EP1606421B1 - Method for producing sugar and saccharated products from saccharated plant materials - Google Patents

Abstract

The invention relates to an extraction liquid for extracting a product including sugar from sugar-containing plant raw materials. The extraction liquid includes a fatty acid compound in an amount of 0.1 to 100 mg/l. The fatty acid compound could be myristic acid, soaps of myristic acid, aldehydes of myristic acid, and/or alcohols of myristic acid. The extraction liquid may additionally include admixed natural, food-compatible resins. The resins could be colophony or other food compatible resins.

Description

The invention relates to a method for producing sugar or sugar-containing by-products of industrial sugar production from sugar-containing vegetable raw materials.

Sugar (sucrose) and sugar products are mainly obtained from the vegetable raw materials sugar beet and sugar cane by mechanically comminuting these plants and extracting or squeezing sugar-containing solutions from the plant parts.

All sugary media, especially those obtained directly from agricultural raw materials, are susceptible to microbial spoilage by bacteria, yeasts and molds within certain temperature ranges, pH values and concentration limits. The risk of attack by microorganisms always means a considerable risk in a food technological process, both in continuous operation and in the storage of raw and intermediate products. Microorganisms can degrade sugars contained in the raw materials to acids and gaseous, sometimes even explosive metabolic products or cause an excessively high germ content of the end products. In the process of sugar beet and cane sugar production there is the risk of microbial decomposition of the disaccharide sucrose into the monosaccharides glucose and fructose, which, in addition to the immediate loss of sucrose, also has other disadvantages, e.g. This causes a stronger syrup discoloration, an increased need for alkalizing agents and an increased accumulation of molasses.

At temperatures up to 50 ° C, which are used in juice extraction with mechanical cell opening, the sugar-containing extraction solutions are the spoilage by all mentioned microorganisms, ie yeasts, molds and bacteria, exposed. In a juice extraction with thermal cell opening, which takes place at temperatures above 50 ° C, however, only more thermophilic bacteria are capable of reproduction. An example for such a thermal extraction process is the currently generally performed extraction of sugar beets for the purpose of sugar production.

It is customary to combat thermophilic bacteria in extraction plants in that the juice stream or the perishable intermediates discontinuous or continuous germ-inhibiting or germicidal agents are added. For example, formalin, dithiocarbamates, peracetic acid, ammonium bisulfite, quaternary ammonium bases, etc., are common in the sugar industry.

Recently, in some sugar factories, when addition of chemical agents is undesirable or prohibited by law, hops products (EP-0 681 029 A, Pollach et al., Sugar Industry 124 (8) (1999) are also used as natural means of controlling microorganisms ), 622-637; Pollach et al., Sugar Industry 121 (2) (1996), 919-926; Hein et al., Zuckerindustrie 122 (12) (1997), 940-949) and resin products (WO 01/88205 A1 Pollach et al., Zuckerindustrie 127 (2002) 921-930). Unfortunately, with the use of these natural agents, selection of resistant bacterial strains or adaptation of bacteria is more often observed than with chemical agents, e.g. Formalin. The latter attacks nonspecifically proteins (Weinberg E.D., J. Soc., Cosmet., Chem., 13 (1962) 89-96) and shows less adaptation of bacteria, but has come into discussion precisely because of the unspecific attack on proteins.

It is known from the field of medicine that in case of lack of effect of an antibiotic by a change of the agent again a germ-inhibiting effect can be achieved, but this is not guaranteed. Bacteria strains that are resistant to a particular agent and thus specialized are successful in its application, but are unlikely to be equally resistant to all alternative agents. A broader range of alternative antimicrobials will most likely have an effect in every case.

US 5,434,182 A discloses the use of various fatty acids (C4-C22) and their esters for controlling bacteria and viruses in animal organisms, including humans. However, according to this US patent, the use of these fatty acids is restricted exclusively to the medical-pharmaceutical field. However, a use of the fatty acids described in the US patent and their esters in sugar production is not obvious to the person skilled in the art, since the requirements for antimicrobial substances in the medical field are known to differ greatly from those of the food industry, in particular sugar production.

Nevertheless, fatty acid esters are used in a variety of manufacturing processes in the food industry. The goal is either to change the physical properties of the solutions or to limit the microbial spoilage.

Thus, US Pat. No. 4,427,454 A discloses the addition of fatty acid glycerol esters for reducing the viscosity and the foam content during sugar production. In contrast, JP59063199 A relates to the removal of starch from various sugar solutions by means of fatty acid glycerol esters, which consist of C8-C22 fatty acids. The use of fatty acid esters for these purposes does not suggest in any way to a person skilled in the art that fatty acid compounds have antimicrobial properties in this context.

