Field of the Invention

This technical solution relates to auxiliary agents and additives for the food and meat industries on the natural basis, especially to lubricating agents for shirring of food casings and for their subsequent stuffing.

Background of the Invention

Shirring is a manufacturing operation applied in the production of edible and non-edible casings, destined for the meat and ^' food industry. These casings, mostly in the form of tubular films ^' are used in the manufacture of sausages, salamis, and similar products of the meat and food industry. Therefore, usually, they replace natural gut in its traditional applications. These synthetic casings are produced from natural polymers (collagen, cellulose) or synthetic polymers (particularly based on polyamide) . In shirring, their main longitudinal dimension is reduced substantially, what facilitates and streamlines the subsequent manufacturing operations. In shirring the films are very stressed mechanically, and therefore, auxiliary substances are applied - lubricants or solutions thereof with other excipients that facilitate this operation and allow ^' its practical implementation. Lubricants also play an irreplaceable role in the actual filling of the casings, the so called stuffing.

At present, food grade mineral oils (white mineral oils} are used as auxiliary (mostly lubricants} and added substances in the food production and in the manufacture of plastics determined for food contact. Intake of mineral oils by food (e.g. because of the use of lubricants or also because of contamination, e.g. from packaging materials) and their possible impact on human health is being evaluated by the European Food Safety Authorities (EU) and also by the Codex Alimentarius iri the last time. Because the up to now available studies highlight the potential risks associated with the use of mineral oils, it is essential for their users, to try to identify the possible alternatives .

An alternative is the use of conventional edible vegetable oils, but they often do not provide sufficient technological efficiency, either in shirring or in the proper stuffing of- casings. Also, the shelf life of synthetic guts and similar casings is negatively affected by the application of natural" oils, which are prone to rancidity.

The use of mineral oils is known also from the patent literature (e.g. U.S. Pat. No. 5, 304, 385}. In contrast to this document, U.S. Patent 3,674,523 discloses the use of vegetable oils, in particular castor, corn, soybean, tung and safflower oils, for preparing of modified cellulosic synthetic guts. This patent; also mentions the use of animal oils, specifically of olein obtained by refining lard. Then, the European Patent No. 0877556 A2 refers to the use of a special solution for shirring that is applied to the inner side of synthetic guts. The aqueous solution comprises a mixture of surfactant, lecithin, cellulose ether, mineral oil and a polyol. However, application of such a mixture does not solve the health point of view, also efficiency of the surface lubrication during application of the stuffing solution from inside is low. The US Patent 4,897,295 mentions the use of synthetic, refined or natural triglycerides,, specifically of Miglyol (R) in the manufacture of pciyamide non ₇ edible casings. To improve the shirring, lubricants based on the partial esters of glycerol, the mono and diacylglycerols , were further suggested, which may be supplemented with sorbitol esters, e.g. trioleate of sorbitol (OS Pat. No. 4, 062, 980).. A disadvantage of said esters of polyfunctional alcohols, ^' especially of glycerol, is their limited lubrication effect, increased susceptibility to rancidity and often also limiting physical properties - e.g. unsuitable solidification point.

Summary of the Invention

The above-mentioned shortcomings of the currently used and proposed lubricants may be overcome by the lubricant according to the invention intended for production, shirring and stuffing of casings in the food and meat industries, whose substance consists in that it is based on alkyl esters of fatty acids or on mixtures of esters of fatty acid with alkyl groups and -that the alkyl in the alkyl group of the fatty acids is methyl/ ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl and its isomers, or that it comprises a mixture of several alkyl esters ^' of different fatty acids.

Further substance of the invention is that the fatty acids or triglycerides used to prepare the lubricating composition aire, of vegetable, animal, synthetic or mixed origin and also that., the solidification point of the alkyl esters of fatty acids . or of their mixtures contained in them, is less than 25°C.

Finally, subject of the lubricant according to the present invention is also that it is applied to casings that are tubular films, i.e. synthetic casings or natural guts, and also that the synthetic casings are made from natural or synthetic polymers such as collagen, cellulose or polyamide.

