DE1567368A1 - Process for the production of starch derivatives - Google Patents

Description

Process for the preparation of starch derivatives The invention relates to Improvements in the synthesis of starch derivatives, the method according to the invention is characterized by @@ ß an alkaline aqueous starch suspension with phosphoric anhydride @urgasetzt, whereby a starch phosphate from the inhibiext-swelling crosslinking Type is obtained.

The primary product is esterified, then neutralized and stenized left, so that a sufficient amount of orthophosphate phate is formed, whereby derivatives result that are acid-resistant, electrolyte-resistant and lower Temperature stable, which have hitherto been produced by using necessary catfish two types of phosphoric acids were used.

These products are useful in the edible grain industry and as paste in the textile industry and elsewhere.

The invention relates to a process for the production of starch derivatives, especially of phosphates and is in the field of agricultural chemistry. With regard to the possible uses of the process-related products the invention also covers the areas of the food industry, the textile industry and the adhesives industry.

Regarding the prior art, it should be noted that it there are two types of phosphoric acid derivatives of starch. One is the diester derivative, that is bound in the networking type.

The other is the monoester derivative which has a phosphoric acid residue with 3 groups of the C6, C2 and C3 positions in the glucose residue of the starch as a monoester is bound. Processes for the preparation of the diester derivative are given in J.Am.Chem.Soc., Volume 72, page 717 (1950) and U.S. Patent 2,928,537, wherein Phosphoroxyahlorid is used. In British Patent 770 565 is a Process described in which sodium trimetaphosphate is used. procedure on the production of the monoester derivative are described in USA patent 2 884412, wherein disodium orthophosphate, monosodium orthophosphate and the like are used.

The applicant asked attempts made to determine the properties of various To regulate starch derivatives according to the intended use and substitutes for the above phosphate crosslinking agents in the field of phosphoric acids and salts of which gas is addicted, that meet the above goals and are more responsive and the phosphate acid renewal in the course of a relatively simple reaction process result. So the applicant has orthophosphoric acid. Sodium orthophosphate, potassium thophosphate, @@@ onium orthephosphate, sodium tripoyl phosphate, sodium metaphosphate, sodium hexametaphosphate, Phosphoric anhydride and the like. Investigated.

In order to regulate the formation of @ert cross-linking bonds of strength, For example, there is the method of observing variations in the source and in solubility and measurement of paste phetography and amylography. in paste photography the veining becomes in the transparency of a watery one Strength refreshment measured while it is @rhitst at a constant rate. In amylography, the change in their Viscosity measured while heating at a constant rate. In paste photography and amylography, we become the community @@. as in Figure 1 and @ vex @@ nsch @ ulicht are, as @@ dices for @ie Beur - @@@ lung de @ education a verne @@ endem @@ ndang used.

It is possible to ground from the starch phosphates obtained above from the network Type various products are obtained, the properties of which are largely dependent on each other varies depending on the degree of venning.

For example, is an elative nis @ rig cross-linked material that is a Bridge to 1000 to 2000 WGE (wesse @ f @ eie Glukeseei @@@@@@ ten) contains, suitable for the production of a high temperature stable, high viscosity paste (paste). In such a highly cross-linked material, as one BrUoke for 100 WGE contains, the swelling is remarkably inhibited and the viscosity is in a neural state quite low. The latter material, however, has a high acidic viscosity Area where a stable paste can be formed. Figure 3 illustrates an amylogram of the material in acidic area.

Such a material is useful in such an area where the viscosity stability in the acidic state is required, in particular as Thickener and as a stabilizer for use in edible condiments, trie sauces, Ketchup, dressings and the like.

Albeit the viscosity stability of the starch due to the manufacturing process of the above crosslinking type starch derivatives is remarkably improved, will a single material that has the property of acid resistance, electrolyte resistance, Aging resistance of the paste at low tea temperature and the like. Equally supplies, needed very often. According to the state of the art, the strength in the Diester derivative converted to the property of acid resistance and electrolyte resistance to lend, while it is transferred to the mono-theater derivative in order to use it with the To provide stability at low temperature. Also in the case if a Derivative is to be produced in which the two requirements should be equally satisfied, orthophosphoric acid su a primary product obtained by terminating the esterification reaction. Be like that according to the prior art, two completely individual reactions are combined closely. Such a method as the above has the drawbacks that several Additions and several types of phosphates are required and at the same time the implementation work steps become noticeably complicated.