JP10070971 A and JP62163678 A describe the use of fatty acid sucrose esters consisting of fatty acids having 8-22 carbon atoms or fatty acid polyglycerol esters. These esters are used to preserve clear liquid foods, such as juices or soups. The composition of the solutions and suspensions to be treated in the context of sugar production is much more complex than with pure clear liquids, especially considering the high sugar concentration, the high temperatures and the presence of turbidity and solids. For this reason, it is not suggested to those skilled in the art both by the application JP10070971 A and by JP62163678 A, fatty acid compounds as antimicrobial substances in the production of sugar or sugar-containing solutions from sugar-containing vegetable raw materials use.

Furthermore, DE 101 36 260 A discloses gelling compositions which, in addition to sugar, acid and gelling agents, comprise further substances which have health-positive effects on the human organism. These additives include lipophilic substances such as omega-3 fatty acids, particularly eicosapentaenoic acid (C ₁₉ H ₂₉ COOH) and docosahexaenoic acid (C ₂₁ H ₃₁ COOH), vitamins, phytochemicals such as polyphenols, immunostimulants, preservatives and vascular prophylactics. The lipophilic substances used serve primarily to reduce foaming.

At the same time, however, it has also been shown that many agents for which a possible antimicrobial effect has been described or proposed in some areas did not show this effect in the context of the industrial sugar production process. On the one hand, this could be due to the material to be treated during the sugar production and to the process conditions that are necessary for this, but on the other hand it could also be e.g. the - sometimes very variable - composition of the contaminating microorganisms may be a reason for the lack of success in sugar production.

The present invention is therefore an object of the invention to provide a method of the kind described, with which the growth of unwanted microbes in the industrial production process of sugar by natural means, especially in the occurrence of microorganisms which against hops and / or resin products are insensitive, can be suppressed.

This object is achieved with a method for producing sugar or sugar-containing by-products of industrial sugar production, such as beet pulp feed, Carbokalk, thick juice and molasses, from sugary vegetable raw materials, which is characterized in that the preparation is carried out, at least in part, in the presence of fatty acid compounds according to the invention which comprise fatty acids or their soaps, aldehydes and alcohols.

Surprisingly, the addition of such fatty acid compounds in the course of the industrial sugar production process has provided an efficient and cost effective way of effectively preventing the growth of undesirable microbes. In particular, thermophilic microorganisms, which are particularly persistent and difficult to control sources of interference in the sugar production process, can be inactivated with the addition of inventive fatty acid compounds according to the invention.

It is not essential that these fatty acid compounds present throughout the manufacturing process. According to the invention, the use of the fatty acid compounds according to the invention can also take place only in selected partial processes. The partial or temporary presence of the added fatty acid compounds has, according to the invention, proven especially in those conditions in which thermophilic microorganisms would thrive particularly well.

As vegetable raw materials according to the invention, of course, especially sugar beet and sugar cane are considered. However, the method according to the invention is applicable in principle to all possible vegetable sources, e.g. in sugar production from sugar palms, dates, sugar millet, sweetcorn, tree juices, e.g. Maple juice, etc ..

Preferably, fat soaps are used according to the invention, but they can also be dissolved in fatty acid solvents, metered in molten form or in solid form by pouring into trough-extraction plants. However, the fatty acid compounds according to the present invention may also be fatty acid alcohols, fatty acid aldehydes. The fatty acid compounds may also be modified, for example by the incorporation of functional groups such as -OH, -SH, -NH ₂ , -F, -Cl, -Br, -I and the like. (except those derivatives which are not toxic or food-grade); It is also possible to use aliphatic side chains and / or one or more (in particular two or three) (unsaturated) double bonds as long as the physicochemical properties of the (aliphatic) basic chain, in particular the solubility in antimicrobial concentrations, and the structure at the C ₁ atom are obtained stay.

When using aliphatic carboxylic acids or soaps as fatty acid compounds, the (industrial) chain length of the chain has to be greater than 6, preferably greater than 8, in particular greater than 10, and less than 22, when tested under industrial sugar production conditions. preferably less than 21, in particular less than 20, as effectively in acceptable doses, so that the following acids and their soaps are considered to be particularly preferred: heptane, capryl, pelargon, caprine, undecane, lauric, tridecane Myristic, pentadecane, Palmitic, heptadecane, stearic, nonadecan, arachin, heneicosanoic acid and the corresponding soaps, in particular the C ₁₀ , C ₁₂ , C ₁₄ , C ₁₆ and C ₁₈ fatty acid compounds (capric, lauric, myristic). , Palmitic and stearin compounds (especially the acids, soaps and alcohols), which are available inexpensively in industrially usable quantities or (like the alcohols) can be easily obtained from them .. Such fatty acid products are well-defined substances which essentially consist of only one active substance.

