WO2002052960A1

WO2002052960A1 - Method and product for improving deteriorated or deteriorating quality caused by oxidation of fats in a material

Info

Publication number: WO2002052960A1
Application number: PCT/FI2001/001013
Authority: WO
Inventors: Simo Laakso; Pekka Lehtinen; Satu Lehto
Original assignee: Suomen Viljava Oy
Priority date: 2000-12-11
Filing date: 2001-11-22
Publication date: 2002-07-11
Also published as: EP1349462A1; FI115439B; FI20002711A; FI20002711A0

Abstract

The invention relates to a method and product for improving the deteriorated or deteriorating quality caused by oxidation of fats in a material, such as food. It is characteristic of the method and product of the invention that oats or oat fraction is added to the material, the oats or oat fraction having activity to remove volatile rancidity products of fats to convert the rancidity products generated in the oxidation of fats to poorly volatile compounds.

Description

Method and product for improving the deteriorated or deteriorating quality caused by oxidation of fats in a material

The present invention relates to a method and product for improving the deteriorated or deteriorating quality caused by oxidation of fats in a material.

For inhibiting oxidation of fats, it is traditional to use antioxidants, to carry out treatment, packaging and storing of the biological material by avoiding oxygenous conditions, or to attempt to make the treatment as fast as possible. Several antioxidant solutions have been developed for the inhibition of oxidation of anhydric oils and fats, with which the stability of materials can be improved. Part of the used antioxidants are natural products, part are synthetic. For example, tocopherol is a natural product, and BHT (butylated hydroxy-toluene), for example, is synthetic. Depending on the use, there are various legislative restrictions for the use of such antioxidants, and adding permissible antioxidants to edible products gives rise to in- creasing critical debate on their effects on health. Typical compounds used for stabilising aqueous mixtures are vitamin E, i.e. tocopherol, vitamin C, i.e. ascorbic acid, and combinations of these. Attention is also being paid to their possible side effects to an increasing extent.

The patent specification WO 90/00015 discloses a method for controllably adding an antioxidant, such as BHA, BHT or TBHQ, into cooking oil for reducing oxidation and rancidity. The patent specification GB 618 409 discloses the use of norhy- droguaiarate acid as antioxidant to prevent rancidity. Crude cottonseed oil is used as antioxidant in the patent specification GB 415 205, and hydroquinone in GB 930 752. The patent specification US 5 395 634 discloses the use of a food-grade anti- oxidant and a non-oxidising gas in the cooking of a food product for reducing or preventing the oxidation of fats and annihilation of vitamins. In the patent specification US 5 753 283, rice bran is stabilised against rancidity by using an anti-lipase enzyme. The patent specification GB 973 535 discloses the use of a flexible, transparent film for preventing the product from rancidity.

In the patent specification GB 451 340, glyceride oils and fats are protected against oxidation or rancidity by infusion with cereal grain, such as barley, oats or maize. The cereals are removed from the oil before it is used.

The patent specification GB 474 597 discloses a method, in which material containing solid matter and fat is protected against rancidity by coating its surface with flour of an oil-containing seed. Such seeds are seeds of wheat, oats, rye, barley and the like.

In the patent specification US 6 113 964, porous, proteinaceous material, for example oats, is used for removing undesired components from a liquid, such as coffee or wine, or gas, such as cigarette smoke. Undesired components, such as caffeine, tannin or nicotine, are removed by adsorption to the pores of a proteinaceous material.

It is common to the known antioxidant solutions and other above shown solutions that they either slow down the oxidation of fats or offer protection against the oxidation of fats for a limited time. Already a very slight oxidation of fats, which hardly is perceptible by even the most modem measuring instruments, is however sufficient to produce small molecular weight, volatile oxidation products of fats to the extent that they have a detrimental effect on taste and smell, or to affect negatively the structures of proteins. The used antioxidants cannot affect the drawbacks, which are generated when the fats have had time to become oxidised before the antioxidants have been added. By coating the material with flour, it is again not possible to eliminate the oxidation inside the product, but the effect is local and directed to the surface of the material.

Thus, because the oxidation of fats cannot be completely prevented even by the best existing methods, there is a need for new solutions, with which these secondary oxi- dation products of fats can be eliminated from the whole product without them having a detrimental effect on the other properties of the material to be protected.

The method and product of the invention are characterised in what is defined in the characterising part of the independent claims.

