TWI541340B - Method of extracting fish oil - Google Patents

Description

Method of making fish oil

This invention relates to a method of making fish oil, and more particularly to a method of making fish oil using an acid treatment.

Functional foods have always played an important role in disease prevention, and there are many raw materials needed to prepare and extract functional foods. Aquatic products are an important source. In the process of aquatic product processing, a large amount of waste is generated, including fins, fish skin, fish internal organs, fish heads, fish bones, etc., wherein the inedible ratio of processed frozen processed aquatic products is as high as 45% to 70%, however fish Waste still contains a lot of nutrients and essences. It is a pity that it is not good to use and waste.

Polyunsaturated Fatty required by the human body Acids, PUFA) cannot be synthesized by yourself and must be obtained from diet. Among them, the most physiologically active Eicosapentaenoic Acid (EPA) and docosahexaenoic acid (DHA) are usually found in the subcutaneous fat of fish. It has been confirmed in medicine that EPA can reduce tristearate. Oil, inhibit thrombosis, lower blood pressure, lower blood fat, etc., and DHA is an important component of brain cells, and is also beneficial to visual cells. Therefore, proper intake of fish oil extracted from the fins can effectively supplement the deficiency of the human body. When raw materials are cheap (due to fish waste), fish oil has the advantages of efficient use of waste, low cost and high nutrition, and has high economic value.

Generally, methods for extracting fish oil include boiled extraction, organic solvent extraction, enzymatic hydrolysis, and supercritical fluid extraction (SFE). However, the fish oil ratio obtained by extraction is not high, for example, a trypsin hydrolysis process, The amount of fish oil extracted is about 4.34%, and the ratio of solid waste after extraction is too high to effectively use fish waste. Therefore, how to reduce the residual rate of solid waste and improve the extraction rate of fish oil is a major issue in the food industry today.

In view of the above problems of the prior art, it is an object of the present invention to provide a method for producing fish oil by using an acid solution to solve the problem that the solid waste of the prior art is very high and the fish oil extraction rate is low.

According to one aspect of the present invention, a method for producing fish oil is provided, comprising the steps of: immersing a fish raw material in an acid liquid to obtain a softened fish raw material; and cooking the softened fish raw material to obtain a fish hydrolyzate; The fish hydrolysate is centrifuged to obtain fish oil.

Preferably, the fish material may comprise fins or fish heads.

Preferably, the acid solution may comprise phosphoric acid, citric acid or hydrochloric acid.

Preferably, the acid solution may have a volume percent concentration of from about 2% to about 8%.

Preferably, the retort treatment can be cooked at from about 100 ° C to about 140 ° C and from about 1 kg/cm ² to about 2 kg/cm ² for about 8 minutes to about 20 minutes.

Preferably, before the softened fish raw material is subjected to the retort treatment, the softened fish raw material may be further washed with water to remove the acid liquid.

As stated above, the method of making fish oil of the present invention may have one or more of the following advantages:

(1) This method can effectively destroy the cell membrane in the fish raw material by using the acid solution, and soften the tissue, so that the proportion of the fish oil finally obtained is higher, and the utilization rate of the fish raw material is improved.

(2) The final residual rate of this method is much lower than that of the prior art, which can effectively reduce the amount of fish waste and achieve the environmental protection purpose of waste reduction.

(3) This method can be used for cooking by using an acid solution, and then it is not necessary to use an organic solvent extracted from the human body to improve the process safety.

S11~S13‧‧‧Steps

Fig. 1 is a flow chart showing the first embodiment of the method for producing fish oil of the present invention.

The invention will be further described in detail by the following preferred embodiments and the accompanying drawings. It should be noted that the experimental data disclosed in the following embodiments are for explaining the technical features of the present invention, and are not intended to limit the manner in which they can be implemented.

Please refer to FIG. 1 , which is a flow chart of Embodiment 1 of the method for producing fish oil of the present invention. As can be seen from the figure, the method for producing fish oil of the present invention may comprise the steps of: immersing the fish raw material in an acid liquid to obtain a softened fish raw material (step S11). The fish raw material may comprise fins or fish heads of any fish species, and the acid liquid may comprise phosphoric acid, citric acid or hydrochloric acid, wherein the acid liquid may have a volume percent concentration of about 2% to about 8%, and is soaked for about 1 hour. The softened fish raw material is subjected to a retort treatment to obtain a fish hydrolyzate (step S12). Before the softened fish raw material is subjected to the retort treatment, the softened fish raw material may be further washed with water to remove the residual acid liquid, and then the retort treatment may be performed at about 100 ° C to about 140 ° C and about 1 kg / cm ² to about Cooking at 2 kg/cm ² for about 20 minutes, where the cooking treatment refers to a temperature and pressure sufficient to hydrolyze the fish. The fish hydrolyzate is subjected to centrifugation to obtain fish oil (step S13).

In Example 2 of the present invention, a fin of a flounder was used as an example of a fish material. First, the fins of the flounder are placed in a sieve, washed with water and drained to remove the impurities attached thereto, which is the raw material of the fish. The fish raw material is immersed in the acid grade of the food grade phosphoric acid at a normal temperature of about 25 to 28 ° C for about 1 hour to obtain a softened fish raw material. The volume percent concentration of phosphoric acid is 2%, 4% and 8%. The softened fish material is washed with water to remove residual phosphoric acid. Then, the washed softened fish raw material is cooked at a high temperature of about 100 ° C to about 140 ° C and a high pressure of about 1 kg / cm ² to about 2 kg / cm ² for about 8 minutes to about 15 minutes, preferably 14 minutes to 15 minutes. To obtain fish hydrolysate. The temperature is preferably from 120 ° C to 130 ° C, and the pressure is preferably from 1 kg / cm ² to 1.5 kg / cm ² . Then, the fish hydrolyzate is placed in a centrifuge at a temperature of about 0 ° C to 25 ° C, and centrifuged at a gravity of 3600 g for about 10 minutes, wherein the temperature is preferably 4 ° C to 6 ° C, and the fish hydrolyzate is layered from above. The order is as follows: fish oil, hydrolyzate and residue, and the upper layer is collected to obtain fish oil.