Especially the myristic acid or soap has been particularly useful according to the invention, especially as far as its antimicrobial activity is concerned. While in some cases myristine esters may exhibit antimicrobial activity, only methyl myristate, but not ethyl and propyl myristate, with an inhibitory concentration of about 100 mg / ml may be considered equivalent to the compounds of this invention. But myristin compounds also have other advantages: myristic acid melts at lower temperatures than the comparable natural resins (eg rosin) or hops, namely at 54 ° C, which is a safety advantage in the application or an application of steam as a heating medium dispensable. The lower melting point of myristic acid to resin and hops is also an application advantage, because there is less risk of scalding and you can get away with waste heat of the sugar industry (hot water). On the other hand, the melting point of 54 ° C., on the other hand, is again not so deep that it comes to sticking due, for example, to the melting of free-flowing bagged material at usual (or higher) ambient temperatures. Thus, myristic acid (C ₁₄ ) is also ideal in terms of application technology. (Note: C ₁₁ has, for example, a melting point of 30 ° C, C ₁₀ a of 31 ° C. These products are neither liquid nor free-flowing and, in terms of performance, not as advantageous as C ₁₄ compounds.) Generally, tests have shown that, as a rule the free fatty acids and their soaps according to the present invention have a better antimicrobial activity than their aldehydes and their esters.

Furthermore, myristic (as opposed to hops) has no (bitter) taste. Finally, myristic acid has one high Ca precipitation on, so that a high elimination can be ensured in the juice cleaning. Myristil alcohol (1-tetradecanol) is also effective at concentrations of 10 ppm or even less (unlike stearyl alcohol, which requires significantly higher concentrations, if any, in the industrial process). Therefore, fatty acid compounds to be used according to the invention are preferably already effective at 100 ppm, preferably at 50 ppm, more preferably at 10 ppm, in particular at 1 to 10 ppm, eg at 55 or 65 ° C.

Sorbic acid compounds or other shorter-chain (C ₆ (caproic acid) or less) or longer-chain (C ₂₂ (behenic acid) or longer) compounds have proved to be unsuitable for the sugar industry, at least in the industrial context. Also, toxic compounds or quaternary ammonium bases, alkoxylated resins, and the like. not industrially applicable.

Many fatty acid compounds are physiologically harmless natural products. Since the sugar production process mainly such harmless products are to be used, especially lauric, myristic, palmitic and stearic acid (s) and their soaps are preferred for this reason. Of course, any combination of fatty acid compounds of the invention can be used.

Although the possibility of an anti-microbial effect of fatty acids has been known or postulated in the past (sorbic acid, a 6-carbon, diunsaturated fatty acid, is used as such and as a potassium salt for food preservation and is considered harmless) and undecylenic acid called antimicrobial agent (Wallhäuser, practice of sterilization - Disinfection - Conservation, 5th ed., Thieme Stuttgart, 1995, p. 520)) and higher free fatty acids even an effect on purebred strains was found (eg LIH-LING et al. , Applied and Environment Microbiol., 58, 1992, pp. 624-629), but these fatty acids have not proven to be useful as disinfectants for mixed cultures. Often still concentrations up to 1 g of fatty acid per liter are said to be effective (Kabara et al., Lipids, 12 (1977) 753-759), which is completely inadequate for sugar production sugar and salt are bacteria-inhibiting, but sugar or salt are evidently not suitable for achieving the effects of the invention in the context of the sugar-making process).

It also turns out that over time the postulated germ-inhibiting effect of fatty acid compounds has proved to be unconfirmable and at the present time is no longer considered to be given or even industrially usable: While in the 3rd edition of Ullmann's Encyclopedia of the Technical Chemistry (1954, Vol. 5, Disinfection and Sterilization, p. 753) is still referred to as a disinfectant via fatty acids (in the 1940s, one was relatively optimistic about the disinfecting effect of fatty acids in medicine), this chapter is 4th edition (1975, Vol. 10, pp 47-48) in the chapter "disinfectants" greatly reduced ("The maximum efficacy of fatty acids should be at C ₁₁ to C ₁₂ ..." or "About the bactericidal action of the soaps strongly contradictory findings before .... ") and in the 5th edition (1987, Vol. A8) is no longer reported in the chapter" Desinfectants ". It can be seen that at normal temperatures there are too many fatty acid insensitive strains of microorganisms and that fatty acids are no longer among the disinfectants today.

If one inoculates at 35-45 ° C, ie those temperatures which are usually used in microbiology, a nutrient medium with unsterile Rohsaft from a sugar beet extraction, then it is usually difficult to detect the pH drop acidification by the addition of fatty acids stop (especially in mixed cultures in which insensitive microorganisms can prevail). On the other hand, the acid formation at 55 ° C and 65 ° C is blocked by fatty acids depending on the chain length at concentrations of 4 - 40 mg / L over a period of 1 to 10 hours. While a maximum of C ₁₁ -C _{12 is} given for the effects observed at normal temperature (Ullmann 1975), for thermophilic microorganisms at the higher temperature the maximum of action is C ₁₄ (myristic acid). It is known that in organic preservative acids, such as sorbic acid, the undissociated form is effective (Wallhäuser, practice of sterilization - disinfection - preservation, 5th ed., Thieme Stuttgart, 1995, P. 507). The same applies to fatty acids with higher chain length (Ullmann 1954). In acidic aqueous media, however, fatty acids of longer chain length can have no effect if the solubility is below the minimum inhibitory concentration of the microorganisms. By application against thermophilic microorganisms at higher temperature, higher solubility fatty acids (C ₁₄ ) in acidic media can be very effective.

