JPH07274826A - Tuna and/or bonito eye socket fatty oil reduced in fish smell - Google Patents

Abstract

PURPOSE:To provide the tuna and/or bonito eye socket fatty oil having specific physical properties, containing highly unsaturated fatty acids such as docosahexatrienoic acid in a considerable amount, and suitable as a food raw material, a medicinal raw material, etc. CONSTITUTION:This tuna and/or bonito eye socket fatty oil has physical properties comprising: (i) the concentration of docosahexaenoic acid contained in the fatty acid residues of the fatty oil is 25-38%, (ii) the concentration of eicosapentaenoic acid contained in the fatty acid residues of the fatty oil is 2-8%, and (iii) the content of the trans isorners is >=4%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to tuna and / or bonito orbital fat with reduced fishy odor. Since the tuna and / or bonito orbital fat of the present invention has a reduced fish odor and returning odor, and contains a considerable amount of highly unsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), It is useful as an oil and fat material for general foods and medical foods.

[0002]

BACKGROUND OF THE INVENTION Oils and fats are one of the three major nutrients in foods, along with proteins and carbohydrates, and play an important role as an energy source. In the Japanese, the ratio of fat energy to total energy in the diet Is currently about 25%. In addition, fats and oils are also important constituents of the living body, and it has been reported that various symptoms and disorders appear when the intake of fats from food is deficient.

Fats and oils are fatty acids 3 in the glycerol skeleton.
The molecule has an ester-bonded structure, and its properties and role in the living body are greatly influenced by the type and combination of fatty acids. Of these fatty acids, many of the polyunsaturated fatty acids have useful physiological functions in vivo for themselves or their metabolites. For example, deficiency of linoleic acid and α-linolenic acid causes symptoms such as skin abnormalities, diminished tissue regeneration ability, and increased susceptibility to disease infection, and these fatty acids are not synthesized in vivo and are ingested from the diet. It is considered an essential fatty acid because it must be present.

Along with these essential fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)
Is a polyunsaturated fatty acid, which has been attracting attention in recent years because it is said to be effective in the prevention and treatment of cardiovascular diseases and other adult diseases. And especially the decrease in platelet aggregation,
Effects on the blood circulation system such as lowering blood cholesterol, lowering blood sugar level, therapeutic and preventive effects on lowering hepatic triglyceride and rheumatism, lowering the incidence of various malignant tumors, immunomodulating effects on atopy, asthma, hay fever, etc. Furthermore, recently, as the actions that have been attracting attention, actions related to the nervous system such as improvement and improvement of learning function and memory ability, suppression of dementia, improvement of visual acuity or suppression of deterioration have been reported [[Development and application of functional lipids "Supervised by Kiyotaka Sato et al., CMC" Food and Development "August 1992 issue, published by Kenko Sangyo Shimbun.

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which have been reported to have various physiological functions as described above, are present in fats of many fishes and whales. These contents differ depending on their parts or the place and time of catch. Eicosapentaenoic acid (EPA) is found in the fats of small fish such as sardines and horse mackerels, and bonito, tuna, marlin,
It is known that fats of large fish such as amberjack and shark contain a large amount of docosahexaenoic acid (DHA), respectively [Handbook of Oil and Fat Chemistry, 4th Edition].

Among these fish species and whales, especially the body fat of tuna and bonito contains a large amount of highly unsaturated fatty acids.

[0007] Tuna, which belongs to the genus Scombridae of the Perciformes mackerel family and whose Latin name is Thunnus, contains 20 to 30% of docosahexaenoic acid (DHA) and 3 to 10% of eicosapentaenoic acid (EPA). This tuna is distributed over almost all tropical and temperate waters,
It is called [English], Thon [French], Thun [German], etc. and is the target of fishing. The total catch of tuna in Japan was about 340,000 tons (1992), and
Currently importing 250,000 tons [1993 edition, Food / Production / Import / Consumption (Fisheries / Fisheries Processed Products), Food Distribution Research Association, 1993]. Above all, bigeye tuna and yellowfin tuna are large in both catch and import.

