.51mg/kg based on the acetone insoluble matter, a sensory index of brown translucent fluid, a yield of dry acetone insoluble matter of low-iron hydrous phospholipid of 96.48%, and an iron removal rate of 89.40%.

Example 2

(1) soaking: adding soybean oil residue into water, and stirring to break the oil residue into granules in water to form a soaking system with oil residue granules as disperse phase and water as continuous phase, wherein the soaking temperature is 70 deg.C, and the soaking time is 3 hr to obtain saturated water-absorbing oil residue. The saturated water-absorbing oil foot obtained is marked by the beginning of the appearance of brown low-iron water-containing phospholipids.

The oil residue is from the Shandong limited company of the Chinese grain yellow sea grain and oil industry and comprises the following substances: the water content was 38.57g/100g, the content of acetone-insoluble matter on a dry basis was 63.61g/100g, and the iron content was 63.45mg/kg in terms of acetone-insoluble matter; the water is purified drinking water, salt and sodium chloride are added into the water, and the adding amount of the salt and the sodium chloride is 0.07 percent of the weight of the purified drinking water; the mass ratio of oil residue to water is 1: 1.5; the grain diameter of the oil residue particles is 0.3-3 mm.

(2) Centrifugal sedimentation: and (3) centrifugally settling the saturated water absorption oil residue, separating out phospholipid metal salt in the form of slag to obtain a fluid substance, wherein the centrifugal rotation speed is 2000rpm, the time is 5min, and the temperature of centrifugal settling is the same as the soaking temperature.

The obtained low-iron hydrous phospholipid had a water content of 74.32g/100g, a dry acetone insoluble content of 93.98g/100g, an iron content of 7.62mg/kg based on the acetone insoluble matter, a sensory index of brown translucent fluid, a yield of dry acetone insoluble matter of 95.59% and an iron removal rate of 88.52%.

Example 3

(1) soaking: adding soybean oil residue into water, and stirring to break the oil residue into granules in water to form a soaking system with oil residue granules as disperse phase and water as continuous phase, wherein the soaking temperature is 80 deg.C, and the soaking time is 2 hr to obtain saturated water-absorbing oil residue. The saturated water-absorbing oil foot obtained is marked by the beginning of the appearance of brown low-iron water-containing phospholipids.

The oil residue is from Jiangsu Zhonghai food and oil industry Co Ltd, and the material composition is as follows: the water content is 39.85g/100g, the content of acetone insoluble matter on a dry basis is 62.23g/100g, and the iron content is 75.07mg/kg based on the acetone insoluble matter; the water is purified drinking water, food additive lactic acid with the concentration of 80% is added into the water, and the adding amount is 0.05% of the weight of the purified drinking water; the mass ratio of oil residue to water is 1: 2; the grain diameter of the oil residue particles is 0.3-3 mm.

The obtained low-iron hydrous phospholipid had a water content of 73.88g/100g, a dry acetone insoluble content of 93.69g/100g, an iron content of 9.78mg/kg based on the acetone insoluble matter, a sensory index of brown translucent fluid, a yield of dry acetone insoluble matter of 94.48% and an iron removal rate of 87.69%.

Example 4

(1) soaking: adding soybean oil residue into water, and stirring to break the oil residue into granules in water to form a soaking system with oil residue granules as disperse phase and water as continuous phase, wherein the soaking temperature is 90 deg.C, and the soaking time is 2 hr to obtain saturated water-absorbing oil residue. The saturated water-absorbing oil foot obtained is marked by the beginning of the appearance of brown low-iron water-containing phospholipids.

The oil foot is from the food and grain and oil industry (nido lake) limited company, and the material composition of the oil foot is as follows: the water content was 37.68g/100g, the content of acetone insolubles on a dry basis was 62.58g/100g, and the iron content was 78.08mg/kg based on the acetone insolubles; the water is purified drinking water, and a food additive sodium hydroxide is added into the water, wherein the addition amount of the sodium hydroxide is 0.03 percent of the weight of the purified drinking water; the mass ratio of oil residue to water is 1: 2.5; the grain diameter of the oil residue particles is 0.3-3 mm.