It has been found according to the invention that the claimed fatty acid compounds should be used in an amount of 0.1 to 100 mg / L, preferably 5 to 40 mg / L, in particular 10 to 25 mg / L. In this case, the fatty acid compounds according to the invention preferably have a minimum inhibitory concentration of less than 50 mg / l, more preferably less than 40 mg / l, particularly preferably less than 30 mg / l, in particular less than 20 mg / l. The presence, at least in part or at least temporarily, of fatty acid compounds according to the invention in this amount in the liquid phase during the sugar production process has proven to be favorable or at least sufficient for the desired germ-inhibiting effect. However, it is clear that, depending on the realization of the sugar production process (continuous / continuous), the concentration of fatty acid compounds may fluctuate, in particular if the products are added batchwise to the production process, for example into the extraction solution. Particularly preferred concentration amounts of the fatty acid compounds to be used according to the invention during the production process are from 5 to 40 mg / L, in particular from 10 to 25 mg / L.

Preferably, the fatty acids are added as fatty soaps. Alkali or alkaline earth (with the exception of calcium), preferably potassium salt solutions, in particular in concentrations of 0.5 to 30%, have proved useful. The fatty acids can also be added as alcoholic solutions or suspensions, in particular as a 1 to 100%, preferably as a 1 to 95%, in particular as a 10 to 80%, ethanol solution. It has been found that the use according to the invention of fatty acid compounds is particularly suitable for combination with further antimicrobial agents in the course of the production process. Preferably, further food-compatible antimicrobial agents are used in the context of such a combination.

In this case, the combination according to the invention with hops, hop derivatives and food-compatible resins is particularly preferred. Sugar production processes using hops or hop derivatives are known e.g. in EP 0 681 029 B1. Methods in which food-compatible resins are used alone and in combination with hops and hop derivatives are described in WO 01/88205 A1. The combination of the further antimicrobial agents with fatty acid compounds according to the invention can be carried out both partially and serially according to the invention. For example, the sugar manufacturing process can be carried out temporarily in the presence of added fatty acid compounds, temporarily using resins and temporarily in the presence of hop products, for example hop β-acids, both sequentially and with each other.

Although the addition of fatty acids according to the invention may take place at any point in the sugar production, the fatty acid compounds according to the invention are preferably present at least in the thermal extraction of sugar-containing plant parts, in particular sugar beets or sugar cane. In this case, for example, myristic soap can be added to the parts of the plant to be extracted after the mechanical comminution of the sugar-containing vegetable raw materials.

Preferred temperature conditions for the use according to the invention of the fatty acid compounds are 50 to 80 ° C, in particular 55 to 70 ° C.

According to a preferred embodiment of the method according to the invention, the claimed fatty acid compounds are used in the extraction of the raw juice. A representation of the usual production process for sugar is contained, for example, in Ullmann's Encyklopadie der Technischen Chemie, 4th ed., Vol. 24, pages 703 to 748, wherein the inventive addition of fatty acid compounds in all the there described (Sub) steps can be made.

Preferably, the claimed fatty acid compounds according to the invention of the extraction solution, with which the sugar is extracted from the sugar-containing plants in raw materials added.

According to a particularly preferred embodiment, membrane treatment processes or ion exchange processes are carried out in the course of the sugar production process in the presence of the fatty acid compounds according to the invention.

Preferably, the claimed fatty acid compounds are used at a sugar concentration of 0.1 to 80%, especially at higher temperatures, for example at temperatures of 50 to 80 ° C.

The danger of the entry of bitter flavors in the sugar products, which has existed in hop products, is therefore not present in the case of fatty acid compounds, since the preferred fatty acid compounds do not taste bitter. Fatty acid compounds with no or negligible taste of their own are therefore advantageous.

The treatment with a fatty acid compound according to the invention is particularly advantageously carried out alternately to a treatment with a hops-based or pine resin-based microorganism-inhibiting agent in order to adapt the microorganisms to the hops or pine resin preparation or to select hops or pine resin-resistant microorganisms to fight.

If no selection or adaptation is observed in a process, a combined agent, e.g. from fatty acid compounds according to the invention and pine resins and / or hop products, in order to achieve a particularly high efficacy of a single combination agent.

