ANTI-OXIDANTS FOR USE IN THE PROTECTION OF EASILY OXIDIZABLE COMPOUNDS, AND A METHOD FOR THE PROTECTION OF EASILY OXIDIZABLE COMPOUNDS AND APPLICATION OF THE ANTI-OXIDANTS

Abstract: Anti-oxidants to protect easily oxidizable compounds in living and dead materials against oxidation, they are natural products, they are soluble in organic as well as acqueous solutions, they are preferably colourless and have no fluore­ scence, they have good flow properties, they have only faint smell and taste in the areas of concentration in question, and they contain primary and secondary amino-groups that are linked to carbon in aliphatic residue.

Description: The invention concerns anti-oxidants to be used for the protection of easily oxidizable compounds, especially polyunsaturated fatty acids, against oxidation. The anti-oxidants also have a growth-stimulating effect on fish, and may be used as an additive in feed. Polyunsaturated marine fatty acids have attracted medical and nutritional attention in recent years because of their ability to protect against heart disease and cancer. It is supposed that the high incidence of these diseases is largely due to defective nutrition, and that the risk may be reduced by a change of eating habits or otherwise by consuming enough of the nutritionally important polyunsaturated fatty acids. Polyunsaturated fatty acids and anti-oxidants are also of importance in the raising of domestic animals and in breeding. Fat is the cheapest source of energy in feed products, hence attempts are made to find diets containing a maximum of fats. Increasing the amount of fat does, however, increases the risk of rancidity. A balance must be found between the amount of fat it is desirable to add and the stability of the fat. In fish feed ethoxyquin is presently in use as an anti-oxidant. The compound is very effective, but is not allowed in foods for human consumption It is worrying for Norwegian fish farms that ethoxyquin has been traced in edible fish. Alternatives to ethoxyquin are not yet available. Anti-oxidants also prevent disease. For example, Norwegian fish farms lost between 100 and 200 million kroner in 1984, as a result of infection in farmed fish. It is supposed that the diseases are linked to poor feed quality, especially rancid fat. The present invention takes as its starting point the marked reduction in the stability of fatty acids in the presence of acid. Acid is produced when fat turns rancid, which gives a positive feed-back leading to an acceleration of the rancidity process. I have postulated that there exists a type of anti-oxidant which counteracts said process by neutralizing the acid. In order to fulfil their intended function, such anti-oxidants must have good fat-soluble properties, and they must be alkaline. Moreover, I have tried to find natural compounds of a known biochemistry. Attention has been centred on polyamines. Said compounds occur in all living organisms, and have a simple structure of primary and secondary amino-groups which can neutralize acid. Polyamines also have physical and chemical properties that render them useful for a number of product types: they are fat and water-soluble, they flow easily, they have no marked taste or smell, and they are colourless. The chemical structure of two natural polyamines is shown below: SPERMIDINE NH₂-CH₂-CH₂-CH₂-NH-CH₂-CH₂-CH₂-CH₂-NH₂ SPERMINE NH₂-CH₂-CH₂-CH₂-NH-CH₂-CH₂-CH₂-CH₂-NH-CH₂-CH₂-CH₂-NH₂ Thus, the invention concerns anti-oxidants which are to be used for protection of easily oxidizable compounds, especially polyunsaturated fatty acids, against oxidization, and which are naturally occurring compounds soluble in organic as well as acqueous solvents, and which are preferably colourless and have no fluorescence and only a faint smell and taste, said compounds being characterized in that they are spermine or spermidine. Furthermore, the invention concerns a method for the protection of easily oxidizable compounds, especially polyunsaturated fatty acids, against oxidization, the method being characterized in that the compounds are mixed with the above anti-oxidants. The above anti-oxidants can be used for oxidation protection of marine oils such as cod liver oil, capelin oil, and their concentrates, foodstuffs such as margarine, chocolate, dressings, meat and fish, feed products such as fish feed, feed for fur-bearing animals, poultry and domestic animals, cat and dog food, cosmetics such as lipstick, and skin creams, technical products such as lubricating oils, petrol, rubber and plastic, and pharmaceuticals. The effect of different polyamines has been tested. Table 1 shows the effect of some common anti-oxidants on capelin oil (from Mallotus villosus) containing 7% easily oxidizable polyunsaturated fatty acids (20:5, 22:6). The stability was investigated by means of an accelerated test, in which the oil was exposed to oxygen at a high temperature (100 o C). The induction time, being the time from the start of the experiment until a rapid increase in a rancidity parameter takes place, is a measure of the effect of an added anti-oxidant. The effects of different anti-oxidants given as % increase in induction time (protection factor) are shown in Table 1. Anti-oxidant 2mM Protection factor Blank 0.0 Vitamin E 133.3 BHA 142.9 Ascorbyl palmitate 723.8 Ethoxyquin 1090.5 Spermidine 2947.6 Spermine 3957.1 The anti-oxidative effect of 200 ppm polyamines on a 30% concentrate of 20:5/22:6 is shown in Table 2. The peroxide development was monitored over a 60-day period. The mean temperature was 26 o C. The analyses were grouped in 7 series (A,B,C,D,E,F and G). Series A Samples were stored in a fridge (4 o C), and samples were drawn from an unopened bottle once a week. Series B Samples were stored in the dark and at room temperature, and the material for analysis was taken from an unopened bottle once a week. Series C 1 sample was stored in the dark in an open bottle at room temperature. Samples were