A skipjack belonging to the genus Scombridae skipjack of the order Perciformes and having a Latin name of Katsuwonus contains 20 to 25% of docosahexaenoic acid (DHA) and 5 to 10% of eicosapentaenoic acid (EPA). . This bonito is distributed almost all over the tropical and temperate waters, and Sk
ipjack, Bonito (UK), Bonite, Listao (France), Bonito
It is called [German] and is subject to fishing. The catch in Japan is about 320,000 tons (1992), and about 30,000 tons is also imported [FY1993 version, food / production / import / consumption (fisheries / fisheries Processed products) ”, published by Food Distribution Research Association, published in 1993].

Further, highly unsaturated fatty acids, especially docosahexaenoic acid (DHA), are present in a very high concentration in the orbital fat, which is the fat existing behind the eyeballs of tuna and bonito. The polyunsaturated fatty acid content of these orbital fats varies depending on the fish species, catching area, and catching time, but in orbital fat of skipjack tuna and skipjack orbital fat,
Docosahexaenoic acid (DHA) is present at 30-43% and eicosapentaenoic acid (EPA) is present at 4-10%. The orbital fat collected from the tuna or skipjack is usually obtained by removing the water-soluble fraction from the oil by a treatment such as acid treatment, degumming, deoxidation and the like.

On the other hand, fragrance is an important factor for food materials. Generally, fish oil is docosahexaenoic acid (DH
A) is a fat and oil with a high utility value that contains a considerable amount of highly unsaturated fatty acids such as A) and eicosapentaenoic acid (EPA), but because it has a unique odor (fish odor), it can be used as a food material. Are limited. This also applies to tuna orbital fat and skipjack orbital fat.

At present, removal of fish odor is attempted by adsorption on activated carbon, activated clay, diatomaceous earth, etc., molecular distillation, or steam distillation. However, tuna orbital fat and bonito orbital fat that have been subjected to such deodorization, or foods containing these orbital fats produce fishy odor during storage. This fish odor is generated mainly by oxidative deterioration of highly unsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). As odorous components, nonadienal, decatrienal, Aldehydes such as hexenal and heptenal and ketones such as octadienone have been reported [Karahadian and Linsay, J. of Am. Oil Chemist
s' Society, Vol.66, no.7, p.953, 1989].

With respect to tuna orbital fat and skipjack orbital fat, the removal of these odorous components and the suppression of their generation are important issues. As described above, adsorption to activated carbon, activated clay, diatomaceous earth, molecular distillation, or Attempts have been made to remove fishy odor by steam distillation. However, tuna orbital fat and skipjack orbital fat treated by these methods also produce fishy odors during storage. Therefore, vitamin E, ascorbic acid and its derivatives, lecithin, and other various antioxidants are used for oxidation. At present, it is essential to suppress deterioration.

On the other hand, as fish oil stabilized by reduction treatment, hardened fish oil made from sardine oil or mackerel oil has been conventionally produced, and has a melting point of 20 to 45 ° C, preferably 35 ° C or higher. It is said that fish oil is easy to use as a food material [Oil and oil handbook, supervised by Yoshiro Abe, published by Sachi Shobo]. However, in such a hydrogenated fish oil, the highly unsaturated fatty acid contained in the fish oil is reduced and disappears. Therefore, among currently available hardened fish oils, docosahexaenoic acid (DHA) and eicosapentaenoic acid (E
PA) is not contained or only a slight amount remains. This situation was similar in the case of orbital fat of tuna and skipjack orbital fat.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its purpose is to be a useful food material because it has many physiological activities, but it produces a peculiar odor. Therefore, it is difficult to use as a food material, or the use of tuna orbital fat and bonito orbital fat, whose use is limited, reduces the generation of fish odor and also causes docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The present invention provides tuna and / or bonito orbital fat containing a large amount of highly unsaturated fatty acids such as).

In order to achieve the above object, the inventors of the present invention performed a reduction treatment of tuna and / or bonito orbital fat and conducted a preservation test thereof. As a result, the generation of fish odor was significantly suppressed and it was excellent. It has been found that it exhibits excellent flavor stability. Then, based on this result, as a result of extensive studies, tuna and / or skipjack containing a considerable amount of highly unsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) while reducing the generation of fish odor. Finding reducing conditions for producing orbital fat,
The present invention has been completed.