The obtained low-iron hydrous phospholipid had a water content of 78.33g/100g, a dry acetone insoluble content of 95.41g/100g, an iron content of 10.98mg/kg based on the acetone insoluble matter, a sensory index of a brown translucent fluid, a yield of dry acetone insoluble matter of the low-iron hydrous phospholipid of 93.15%, and an iron removal rate of 86.90%.

Example 5

(1) soaking: adding soybean oil residue into water, and stirring to break the oil residue into granules in water to form a soaking system with oil residue granules as disperse phase and water as continuous phase, wherein the soaking temperature is 95 deg.C, and the soaking time is 1 hr to obtain saturated water-absorbing oil residue. The saturated water-absorbing oil foot obtained is marked by the beginning of the appearance of brown low-iron water-containing phospholipids.

The oil foot is from Louisafu (Bazhou) feed protein Co., Ltd, and comprises the following substances: the water content is 37.99g/100g, the content of dry acetone insoluble substances is 63.08g/100g, and the iron content is 96.23mg/kg based on the acetone insoluble substances; the water is purified drinking water, food additives of citric acid and common salt and sodium chloride are added into the water, the addition amount of the citric acid is 0.028 percent of the weight of the purified drinking water, and the addition amount of the common salt is 0.052 percent of the weight of the purified drinking water; the mass ratio of oil residue to water is 1: 3; the grain diameter of the oil residue particles is 0.3-3 mm.

(2) Centrifugal sedimentation: and (3) centrifugally settling the saturated water absorption oil residue, separating out phospholipid metal salt in the form of slag to obtain a fluid substance, wherein the centrifugal rotation speed is 1000rpm, the time is 10min, and the temperature of centrifugal settling is the same as the soaking temperature.

The obtained low-iron hydrous phospholipid had a water content of 73.02g/100g, a dry acetone insoluble content of 92.50g/100g, an iron content of 13.48mg/kg based on the acetone insoluble matter, a sensory index of brown translucent fluid, a yield of dry acetone insoluble matter of the low-iron hydrous phospholipid of 92.65%, and an iron removal rate of 87.02%.

Example 6

The oil foot is from Qinhuang island Jinhai grain and oil industry Co Ltd, and comprises the following materials: the water content is 40.43g/100g, the content of acetone insoluble matter on a dry basis is 60.89g/100g, and the iron content is 98.59mg/kg based on the acetone insoluble matter; the water is purified drinking water, and a food additive citric acid is added into the water, wherein the addition amount of the citric acid is 0.038 percent of the weight of the purified drinking water; the mass ratio of oil residue to water is 1: 3.5; the grain diameter of the oil residue particles is 0.3-3 mm.

(2) Centrifugal sedimentation: and (3) centrifugally settling the saturated water absorption oil residue, separating out phospholipid metal salt in the form of slag to obtain a fluid substance, wherein the centrifugal rotation speed is 1500rpm, the time is 5min, and the temperature of centrifugal settling is the same as the soaking temperature.

The obtained low-iron hydrous phospholipid had a water content of 73.38g/100g, a dry acetone insoluble content of 93.56g/100g, an iron content of 13.52mg/kg based on the acetone insoluble matter, a sensory index of brown translucent fluid, a yield of dry acetone insoluble matter of 92.03g/100g, and an iron removal rate of 87.38%.

Comparative example 1

A method for preparing hydrated phospholipid from soybean oil foot is disclosed in patent CN107325125A, and comprises the following steps:

adding 0.53 times of drinking purified water and 0.03% of sulfuric acid into soybean oil residue, heating to 85 deg.C, standing for 6 hr, and centrifuging at 85 deg.C and 4500r/min for 5min to obtain hydrated phospholipid. The soybean oil residue is produced by Zhongliang Huanghai grain and oil industry (Shandong) Co., Ltd, and has a water content of 38.57g/100g, a dry acetone insoluble content of 63.61g/100g, and an iron content of 63.45mg/kg based on the acetone insoluble.