The third embodiment of the present invention is similar to the preparation method of the second embodiment except that the acid solution soaked in the fish raw material is citric acid at a volume concentration of 2%, 4% and 8%.

The fourth embodiment of the present invention is similar to the preparation method of the second embodiment, except that the acid solution soaked in the fish raw material is hydrochloric acid, and the volume percent concentration is also 2%, 4% and 8%.

The method of Comparative Example 1 is a general boiled extraction method, that is, the fish raw material is not soaked by the acid solution, and is directly cooked by water, and then subjected to a subsequent centrifugation step to obtain fish oil.

The solid residue ratio and the fish oil extraction ratio of the fish oil obtained in Examples 2 to 4 of the present invention and Comparative Example 1 were compared. The results are shown in Table 1. Solid residue rate After the fish material is processed, the ratio of unmanageable residue remains. Since fish are rich in polyunsaturated fatty acids, the oxidation of oils and fats is quite remarkable during processing and storage. Therefore, when processing aquatic products, attention must be paid to the quality degradation caused by oxidation of oils and fats. Here, the TBA method (thiobarbituric acid method) is used, which utilizes the combination of malondialdehyde and 2-thiopropionamidine produced in the oxidation of oil to produce a red substance. A spectrophotometer measures its absorbance as an indicator of grease oxidation. Therefore, the TBA value can express the quality of fish oil.

As can be seen from Table 1, in Example 2 of the present invention, when immersed in 2% phosphoric acid, the solid residue ratio is only 11.96%, which is much lower than the value of Comparative Example 1 of the general boiled extraction method of 27.25%. It can effectively reduce fish waste and improve utilization rate to achieve environmental protection. On the other hand, fish oil extraction rate is 31.04%, which is higher than the value of Comparative Example 1 18.08%, so it can effectively improve the utilization rate of fish raw materials. If soaked in 4.0% and 8.0% phosphoric acid, the fish oil extraction rate is only slightly reduced, but the residual rate is greatly reduced by more than half. The fish oil TBA value is about 6 to 9, which is lower than that of Comparative Example 1. When the volume fraction of citric acid used in Example 3 was 2%, the solid residue ratio was 20.09%, which was still lower than that of Comparative Example 1, and the fish oil extraction rate was also 31.1%, and the concentration was increased to 4%. The fish oil extraction rate can be significantly improved to 38.30%, and the solid content can be greatly reduced to 9.08% when the concentration is increased to 8%. The fish oil TBA value is about 5 to 12, which is similar to Comparative Example 1. On the other hand, Example 4 immersed in hydrochloric acid had the lowest solid residue ratio compared with the other examples, almost one tenth of the value of Comparative Example 1, and the fish oil extraction rate was also higher than that of Comparative Example 1, while fish oil The TBA value is approximately 7 to 11. Therefore, phosphoric acid, citric acid and hydrochloric acid do help to effectively destroy the cell membrane in the fish raw material and soften its tissue, leaving less waste solids and producing more fish oil, and the higher the concentration, the higher the solid residue rate. The lower the pH, the TBA value of the fish oil extracted at the same time is not far from the TBA value of the fish oil extracted by boiling water, and the fish oil quality can be maintained.

In view of the practical process, it is not always possible to make fish oil immediately after washing the fish raw materials. Therefore, the fifth embodiment of the present invention provides a method for preserving fish oil for the production of fish oil. Example 5 is similar to the preparation method of Example 2, except that after obtaining the fish raw material, it is first stored at about -20 ° C for freezing. The fish raw material is intended to maintain the freshness of the fish raw material; when the fish oil is to be manufactured, the frozen fish raw material is thawed at about 4 ° C for about 16 hours to obtain the thawed fish raw material. The thawed fish material is immediately subjected to a subsequent step of soaking the acid. The fish oil thus obtained can still retain the activity of the original ingredients and maintain the reliability of the product.

In summary, referring to Table 1, the method for producing fish oil of the present invention comprises immersing fish raw materials such as fins in an acid solution, so that the acid solution effectively destroys the cell membrane in the fin and softens the tissue in the fin. As well as retort treatment and centrifugation, the amount of waste solids that cannot be used is greatly reduced, and fish waste is more effectively utilized, and more fish oil is more easily produced, and the process is safe and the industrial competitiveness is enhanced.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

S11~S13‧‧‧Steps

Claims (3)

A method for producing fish oil, comprising the steps of: immersing a fish raw material in an acid solution to obtain a softened fish raw material, wherein the acid liquid comprises phosphoric acid, citric acid or hydrochloric acid, and the acid liquid is in a volume The concentration is from about 2% to about 8%; the softened fish raw material is cooked at a temperature between 100 ° C and 140 ° C and between 1 kg / cm ² and 2 kg / cm ² for 8 minutes to 20 minutes to obtain a fish. a hydrolyzate; and centrifuging the fish hydrolysate to obtain a fish oil. The method of claim 1, wherein the fish material comprises a fin or a fish head. The method of claim 1, wherein the softened fish material is washed with water to remove the acid solution before the softened fish material is subjected to the retort treatment.