JPH04248896A - Method for suppressing oxidation of oil and fat - Google Patents

Abstract

PURPOSE:To provide a new method for suppressing the oxidation of oil and fat. CONSTITUTION:Oxidation of oil and fat can be effectively suppressed by adding a superoxide dismutase and casein sodium to the aqueous phase of an O/W-type emulsion.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides an oil-in-water emulsion whose oil phase is composed of fatty acids including polyunsaturated fatty acids, in which the aqueous phase contains superoxide dismutase (hereinafter abbreviated as SOD). By coexisting with sodium caseinate, the active oxygen scavenging activity of SOD is dramatically increased, and by suppressing the oxidative deterioration of unsaturated fatty acids caused by active oxygen, the physiological activity of unsaturated fatty acids can be effectively utilized in foods, etc. This is a novel method for suppressing oxidative deterioration of oils and fats that can be used for

0002

BACKGROUND OF THE INVENTION Recently, as the physiological activities of polyunsaturated fatty acids have become clearer, oils and fats containing them have been attracting attention. For example, perilla oil containing α-linolenic acid, evening primrose oil containing γ-linolenic acid, fish oil containing EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), and polyunsaturated fatty acids produced by microbial fermentation. There are oils and fats. However, these oils and fats containing polyunsaturated fatty acids easily generate peroxides when exposed to light or catalysts, and this decomposition causes autoxidation reactions, which are radical chain reactions, to progress, easily causing quality deterioration. Therefore, it was extremely difficult to use it in actual food form.

[0003] Further, in order to suppress this oxidative deterioration, many antioxidants have been investigated, and tocopherols are commonly used at present. Tocopherol is excellent not only in its antioxidant properties but also in safety. Among them, α-tocopherol in particular has physiological effects as vitamin E and is an excellent antioxidant. However, although tocopherol has excellent effects in oil, it is also known that it acts as an oxidation promoter in systems where water coexists (JAOCS57:225 (1)
980), JAOCS 61:1212 (1984)
), it is not expected to be very effective as an antioxidant in emulsified foods where water and oil coexist.

[0004] Although spices have been studied as having antioxidative effects in emulsification systems, their effects have not reached a practical level with oils and fats that contain a large amount of polyunsaturated fatty acids; There is no method to suppress the oxidation reaction.

As a method for solving this problem, a method has recently been reported that uses the enzyme SOD, which has active oxygen scavenging activity, to suppress the oxidation of fats and oils. For example, a method found in JP-A-60-1295 has been shown to inhibit the oxidation reaction of ricinoleic acid, a fatty acid.
J. Agric. Food Chem. 1989, 3
7, 23-28, linoleic acid and the like have been studied.

However, in these experimental examples, the enzyme S
The active oxygen scavenging activity of OD is not fully expressed, and S
The amount of OD added to the fatty acid was large, and if the method was to be applied to fats and oils containing polyunsaturated fatty acids, the amount added would have to be further increased, creating a problem in actually applying it to foods.

In addition, as shown in Example 1 of the present invention, there is a problem in that an oil-in-water emulsion in the presence of an emulsifier (sugar ester/lecithin) has only a slight oxidation inhibitory effect on polyunsaturated fatty acids. there were.

[0008]

[Problem to be solved by the invention] The problem to be solved is to sufficiently express the active oxygen scavenging ability of SOD, which is an in vivo enzyme, in food form, and to suppress the oxidation of fats and oils containing polyunsaturated fatty acids. By doing so, it is possible to effectively utilize the physiological activity inherent in polyunsaturated fatty acids in foods and the like.

[0009]

[Means for Solving the Problems] The present inventors have discovered that the active oxygen scavenging activity of SOD is significantly improved by coexisting sodium caseinate in the aqueous phase of an oil-in-water emulsion, and have completed the present invention. It has arrived. That is, the present invention provides an oil-in-water emulsion in which SO is added to the aqueous phase.
This is a method for suppressing the oxidation of fats and oils, which is characterized by coexisting D and sodium caseinate. Using the method of the invention,
The purpose of using the active oxygen scavenging ability of SOD in foods to suppress the oxidative deterioration of fats and oils containing polyunsaturated fatty acids is achieved using a simple method without impairing the characteristics of foods such as taste, color, and odor. It was realized. The present invention will be explained in more detail below.

