NO137071B - PROCEDURES FOR MANUFACTURING A MARGAR FAT. - Google Patents

Description

The invention relates to a method for

position of a margarine fat suitable for use in butter-

only foodstuffs.

Margarine is essentially a plastic, spreadable substance

product where an aqueous phase, often containing milk or milk solids, is emulsified in an edible fat. The consistency of margarine and similar products, in which slightly smaller amounts of fat may be mixed, largely derives from its fat composition. This can include several components, usually including liquid and solid fat components.

In the production of margarine and other spreadable fat-emulsion foods, the properties of naturally occurring fats and glyceride oils have been modified using various techniques, including hardening and interesterification, in order to satisfy the critical requirements for the product. Possibly the most stringent requirement of these is the provision of good melting properties to achieve a cool, buttery melting of the product in the mouth, i.e. in an area with body temperature, approx. 35°C, while ensuring that the product at ambient temperature, i.e. approx. 20°C, retains sufficient volume so that it can be spread well.

These properties are in relation to the dry matter content of the margarine fat at the relevant temperatures and can be determined using the stabilized dilations of the oil to be discussed below.

In the applicant's French patent document no. 1,598,070, a fat product is described which is suitable for the production of margarine, comprising a liquid fat component and a hard fat component, both of these components satisfying specified requirements, where only the hard fat component is randomized and is saturated. In the applicant's Swedish patent document no. 352,520, margarine fat mixtures are described which comprise an interesterified base fat which is usually mixed with an additional fat, but neither the base fat nor the resulting mixture satisfies the combined requirements of the present invention. Among other publications, it can be mentioned that British patent no. 832,377 is limited to products containing at least 50% saturated fatty acids, and British patent no. 820,269 is limited to those where palmitic acid is not the main saturated fatty acid. British patent no. 927,534 fails to disclose the combined claims made by the present invention for a maximum of 40% saturated fatty acids including palmitic acid as the main part. The result is either a too low content of trans acid or too much stearic acid is present,

according to the method used in the manufacture of the products to which the patent relates. Similar to what is stated regarding British Patent No. 832,377, British Patent Nos. 903,141 and 1,212,720 are limited to products containing 30% or more of un-interesterified fat.

Based on all the above-mentioned publications, the expert in the field could not arrive at the object of the present invention, which constitutes a significant contribution to the state of the art by using significant amounts of palmitic acid for margarine fat compositions.

The invention therefore relates to a method for the production of a margarine fat which is suitable for use in spreadable foods, the method being characterized by the following steps: a) corandomization, at a temperature of from 50 to 100°C, of a mixture which essentially consists of of

25-65% by weight of a palmitic acid fat with 75-35% by weight of a C, ,-C,D vegetable oil in the practical absence of

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water and in the presence of an effective amount of an alkali metal catalyst; and b) partially curing at least one of the components of the mixture in the presence of an effective amount of a metal hydrogenation catalyst under isomerization conditions, and continuing said steps until the total fatty acid content of the glycerides in the mixture consists of 3-15% trans-acid and at most 35% saturated fatty acid, of which palmitic acid predominates, as these amounts are given by weight of the total fatty acid content and its dilatation value at 20°C is at least 275 and at 35°C at most 90.

The palmitic fat used in the method according to the invention contains at least 25% palmitic acid and is preferably a vegetable oil, e.g. palm oil or cottonseed oil, although animal fats, e.g. tallow and lard can be used. Preferably, practically all of the margarine fat is interesterified, but additional small amounts, ie up to 20%, but preferably up to 10%, of non-interesterified components may also be present.

The trans acid can be introduced either by the palmitic fat

or of the vegetable oil. For this purpose, the fat or oil is modified by a method which involves the isomerization of part of the unsaturated acid content. This can conveniently be carried out by means of light hydrogenation, especially in the presence of a selective catalyst which hydrogenates polyunsaturated acids, especially linolenic acid, without significantly increasing the saturated fatty acid content of the hydrogenated fat or oil. It is particularly well suited to carry out the isomerization by partial hydrogenation, in the presence of a selected catalyst, of soybean oil, which is made more stable against destruction by the hydrogenation of significant amounts of linolenic acid normally present in this oil. trans-

the acid may be trans-oleic acid, trans-palmitoleic acid or trans,trans-linoleic acid.

The mixing, interesterification and isomerization/hydrogenation steps of the method according to the invention can be carried out in any order. For example, a polyunsaturated, liquid, vegetable oil can first be easily hydrogenated by an increase in JT of e.g. 5-30, for introducing a sufficient amount of trans acid into the oil to provide at least 3% in the final margarine fat, and the modified liquid oil is then mixed and interesterified with the palmitic fat. Alternatively, the palmitic acid itself can be readily hydrogenated to provide the required trans acid, mixed and interesterified with the liquid vegetable oil. In a third method, the two main components can be mixed together, interesterified and easily hydrogenated to provide the trans acid.