As fats oxidise, hexanal is formed, which is the principal cause for the detrimental effect on taste and smell and health hazards in the products. Oats can remove the generated hexanal considerably more efficiently than other varieties of grain even when the hexanal amounts are so low that no other methods are known for its re- moval. Oats convert hexanal into other compounds, mainly hexanoic acid so that it no longer can be released from oats when heating even to the temperature of 95°C; thus the method of the invention works in manufacturing processes which include heat treatments and in which fats are easily oxidised. Thus, oats can be added to materials exposed to the oxidation of fats, in which case the biologically active components of oats remove the rancidity products that are generated in the oxidation of fats and that are most easily found to be detrimental. In such mixtures, for example, the release of hexanal can no longer be observed. In ad- dition, it is possible to remove rancidity products that have already gathered into the material due to the oxidation of fats. For achieving the desired effect, oats can be added before the processing, during or after the processing, and to already finished products.

The method of the invention is very simple, because it essentially only comprises the adding of oat material to dry or aqueous material. According to the invention, it is possible to use either the fraction of oats that most effectively eliminates the rancidity products, or the fraction(s) that are best suited for the purpose of use due to the cost or other properties, or powder ground from a whole kernel, or a whole kernel.

In the method and product of the invention, biologically active oats are used. In this connection, the term "biologically active" refers to that oats or a fraction isolated from oats has not been inactivated so that the activity discharging volatile rancidity products of fats would have disappeared.

The biological activity of oats can be detected, for example, so that the hexanoic acid generated and/or hexanal vanished is determined from a mixture of hexanal standard and oats in a measuring flask. For example, the methods mentioned below or other methods known for those skilled in the art can be used as measuring methods.

Achieving the effect according to the invention, i.e. eliminating the concentration of rancidity products exceeding the human identification threshold, requires only a very small amount of oat material. The amount needed depends, for example, on what kind of fraction of oats is used, or whether whole flour is used. In the tests explained below, the concentrated protein fraction of flour has been found to be a very efficient fraction removing the rancidity products. Further, the amount of oats needed depends on the composition of the subject, and on the handling method and handling conditions. In addition, the amount needed depends on the exposure time, i.e. if the oat material can stay in contact with the material to be protected for a sufficiently long time, a smaller amount is enough to achieve the effect. On the other hand, more oat material is needed, if the exposure time is short. A short time may be the case, for example, if one wants the oat material to affect before the temperature is raised so high that the biological activity of oats is destroyed. Thus, when necessary, so small amounts of oats can be used that they do not bring with them properties and side effects typical of oats, such as grain-like properties. For achieving the desired effect, even 0.5 % by weight of oat flour or even 0.1 % by weight of protein fraction of oats can be a sufficient amount. On the other hand, more oats can be added and still achieve the effect according to the invention, while simultaneously utilising other good properties of oats, which have been given below. A preferable amount can be, for example, 10 % by weight.

According to the invention, oats or oat fractions can be mixed with foods for improving their quality and preservability, or used for raw materials or during manu- facture to prevent the rancidity caused by the oxidation of fats. Further, according to the invention, oats or oat fractions can also be used for non-food purposes, for example, as deodorizing agents in health and sanitary products and cosmetic manufactures, as components in packaging materials and in paper coatings, i.e. generally in uses in which rancidity cannot be completely prevented, for example, by using tradi- tional antioxidants.

Oats are a material that is easily available, that further is inexpensive and non- perishable. It also is a traditional food material, which does not contain any known health risks. The industrial processing of oats is relatively simple, and many different fractions can be separated from them with well-known techniques.

In addition to the removal of rancidity products, adding oats and oat fractions to foods also increases the nutritional value of foods. Oat material increases the amount of soluble and insoluble nutrient fibre and healthy polyunsaturated fat in food, its protein composition is advantageous, and the vitamin concentration high. Oats also have antiallergenic properties. Oats have a better viscosity formation abil- ity than other cereals, so that they act, for example, as binding agent, plasticizing agent, moisture detention agent and lubricant.

The invention is next explained in more detail, referring to examples and figures illustrating advantageous embodiments.

Figure 1 presents the absorption of hexanal in aqueous solution to flours of different cereals.

Figure 2 presents the release of hexanal at different headspace temperatures from a mixture of oat flour and water and from a mixture of oat flour and water supplemented with hexanal. Figure 3 presents the ratios of releasing hexanal and pentylfuran in mixtures of oat flour and water (samples 2 and 4), and in mixtures of flour and water supplemented with hexanal (samples 1 and 3). The incubation time for samples 1 and 2 was 6 hours, and the incubation time for samples 3 and 4 was 24 hours.