It is well known that polyunsaturated fatty acids are easily oxidized by light, metal catalysts, heat, etc., but in the initial reaction, active oxygen species such as super

[0011] SOD is also called superoxide dismutation enzyme (
EC1.15.1.1. ), is known as an enzyme that catalyzes the disproportionation reaction of the superoxide anion radical, and suppresses the oxidation reaction of lipids, etc. in vivo (
(according to Enzyme Handbook). In addition, SOD exists widely in the living world, and depending on the type of living thing, it may contain iron, manganese, copper, etc.
Although it has a metal such as zinc as its active center, it is known to exhibit the same activity regardless of the type of metal.

[0012] The SOD used in the present invention is not particularly limited in its origin; for example, those obtained from bovine red blood cells and liver, or those obtained from microorganisms such as yeast and bacteria can be used. can.

[0013] In the present invention, the amount of SOD added varies depending on the type and content of polyunsaturated fatty acids in the fat and oil, but is generally 5 to 100 units/g, preferably 10 to 50 units/g of the fat. A corresponding amount may be added to the aqueous phase forming the oil-in-water emulsion.

[0014] As sodium caseinate to be coexisted with SOD used in the present invention, commercially available sodium caseinate can be used as is, and the amount added is 0.01% to 10%, based on the aqueous phase forming the oil-in-water emulsion. Preferably 0.
It may be added in an amount of 1% to 3%. Although excessive addition of sodium caseinate does not inhibit SOD activity, excessive addition is not preferable in view of bacterial contamination.

[0015] As the fats and oils containing polyunsaturated fatty acids, α
- Perilla oil containing linolenic acid, evening primrose oil containing γ-linolenic acid, fish oil containing EPA/DHA, and fats and oils containing polyunsaturated fatty acids produced by microbial fermentation, and concentrated polyunsaturated fatty acids from them. However, there are no particular restrictions on these oils and fats, such as safflower oil, rapeseed oil, etc., which are generally used as edible oils.
There is no problem in using soybean oil or the like.

In order to produce an oil-in-water emulsion, an oil or fat containing a polyunsaturated fatty acid may be emulsified into an oil-in-water emulsion in an aqueous solution containing an emulsifier, sodium caseinate, and SOD. There are two ways to add SOD: the above-mentioned method in which it is dissolved in the aqueous phase before emulsification treatment, and the method in which it is added after emulsification treatment.In the latter case, adding enzyme powder directly to the emulsion results in uniform dispersion. May be difficult to dissolve;
In this case, it is preferable to dissolve SOD in distilled water or a buffer solution in advance and add it to the emulsion.

The emulsifier used in the present invention is not particularly limited in type, but sucrose fatty acid esters, polyglycerin fatty acid esters, lecithin, sorbitan fatty acid esters, etc., which are usually approved as food additives, can be used alone or in combination. Bye. There is also no particular restriction on the amount of emulsifier added, but it is usually 0.1 to 5.0 to the emulsion.
It may be added in an amount of 0.4 to 3.0% by weight, preferably 0.4 to 3.0%. Examples of the present invention will be described below, and it will be clarified that the oxidation of fats and oils containing polyunsaturated fatty acids shown in the examples is significantly suppressed by SOD in the presence of sodium caseinate. Of course, the present invention is not limited to the examples.

[0018]

[Example] Example 1 When preparing an oil-in-water emulsion, using stearic acid sugar ester (HLB = 11) as an emulsifier, the difference in the antioxidant power of SOD between a system with and without sodium caseinate added. I saw it. For the oil phase component of the emulsion, purified fish oil obtained from sardines containing EPA and DHA, which are polyunsaturated fatty acids, was used. Furthermore, the EPA
- The total DHA content was 21%. distilled water 20
0g of stearic acid sugar ester as an emulsifier
After adding 2 g of sodium caseinate and heating and stirring to fully dissolve the mixture, the mixture was cooled to room temperature, and 4000 units (20 units/g of oil) of purified powder SOD obtained from cow liver was added and dissolved with stirring. 200 g of the above fish oil was added dropwise to this enzyme aqueous solution while stirring to perform preliminary emulsification, and then emulsified into an oil-in-water emulsion using a high-pressure homogeneous emulsifier. Separately, among the above-mentioned preparation conditions, the same method was used to prepare a sample without the addition of both sodium caseinate and SOD, a sample without the addition of only SOD, and a sample without the addition of only sodium caseinate (Table 1 ). These four emulsified solutions were stored in a dark place at 35°C, and the oil and fat components were extracted and removed with a mixed solvent of chloroform and methanol, and then the peroxide value was measured to determine the oxidation rate. The results are shown in Table 2.