With the help of the invention, a significant proportion -

as much as 60% or more, by weight of the total fat content - of palm oil is incorporated into margarine without resulting in the excessive post-crystallization tendency which characterizes palm oil itself.

The invention is very useful for providing

of margarine fat containing from 25 to 65% palm oil, but particularly suitable margarine fat is provided by the invention with a content of palm oil, corandomized with an approximately equal number of parts of liquid vegetable oil. With higher proportions of palm oil, it becomes very difficult to achieve a suitable consistency.

Suitable liquid oils with which the palm oil or other palmitic fat can be interesterified include soybean oil, melon seed oil, peanut oil, safflower oil, sunflower oil and corn oil. Such oils can also be used without interesterification in smaller quantities in the method according to the invention, and as additive oils, apart from C, r , 0 sources, lauric oils and C22 oils, e.g. rapeseed oil, is used in connection with the invention.

Soybean oil is particularly preferred for use in the method according to the invention as the liquid vegetable oil which is corandomized with the palm oil. In the production of soft margarines, i.e. table packing margarines that can be spread straight from the fridge, it is desirable to avoid a product that appears oily at normal ambient temperatures, e.g. about. 20°C. By providing a margarine which meets this requirement while containing as much as .50% or even more of palm oil, and by avoiding slow melting which gives an unpleasant taste, soybean oil is satisfactory and inexpensive. It can be easily cured before use in connection with the invention to improve resistance to off-flavor development and to provide the source of trans acids as other liquid vegetable oils used in connection with the invention can. Vegetable oils that are semi-solid, e.g. coconut oil, can provide the corandomized mixture with palm oil or other palmitic fat for carrying out the invention, although they are used in small quantities such as for additive oils in the interesterified mixtures according to the invention.

The consistency of margarine can be expressed by the penetration value and the expansion value in the range of its melting point.

Expansion values express the dry matter content of the fat. The fat in soft margarines exhibits expansion values at 10°C of 500-550, which corresponds to a dry matter content of 20-22%, and at 20°C of approx. 275, i.e. 11% dry matter. With the soft margarines provided according to the invention, a relatively smooth temperature/solids content curve is possible, in which the expansion value even at 30°C is at least 90, equivalent to 3.6% solids content, while the expansion at 35°C is not is more than 90, which gives a satisfactory "mouth feel".

Full description of the method for determining dilation values is given in J. Am. Oil Chem. Soc., (1954), 31, pp. 98-103.

The margarine's consistency can also be expressed using the penetration or C values. These are obtained by measuring the penetration depth in mm x 10 in margarine after 5 seconds, using a cone which is turned upside down and loaded with an 80 gram weight and with a blunt end with a conical angle of 40°. Based on this measurement, the penetration value is obtained according to the following equation:

where k is a function of the cone angle. The difference in consistency at 5°C and 20°C should be represented in the products according to the invention by means of a drop of approx. 300 units or more. Provided that a value of 800 units is not significantly exceeded at 5°C, the product will also be able to be lubricated straight from the household fridge. See J. Am. Oil Chem. Soc., 1959 (36) page 345, Haighton. on the other hand, low values may reflect excessive oiliness in the product.

These penetration and dilatation properties are provided in the products according to the invention by means of a meticulous selection of the vegetable oils and their proportions in which the palm oil or other palmitic fat can be interesterified.

In the margarine fats according to the invention, such liquid, vegetable oils are preferred in practically equal proportions corandomized with palm oil, which without significant change in the dilation of the mixture after the interesterification nevertheless improves the penetration values noticeably. Soybean oil, both hydrogenated and non-hydrogenated, is preferred. Other oils or fats in smaller quantities can be included in the margarine fat, either by simple mixing or by corandomization with the other two components, so that a predetermined consistency is achieved, but preferably this does not exceed 10% of the total fat weight.

The palmitin fat can be randomized either in batch or continuously, e.g. in accordance with the method described in the applicant's British patent 1,236,233. An alkali metal or a hydroxide or alkoxide of such, preferably a lower alkoxide, e.g. metoxide or ethoxide. The alkali metal is usually sodium, although other alkali metals, e.g. lithium or potassium, their hydrides, hydroxides and alkoxides can be used.

In accordance with common practice in interesterification processes, moisture must be largely excluded from the reaction, and the free fatty acid content of the palm oil mixture should be low, so that the production of soap by-product is reduced to a minimum. A suitable catalyst concentration is approx. 0.01%, but amounts from 0.001 to 0.1% are also effective. It is desirable to use as little catalyst as possible, which simplifies the purification of the interesterified product. The randomization reaction progresses very quickly, despite the fact that there may be a significant initial period. The mixture should therefore be vigorously agitated at an elevated temperature, preferably from 50 - 100°C, while the catalyst is introduced. This can suitably be in the form of a concentrate in a suitable, liquid medium, preferably the mother alcohol for an alkali metal alkoxide, e.g. sodium methoxide in methanol. Alkali metals themselves can be introduced dispersed in an inert solvent, e.g. xylene.

