DE526917C - Process for the preservation of materials which can be decomposed by microorganisms, in particular food - Google Patents

Description

Process for preserving decomposable by microorganisms Materials, especially foodstuffs By patent 438 588, K1. 53k, is a Process for preservation become known in which the materials to be preserved exposed to non-toxic alcohol ester carbocyclic acids.

It has now been found that the esters having -2 or more carbon atoms contained in alkyl, a very special one, which increases with the number of carbon atoms preservative effect, so that a perfect preservation by the higher esters or ester mixtures with mostly lower concentrations is achieved. It was by no means easy to foresee. Furthermore means the lesser addition of preservatives a complete avoidance of any Damage to health, as the higher esters of p-oxybenzoic acid also per se are even less harmful to health than the methyl ester. It is namely the lowest dose that triggers symptoms of poisoning in the animal for the Methyl ester a g, for the ethyl and propyl ester, however, 3 to [g per kg animal weight. In the preservation of sensitive foods are also as a result of lower concentrations of the higher esters that are sufficient for safe preservation taste disturbances avoided with even greater certainty.

The table shows the minimum concentration of the esters of p-O_xybenzoic acid required under the same conditions in culture experiments of the putrefactive pathogen Bacterium coli and the mold Penicillium glaucum on altar medium to permanently prevent development and in fermentation experiments with top-fermenting distiller's yeast and sugar solution to permanently prevent fermentation. Development. Ver prevention hindrance the yeast BaCterium Penicillium fermentation coli glaucum I. Methylester ..I o 1 5 ° / 'o, r 0! 0 Ethyl ester ... 0.110j'0 0.05 0l0 Propyl ester. . 0.075 '.,' O I 0.04% 0.03 0/0 Butyl ester ... 0.02 0/0 0.03 0/0 Amyl ester ... 0.03 0/0 0.018o / " Isoamyl ester '0.0120 / 0 Benzyl ester. . 0.03 0 / `0 0.01501" 0.012 '/ " Under the conditions chosen for the fermentation tests, the methyl and ethyl esters in the maximum possible concentrations could not prevent fermentation. Mixtures of 0.25% squeezed top-fermenting distillery yeast and 0.8% dextrose solution were used for these experiments; fermentation was carried out at 30 °. When 0.05 g yeast was used instead of o, the ethyl ester in the maximum concentrations attainable under the test conditions could prevent fermentation, but not the methyl ester irr the attainable maximum concentration o 25%. Therefore, materials which are subject to decomposition by yeast fermentation, e.g. B. unsweetened fruit juices, unsweetened fruit pulps, cannot be preserved with sufficient certainty by the methyl ester, but by the higher esters.

Freshly squeezed jobannisberry juice cannot be protected against fermentation with the maximum possible addition of 0.2; "1" p-oxybenzoic acid methyl ester, but can be protected against fermentation by o; o5 "pO: xybenzoic acid propyl ester. 10% aqueous malt extract solution behaves in the same way against both esters However, fermentation does not take place with an addition of 0.04% p-oxybenzoic acid propyl ester. In jelly marinades, adding 0.15 "/" methyl ester prevents the formation of mold, but not the development of the so-called spheroidal bacteria; but an addition of 0.05 "j" of a mixture of equal parts of ethyl and propyl esters of p-oxybenzoic acid. A starch paste inoculated with Bacillus prodigiosus, Bacterium fluorescens, Penicillium glaucum and Bacterium coli became with the addition of 0.15% methyl ester within Still liquid for 2 months, with the addition of 0.03 % amyl ester it remained unchanged. A tragacanth starch jelly in glycerine was made possible by adding only 0.04% of p-oxybenzoic acid butyl esters are protected against decomposition in the same way as by adding a minimum of 0.15 "1o methyl ester of p-oxylbenzoic acid.

By using mixtures of such esters with one another or with the methyl ester, the effect can be further improved, ie one either achieves effects which do not occur with the esters alone, or one achieves the same effect with a lower concentration than when using the esters alone. Thus, Bacillus pyocyaneus still develops in nutrient broth despite the addition of the practically possible maximum concentration of 0.3 "/ o methyl ester or 0.15" / "ethyl ester of p-oxybenzoic acid; However, the development completely fails if 0.15% of each of these two esters is added together to the nutrient broth.

The isomeric esters of m-oxybenzoic acid behave quite similarly.

Example i Add 0.45 per mille to freshly squeezed raspberry juice p-Oxybenzoic acid propyl ester, by dissolving the ester in a little alcohol and this Allow the solution to slowly run into the juice, which has been agitated by stirring and the like, and then add it equally distributed.

Examples When making a jelly from starch, tragacanth etc. one dissolves 0.15 per mille of benzyl p-oxybenzoate in the water to be used for the preparation of the jelly. EXAMPLE 3 In the preparation of a malt extract solution, 0.3 per milliliter of butyl p-oxybenzoate is dissolved beforehand in the water to be used to prepare the solution. EXAMPLE 4 Pressed vegetable juice is admixed with 0.8 per milliliter of a mixture of 50 parts of ethyl and 50 parts of propyl ester of p-oxybenzoic acid by dissolving the mixture in five times the amount by weight of alcohol and allowing this solution to drip into the pressed juice while stirring. EXAMPLE s In the production of jelly marinades, a mixture of 6o parts propyl ester and 40 parts ethyl ester of p-oxybenzoic acid is dissolved in the water to be used for the preparation of the jelly infusion with heating in such amounts that the ester content of the finished marinade is 0.5 per Mille is. For example, el6 strawberries are boiled in their own juice without adding sugar, and then 0.3 per mille of propyl ester and 0.45 per mille of methyl ester of p-oxybenzoic acid are dissolved in the still hot mass while stirring.

Claims (2)

PATENT CLAIMS: i. Process for preserving by microorganisms decomposable materials, especially food, characterized in that the decomposable materials from the action of esters of p- or m-oxybenzoic acid with at least 2 or more carbon atoms in the alkyl are exposed. 2nd embodiment of the method according to claim i, characterized by the use of mixtures these esters with one another or with the methyl ester of the acid.