CN112552997B

CN112552997B - Method for preparing fish oil by taking fish cooking liquor as raw material and fish oil

Info

Publication number: CN112552997B
Application number: CN202011379784.5A
Authority: CN
Inventors: 王鹏; 王新宇; 李银平; 刘瑞志; 王欣欣; 闫鸣艳; 乔乐克
Original assignee: Ocean University of China
Current assignee: Ocean University of China
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2022-04-01
Anticipated expiration: 2040-11-30
Also published as: CN112552997A

Abstract

The invention belongs to the field of comprehensive utilization of byproducts in marine product processing, and particularly relates to a method for preparing fish oil by taking cooking liquor of a fish can as a raw material and the fish oil. The method of the invention comprises the following steps: 1) adding alcohol into the fish can cooking liquor until the volume fraction of the alcohol is 55-85%; 2) fully mixing the solution system after adding the alcohol, standing, separating into the supernatant, the middle oil layer and the lower layer, and taking the middle oil layer to obtain the primary product containing the fish oil. According to the method, the cooking liquor can be ingeniously divided into three layers by adding the ethanol solution, so that a foundation is laid for subsequent material refining. The method has short production period; and the technological process is stable through the selection and optimization of technological parameters and raw materials, the discharge amount of wastewater is small, the cost is low, and a good foundation is laid for industrial mass production.

Description

Method for preparing fish oil by taking fish cooking liquor as raw material and fish oil

Technical Field

The invention belongs to the field of comprehensive utilization of byproducts in marine product processing, and particularly relates to a method for preparing fish oil by taking fish cooking liquor as a raw material and the fish oil.

Background

The east Lin West Pacific in China has rich fish resources, and the fish is usually processed into products such as canned fish, fish steaks and the like in industrial production. Cooking is one of the main links in fish processing, and after cooking, fish juice can be lost in cooking liquor, and about 3 tons of cooking liquor can be produced every 1 ton of fish is produced. Some enterprises directly dump and lose cooking liquor as waste liquor, which not only causes huge waste of resources, but also causes serious environmental pollution. In the prior art, cooking liquor is mainly treated by enzymolysis or other treatment to prepare seasonings, but the added value of the seasonings is low, so that the efficient utilization of the cooking liquor for fish cannot be realized.

Disclosure of Invention

Aiming at the problem that no effective treatment method for the canned fish cooking liquor exists in the prior art, the invention provides a method for extracting fish oil from the canned fish cooking liquor.

The method comprises the following steps:

1) adding alcohol into the fish can cooking liquor until the volume fraction of the alcohol is 55-85%;

2) fully mixing the solution system after adding the alcohol, standing and/or centrifuging, separating into the supernatant, the middle layer and the lower layer, and taking the middle layer to obtain the primary product containing the fish oil.

The invention discovers for the first time that the cooking liquor generated in the can processing process can be divided into three layers skillfully by adding alcohol to the volume fraction, and further analysis shows that the supernatant mainly contains small molecular peptides and amino acids, the middle oil layer mainly contains grease, and the lower layer precipitate mainly contains fish glue proteins.

Preferably, alcohol is added into the fish can cooking liquor until the volume fraction of the alcohol is 70-80%; the volume fraction of the alcohol is adjusted to the range, so that the yield of the fish oil can be effectively improved.

Preferably, the specific operation of the sufficient mixing is to perform ultrasonic treatment on the solution system, wherein the temperature of the mixed solution is adjusted to be 35-45 ℃ in the ultrasonic treatment process, the ultrasonic power is 200-600W, and the ultrasonic time is 60-120 min. Researches show that the fish oil is often combined with macromolecular substances such as protein or sugar, the fish oil can be effectively separated from the macromolecular substances such as protein or sugar after the treatment, emulsion breaking is realized, the fish oil is further dissociated, the layered fish oil is better enriched in the middle layer, and the yield and the purity of the fish oil can be improved.