An effective check to determine that the interesterification reaction has proceeded can be made by comparing the crystallization rate of the product with the value for the original mixture before the interesterification. The effect of the interesterification is to suppress the slow crystallization tendency of palm oil. Accordingly, similar samples are cooled in dilatometers under the same conditions by immersion in ice, and the rate of crystallization, compared by means of dilatation readings, is measured at regular intervals.

The margarine fat can be processed into a margarine by emulsifying the aqueous phase in suitable amounts into the fat and cooling and kneading the fat in the orthodox way. The water phase may contain additives which are common for margarine, e.g. an emulsifier, e.g. lecithin and mono- and di-glycerides of long-chain fatty acids, and salt. Oil-soluble additives, e.g. buttery flavorings and vitamins, can be incorporated into the oil phase. The water phase may also contain milk solids and may consist, at least in part, of milk, including milk substitutes, e.g. soy milk.

The proportions of water phase and oil phase can be adapted to the legal rules set out for margarine. Alternatively, a higher proportion of water phase can be used in the preparation of a low-fat spreadable product containing as little as 40% fat by weight, or even less.

The emulsion is preferably crushed and cooled in continuously working scraped surface heat exchanger units, known as "Votator" units, from which it can be packed directly into retail packs.

However, it should be understood that fats suitable for use as dough shortening fat, with the advantages that they can easily be is worked directly after removal from the refrigerator, can also be produced in accordance with the invention by randomizing mixtures of palm oil and a liquid vegetable oil, where both are isomerised.

In the following, the invention will be described by means of examples.

Example I

Soybean oil (JT approx. 130), refined by washing with

aqueous alkali and water, was boiled with aqueous solutions of sodium carbonate and sodium silicate, then washed with water, dried and bleached. The iodine number was then increased by approx. 20 units by batch hydrogenation. The dilations of the hydrogenated soybean oil were as follows: D10 = 200 ~ 30' D20 = 80 - 20• Its trans content was approx. 10%, and its slip melting point was 28 C.

Equal parts by weight of refined palm oil (JT 45-50) and the hydrogenated soybean oil were mixed, alkali treated to a free fatty acid content of less than 0.1% and dried to a moisture content (Karl Fischer method) of less than 0.02%.

The vigorously stirred mixture of the oils was randomized at 95°C using 0.01 wt% sodium methoxide in the form of a methanol solution. The randomized mixture was washed, dried, bleached with fuller's earth, filtered and deodorized. Its content of saturated fatty acids was less than 35%. There was little change in the dilatation upon interesterification.

When cooled to approx. 60°C, margarine-vitamins and flavor additives were incorporated into the randomized oil mixture, together with 0.1% by weight lecithin and 0.3% by weight monoglyceryl palmitate as an emulsifier.

A water phase containing 1.25% by weight of salt and 1% by weight of milk solids (non-fat) was emulsified in an amount of 16% by weight into the fat. The quantities of the ingredients are all expressed on the basis of the whole margarine mixture. The emulsion was kneaded and cooled by passage through "Votator" A and B units followed by a pre-crystallization unit. At an outlet temperature from the last unit of approx. 10°C, the product was packed by pouring into 22 7 gram tubs for retail sale.

The margarine product showed a penetration Cg significantly below 800. It could be spread directly after storage in a household refrigerator and proved to be pleasantly free of oiliness at ambient temperatures up to approx. 18°C. With regard to taste, it was found to be free from suchness and showed no unpleasant taste. The margarine fat had a trans content of approx.

5% and the dilations DlQ 550, D2Q 300, D3c 125, D35 75.

Examples 2-7

In these examples, margarine fat was prepared by corandomization of palm oil, refined as indicated in Example I, with a variety of liquid oils. The trans-acid content was provided by precuring the palm oil to a drop melting point of 45°C, either in part (Examples 2, 4 and 5) or all of the palm oil (Example 6), or by curing part or all of the liquid oil component, in the case of soybean oil to 28°C (Example 3) or 38°C (Examples 7 and 8). In other respects, the procedure set forth in Example I was followed. Further details are given in Table 1, from which it appears that, although all the blends show D^g < 90, indicating that when the product margarine contains less than approx. 35% total, saturated fatty acids, it is thin-melting in the mouth, the expansions at lower temperatures show that there is good spreadability, both at ambient temperatures and at 5°C, i.e. straight from a household refrigerator. These properties were confirmed by the appearance and taste of the margarine. When compared with control tests where the trans-acid was omitted from otherwise closely comparable mixtures, a more favorable relationship was observed between D2Q and D^ in the margarine fat according to the invention, the latter increasing more slowly in the presence of trans-acid as The D2Q value increased with changes in the fat composition.