Figure 4 presents the amount of hexanal releasing from the mixture of flour and water supplemented with hexanal at different headspace temperatures with an auto- claved and not autoclaved oat flour.

Figure 5 shows the ability of oats and their different fractions to remove externally supplied hexanal.

Figure 6 shows the formation of hexanoic acid and 1-hexanol from hexanal added to oat flour with different incubation times.

Figures 7a-e present the influence of oat flour on the amount of volatile compounds after the "cooking" of meatballs as a function of storage time; a) hexanal, b) pen- tanal, c) octanal, d) 1-hexanol, e) pentylfuran.

Figure 8 shows the amount of volatile compounds in a meatball dough and in a cooked dough.

Figure 9 shows the ability of oat flour, a whole kernel and husks to remove externally supplied hexanal.

Example 1

The better ability of oats to remove hexanal than that of other cereals becomes evident from measurements, in which 0.033g of freshly ground grain was mixed with 0.4ml of aqueous solution of hexanal, with the hexanal concentration of lOppm. The mixture was closed into a hermetically sealed measuring flask, and the equilibrium concentration of hexanal was observed in the gas phase of the measuring flask as the function of time. By comparing the thus measured hexanal concentrations with the control concentrations, which were obtained when the measuring flask contained the respective amount of mere aqueous solution of hexanal, it was possible to calculate the differences in the ability of cereals to prevent the release of hexanal to the gas phase.

The measurements were carried out by using a static HP7694 Headspace injector (Hewlett-Packard Company, USA), which was connected to an HP5890 SERIES II gas chromatograph. The HP5971A mass selective detector was used as detector. The sample was placed into a hermetically sealed measuring flask and stabilised in the oven of the injector at 60°C for 25 minutes. After this, a sample was injected from the gas phase of the measuring flask to the gas chromatograph, in which the column was HP-5MS. The run began with the temperature of 40°C for four minutes. After this, the temperature of the oven was raised by 20°C a minute linearly until the temperature was 200°C. Finally, the temperature was kept at 200°C for five minutes. The total run time was 17 minutes. The hexanal in the gas phase of the sample was identified, and its concentration was determined by the mass fragments 56 and 44.

The hexanal solution was prepared by pipetting 0.1ml of hexanal into 99.9ml of mil- liQ water, i.e. deionised water. The mixture was dispersed by a Janke & Kungel homogenizer with full power for 30 seconds. The obtained base solution was lOOOppm in relation to hexanal, and the dilutions used in the tests were prepared from this. Of the obtained solution, a solution of lOppm was prepared by pipetting 1ml of the base solution into 99ml of milliQ water and dispersed as above for 10 seconds.

Figure 1 shows the ability of flours produced from different cereals to remove hexanal as the function of time. The method described above has been used in the measurements. It can be seen from Figure 1 that the oat varieties Neli (with husk) and Lisbeth (without husk) remove hexanal clearly faster than the other examined cereals. Also the significance of exposure time for the needed amount of flour can be concluded from Figure 1. If the exposure time is longer, a smaller amount of flour is sufficient, when again a shorter exposure time requires a larger amount of flour for achieving the same effect.

Table 1 also shows the ability of flours produced of different cereals to remove hex- anal by using the method described above.

Table 1 The ability of different cereals to remove hexanal in a closed measuring flask.

It can be seen from Table 1 that flours manufactured of both the oat varieties re- moved hexanal at first with a double speed compared to rye flour, which was the next most effective. The differences between oats with husk and oats without husk are small. The oat flours removed hexanal almost totally (90%) in 64 minutes, as with the next most effective rye flour, the time was about 1.5 times longer. The removal with oat flours was complete (>99%) in about 110 minutes.

Thus, oat flours were clearly more effective removers of hexanal than flours manufactured of other typical cereals.