The resulting hydrated phospholipid had a water content of 64.19g/100g, a dry acetone insoluble content of 90.12g/100g, an iron content of 63.45mg/kg based on acetone insoluble, and a sensory index of brown translucent fluid.

Compared with the hydrated phospholipid prepared in the comparative example 1, the main differences comprise the following aspects:

first, hydration method and phospholipid water content differ: the hydrated phospholipid is prepared by a homogeneous hydration method, soybean oil residue and water need to be uniformly mixed, the water adding amount in the hydration operation is 0.25-0.74 times of the weight of the oil residue, and the water is more than that of the oil residue, so the water absorption capacity of the hydrated phospholipid is far from reaching the saturation degree, and the water content of the phospholipid is only 64.19g/100 g; the low-iron water-containing phospholipid is prepared by a soaking hydration method, soybean oil residue takes granules as a disperse phase, water is taken as a continuous phase to form a soaking system, the water adding amount in the hydration operation is 1.0-3.5 times of the weight of the oil residue, so that redundant free water is ensured to exist around the phospholipid, the water absorption capacity of the phospholipid is ensured to be saturated, and the saturation value is 70-80g/100 g. Only when the water content of the phospholipids is saturated, the acetone-insoluble content of the phospholipids reaches a maximum value, which is 92.5-95.5g/100 g. The effect that the water absorption of the phospholipid reaches saturation is as follows, and firstly, the acetone insoluble substance content of the phospholipid is the highest; secondly, separating phospholipid metal salt; thirdly, the method is beneficial to the separation operation of phospholipid, phospholipid metal salt and grease in the oil residue.

Secondly, the phospholipid purity was different: the content of dry acetone insoluble substances of the hydrated phospholipid is 90-92g/100g, phospholipid metal salt cannot be removed, and the patent hydrated phospholipid is bleached and decolored by adopting hydrogen peroxide, so that the natural property of the phospholipid is damaged, and the quality guarantee period and the food safety are reduced; the content of the dry acetone insoluble substance of the low-iron water-containing phospholipid is 92.5-95.5g/100g, and phospholipid metal salt can be removed. The phospholipid metal salt is a dark red substance, and removal of the phospholipid metal salt is beneficial to preparation of yellow powder phospholipid. The powdered phospholipid prepared by the low-iron aqueous phospholipid is natural yellow and does not need chemical bleaching.

Comparative example 2

A method for preparing liquid crystal state phospholipid from soybean oil foot is derived from the research on liquid crystal state separation and purification of soybean phospholipid in the literature, and comprises the following steps:

adding 0.67 times of drinking purified water to soybean oil residue, mixing, heating to 70 deg.C, standing for 4 hr, and centrifuging at 70 deg.C and 4500r/min for 5min to obtain liquid crystal phospholipid. The soybean oil foot is produced by Qinhuang island Jinhai grain and oil industry Co Ltd, the water content is 40.43g/100g, the content of acetone insoluble matter is 60.89g/100g, and the iron content is 98.59mg/kg calculated by the acetone insoluble matter.

The obtained liquid crystal state phospholipid had water content of 64.08g/100g, dry acetone insoluble content of 86.06g/100g, iron content of 98.59mg/kg based on acetone insoluble, and sensory index of brown translucent fluid.

Liquid crystal state phospholipid is distributed on a drying tray through a circular feed port with the aperture of 2mm according to the same strip shape and density as the example 1, and is dried for 240min at 65 ℃ in a batch type vacuum drying oven to obtain brown block solid phospholipid, the water content of the brown block solid phospholipid is 6.79g/100g, and the content of dry base acetone insoluble substances is 86.06g/100 g; and (3) crushing the brown solid phospholipid, sieving the crushed brown solid phospholipid by using a 18-mesh sieve, and drying the powder phospholipid in a vacuum drying oven at 60 ℃ for 30min to obtain powder phospholipid, wherein the water content of the powder phospholipid is 1.38g/100g, the content of dry acetone insoluble substances is 86.06%, the iron content is 98.59mg/kg based on the acetone insoluble substances, and the sensory index is brown powder.