[0016]

The fish odor-reduced tuna and / or bonito orbital fat of the present invention can be obtained by subjecting tuna and / or bonito orbital fat obtained from tuna or bonito to a reduction treatment. it can. The tuna orbital oil used as a raw material is tuna ( Perciformes mackerel Scombridae
(Tuna) Use the one that has been oiled from the back of the eyeball.
In addition, bonito orbital fat is bonito (Perciformes Scomaceae Scom
The oil extracted from the back of the eyeball is used.

Tuna with reduced fish odor according to the present invention and / or
Alternatively, the reduction treatment performed to obtain bonito orbital fat is performed in the presence of a catalyst, and examples of the catalyst that can be used here include nickel catalysts such as reduced nickel, nickel formate, Raney nickel, nickel boride, lithium aluminum hydride, and hydrogenation. Examples thereof include sodium boron, a metal catalyst composed of platinum, palladium, iron, copper, and the like, and a lanthanum-based or calcium-based hydrogen storage (storage) alloy. These catalysts are appropriately selected and used according to their catalytic activity and required reaction conditions.

Next, the procedure of the reduction process will be described.
First, orbital fat obtained from tuna or bonito and a catalyst selected appropriately are injected into a reaction container. The ratio of the orbital fat to the catalyst varies depending on the catalyst species used, and is therefore determined according to the catalyst species used. Further, the orbital fat and the catalyst do not necessarily have to be injected together into the reaction container, and the catalyst may be injected after the orbital fat is injected first to reach a predetermined condition, or vice versa. Do not mind. Further, the reaction vessel is preferably a pressure resistant type and equipped with a stirring device, but the shape and size thereof are not particularly limited, and may be a batch type or a continuous type. Absent.

The orbital fat and the catalyst supplied to the reaction vessel are sufficiently degassed and dehydrated by performing depressurization operation (5 torr or less) while stirring. If the orbital fat to be used is sufficiently dehydrated, it is not always necessary to perform this depressurization operation. After this operation is completed, the reaction container is heated to a predetermined reaction temperature. This reaction temperature range varies depending on the catalyst species used, so it is determined according to the catalyst species used. Then, when the temperature reaches the predetermined reaction temperature, hydrogen gas is supplied to the reaction container as necessary to start the reduction reaction.

After a lapse of a predetermined time from the start of the reduction reaction, the stirring is stopped, and when hydrogen gas is used, the hydrogen gas is removed from the reaction vessel, or depending on the catalyst species used, The reduction reaction is stopped by adding water, acid, or alkali. Further, when using a reaction container capable of rapid temperature control, the temperature of the orbital fat in the reaction container is rapidly reduced to 50 ° C or less, preferably 10
It is also possible to stop the reduction reaction by cooling to below the temperature.

After that, the reduced orbital fat is taken out from the reaction container. At that time, it is preferable to cool the orbital fat to 20 ° C. or lower in order to avoid oxidative deterioration. Then, impurities such as catalyst and water are removed from the orbital fat taken out from the reaction container. As a method for removing these, filtration operation is effective for removing solids. When performing this filtration operation, activated clay or diatomaceous earth may be used as a filter aid, if necessary. In addition, activated clay or diatomaceous earth may be mixed with an adsorbent such as silica gel or florisil. On the other hand, in order to remove water, it is easy to carry out vacuum drying, but freeze drying or a dehydrating agent may be used.

By carrying out such an operation, the tuna and / or bonito orbital fat of the present invention having a reduced fishy odor can be obtained, but if necessary, a deodorizing operation such as steam distillation may be carried out. Absent. The obtained orbital fat is preferably stored in a refrigerator after adding an antioxidant and blowing an inert gas in order to prevent oxidative deterioration during storage.