[0019]

[Table 1]

[0020]

[Table 2]

[0021] Table 2 shows the change in peroxide value over time, and when comparing Comparative Examples 1-1 and 1-3, the antioxidant effect was not so significant despite the addition of the enzyme SOD. Not yet. However, in Example 1 in which sodium caseinate was added to the enzyme SOD, the oxidation reaction did not substantially proceed at all, indicating that the enzyme activity was significantly increased by the addition of sodium caseinate. The reason why the oxidation rate is slightly lower in Comparative Example 1-2 than in Comparative Example 1-1 is probably because sodium caseinate itself also has an antioxidative effect.

Example 2 Next, an oil-in-water emulsion was prepared in the same manner as in Example 1 except that the emulsifier stearic acid sugar ester was replaced with lecithin, and the effect of adding sodium caseinate on SOD activity was examined. As in Example 1, as comparative examples, sodium caseinate and SOD were not added, SO
Three samples were prepared using the same method, one with no addition of D and one with only sodium caseinate removed (Table 3). Table 4 shows the change in peroxide value over time.

[0023]

[Table 3]

[0024]

[Table 4]

When lecithin was used as an emulsifier, SOD enzyme activity was not expressed at all unless sodium caseinate was added (Comparative Example 2-3). Considering that in Example 1, in which sugar ester was used as an emulsifier, a slight antioxidant effect was observed even in the system without sodium caseinate, it is clear that the expression of SOD activity is greatly influenced by the emulsification state. It is. However, as shown in Table 4, even when lecithin is used as an emulsifier, addition of sodium caseinate makes it possible to express enzyme activity and completely suppress the oxidation reaction.

Example 3 Next, the effect of changing the amount of SOD added was examined. The amount added is 5 units/oil, no SOD added. g, 10 units/oil. g, 20 units/oil. I did it with g. The oil and fat used were 200 g of purified sardine oil, and the aqueous phase component was 200 g of distilled water with 4 g of sodium caseinate and 2 g of lecithin added. The preparation method was the same as in Example 1, and the oxidation inhibiting effect was examined in the same manner. The results are shown in Table 5.

[0027]

[Table 5]

As shown in Table 5, a significant effect was observed in the SOD-added group. Especially SOD10 units/oil. The effect was significant when adding more than 1 g.

Example 4 The effect of adding SOD was examined using perilla oil containing α-linolenic acid as the fat and oil to be emulsified. Perilla oil was extracted by pressing and treated with a silica gel column, and the neutral oil fraction was collected and used for the test. The emulsifier and preparation were carried out in the same manner as in Example 1, and the amount of SOD added was 20 units/oil. It was set as g. As a comparison, Table 6 shows the results for perilla oil itself that is not emulsified and for perilla oil in an emulsified solution without addition of SOD or sodium caseinate.

[0030]

[Table 6]

Table 6 shows that emulsified perilla oil tends to be slightly more susceptible to oxidation than perilla oil itself when only the emulsifier sugar ester is used;
The product to which D and sodium caseinate were added did not undergo any oxidation, indicating its high effectiveness.

Example 5 Next, SOD of microbial origin was used for comparison with SOD obtained from bovine liver. The origin of microorganisms is the yeast Saccharomyces cerev.
isiae var. ellipsoidus A
J. from TCC560. Agric. Food Che
m. 1989, 37, 23-28 was used. Preparation of emulsified solution is as in Example 1.
Using the same fat and oil raw materials and emulsifier, the amount of SOD added was 10
Unit/Oil. The same method was used except that the temperature was changed to g. As a comparative example, SOD obtained from bovine liver was tested under the same conditions. The results are shown in Figure 7, and the SOD of microbial origin showed a higher antioxidant effect despite the same number of added units.

[0033]

[Table 7]

[0034]

As explained above, the present invention improves the activity of superoxide dismutase by coexisting superoxide dismutase and sodium caseinate, which is inexpensive and does not impair the characteristics as a food, in the aqueous phase of an oil-in-water emulsion. By dramatically increasing oxygen scavenging activity and suppressing oxidation of fats and oils, there is an advantage that the physiological activity originally possessed by polyunsaturated fatty acids can be effectively utilized in foods and the like. Actual foods that are in the form of oil-in-water emulsions include dressings, mayonnaise, cream, and artificial milk, and until now it was impossible to add these products due to oxidative deterioration of polyunsaturated fatty acids. It can also be applied to other foods without deteriorating quality such as flavor.

Claims (1)

[Claims] 1. A method for inhibiting oxidation of fats and oils, which comprises coexisting superoxide dismutase and sodium caseinate in the aqueous phase of an oil-in-water emulsion.