The ability of oat flours to remove hexanal can be thought to be dependent on the time the oats are kept ground before they become into contact with hexanal. Likewise it can be thought that the time the flour is in contact with hexanal can have an influence on to which extent removed hexanal is returned. For finding out these matters, flours were allowed to age in a closed vessel at room temperature before hexanal was added (flour age in days). The contact times between hexanal and flours were varied within large limits, and the contact was allowed to take place at room temperature (20°C) (incubation time in hours). Table 2 shows how the concen- tration of hexanal decreased in the gas phase of the closed measuring flask at a temperature of 60°C (removal percentage). The mixture was then heated at a temperature of 95°C for one hour to possibly release the vanished hexanal from the oat flour, and the concentration of hexanal was measured again in the gas phase at the temperature of 95°C (permanently removed hexanal, in %). The initial concentration of hexanal was lOppm in 0.4ml of water, and the amount of flour was 0.033g.

Table 2 The effects of the oat flour age and the contact time for freshly ground flour and hexanal on the ability of the flour to remove hexanal

It can be seen from Table 2 that the flour age or the contact time between flour and hexanal had no influence on the ability of the flour to remove hexanal. Further, it can be seen from Table 2 that oat flours that had removed 99% or more of the supplied hexanal, returned only a very small share of the hexanal they had removed when the samples were heated at 95°C for one hour before carrying out the measurements at 95°C. Depending on the sample, 87.0 - 98.5% of the given hexanal (10 ppm) had been removed permanently. Also at this temperature, the flour age or the removal time of hexanal cannot be observed to have any correlation as to how permanent the removal of hexanal is.

However, it can be observed from Table 2 that flour that was heated at the temperature of 95°C released somewhat more hexanal than flour heated merely at 60°C. The result could refer to that the treatment of flour at a high temperature might in some situations lead to the return of the hexanal already removed. For explaining this a mere aqueous mixture of oat flour (0.033 g flour in 0.4 ml of water) and the respective amount of mixture, to which 10 ppm of hexanal was first absorbed, were heated side by side at 60, 80 and 95°C for three hours, and the released hexanal was determined as above. Figure 2 shows that the samples treated with hexanal released somewhat more hexanal than the mere flours. However, the amount only corre- sponds to 15% of the external hexanal absorbed into the sample. Likewise the samples, into which no hexanal was absorbed, also released hexanal at higher temperatures. Thus, only a slight part of hexanal observed in the heat treatment (95°C) can have originated from the externally added hexanal. Hexanal, which was released at the temperature of 95°C, can thus have been generated for a large part as a result of the oxidation of fats during the heating situation. In the oxidation of fats, hexanal and pentylfuran are formed in a constant relation with each other. A flour sample releasing hexanal bound to it externally, thus gives a different ratio of hexanal to pentylfuran from a flour sample only releasing hexanal that is formed in it during heating. This was tested by closing two samples of the same size of mixtures of oat flour and water (0.033 g flour in 0.4 ml of water) into a measuring flask so that 10 ppm of hexanal was mixed with the other mixture as before. The mixtures were allowed to stay at room temperature for 6 and 24 hours, after which they were heated at the temperature of 100°C for one hour. Figure 3 shows the proportional headspace responses of pentylfuran and hexanal, of which the samples 1 and 2 had been incubated for six hours at room temperature and the samples 3 and 4 for 24 hours. Hexanal was added to the samples 1 and 3 in the way described above. Figure 3 shows that the flour mixtures supplemented with hexanal gave practically the same ratio of hexanal and pentylfuran as the mere mixture of oat meal and water. On the basis of Figures 2 and 3, it can thus be concluded that oat flour releases only a very small amount or nothing at all of the externally supplied hexanal already removed by it once.

Example 2 Use of autoclaved oat flour

Oat flour was autoclaved at 120°C and a pressure of 2 bar for 15 minutes. 0.4 ml of aqueous solution of hexanal (10 ppm) was then mixed with 0.033 g of flour, and the mixture was incubated as in Example 1 for three hours. After this, the amount of releasing hexanal was measured at the headspace temperature of 60, 80 and 90°C. Figure 4 shows the hexanal removed by the autoclaved flour in relation to the externally supplied hexanal. When comparing the amount of hexanal removed during three hours to the hexanal removed by the unautoclaved flour in Figure 1, it can be concluded that the main part of the oats' ability to remove hexanal is due to biological activity.