By this reduction treatment, the above-mentioned fishy odor components contained in the tuna orbital fat and bonito orbital fat and their precursors are reduced, isomerized or decomposed to be converted into chemical components which do not generate fishy odor. Therefore, the generation of fish odor is reduced, but a considerable amount of highly unsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) remains. The tuna and / or bonito orbital fat with reduced fish odor of the present invention contains docosahexaenoic acid (DHA) in the range of 25 to 38%, and eicosapentaenoic acid (EPA) in the range of 2 to 8%. It is contained in the range of. Further, the trans isomer content of the tuna and / or bonito orbital fat of the present invention with reduced fishy odor is 4%.
As described above, the orbital fat was sufficiently stabilized.
On the other hand, normal tuna orbital fat and skipjack orbital fat
Almost no positional isomer, trans isomer content of 1
It was 2% or less. The trans isomer content was determined by the Japan Oil Chemistry Association, standard oil and fat analysis test method 2.4.24.
, Or Official and Tentative Methods of the
American Oil Chemists' Society, Official Method
Performed according to Cd 14-61.

If necessary, the tuna and / or bonito orbital fat of the present invention having a reduced fish odor can be mixed with other edible oils or fats, or the tuna and / or bonito orbital can be used in advance. It is also possible to produce a tuna and / or bonito orbital fat of the present invention with reduced fish odor by mixing the fat with other edible oils and fats and then subjecting the mixture to a reduction treatment.

Furthermore, the tuna and / or bonito orbital fat of the present invention having a reduced fish odor was subjected to a preservation test and sensory evaluation was conducted.
It was confirmed that the flavor was also excellent. Therefore, the tuna and / or bonito orbital fat with reduced fish odor of the present invention is suitable for use as a food material, and drinks such as milkshake, coffee drink, lactic acid bacteria drink, ice cream, jelly, mousse, It is useful as a raw material for all types of foods such as desserts such as yogurt, miso, meat, fish products, milk powder, cheese food, dairy products such as fat spreads and baby food, and can also be used as a raw material for pharmaceuticals. . Further, by using the tuna and / or bonito orbital fat with reduced fish odor of the present invention, the addition amount of the antioxidant that was conventionally used to ensure the flavor stability of the tuna orbital fat and bonito orbital fat was used. Can also reduce its use. Hereinafter, the present invention will be described in more detail with reference to examples.

[0026]

Example 1 Purified tuna orbital fat (DHA: 35.5%, E
PA: 7.2%, trans isomer content: 1.4%) 500g was charged into a reaction vessel (2l) and reduced nickel catalyst 0.50g (0.
10% by weight) was added. After degassing and dehydration operations with stirring to 5 torr or less, the hydrogen pressure was 3 kg.
The reduction reaction was performed at 130 ° C. for 10 minutes in an atmosphere of / cm ² . Then, hydrogen gas was removed from the reaction vessel to stop the reduction reaction, cooled to 20 ° C. or lower, and then treated with activated clay to obtain 378 g of orbital fat of the present invention with reduced fish odor. In addition,
The tuna orbital fat had a DHA content of 29.3% and an EPA content of 4.9%. The trans isomer content is
It was 6.3%.

Next, a preservation test was conducted on the refined tuna orbital fat used as a raw material and the tuna orbital fat obtained in this example. 50 g of each orbital fat was placed in a glass lidded container having a volume of 100 ml, 20 mg of tocopherol was added as an antioxidant, and the mixture was stored in an oven kept at 50 ± 1 ° C. to perform a forced deterioration test. The sensory evaluation was carried out by 10 trained professional panelists, and the strength and preference of fish odor were evaluated according to the criteria shown in Table 1.

[0028]

[Table 1] ──────────────────────────────────── Evaluation point Fish odor intensity Preference ── ────────────────────────────────── 0 Not feeling at all Very bad 1 Almost not feeling Bad 2 Slightly feeling slightly Bad 3 Feels odor Neither 4 Feels slightly stronger Good 5 Feels stronger Very good ───────────────────────────────── ────

Table 2 shows the results for each tuna orbital fat subjected to the forced deterioration test, using the average value of the evaluation scores of all the panelists as the sensory evaluation score.