When a sugar-containing substrate, such as a sugar-containing liquid culture medium, as is customary in microbiology, either unsterilized or incubated after inoculation of a bacterial strain, it comes to acid formation, which can be most easily recognized by a pH drop. The same phenomenon occurs in the incubation of normal sugary plant juices, eg beet juice. A drop in pH due to sugar degradation means a loss of sugar and a need for alkalizing agents in an industrial process, eg the production of sugar juice from sugar beets. In addition, a pH drop with an increase in the germ content in the substrate is often associated with an unpleasant gas and nitrite formation. This arrangement also provides an efficient system for determining the antimicrobial activity of substances in the sugar manufacturing process.

For example, during acid formation caused by thermophilic microorganisms at higher temperatures, e.g. a solution of fatty acid compounds according to the invention is added, it comes from a certain concentration of 10 ppm to stop the acid formation and the associated pH drop. Thus, the disadvantages associated with acid formation can be overcome by adding e.g. Myristic acid can be avoided to a sugary substrate. Preferably, therefore, work is carried out at elevated temperatures because the fatty acid compounds are less soluble in cold aqueous systems than in warm systems. For reasons of better solubility, they can therefore be used particularly well at elevated temperatures against thermophilic microorganisms. In addition, the microorganism flora is limited to a few bacterial species at high temperatures.

Compared to yeasts, fatty acid compounds according to the invention, for example myristic acid, surprisingly have a significantly lower activity than thermophilic bacteria. In addition, they are poorly soluble under the yeast and pine yeast pH and temperature conditions, so that the properties known from hop and pine resin products, which primarily inhibit the bacteria, also occur in fatty acid compounds. In an application of fatty acid compounds according to the invention in the field of beet extraction, ie before the juice purification with lime and carbon dioxide, these fatty acid compounds are separated to a high degree. Form fatty acids Ca-insoluble soaps which are precipitated from the process stream together with calcium carbonate. This represents an advantage of fatty acids as a bacteriostatic agent for sugar beet extraction because Ca precipitability significantly reduces the amounts remaining in the molasses and the traces adhering to the finished sugar. Those residual amounts of fatty acids which are not precipitated in the juice purification as Ca salts and enter the molasses intended for utilization by yeasts can therefore be regarded as safe in comparison to some chemical agents, such as quaternary ammonium bases.

According to a further aspect, the present invention also relates to an extracting liquid for extracting sugar-containing vegetable raw materials, which contains added (i.e., not naturally present in this amount) fatty acid compounds in addition to the usual constituents of this extracting liquid. Such extraction fluids contain in addition to the extracted sugar (sucrose), glucose and fructose in traces, as well as ingredients that are characteristic of the respective vegetable raw material, such as betaine (in sugar beet) or aconitic acid (sugar cane). Other ingredients may include amino acids such as alanine, asparagine and glutamic acid, isoleucine, leucine, threonine or valine (in the range 10-200 mg / L raw juice), oxalate, citrate, lactate or maleate (10 - 5000 mg / L raw juice) Shikimic acid or flavonoids or phenolic components such as caffeic acid, 3,4-dihydroxybenzoic acid, chlorogenic acid, apigenin, swertisin, luteolines or tricin. (Schneider, Technology of Sugar ", Verlag Schaper, Hannover (1968), 247-253, van der Poel et al.," Sugar Technology ", Verlag Dr. Bartens, Berlin (1998), 152-157, van der Poel et al., "Zuckertechnologie", Verlag Dr. Bartens, Berlin (2000), 163-168).

According to a preferred embodiment, the extraction liquid according to the invention additionally contains added hops, hop derivatives and / or food-compatible resins.

According to a further aspect, the present invention also relates to sugar or sugar-containing by-products of industrial sugar production from vegetable raw materials, which according to the invention Method are available and accordingly contain a (residual) content of added fatty acid compounds. This content can readily be detected by analytical methods known per se, such as gas chromatography, etc. Sugar or sugar-containing by-products of industrial sugar production which are preferred according to the invention have a content of fatty acid compounds starting from the detection limit of up to 1 ppm. However, according to the invention, too, preferred products are all sugars and by-products of sugar which are produced in industrial sugar production, such as beet pulp feed, carbolic lime, concentrated juice and molasses. Beet pulp feed, which is made available, for example, as a pressed product, represents a particularly favorable growth environment for unwanted microorganisms. Such infestation can, of course, decisively impair the feed quality of these products. The presence of added fatty acid compounds not only reduces such product damage, but also the formation of undesirable odor.

In another aspect, the present invention also relates to the use of fatty acid compounds of the invention in the production of sugar. In this case, the use for inhibiting thermophilic microorganisms, in particular for the inhibition of Bacillus, Thermus and Clostridia, is particularly preferred.

The invention will be explained in more detail with reference to the following examples, to which, of course, it is not restricted.