Compared with the liquid crystal state phospholipid prepared in the comparative example 2, the liquid crystal state phospholipid mainly has the following differences:

first, differences in hydration methods: the liquid crystal state phospholipid is prepared by a homogeneous hydration method, soybean oil residue and water need to be uniformly mixed, and the water adding amount in the hydration operation is 0.67 times of the weight of the oil residue, so the water absorption capacity of the liquid crystal state phospholipid is far from the saturation degree, the water content is only 64.08g/100g, and the defect is completely the same as that of the patent hydrated phospholipid; the low-iron water-containing phospholipid is prepared by a soaking hydration method, soybean oil residue takes granules as a disperse phase, water is a continuous phase to form a soaking system, the water adding amount in the hydration operation is 1.0-3.5 times of the weight of the oil residue, the water absorption capacity of the phospholipid is ensured to be saturated, and the water content of the low-iron water-containing phospholipid is 70-80g/100 g.

Secondly, the phospholipid purity was different: the content of the liquid crystal state phospholipid in dry acetone insoluble substances is 86.06g/100g, phospholipid metal salt cannot be removed, the solid phospholipid prepared by drying is brown, and the powder phospholipid is brown; the content of the dry acetone insoluble substance of the low-iron water-containing phospholipid is 92.5-95.5g/100g, so that the phospholipid metal salt can be removed, and the content of the dry acetone insoluble substance of the low-iron water-containing phospholipid and the dry acetone insoluble substance of the low-iron water-containing phospholipid has larger difference. The solid phospholipid and the powder phospholipid prepared from the low-iron water-containing phospholipid are both yellow.

Comparative example 3

A method for preparing powdered soybean phospholipid is disclosed in patent CN103665029A, and comprises the following steps:

mixing soybean oil residue and anhydrous acetone in a weight ratio of 1:10, stirring and extracting for 20min under the conditions of normal pressure and room temperature, performing centrifugal separation for solid-liquid separation, wherein the centrifugal time is 1min, the centrifugal speed is 4000rpm, and collecting solid parts.

The soybean oil foot comes from Qinhuang island Jinhai food and oil industry Co Ltd, and the material composition is as follows: the water content was 40.43g/100g, the dry acetone insoluble content was 60.89g/100g, and the iron content, calculated as acetone insoluble, was 98.59 mg/kg.

Mixing the solid part obtained in the step with anhydrous acetone in a weight ratio of 1:10, stirring and extracting for 20min under the conditions of normal pressure and room temperature, then performing centrifugal separation for solid-liquid separation, wherein the centrifugal speed is 5000rpm, and collecting the solid part, wherein the centrifugal time is 1 min. Crushing the solid part, and drying at 60 deg.C under vacuum for 5 hr to obtain soybean powder phospholipid, wherein the content of acetone insoluble matter is 95.58g/100g, the content of iron is 98.59mg/kg based on acetone insoluble matter, and the weight loss by drying is 0.54g/100g, and the soybean powder phospholipid is brown powder.

Compared with the powder phospholipid prepared in the comparative example 3, the main differences comprise the following aspects:

first, the difference between environmental protection and food safety: the comparative example 3 is the powdered phospholipid prepared by the solvent method, the solvent method has the environmental pollution caused by solvent volatilization, the drying loss of the product is 0.54g/100g, the components reduced by drying are the solvent, and the potential safety hazard of the food with residual solvent exists; the powder phospholipid prepared by the application of the invention belongs to a hydration method, has no environmental pollution, the drying decrement of the product is less than or equal to 2g/100g, the component of the drying decrement is water, and no potential safety hazard of food exists.

Secondly, the differences in color and luster: the powdered phospholipid prepared in comparative example 3 cannot remove phospholipid metal salts, and has a long drying time for reducing solvent residue and a darker color; the low-iron water-containing phospholipid of the invention can remove phospholipid metal salt, the drying time for preparing the powder phospholipid is short, and the color of the phospholipid is natural yellow.