Preferably, the mixed solution is kept stand for 10-14 hours at room temperature after the ultrasonic treatment is finished, and/or the material is centrifuged after the standing is finished, so that the layered state of the material is better through centrifugation.

Preferably, the cooking liquor is freed of sediment and floaters prior to the addition of alcohol thereto.

Preferably, the obtained primary product containing fish oil is refined by the following method:

1) mixing the primary product containing the fish oil with water, washing the primary product containing the fish oil with water, and standing to obtain an oil layer;

2) and adding enteromorpha polysaccharide into the oil layer to remove heavy metals in the oil layer.

The invention finds that aiming at the fish oil, the addition of the enteromorpha polysaccharide into the fish oil has a remarkable effect on removing the heavy metal ions compared with the addition of other types of polysaccharides (such as chitosan), and the content of the heavy metal ions in the fish oil can reach the standard after the adsorption of the enteromorpha polysaccharide.

Preferably, the volume ratio of the primary product containing fish oil to the water is 1: 1-10.

Preferably, the specific mixing operation is to heat and stir the mixed solution, wherein the temperature of the mixed solution is adjusted to 35-50 ℃, the stirring speed is 50-100rpm, the stirring time is 30-120 min, and then the mixed solution is centrifuged at 4000-10000r/min for 5-15 min.

Preferably, the specific operation of refining the crude fish oil is to add enteromorpha sulfated polysaccharide into the fish oil, the addition amount of the enteromorpha sulfated polysaccharide is 0.1-1% of the mass of the fish oil, stir and react for 30-180min, and then centrifuge for 5-10min at 4000-10000 r/min. The treatment is favorable for comprehensively removing heavy metal ions in the fish oil.

Preferably, the chemical oxygen demand of the fish cooking liquor is 110000-120000 mg/L, the ammonia nitrogen is 550-650 mg/L, and the total nitrogen content is 11000-12000 mg/L;

more preferably, the fish cooking liquor is bonito cooking liquor.

Another object of the present invention is to protect the fish oil produced by the method of the present invention.

The invention has the following beneficial effects:

1) according to the method, the cooking liquor can be ingeniously divided into three layers by adding the ethanol solution, wherein the middle layer is mainly a fish oil layer, and a foundation is laid for simply and efficiently preparing the fish oil product.

2) The production process has short production period and simple operation, and is favorable for industrial large-scale popularization.

Drawings

FIG. 1 is a pictorial depiction of a slice of cooking liquor after treatment in accordance with the method described in example 1;

FIG. 2 shows the fish oil prepared in example 1.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The cooking liquor related to the embodiment is bonito cooking liquor, the chemical oxygen demand is 115000mg/L, the ammonia nitrogen is 580mg/L, and the total nitrogen content is 11400 mg/L.

Example 1

This example relates to a method for preparing fish collagen, which includes the following steps (the layered picture of this example is shown in fig. 1, and the picture of the fish oil obtained by preparation is shown in fig. 2):

1) taking 10L of fish cooking liquor, and removing precipitate and floating liquid by absorbent cotton to obtain clear fish cooking liquor;

2) adding 20L 95% ethanol into the clear liquid of the fish cooking liquid obtained in the step 1) until the volume fraction of the ethanol in the mixed liquid is 75%, carrying out ultrasonic treatment for 90min at 40 ℃ under the condition of 400W, standing for 12h, separating the mixed liquid into the top clear liquid, a middle oil layer and a lower sediment, and taking the middle oil layer;

3) and (3) mixing the intermediate oil layer according to the volume ratio of 1: 5, mixing the mixture with distilled water, heating and stirring the mixture, adjusting the temperature of the mixture to be 50 ℃ in the heating and stirring process, stirring at 100rpm for 30min, centrifuging at 10000r/min for 5min, and removing a lower water layer;

4) adding Enteromorpha sulphated polysaccharide into the fish oil at the upper layer, wherein the addition amount is 1% of the fish oil by mass, stirring for reaction for 40min, centrifuging at 4000r/min for 10min, and taking the supernatant of the fish oil.