Example 3 Use of the protein fraction of oats for removing rancidity products

Fresh oat flour was processed into fibre, starch and protein fractions. Oat flour (65 g) was mixed with water (210 ml). The suspension was mixed with a blade mixer for 14 minutes in a water bath (15°C). The suspension was homogenised in an ice bath by using Ultra-Turrax homogeniser (Janke & Kungel) for one minute. The mixture was washed with 400 ml of distilled water in a continuous centrifugal juicer (AEG). The material left in the refuse part of the juicer formed the fibre fraction, and the mixture of protein and starch was recovered from the juice part. The fibre fraction was further washed with 200 ml of distilled water for removing residue protein and starch. The washing water was combined with the protein-starch mixture. The protein-starch mixture was screened by using a screen of 90μm for removing fine fibres. The fibre remaining on the screen formed the fibre fraction which was still washed with 100 ml of distilled water, and the washing water was combined with the protein-starch mixture. The protein-starch mixture was centrifugated (10 000 rpm, 20 minutes, Sorvall RC5B) so that the protein and starch fractions separated as different layers. The lowermost layer formed the starch fraction, the uppermost layer the protein fraction. The protein fraction was recovered by scraping from top of the starch layer. The fractions were frozen and freeze dried.

The ability of each fraction to remove hexanal was compared with the respective ability of unfractioned flour. The measuring conditions and mixture proportions were as described in Example 1. It can be seen from Figure 5 that the efficiency of the protein fraction to remove hexanal is even slightly better than that of oat flour. The efficiency of the starch fraction is approximately similar to that of whole oat kernels. The efficiency of the fibre fraction is between the protein fraction and the starch fraction. The fibre fraction contains about 15 % by weight of protein, which in its part probably explains its efficiency.

On the basis of fractioning and related measurements it can be concluded that the properties of oats removing the rancidity products are essentially due to the properties of their biologically active protein fraction.

Example 4 Bioconversion of hexanal

Aqueous solution of hexanal (0.4 ml) was mixed with 0.033 g of biologically active oat flour, as described in Example 1, and the mixtures were allowed to stand in closed headspace flasks for different lengths of times. The headspace responses were measured at 60°C as the function of incubation time for hexanal, 1-hexanol. Hexanoic acid was extracted with n-hexane from a flour-water mixture supplemented with hexanal, methylated with a known method (Suutari M., Liukkonen K., Laakso S., Temperature adaptation in yeasts; the role of fatty acids, J. Gen. Micro- biol. 135, 1469-1474, 1990), and hexanoic acid was determined gas chromato- graphically as methyl ester by using HP 5890 Series II gas chromatograph. The column was HP-FFAP (15 m), running temperature was 45°C, of which the temperature was raised by 25°C/min to 200°C. The ranning time was 20.2 minutes. It can be seen from Figure 6 that hexanal is mainly convered to hexanoic acid, and to a slight extent to 1-hexanol. It can be concluded from Figure 6 and the observation in Ex- amples 1 - 3 that the vanishing of hexane is essentially due to the biological activity of oats, which converts hexanal to more poorly volatile odourless compounds.

Example 5 Cooking and preservation test of minced meat

Minced meat of pork and beef (40/60 %) containing 13% fat and flour freshly ground from Neli oats were used in the test. Doughs were prepared from the materials with the following mixture proportions:

- minced meat 100 g, water 0.5 dl (50 g) (1)

- minced meat 100 g, water 0.5 dl and oat flour 20 g (2)

The doughs were prepared by mixing with Moulinex Multitrio mixer and cooking in a microwave oven as plates of 10 cm x 10 cm x 1cm with full power for 2.5 minutes. The doughs were prepared separately by avoiding the standing, drying and excess oxidation of the dough. The cooked dough was minced by using the mixer mentioned above. The mixture was weighted into measuring flasks 1.0 ± 0.01 g, the flasks were closed and kept at room temperature. The headspace measurements were carried out at three day intervals at stabilising temperatures of 60°C and 100°C according to the method described above.

Figures 7a-e show the concentrations of compounds typically caused by the oxidation of fats in a measuring flask as the function of storage time. It can be seen from the Figures that the manufactures containing only minced meat and water differ de- cidedly from the manufactures supplemented with oat flour especially during 0 - 3 days.

In the manufactures containing only minced meat, the concentrations of hexanal, pentanal, octanal, hexanol and pentylfuran are high immediately at the beginning of the storage, when the measuring temperature is 100°C. The concentrations decrease as the function of time, with the exception of the hexanol concentration. Measured at the temperature of 60°, respectively, the concentrations of these compounds are lower, but the changes during the storage follow the same profiles that were obtained at the higher temperature.