It will also be seen that with increasing trans-acid content, the dilatations at lower temperatures tend to increase, even where the saturated fatty acid content decreases.

The fatty acid analysis from these examples is reproduced in more detail in table 2.

Example 8

This example was carried out to show that good oral response can be combined with satisfactory hardness at 20°C, which gives good spreadability at the mentioned temperature, when, in accordance with the invention, sufficient trans acid is present in the fat. Further details regarding the product were as follows:

Dilations Dq 695, D1Q 595, D2Q 325, D3Q 135, D35 50

The margarine was prepared as follows:

An emulsion of the melted fat with 20% water phase and including flavorings, salt, milk and emulsifiers in usual amounts, was prepared at 41°C pg passed at a rate of 3 kg/hour through, in sequence, a series of tube units with a scraped surface , in which the first emulsion was mixed with 75% recycled crystallized material and was agitated at 250 rpm.

From this recrystallizer the slightly cooled emulsion was transferred partially to the second unit, which was a "Votator" A unit, agitated at 800 rpm, and from there to an uncooled post-crystallization unit which was also agitated. The remaining portion exiting the "A" unit was recycled as described to the pre-crystallizer.

Refrigerant was circulated to the "A" unit at 0°C.

The softness of the product, measured by determining penetration values as already described, 1 week after the production of the margarine, was increased by increasing the speed of the post-crystallization agitator, from 250 to 700 rpm. This produced, with regard to the other process conditions, an increase in the inlet temperature in the pre-crystallizer from 27 to 28°C and for the outlet temperature from the post-crystallizer from 11.5 to 12°C, against a fall in the latter's inlet temperature from 11 to 8°C.

The change in C values was as follows:

A penetration value of approx. 1000 is too high for light spreading on bread. The reductions thus show that with increased kneading of the margarine, it becomes more plastic and can then be easily spread at these temperatures, without physically affecting the state of the margarine at 20°C, which in both cases is very soft, but not pourable.

A number of margarines were also prepared from inter-esterified mixtures of palm oil, sunflower oil and olive oil, where the main saturated fatty acid was random palmitic acid, but with the omission of trans acid. It proved impossible from these fat mixtures to achieve the combination of their melting properties and adequate fullness at 20°C, which indicated good lubricity at this temperature, shown by D2q 275 and D^^ 90, shown by the product of Example 8.

Examples 9 and 10

In these examples, the effect of lowering the total saturated fatty acid content to approx. 35%. For this purpose, the conditions used in Examples 2-7 were repeated for the preparation of two margarine samples based on palm oil, sunflower oil and soybean oil which had been hardened to 38°C in the ratios 55:20:25 (Example 9) and 45:30: 25 (Example 10), interesterified as previously described. Further details regarding the margarine products appear in Table 3.

Although both margarines were satisfactory and showed good melting properties, the lower total saturated fatty acid content in Example 9 is reflected in the expansion properties of the fat, proving that the margarine could be spread directly from the refrigerator, and that it is thin melting.

Example 11

In this example, a major part of the palmitic acid content of a margarine fat in accordance with the invention was provided by cottonseed oil, in a mixture of 20:45:35 parts by weight of palm oil, cottonseed oil and soybean oil, the latter having been hardened to 38°C.

Further details appear in table 4 and show that palmitic fat can generally be used to provide the palmitic acid requirements according to the invention.

Examples 12 and 13

In these examples, margarine samples were prepared on the basis of inter-esterified mixtures of equal parts of palm oil and corn oil. The trans content was provided by partial hydrogenation of the corn oil in Example 12 before randomization, and in Example 13 by partial curing of the mixture after randomization. Further details appear in table 5.

Both examples show a favorable relationship between the expansions at 20°C and 35°C. The product from example 12 is additionally thin-melting at 35°c.

The examples show that the trans acid content in the products according to the invention can be introduced before or after interesterification.

Claims (1)

Process for the production of a margarine fat suitable for use in spreadable foodstuffs, characterized by the following steps: a) corandomization, at a temperature of from 50 to 100°C, of a mixture consisting essentially of 25-65% by weight of a palmitic acid fat with 75-35% by weight of a C₂₂₂₂₂ vegetable oil in the substantial absence of water and in the presence of an effective amount of an alkali metal catalyst; and b) partially curing at least one of the components of the mixture in the presence of an effective amount of a metal hydrogenation catalyst under isomerization conditions, and continuing said steps until the total fatty acid content of the glycerides in the mixture consists of 3-15% trans-acid and at most 35% saturated fatty acid, of which palmitic acid predominates, as these amounts are given by weight of the total fatty acid content and its dilatation value at 20°C is at least 275 and at 35°C at most 90.