Example 1:

A liquid nutrient medium, as is common in microbiology, consisting of 10 g Bacto-peptone, 5 g meat extract, 5 g yeast extract, 1 g glucose, 1 g K ₂ HPO ₄ , 0.1 g MgSO ₄ .7H ₂ O and 0.01 g FeSO ₄ * 7H ₂ O per liter of distilled water is sterilized in the usual manner for 20 min at 120 ° C and in a tempered at 65 ° C vessel with 20 ml of raw juice inoculated from a large-scale sugar beet extraction, wherein the pH Value is registered on a recorder. After the growth of thermophilic bacteria, the pH decreases progressively. This indicates acidification caused by microorganisms.

In the present example, such microorganisms cause an increasingly greater pH drop (ΔpH / h) from about 4 hours incubation. By adding 1 mL of 1% alcoholic solution of myristic acid per liter of culture fluid, the pH drop is suddenly and sustainably stopped after 5 hours. It results in a minimum of 14 hours effectiveness at a concentration of 10 mg myristic acid per liter of culture fluid. The effect is due to the fatty acid, since only amounts of 40 - 60 mL of alcohol per liter of culture fluid to an impairment of such a culture. Time (h) 0 1 2 3 4 4.25 4.50 4.75 5 5.10 5.50 6 7 10 13 16 19 pH 6.95 6.94 6.94 6.93 6.90 6.86 6.80 6.72 6.55 6.47 6.47 6.47 6.48 6.50 6.53 6.55 6.53 ApH / h 0.01 0.00 0.01 0.03 0.16 0.24 0.32 0.68 0.80 0.00 0.00 -0.01 -0.01 -0.01 -0.01 0.01

Addition of 10 mg / L myristic acid at pH 6.47

Example 2:

In a mixed culture according to Example 1, the growth of thermophilic bacteria manifests itself in an increasingly greater pH drop (ΔpH / h). By adding 1 mL of 1% alcoholic solution of palmitic acid per liter of culture fluid, which corresponds to 10 mg / L, the pH drop is immediately completely stopped after 5 hours, but after 1.5-2 h, it comes in contrast to Example 1 to a new pH drop in the culture. A further addition of palmitic acid up to a total concentration of 50 mg / l can no longer stop this pH drop, but only to delay from 0.13 to 0.07 pH units per hour. The example shows a principal effect of palmitic acid (C ₁₆ ), but it is only of very short duration. Stearic acid (C ₁₈ ) and oleic acid (C _{18: 2} ) behave very similarly, while behenic acid (C ₂₂ ) shows no effect whatsoever in such an example. Time (h) 0 1 2 3 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.10 6.00 6.50 7 8th 9 pH 7.06 7.05 7.04 7.04 7.03 7.02 6.98 6.93 6.86 6.77 6.61 6.52 6.53 6.53 6.49 6.36 6.29 ApH / h 0.01 0.01 0.00 0.02 0.04 0.16 0.20 0.28 0.36 0.64 0.90 -0.01 0.00 0.08 0.13 0.07

Addition of 10 mg / L palmitic acid at pH 6.52 and 4 x 10 mg / L between pH 6.49 and 6.36

Example 3:

In a mixed culture according to Example 1, a pH drop by thermophilic bacteria occurs. A double addition of 1 ml of 1% alcoholic solution of lauric acid (C ₁₂ ), corresponding to a concentration of 20 mg / L, still leads to no effect. Only a third addition of 1 mL solution, corresponding to a total concentration of 30 mg / L, stops the pH drop. In the case of undecanoic acid (C ₁₁ ), an effect is achieved in such an example only at 40 mg / L. With sorbic acid (C _{6: 2} ), a known preservative, surprisingly, even at 150 mg / L, no effect is achieved. This shows that the effect of fatty acids at higher temperatures can not be deduced from literature data on mesophilic microorganisms. Time (h) 0 1 2 3 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5 6 7 8th 9 10 pH 7.08 7.08 7.07 7.06 7.03 6.99 6.94 6.87 6.74 6.49 6.49 6.49 6.50 6.51 6.52 6.52 6.53 ApH / h 0.00 0.01 0.01 0.12 0.16 0.20 0.28 0.52 1.00 0.00 0.00 -0.01 -0.01 -0.01 0.00 -0.01

Addition of 3 x 10 mg / L lauric acid between pH 6.74 and 6.49

Example 4:

A liquid nutrient medium as in Example 1 is inoculated into a purebred strain DSMZ 457 of the German Collection of Microorganisms and Cell Cultures GmbH. A pH drop starting after 1 hour can be stopped by adding 0.2 mL 1% alcoholic solution of myristic acid (C ₁₄ ) twice, corresponding to a concentration of only 4 mg / L. After 4 hours, a renewed drop in pH sets in, which can be stopped by a further addition of 2 mg / L, for a total of 6 mg / L, for a further 7 hours. This example demonstrates that effects similar to pure cultures can be achieved, even at very low concentrations. Time (h) 0 1 2 3 4 4.50 5 6 7 8th 9 10.2 11 12 13 14 15 pH 7.08 7.07 7.04 6.99 6.81 6.51 6.50 6.51 6.51 6.51 6.48 6.39 6.39 6.39 6.39 6.39 6.39 ApH / h 0.01 0.03 0.05 0.18 0.60 0.02 -0.01 0.00 0.00 0.03 0.08 0.00 0.00 0.00 0.00 0.00