Application example 1

Use of the low iron aqueous phospholipid of example 2 to prepare solid phospholipid, low iron powdered phospholipid, with reference to figures 3 and 4, comprises the following steps:

(1) concentrating the low iron aqueous phospholipid prepared in example 2 to obtain a concentrated aqueous phospholipid; (2) stirring the concentrated aqueous phospholipid to obtain an aqueous phospholipid elastomer; (3) drying the aqueous phospholipid elastomer to obtain strip-shaped solid phospholipid; (4) and (3) crushing, sieving and drying the strip-shaped solid phospholipid to obtain the low-iron powder phospholipid.

Step (1) preparation of concentrated aqueous phospholipid: the low-iron aqueous phospholipid obtained in example 2 was concentrated to a water content of 55g/100g at 95 ℃ in a vacuum thin film evaporator to give a concentrated aqueous phospholipid having a dry acetone insoluble content of 93.98g/100g, an iron content of 7.62mg/kg based on the acetone insoluble content and a brown translucent fluid as sensory index.

Step (2) preparation of aqueous phospholipid elastomer: and (2) pushing the concentrated aqueous phospholipid obtained in the step (1) into a stirrer at the speed of 80cm/min, wherein the stirring speed is 900rpm, and the stirring time is 10s, so that the continuously output aqueous phospholipid elastomer is obtained, and the water content and the acetone insoluble content of the aqueous phospholipid elastomer are the same as those of the concentrated aqueous phospholipid, but the sensory index is changed into yellow opaque semisolid.

Preparing solid phospholipid by the step (3): and (3) feeding the water-containing phospholipid elastomer continuously output in the step (2) into a normal-pressure continuous dryer through a feed inlet with the aperture of 3mm, and drying at 150 ℃ for 8min to obtain continuously output strip-shaped solid phospholipid, wherein the water content of the strip-shaped solid phospholipid is 7.33g/100g, the content of dry acetone insoluble substances is 93.98g/100g, and the sensory index of the strip-shaped solid is yellow strip-shaped solid.

Step (4) preparing low iron powder phospholipid: and (3) crushing the strip-shaped solid phospholipid obtained in the step (3), sieving the powder by using a 18-mesh sieve, and performing vacuum drying in a double-cone rotary vacuum dryer at 60 ℃ for 40min to obtain the low-iron powder phospholipid, wherein the water content of the low-iron powder phospholipid is 1.38g/100g, the content of the dry acetone insoluble substances is 93.98g/100g, the iron content is 7.62mg/kg based on the acetone insoluble substances, the sensory index of the low-iron powder phospholipid is yellow powder, and the product meets the national standard GB28401 food additive phospholipid.

Application example 2

Use of the low iron aqueous phospholipid of example 4 to prepare solid phospholipid, low iron powdered phospholipid, with reference to figures 3 and 4, comprises the following steps:

(1) concentrating the low iron aqueous phospholipid prepared in example 4 to obtain a concentrated aqueous phospholipid; (2) stirring the concentrated aqueous phospholipid to obtain an aqueous phospholipid elastomer; (3) drying the aqueous phospholipid elastomer to obtain strip-shaped solid phospholipid; (4) and (3) crushing, sieving and drying the strip-shaped solid phospholipid to obtain the low-iron powder phospholipid.

Step (1) preparation of concentrated aqueous phospholipid: the low-iron aqueous phospholipid obtained in example 4 was concentrated to a water content of 45g/100g at 105 ℃ in a vacuum thin film evaporator to give a concentrated aqueous phospholipid having a dry acetone insoluble content of 95.41g/100g, an iron content of 10.98mg/kg based on the acetone insoluble content and a brown translucent fluid as sensory index.