[0030]

[Table 2] ──────────────────────────────────── Fish odor strength Preferability Oils and fats ── ───────────────────── Day 0 Day 3 Day 0 Day 3 ───────────────── ─────────────────── Refined tuna orbital fat 0.9 2.9 4.1 3.3 Tuna orbital fat of the present invention 0.6 1.5 4.5 3.9 ───────────── ───────────────────────

The tuna orbital fat of the present invention had a weak fishy odor intensity from day 0 of storage as compared to the purified tuna orbital fat, and was highly evaluated for its favorableness. Further, even on the 3rd day of storage, the generation of fish odor was suppressed in the tuna orbital fat of the present invention, and the favorable evaluation was also high.

[0032]

Example 2 Purified skipjack orbital fat (DHA: 36.5%, E
PA: 9.8%, trans isomer content: 1.7%) 300g was charged into a reaction vessel (1l) and Raney nickel catalyst 0.15g.
(0.050% by weight) was added. And 5 while stirring
After performing deaeration and dehydration operations so that the pressure was not more than torr, a reduction reaction was performed at 110 ° C. for 30 minutes in an atmosphere having a hydrogen pressure of 4 kg / cm ² . After that, hydrogen gas was removed from the reaction vessel to stop the reduction reaction, cooled to 20 ° C. or lower, and then treated with activated clay to obtain 225 g of skipjack orbital fat of the present invention with reduced fish odor. The DHA content of skipjack orbital fat was 30.3%, E
The PA content was 7.6%. The trans isomer content was 7.5%.

Next, a storage test was carried out on the purified skipjack orbital fat used as a raw material and the skipjack orbital fat obtained in this Example. Each skipjack orbital fat 50g 100ml capacity
Was placed in a glass container with a lid, 20 mg of tocopherol was added as an antioxidant, and the mixture was stored in an oven kept at 30 ± 1 ° C. to perform a forced deterioration test. The sensory evaluation is
The test was carried out by 10 trained professional panelists, and the strength and the liking of fish odor were evaluated in the same manner as in Example 1 according to the criteria shown in Table 1. The results are shown in Table 3.

[0034]

[Table 3] ──────────────────────────────────── Fish odor strength Preferability Oils and fats ── ───────────────────── Day 0 Day 10 Day 0 Day 10 ────────────────── ─────────────────── Refined skipjack orbital fat 1.0 3.6 4.0 2.2 Skipjack orbital fat of the present invention 0.7 2.5 4.4 3.4 ───────────── ───────────────────────

The bonito orbital fat of the present invention had a weak fishy odor intensity from day 0 of storage and was highly evaluated as compared with the purified bonito orbital fat. Further, even on the 10th day of storage, the fish odor was suppressed from being generated in the skipjack orbital fat of the present invention, and the favorable evaluation was also high.

[0036]

Example 3 200 g of purified tuna orbital fat (DHA: 35.5%, EPA: 7.2%, trans isomer content: 1.4%) that had been sufficiently deaerated and dehydrated was dissolved in 500 ml of hexane to prepare a reaction vessel (2 l). ), And the palladium catalyst (Pd-CaC
10 g of O ₃ ) was added. Then, the reduction reaction was carried out for 1 hour at room temperature (25 ° C.) in a hydrogen atmosphere of 1 kg / cm ² . afterwards,
After removing the orbital fat from the reaction vessel and removing the catalyst by filtration, hexane was removed by drying under reduced pressure, and the tuna orbital fat of the present invention was treated with activated clay to reduce the fish odor.
149g was obtained. The tuna orbital fat had a DHA content of 32.5% and an EPA content of 3.3%. The trans isomer content was 7.6%.

Next, the refined tuna orbital fat used as a raw material and the tuna orbital fat obtained in this Example were mixed with soybean oil, and a storage test was conducted. The DHA content and the EPA content in the refined tuna orbital fat and the tuna orbital fat obtained in this example were mixed with soybean oil so that the DHA content was 10.0% in the mixed oil. Put 50 g of each mixed oil in a 100 ml glass container with a lid,
Tocopherol 20mg is added as an antioxidant, and 50 ± 1
The sample was stored in an oven kept at ° C and subjected to a forced deterioration test. The sensory evaluation was conducted by 10 trained professional panelists, and Table 1 shows the intensity and preference of fish odor.
The same procedure as in Example 1 was performed according to the criteria shown in. The results are shown in Table 4.