Addition of 2 x 2 mg / L myristic acid between pH 6.81 and 6.51 and another 2 mg / L at pH 6.39

Example 5:

It produces a mixed culture according to Example 1, but incubated at 35 ° C. A 5-hour onset of pH drop can not be stopped by 11 consecutive additions of 1 mL 1% alcoholic solution of myristic acid per liter of culture, corresponding to 110 mg / L, and a further addition of 4 mL, ie a total of 150 mg / L , This example shows the characteristic difference in behavior between mesophilic and thermophilic mixed cultures. Time (h) 0 1 2 3 4 4.50 4.75 5.00 5.25 5.50 5.75 6.00 6.25 6.50 6.75 7.00 7.25 pH 7.06 7.05 7.04 7.03 7.02 7.01 6.99 6.95 6.90 6.81 6.70 6.55 6.41 6.30 6.19 6.06 5.94 ApH / h 0.01 0.01 0.01 0.01 0.02 0.08 0.16 0.20 0.36 0.44 0.60 0.56 0.44 0.44 0.52 0.48

Addition of 11 x 10 and 1 x 40 mg / L myristic acid between pH 6.55 and 6.30

Example 6:

A mixed culture according to Example 1 is produced. A 4-hour onset of pH drop can be stopped suddenly and sustainably by adding 1 mL of 1% aqueous solution of myristic acid as the potassium salt per liter of culture fluid. It results in a minimum of 12 hours effectiveness at a concentration of 10 mg myristic (as potassium salt) per liter of culture fluid. Time (h) 0 1 2 3 4 4.25 4.50 4.75 5 6 7 8th 9 11 13 15 17 pH 6.92 6.90 6.89 6.89 6.85 6.82 6.75 6.67 6.46 6.46 6.46 6.47 6.46 6.46 6.46 6.45 6.45 ApH / h 0.02 0.01 0.00 0.04 0.12 0.28 0.32 0.84 0.00 0.00 -0.01 0.01 0.00 0.00 0.00 0.00

Addition of 10 mg / L myristic acid as potassium salt at pH 6.46.

Example 7:

A beet extraction plant for the continuous processing of 12,000 tons of beets per day, consisting of an extraction tower and Schnitzelmaischen is operated without the addition of known means for reducing the bacterial activity, such as formalin, dithiocarbamates, hop and resin products. The raw juice contains a lactic acid content of 630 - 790 mg / L. By dosing a soap solution containing 20% myristic acid in a quantity of 200 L each at 9, 13 and 17 o'clock, which corresponds to a dosage of 10 g / t turnip, the lactic acid content during the day can be lowered to 450 - 550 mg / L , The aim would be automatic dosing with uniformly distributed over 24 h doses.

Example 8 Determination of MIC Values: Effect of fatty acids or their alcohols in comparison to fatty acid esters

The minimum inhibitory concentration (MIC) of an antimicrobial substance is considered to be the minimum concentration at which this substance is effective, i. the lower this value, the less antimicrobial must be added to stop the growth of microorganisms. To illustrate the antimicrobial effect in the context of sugar production, experiments with myristin compounds are carried out by way of example.

A liquid nutrient medium, as is common in microbiology, consisting of 10 g Bacto-peptone, 5 g meat extract, 5 g yeast extract, 1 g glucose, 1 g K ₂ HPO ₄ , 0.1 g MgSO ₄ .7H ₂ O and 0.01 g FeSO ₄ * 7H ₂ O per liter of distilled water is sterilized in the usual manner for 20 min at 120 ° C and in a tempered at 65 ° C vessel with 20 ml of raw juice inoculated from a large-scale sugar beet extraction, wherein the pH Value is registered on a recorder. After the growth of thermophilic bacteria, the pH decreases progressively. This indicates acidification caused by microorganisms.

The MIC values are determined by stepwise addition of fatty acid compounds in 10 mg / l steps until stabilization the pH value, which indicates the end of the microorganism growth, or would be excluded in any case up to a maximum concentration of 150 mg / l over the industrial use for economic reasons anyway. The results are shown in the following table: Product (dissolved in ethanol) Min. Remmkonz - (MIC) [mg / l] Propyl myristate no effect at maximum concentration (> 150) Ethyl myristate no effect at maximum concentration (> 150) myristyl 10 myristic 10

The experiments show that the free fatty acid (in this case myristic acid) and its alcohol have an MIC value of 10 mg / l in each case, but the corresponding esters are ineffective in the concentration range tested.