Step (2) preparation of aqueous phospholipid elastomer: and (2) pushing the concentrated aqueous phospholipid obtained in the step (1) into a stirrer at the speed of 40cm/min, wherein the stirring speed is 1100rpm, and the stirring time is 20s, so that the continuously output aqueous phospholipid elastomer is obtained, and the water content and the acetone insoluble content of the aqueous phospholipid elastomer are the same as those of the concentrated aqueous phospholipid, but the sensory index of the aqueous phospholipid elastomer is changed into yellow opaque semisolid.

Preparing solid phospholipid by the step (3): and (3) feeding the water-containing phospholipid elastomer continuously output in the step (2) into a vacuum continuous dryer through a feed inlet with the aperture of 4mm, and drying at 130 ℃ for 15min to obtain continuously output strip-shaped solid phospholipid, wherein the water content of the strip-shaped solid phospholipid is 5.47g/100g, the content of dry acetone insoluble substances is 95.41g/100g, and the sensory index of the strip-shaped solid is yellow strip-shaped solid.

Step (4) preparing low iron powder phospholipid: and (3) crushing the strip-shaped solid phospholipid obtained in the step (3), sieving the powder by a 18-mesh sieve, and performing vacuum drying in a double-cone rotary vacuum dryer at 60 ℃ for 30min to obtain the low-iron powder phospholipid, wherein the water content of the low-iron powder phospholipid is 1.23g/100g, the content of the dry acetone insoluble substances is 95.41g/100g, the iron content is 10.98mg/kg based on the acetone insoluble substances, the sensory index is yellow powder, and the product meets the national standard GB28401 food additive phospholipid.

The above detailed description is specific to one possible embodiment of the present invention, and the embodiment is not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention should be included in the technical scope of the present invention.

Claims

1. A low-iron aqueous phospholipid is characterized in that the main components of the low-iron aqueous phospholipid are phospholipid, grease and water, and the water content is 70-80g/100 g; the content of acetone insoluble substances is 92.5-95.5g/100g on a dry basis; the iron content is less than or equal to 18mg/kg based on the acetone insoluble substance.

2. The low iron aqueous phospholipid of claim 1 wherein the sensory attribute of the low iron aqueous phospholipid is a brown translucent fluid.

3. The low iron aqueous phospholipid of claim 1, wherein the preparation of the low iron aqueous phospholipid comprises the steps of:

(2) carrying out centrifugal sedimentation on the saturated water absorption oil residue to obtain a fluid substance;

4. The low-iron aqueous phospholipid as set forth in claim 3, wherein the mass ratio of the soybean oil foot to the water in the step (1) is 1: 1-3.5; the soaking temperature is 60-95 ℃; the soaking time is 1-3 h.

5. The low-iron aqueous phospholipid as set forth in claim 3, wherein the soybean oil foot in the step (1) has a particle size of 5mm or less, preferably 3mm or less.

6. The low-iron aqueous phospholipid as defined in claim 3, wherein the centrifugal sedimentation in the step (2) is batch centrifugal sedimentation at a temperature of 60-95 ℃ and a centrifugal rotation speed of 500-2000rpm for a period of 5-15 min.

7. The low-iron aqueous phospholipid as set forth in claim 3, wherein the temperature of the standing layer in the step (3) is 60 to 95 ℃.

8. The low-iron aqueous phospholipid as set forth in claim 3, wherein the preparation method further comprises adding an electrolyte to the soaking system, preferably, the electrolyte has a mass fraction of 0.01-0.3% in water.

9. The low iron aqueous phospholipid of claim 8 wherein the electrolyte comprises at least one of an acid, a base, and a salt, preferably wherein the electrolyte is at least one of sodium DL-malate, L-malic acid, DL-malic acid, glacial acetic acid, citric acid, potassium citrate, sodium citrate, monosodium citrate, sodium gluconate, lactic acid, potassium lactate, sodium lactate, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium sulfate, potassium chloride, potassium hydroxide, sodium hydroxide, hydrochloric acid, phosphoric acid, and sodium chloride.

10. Use of a low iron aqueous phospholipid as defined in any one of claims 1 to 9 in the preparation of a low iron powder phospholipid.