[0038]

[Table 4] ──────────────────────────────────── Fish odor strength Preferability Oils and fats ── ────────────────── Day 0 Day 14 Day 0 Day 14 ───────────────────── ──────────────── Refined tuna orbital fat mixed oil 0.9 2.7 4.1 3.0 Tuna orbital fat mixed oil of the present invention 0.6 1.6 4.4 3.6 ───────────── ────────────────────────

The tuna orbital fat mixed oil of the present invention had a weak fishy odor intensity from day 0 of storage and was highly evaluated as compared with the refined tuna orbital fat mixed oil. Further, even on the 14th day of storage, the generation of fishy odor was suppressed in the tuna orbital fat mixed oil of the present invention, and the favorable evaluation was also high.

[0040]

Example 4 Purified tuna orbital fat (DHA: 36.0%, E
PA: 7.0%, trans isomer content: 1.4%) and purified skipjack orbital fat (DHA: 34.5%, EPA: 8.9).
%, Trans isomer content: 2.1%) to 50 by weight
Mixed fat mixed in a ratio of 50 (DHA: 35.3%, EP
A: 7.8%, trans isomer content: 1.8%) (500 g) was charged into a reaction vessel (1 l), and 0.5 g (0.10% by weight) of a reduced nickel catalyst was added. Then, after degassing and dehydrating operations with stirring to 5 torr or less, the hydrogen pressure was 3 kg / c.
The reduction reaction was performed at 130 ° C. for 15 minutes in an atmosphere of m ² . Then, hydrogen gas was removed from the reaction vessel to stop the reduction reaction, cooled to 20 ° C. or lower, and then treated with activated clay to obtain 380 g of the fish odor-reduced tuna and skipjack orbital fat of the present invention. In addition, DHA of this tuna and bonito orbital fat
The content was 27.9% and the EPA content was 4.3%. The trans isomer content was 6.8%.

Next, a preservation test was carried out on the refined orbital fat of tuna and bonito used as a raw material and the orbital fat of tuna and bonito obtained in this Example. 50 g of each oil and fat prepared by adding corn oil so that the DHA content of tuna and bonito orbital fat would be 25% was put in a 100 ml capacity container with a glass lid, and 20 mg of tocopherol was added as an antioxidant. The sample was stored in an oven kept at ± 1 ° C and subjected to a forced deterioration test. The sensory evaluation was carried out by 10 trained professional panelists, and the fish odor intensity and preference were evaluated in the same manner as in Example 1 based on the criteria shown in Table 1. The results are shown in Table 5.

[0042]

[Table 5] ──────────────────────────────────── Fish odor strength Preferability Oils and fats ── ────────────────── Day 0 Day 5 Day 0 Day 5 ──────────────────── ──────────────── Purified orbital fat mixed oil and fat 1.0 3.4 4.0 2.8 Orbital fat mixed oil and fat of the present invention 0.6 1.8 4.3 3.7 ────────────── ──────────────────────

The tuna and bonito orbital fat of the present invention comprises
Compared with the refined orbital fat of tuna and bonito, the fish odor intensity was weak from the 0th day of storage, and the preference for it was high. Also,
Even on the 5th day of storage, the generation of fish odor was suppressed in the tuna and bonito orbital fat of the present invention, and the favorable evaluation was also high.

[0044]

INDUSTRIAL APPLICABILITY The tuna and / or bonito orbital fat with reduced fish odor according to the present invention produces less fish odor which has a sensory adverse effect, and moreover, docosahexaenoic acid (DH).
Since it contains a large amount of highly unsaturated fatty acid such as A) and eicosapentaenoic acid (EPA), it is suitable for use as a food material and can also be used as a pharmaceutical material.

Claims (1)

[Claims] 1. Tuna and / or bonito orbital fat with reduced fishy odor having the following characteristics: (1) The concentration of docosahexaenoic acid (DHA) contained in the fatty acid residues of fats and oils is in the range of 25 to 38%. (2) The eicosapentaenoic acid (EPA) concentration contained in the fatty acid residue of the oil is in the range of 2 to 8%. (3) The trans isomer content is 4% or more.