Alkyl esters of fatty acids are substances that are useful lubricants in the production, shirring, and stuffing of a wide range of edible and non-edible casings in the food and meat processing industries, in particular of synthetic casings. Moreover, in many cases their purchase price is lower than that of the petroleum and synthetic lubricants. Synthetic tubular casings can be made both from the natural polymers - e.g. the collagen or cellulose tubular film in the shape of gut . and,;.:from synthetic polymers, e.g. polyamide tubular casings. The proposed lubricants are also effective in the application of natural;, e.g. ovine guts in the meat industry.

The Alkyl group of the respective alkyl ester of a fatty acid is chosen with regard to the application, the material of the food casing and also with regard to health safety. It is known that alkyl esters of fatty acids are metabolized in the human body to free fatty acid and the corresponding alcohol. A number of simple alcohols (e.g. methanol, ethanol and isopropanol) are endogenous components of the metabolism of sugars and "iratty acids, therefore, they are not dangerous substances in- the ^' concentrations normally present in the human body. Whereas the lubricants proposed are only auxiliary agents, dosed in small quantities, their concentration in the final product is very low and the condition of health safety referred to in the preceding sentence is therefore complied with in their practical application. Thus, lubricants are formed preferably by alkyl esters of fatty acids, in which the alkyl group is either methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl and its isomers or a mixture of said alkyl groups.

The fatty acids used for preparing of the fatty acids alkyl esters can be higher fatty acids, such as oleic acid or palmitic acid, but also fatty acids with shorter chain, such as the capric acid or the caprylic acid. Preferably, the alkyl esters are made from a mixture of fatty acids derived from the source of plant or animal origin, the resulting lubricant is then prepared by modification of e.g. sunflower and soybean oil,, lard or tallow, or of a mixture of different plant and animal triglycerides. Similarly, for the preparation of alkyl esters of fatty acids it is possible to use the fatty acid itself or acyl glycerols of animal, vegetable or mixed origin as a source. However, purely synthetically produced alkyl esters of fatty acids prepared from fatty acids obtained synthetically or. synthetically obtained triglycerides can also be used.

Said alkyl esters of fatty acids have a high lubricating effect in the shirring and stuffing of food industry casings. The effect overcomes the lubricating properties of the triglycerides, whether of the natural or the synthetic origin ^' . The effect is comparable to or better than when using some conventional mineral oil. Apart from him, however, said ^' alkyl esters of fatty acids represent a far smaller risk in terms of health safety. From the technological standpoint, it is also important that a large amount of said alkyl esters of , fatty acids have the freezing point lower than 25°C.

Examples of Invention Embodiments

Example 1

Edible collagen casing was lubricated with 6% of ethyl oleate (on dry basis), and shirred on a standard shirring machine. Using a lubricant led to preparation of sticks (i.e. shirred casings) of uniform surface. Consistent quality control confirmed that the difference in quality of products when, using mineral oil of pharmaceutical grade and the above-mentioned ethyl ester of oleic acid was statistically insignificant . ^■ : This result was confirmed further in the operational tests _: of stuffing of the collagen casing with meat mixture. From a statistical point of view, the rate of going bad was in this case better than when using mineral oil of pharmaceutical grade. Sensory quality control of the final meat product did not reveal any statistically significant difference between the product prepared by standard procedure and the product, for which production the above-mentioned ethyl oleate was used.

Example 2

Cellulose casing was lubricated with 4.3% mixture of methyl esters of higher fatty acids derived from lard and isopropyl esters of higher fatty acids derived from soybean oil ^* and stirred in a standard stirring machine. The use of lubricant has led to the preparation of sticks (i.e. the stirred casings) of uniform surface. Consistent quality control confirmed that in case that the mixture of alkyl esters of fatty acids was used the quality of the product was higher than when the usual- standard lubricant was used. The process of stuffing into the cellulose casing was also realized without any observable defects and the desired level of quality of the final product was achieved.