JPH05331487A - Deodorization of fish oil and fish oil-containing food - Google Patents

Abstract

PURPOSE:To obtain a highly refined fish oil emitting little fishy smell even after the storage over a long period and utilizable as an oil-containing food such as mayonnaise and margarine by treating a fish oil with a porous polymer resin to remove the odorous component by adsorption. CONSTITUTION:A fish oil such as tuna oil refined by conventional refining process comprising deacidification, decoloration and deodorization steps is dissolved in n-hexane and passed through a column packed with a porous polymer resin to effect the adsorption of the polar substances in the solution to the resin. The fish oil remaining in the n-hexane solution as a non-adsorbed substance is passed through the column and the resin is washed by passing n-hexane through the column. The effluent liquid and the washing liquid are joined together, concentrated under reduced pressure and subjected to steam distillation under reduced pressure to remove the precursor substances for odorous component without deteriorating the chemical structure of the oil. The objective highly refined fish oil produced by this process emits little fishy smell even after the storage over a long period and is widely utilizable as foods containing oil and fat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing method for fish oil and a food containing the fish oil obtained by the deodorizing method.

[0002]

2. Description of the Related Art Fish oil contains ω-3 polyunsaturated fatty acids (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), which have recently been noted for their physiological effects.
It is expected that daily intake of it will prevent adult diseases. However, unrefined fish oil that has just been squeezed contains amines, fatty acids and carbonyl compounds, which give off a fishy odor characteristic of fish, which limits its use as edible oil.

Therefore, vacuum steam distillation and molecular distillation are available as means generally used for the purpose of deodorizing.
Various devices, conditions and ancillary means have been used to efficiently remove odorous components.

[0004]

However, although the deodorized fish oil thus obtained is almost tasteless and odorless immediately after refining, odorous components are formed again during the storage period to give a so-called back odor. Therefore, it cannot be used for oil-and-fat-containing foods that require a long shelf life for distribution. The cause of this returning odor is that non-volatile amines and carbonyl compounds that cannot be completely removed by distillation or the like generate odorous components over time. Since all of these amines and carbonyl compounds have polar groups, they can be adsorbed and removed by using an inorganic adsorbent such as silica gel, alumina, magnesium silicate or the like.

However, it is difficult to recycle the inorganic adsorbent, and it is troublesome to dispose of the inorganic adsorbent each time, resulting in a high cost. Moreover, the polyunsaturated fatty acid is contained in the fish oil to be processed, and the lipid peroxidation is likely to occur due to the catalytic action of the metal in the inorganic adsorbent. The present inventor has continued diligent research, and the fish oil obtained by adsorbing and removing the polar compound group, which is a precursor of these odorous components, using a porous polymer resin,
It was discovered that odor did not return during the subsequent storage period, and the present invention was completed.

[0006]

The first aspect of the present invention is a method for deodorizing fish oil, which comprises adsorbing and removing odorous components by treating fish oil with a porous polymer resin. 2 is a fish oil-containing food characterized by containing fish oil obtained by the deodorizing method of the present invention.

In the deodorizing method of the present invention, the fish oil purified through the conventional steps of deoxidation, decolorization and deodorization (vacuum steam distillation) is preferably 10 to 50%, preferably 20 to 30%.
Dissolve the non-polar organic solvent so that the concentration becomes%. The non-polar organic solvent is preferably a hydrocarbon solvent such as n-hexane, petroleum ether, cyclohexane or toluene. Next, this solution is passed through a column filled with a highly polar or medium polar porous polymerized resin to adsorb the polar compound group on the resin. After completion of passing the solution, the eluted solution is concentrated and subjected to vacuum steam distillation to obtain a tasteless and odorless highly purified fish oil.