In manufactures supplemented with oat flour, the responses of hexanal, pentanal and octanal are very low or completely below the measuring accuracy right at the beginning of the preservation test and at the measuring temperature of 100°C. Further, the concentrations stay at a stable level all through the storage. Respectively, the amounts of hexanol and pentylfuran are high at the beginning of the storage, which indicates that hexanal has formed during the manufacture, but it has been removed and convered partly to hexanol by the oat flour. The manufactures supplemented with oat flour release practically no rancidity products measured at the temperature of 60°C.

Thus, it can be concluded that oats reduce the concentration of hexanal formed in the processing, and also remove other aldehydes forming in the rancidity.

Example 6 The influence of oat flour on rancidity products releasing from uncooked meat dough and during cooking

Meat dough and meat dough supplemented with oat flour were prepared and the doughs were cooked as in Example 5. Before and immediately after cooking, the concentrations of hexanal, pentanal, heptanal and 1-ρentanol were determined at 60°C as is shown in Example 1. It can be seen from Figure 8 that raw meat dough without oats releases slight amounts of hexanal and 1-pentanol at the temperature of 60°C which cannot be observed at all when the dough contains oat flour. Cooking causes a strong formation of hexanal in the mere minced meat dough. Likewise, the formation of pentanal and slight amounts of 1-pentanol and heptanal can be observed. As the amount of oat flour mentioned in Example 5 was added to the dough before cooking, hexanal is released only less than 9% of the amount that is released due to the cooking of the mere meat dough. Respectively, adding oat flour during cooking caused pentanal, 1-pentanol and heptanal to disappear completely.

Thus, oat flour can eliminate the principal rancidity products generated in food raw materials and their cooking.

Example 7 Use of whole kernels and husks for removing rancidity products

Hulls and husks were removed from whole, unbroken Neli oat kernels by tweezers and being careful not to damage the surface of the kernel. A sample of 0.033 g of the fresh flour prepared from the hulls and husks (later husks) and unpeeled kernels was weighed into separate measuring flasks, and 0.4 ml of hexanal with the concen- tration of 10 ppm was added to the measuring flask. Respectively, whole, peeled oat kernels and aqueous solution of hexanal were closed into the measuring flasks in the same proportions as before. The removal of hexanal was observed as the function of time as decrease in headspace response at measuring intervals of one hour. It can be seen from Figure 9 that also husks and whole kernels without husks removed hex- anal, and the removal was carried out by these approximately at the same speed. 50% of hexanal (10 ppm) were removed within about four hours, and in case of husks, 90% were removed in about nine hours. Within the limits of the measuring accuracy, the kernels without husks could not be observed to form 1-hexanol. In- stead, husks formed slight amounts of hexanol, as about 90% of hexanal had been removed. The slight formation of 1-hexanol may be an indication of microorganisms associated to the husks.

However, the ability of husks and a whole kernel without husk to remove hexanal was essentially lower than that of oat flour.

It can be concluded from the results that the ability to remove hexanal found in oat flour is also slightly apparent in whole oat kernels and husks of the kernel.

Claims

1. Method for improving the deteriorated or deteriorating quality caused by oxidation of fats in a material, characterised in that oats or oat fractions are added to the material, the oat or oat fraction having activity to remove volatile rancidity products of fats, to convert the rancidity products generated in the oxidation of fats to poorly volatile compounds.

2. Method according to claim 1, characterised in that oats or oat fraction are thoroughly mixed to the material so that they are distributed substantially ho- mogenically to the whole material.

3. Method according to claim 1 or 2, characterised in that the oats are flour ground from kernels with or without husks.

4. Method according to claim 1 or 2, characterised in that the oat fraction is a protein fraction.

5. Method according to one of the claims 1 - 4, characterised in that the mate- rial is food.

6. Method according to claim 5, characterised in that the food is meat.

7. Product for improving the deteriorated or deteriorating quality caused by oxidation of fats in a material, characterised in that the product contains oats or oat fraction, the oats or oat fraction having activity to remove volatile rancidity products of fats, to convert the rancidity products generated in the oxidation of fats to poorly volatile compounds.

8. Product according to claim 7, characterised in that it further optionally includes liquid and filler agents.

9. Method according to any of the claims 1 - 6 or product according to any of the claims 7 or 8, characterised in that hexanal and other aldehydes are converted to acids with the help of oats or oat fraction.

10. The use of oats or oat fraction, the oats or oat fraction having activity to remove volatile rancidity products of fats, to improve the deteriorated or deteriorating quality caused by oxidation of fats in a material.