taken 3 times a week. The series D, E, F and G The samples were stored in the dark in a sealed bottle and at room temperature. After sample taking, the bottles were agitated 5 times and sealed. Series D has no anti-oxidant, series E contains 200 ppm TBHQ (tertiary butyl hydroxy kinon), to series F has been added 200 ppm octyl gallate. Series G contains 200 ppm spermine. The series C and D differ from each other in that C was open constantly, whereas D was opened 3 times a week and agitated. Measuring was performed 3 times a week. Series Temp. Conditions Open/sealed Anti-oxidant Oxidation rate A 4 SEALED -0.027 B 26 SEALED -0.177 C 26 OPEN 5.397 D 26 OPEN/SEALED 3.597 E 26 OPEN/SEALED TBHQ 3.414 F 26 OPEN/SEALED OCTYL GALLATE 3.210 G 26 OPEN/SEALED X 0.090 The investigation shows that spermine in open bottles gives the same protection as storage in sealed bottles. TBHQ and octyl gallate do not induce significant increases in stability. The anti-oxidative effect depends both on the type of polyamine and on its concentration (Table 3). On a molar basis, the effect of putrescine is not as favourable as that of spermine. The variation in effect corresponds closely to the number of amino groups in the various polyamines the tests were performed on 30% concentrate of 20:5/22:6. Oxygen exposure at 70 o C was used. The anti-oxidative effect of polyamines has been confirmed through examining the fatty acid profile at different times during the oxidation process. Table 4 shows the fatty acid profile of capelin oil, stabilized by 0.8 mM spermine, at 0, 24.5 and 28.5 hours. The oil was oxidized at 100 o C, and had an induction time of 24.5 hours. Fatty acid Composition after no. of hours % variation from t = 0 0 24.5 28.5 t = 24.5 t = 28.5 18:4 1.6 1.5 0.7 -6.3 -56.3 20:5 4.0 4.0 1.3 0.0 -67.5 22:6 2.1 2.1 0.5 0.0 -76.2 Stabilisation of polyunsaturated fatty acids in fish feed is regarded as a key to increased growth, good general condition and reduced mortality. The effect of spermine on char spawn is described below and in Table 5. The results are: 1. 200 ppm spermine in fish feed has no apparent negative effects on the fish. 2. Mortality is reduced from 4.5% in the monitor group to 1.1% in the pilot group. 3. The growth rate increases by 20% in the pilot group (Table 5). It is concluded that polyamines may be used in fish feed. The growth test was performed on 4 groups of char spawn. The total number of individuals was 332. The spawn was acclimatised over a 14-day period, during which time the temperature was increased gradually from 2.5 to 8.8 o C. During the acclimatisation period the spawn was fed EWOS ST40-2. The feed given to each of the groups was: A. Commercial EWOS ST40-2, stabilised with 200 ppm ethoxyquin. B. Freeze-dried capelin roe with added vitamins and minerals, but with no anti-oxidant. C. Freeze-dried capelin roe with added vitamins, minerals and 200 ppm ethoxyquin. D. Freeze-dried capelin roe with added vitamins, minerals and 200 ppm spermine. Example 1 Marine oils, such as capelin oil, cod liver oil, cod liver oil capsules and concentrates of polyunsaturated fatty acids are stabilised by adding the polyamines at a suitable stage of the production process. In the case of oils produced at low temperatures, the anti-oxidants may be added before boiling. The concentration of the additive will depend on (a) what improvement in stabilisation is desired, and (b) what is the upper limit for anti-oxidants approved by the Health authorities. Example 2 Foodstuffs such as margarine, chocolate and dressings are stabilised by adding the polyamines at a suitable stage of the production process. The antioxidants may be added either as an acqueous solution or mixed with oil. Example 3 Feed products such as fish feed and feed for fur-bearing animals are stabilised by adding the anti-oxidant at a suitable stage of the production process. The polyamines may be added to the raw materials (fish, fish offal, meat offal etc.) together with other water or fat-soluble additives. Example 4 Cosmetics (both water and fat-based) may be stabilised by mixing in the polyamines at a suitable stage of the production process. Example 5 Technological products such as petrol, lubricating oils, plastic, rubber and floating crystals are stabilised by mixing in the anti-oxidant at a suitable stage of the production process. In the case of polymer products, this may be before initiation is carried out. Example 6 Pharmaceuticals are stabilised by adding the polyamines in a concentration as stipulated by the Health Authorities. Polyamines may also be produced as separate pharmaceuticals and in suitable dispensary forms (tablets, retard tablets, solublets, pills, capsules, powders, granulates, mixtures, suppositories, injectabilia, infusion fluids, ampulles, dialytica, ointments, liniments, spray fluids etc.)

Claims: Anti-oxidants which are to be used for protection of easily oxidizable compounds, especially polyunsaturated fatty acids, against oxidation, and which are naturally occurring compounds soluble in organic as well as acqueous solvents, and which are preferably colourless and have no fluorescence, and which have only faint smell and taste, characterized in that they are spermine or spermidine. Anti-oxidants according to Claim 1, characterized in that they are growth factors for fish. A method for the protection of easily oxidizable compounds, especially polyunsaturated fatty acids, against oxidization, characterized in that the compounds are mixed with antioxidants according to Claim 1. A method for increasing the growth rate in farmed fish, characterized in that anti-oxidants according to Claim 1 are mixed into the feed. A method according to Claims 3 and 4, characterized in that the anti-oxidants are used in concentrations of 2-1,000 ppm.

Inventors: LOVAAS, ERIK
Applicants: SPAREBANKEN NORD-NORGE
Application year: 1986
Main classification: C09K15
IPC codes: A61Q17, C09K15, C11B5, A61K47, A23K3, A23L3, A61K8