The used resin does not need to be regenerated with an acid or a base, and can be repeatedly used by simply regenerating and washing it with a polar solvent such as methanol or acetone. Examples of the highly polar porous polymer resin used in the present invention include Amberlite IR-118B (manufactured by Rohm and Haas Company), Diaion WK-.
Acidic cation exchange resin such as 11 (manufactured by Mitsubishi Kasei Co., Ltd.), or Amberlite XAD-11, XAD-12.
Highly polar adsorbing resins such as those mentioned above can be preferably used, and examples of the medium polar porous polymerized resin include Diaion PA.
-306, WA-20, basic anion exchange resin, or Amberlite XAD-7, XAD-8, H
P-2MG (Mitsubishi Kasei Co., Ltd.) Duolite S-7
61 (manufactured by Chemical Process Company), KS,
A medium polar adsorbent such as HS (manufactured by Hokuetsu Carbon Co., Ltd.) can be preferably used.

Further, the fish oil obtained by the deodorizing method of the present invention is a fat and oil which can withstand long-term storage without the precursors of odorous components removed without impairing its chemical structure.
It can be widely used for oil and fat processed foods such as dressing, mayonnaise and margarine.

[0010]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples. (Example 1) Ordinary deoxidation, decolorization, and deodorization (vacuum steam distillation)
400 g of tuna oil refined through the process, 2 L of n-hexane
And then passed through a column filled with 200 ml of HP-2MG to adsorb and remove polar substances in the solution, and the fish oil was passed through the n-hexane solution as a non-adsorbed substance. After the passage of the liquid, 200 ml of n-hexane was passed through the column to wash the resin. The passing solution and the washing solution were combined and concentrated under reduced pressure, followed by vacuum distillation under reduced pressure to obtain 390 g of highly purified fish oil.

After the passage of the liquid and washing with n-hexane, the resin was regenerated by passing and washing with 800 ml of acetone and then with 600 ml of n-hexane. The thin layer chromatography of the fish oil obtained in this example is shown in FIG. As can be seen from Fig. 1, the raw fish oil (vacuum steam distillation deodorized fish oil) has a spot of polar impurities near the origin, but this has disappeared in highly refined fish oil, and polar substances have been removed. Table 1 shows the results of measuring nitrogen in this fish oil using a total nitrogen analyzer TN-05 (manufactured by Mitsubishi Kasei Co., Ltd.). According to this, the nitrogen content is significantly reduced compared to the raw fish oil, and the effect of adsorptive removal of amines is recognized.

[0012]

[Table 1]

Next, the generation of fish odor was observed for the re-deodorized product of this highly refined fish oil and the raw fish oil (normal vacuum steam distillation treatment product). 50 g of each sample was placed in a 100 ml sample bottle and sealed, and the degree of odor generation was observed with time at room temperature. The results are shown in Table 2.

[0014]

[Table 2]

(Example 2) Highly purified fish oil 42 obtained in Example 1
g, egg yolk 7 g, vinegar 5.5 g, water 41.3 g by stirring and emulsifying with a blender, add to this 0.4 g, corn starch
2.7 g and 1.1 g of salt were added, and the mixture was further stirred and mixed to obtain 100 g of fish oil-containing salad dressing. (Example 3) Tuna red meat was steamed at 105 ° C for 30 minutes and appropriately cut, 85 g was put in a can for cans having a diameter of 7 cm and a height of 3.6 cm, and 50 g of the highly refined fish oil obtained in Example 1 was added. After that, it is sealed with a vacuum wrapping machine and kept at 115 ° C in a retort at 60 ° C.
It was sterilized by heating under pressure for minutes to make canned tuna oil pickles.

[0016]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a fish oil that hardly produces fish odor even after long-term storage, and the fish oil according to the present invention can be widely used as an oil / fat-containing food.

[Brief description of drawings]

FIG. 1 is a diagram showing thin layer chromatography of fish oil.

Claims (2)

[Claims] 1. A method for deodorizing fish oil, which comprises adsorbing and removing odorous components by treating fish oil with a porous polymer resin. 2. A fish oil-containing food product, which contains fish oil obtained by the deodorizing method according to claim 1.