Example 2

This example relates to a method for preparing fish oil, which is different from example 1 in that ethanol is added in step 2) until the volume fraction of ethanol in the mixed solution is 55%.

Example 3

The embodiment relates to a preparation method of fish oil, which is different from the embodiment 1 in that the ultrasonic treatment is not performed on the materials in the step 2), the operation of fully mixing is to perform heating and stirring treatment on the materials, the temperature of the mixed solution is adjusted to 45 ℃ in the heating and stirring treatment process, the stirring speed is 150rpm, and the stirring time is 80 min.

Example 4

The embodiment relates to a preparation method of fish oil, and compared with embodiment 1, the difference is that the specific refining operation is to add enteromorpha sulfated polysaccharide into the fish oil, the addition amount is 0.5 percent of the mass of the fish oil, stir and react for 50min, and then centrifuge for 5min at 10000 r/min.

Comparative example 1

The difference from example 1 is that 95% ethanol was added to the fish cooking clear liquid until the volume fraction of ethanol in the mixed liquid was 40%. As a result, the cooking liquor cannot be divided into three layers, and fish oil cannot be extracted simply and rapidly.

Examples of the experiments

1) The yield and appearance of fish oil of examples 1-4 are characterized in table 1:

TABLE 1

Wherein the fish oil yield is calculated by the weight ratio (%) extracted fish oil/weight of crude fat in the raw material x 100%. The quality of the refined fat in the raw material is measured by a Soxhlet extraction method.

2) The results of the heavy metal content in fish oil are shown in table 2:

TABLE 2

From the results, the heavy metals in the product after the treatment by the method of the invention all meet the national standard.

3) The fish oil obtained in example 1 was analyzed for the types of fatty acids, and the results are shown in table 3:

TABLE 3

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A method for preparing fish oil by taking fish cooking liquor as a raw material is characterized by comprising the following steps:

1) adding alcohol into the fish can cooking liquor until the volume fraction of the alcohol is 55-85%; the chemical oxygen demand of the fish cooking liquor is 110000-120000 mg/L, the ammonia nitrogen is 550-650 mg/L, and the total nitrogen content is 11000-12000 mg/L;

2) fully mixing the solution system added with the alcohol, standing and/or centrifuging, separating into the supernatant, the middle layer and the lower layer, and taking the middle layer to obtain a primary product containing the fish oil;

the specific operation of the sufficient mixing is to carry out ultrasonic treatment on the solution system, wherein the temperature of the mixed solution is adjusted to be 35-45 ℃ in the ultrasonic treatment process, the ultrasonic power is 200-600W, and the ultrasonic time is 60-120 min.

2. The method for preparing fish oil from fish cooking liquor as raw material according to claim 1, wherein the mixed liquor is kept standing for 10-14 h at room temperature after the ultrasonic treatment;

or, layering by centrifugation after standing.

3. The method of claim 1, wherein the precipitate and floaters are removed from the fish cooking liquor before adding alcohol to the cooking liquor.

4. The method of claim 1, wherein the fish oil-containing raw material is refined by the following steps:

5. The method for preparing fish oil from fish cooking liquor as claimed in claim 4, wherein the volume ratio of the primary product containing fish oil to the water is 1: 1-10, wherein the specific operation of mixing is to heat and stir the mixed solution, the temperature of the mixed solution is adjusted to be 35-50 ℃ in the process of heating and stirring, the stirring speed is 50-100rpm, the stirring time is 30-120 min, and then the mixed solution is centrifuged at 4000-10000r/min for 5-15min to remove the lower layer.

6. The method for preparing fish oil from fish cooking liquor as claimed in claim 4, wherein the amount of Enteromorpha polysaccharide is 0.1-1% of the fish oil by mass, the stirring reaction is carried out for 30-180min, and then the centrifugation is carried out for 5-10min at 4000-10000 r/min.

7. The method for producing fish oil from a fish cooking liquor as claimed in any one of claims 1 to 6, wherein the fish cooking liquor is bonito cooking liquor.