Example 9: Determination of MIC values: myristic and lauric acid

The determination of the MIC values, comparable to Example 8, by stepwise addition of fatty acid compounds in 2 mg / l steps to stabilize the pH, which indicates the end of microorganism growth. The fatty acid compounds used in this example are myristic acid and lauric acid or their potassium salts. The acids were used both individually and in a 1: 1 mixture, the salts exclusively in a 1: 1 mixture. The results are shown in the following table: Product (dissolved in ethanol) Min. Inhibiting conc. (MIC) [mg / l] myristic 6 Myristic and lauric acid (1: 1) 8th Potassium myristate and laurate (1: 1) 8th lauric acid 18

The experiments show that myristic acid (6 mg / ml) can be used successfully in a much lower concentration than lauric acid (18 mg / ml). Surprisingly, with a 1: 1 mixture of both acids (8 mg / ml) a similar MIC could be determined as in the exclusive addition of myristic acid. Similarly efficient was a 1: 1 mixture of both potassium salts (8 mg / ml).

Claims (20)

1. A method of producing sugar or sugar-containing by-products of industrial sugar production, such as beet chip animal feed, carbonated lime, thick juice and molasses, from sugar-containing plant raw materials, characterised in that the production at least partially is carried out in the presence of admixed fatty acids, or the soaps, aldehydes and alcohols thereof, respectively.
2. A method according to claim 1, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, have a chain length of more than 8, in particular more than 10, and of less than 21, in particular less than 20.
3. A method according to claim 1 or 2, characterised in that heptanoic, caprylic, pelargonic, caprinic, undecanoic, lauric, tridecanoic, myristic, pentadecanoic, palmitic, heptadecanoic, stearic, nonadecanoic, arachidic, henicosanoic acid or the associated soaps are used as the fatty acid compounds.
4. A method according to any one of claims 1 to 3, characterised in that the acids, soaps or alcohols of the C₁₀, C₁₂, C₁₄, C₁₆ and C₁₈ fatty acid compounds are used.
5. A method according to any one of claims 1 to 4, characterised in that the fatty acids or the soaps, aldehydes and alcohols thereof, respectively, are used in an amount of from 0.1 to 100 mg/l, preferably from 5 to 40 mg/l, in particular from 10 to 25 mg/l.
6. A method according to any one of claims 1 to 5, characterised in that the fatty acid compounds are used as soaps, preferably as alkaline or alkaline earth salt solutions or suspensions, in particular as potassium salt solutions, in particular as a 0.5 to 35% potassium salt solution.
7. A method according to any one of claims 1 to 6, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, are used as an alcoholic solution or suspension, preferably as a 1 to 95%, in particular a 10 to 80% ethanol solution.
8. A method according to any one of claims 1 to 7, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, are used in combination with further food-compatible antimicrobial agents, in particular in combination with natural, food-compatible resins, hop or hop derivatives or combinations thereof.
9. A method according to any one of claims 1 to 8, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, are at least used in the thermal extraction of sugar-containing plant parts, in particular of sugar beets or sugar cane.
10. A method according to any one of claims 1 to 9, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, are added to the extraction solution with which the sugar is extracted from the sugar-containing plant raw materials.
11. A method according to any one of claims 1 to 10, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, are added at least during membrane treatment methods and/or during ion exchange methods.
12. A method according to any one of claims 1 to 11, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, are used at a sugar concentration of from 0.1 to 80%, in particular 60 to 70%, in particular at a temperature of from 50 to 80°C.
13. A method according to any one of claims 1 to 12, characterised in that the fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, are used during the recovery of the sugar from the thick juice.
14. A method according to any one of claims 1 to 13, characterised in that the plant raw material is sugar beet or sugar cane.
15. An extraction liquid for extracting sugar-containing plant raw materials, characterised in that it contains additionally admixed fatty acids, or the soaps, aldehydes and alcohols thereof, respectively.
16. An extraction liquid according to claim 15, characterised in that it contains additionally admixed natural, food-compatible resins, in particular colophony or colophony derivatives, hop or hop derivatives.
17. A sugar or sugar-containing by-product of industrial sugar production from plant raw materials, obtainable by a method according to any one of claims 1 to 14, having a content of admixed fatty acids, or the soaps, aldehydes and alcohols thereof, respectively.
18. A sugar-containing by-product of industrial sugar production according to claim 17, selected from the group consisting of beet chip animal feed, carbonated lime, thick juice and molasses.
19. The use of fatty acids, or the soaps, aldehydes and alcohols thereof, respectively, in the production of sugar.
20. The use according to claim 19 for inhibiting thermophilic microorganisms, in particular for inhibiting Bacillus, Thermus and/or Clostridia varieties.