According to one feature of the present invention, in the manufacture inhibited-swelling crosslinking type starch phosphate using Phosphoric anhydride provided a method according to which starch is suspended in water, the pH of the aqueous starch suspension is adjusted to alkaline by adding an alkali metal hydroxide or an alkaline earth metal hydroxide is added, phosphoric anhydride in the aqueous Starch suspension hydrated to so several types of phosphoric acid with different Create hydration levels that allow the starch at a temperature below that Gelatinization temperature of the starch and is implemented at a value above 8.0, and from the suspension a starch phosphate of the inhibited-swelling crosslinking type wins. An alkali metal carbonate can be added to the suspension as a buffering agent. to keep the suspension £ Ur in the alkaline range for a long time.

In addition, according to the present invention, the reacted becomes alkaline Suspension neutralized by adding an acid. ben and, left standing is until a sufficient amount of orthophosphate is formed, then the aqueous Phase filtered to obtain a cake that contains a sufficient amount of phosphate has absorbed. The cake is dried and up to a temperature of 110 to Heated to 170 ° C to promote esterification, forming a starch derivative will.

Looking for an agent of a single phosphoric acid or a single salt of them that form mono- and diesters in excellent yields As noted above, it has been found that among various agents studied Phosphoric anhydride and a fresh aqueous solution of it are remarkable crosslinking agents Have an effect. The procedure is described in more detail below.

Phosphoric anhydride is dissolved in water and quiet for a while left to stand, during which a sample is extracted and chromatographed every hour is being developed. Bß is caused by the change in the amount of phosphoric anhydride measured on the elapsed time and the reduction in the amounts of various Phosphoric acids formed therein, such as metaphosphoric acid, pyrophosphoric acid, Orthophosphoric acid and Like., is also measured accordingly. It turns out that the formation of such various phosphoric acids as above mentioned, can be regulated largely independently by the state of the Standing still is varied, especially when the hydration of the phosphoric anhydride begins. However, it has also been found that in each case such polymers such as metaphosphoric acid, pyrophosphoric acid and the like. Formed at an early stage while the amount of orthophosphoric acid increases with the lengthening of the period of standing still gets bigger and bigger.

If the phosphoric acids are reacted with the starch, metaphosphoric acid, Pyrophosphoric acid, tripolyphosphoric acid and the like. Provide the diester bond while Orthophosphorus-X gives the monoester bond, olme diester bond in, form.

@@@@@@ of the present invention making use of the phenomenon ge @@@ cht that phosphoric anhydride in an aqueous solution, as described above, is actively converted, this is used as a diesterifying agent at the early stage of hydration and @ after the diester formation has ended, the liquid reagent by an acid such as phosphoric acid, hydrofluoric acid, sulfuric acid and the like, neutralized. The centralized reagent is left to stand still, until as much orthophosphoric acid has formed as possible. The one absorbed by the starch Orthophosphoric acid is then removed from the mother liquor by filtration along with it separated as a cake which is then debydrated and dried. After drying the phosphate absorbed in the cake is dehydrated and esterified.

According to the invention, the phosphoric acid to be used is the only substance is phosphoric anhydride. It is possible, the only substance Phosphoric anhydride as a monoester-forming agent and as a diester-forming agent for starch according to the rate of active conversion of phosphoric anhydride to use in a solution.

In the method of the present invention, starch comprises as a starting material above-ground starches, such as corn, wise men and the like, and underground starches, such as from the sweet potato, potato, cassava and the like .. pretreated oxidized starch, Acid-treated starch and other chemically processed starches are also used included in the starting material. It is also possible to use the method according to the invention with high starch powder, such as potato powder, sweet potato powder, flour, corn flour and the like, to be acid-proof, electrolyte-proof and low-temperature stable Paste material for food and industry see below.

According to the invention is also achieved by the reaction of phosphoric anhydride with aqueous starch suspension at a temperature below the gelatinization temperature the starch phosphate obtained from the crosslinking type neutralizes except for one pH from 4 to 7.5 by adding an acid such as hydrochloric acid, sulfuric acid, Phosphoric acid or the like is added, and then left to stand still, until the mixture of the various phosphoric acids as far as possible in orthophosphoric acid is converted. This rest period makes several hours to one Day off. After this period, the liquid reagent is filtered, leaving a cake is obtained. After dehydration, the cake has 1 to 7.5 wt% phosphoric acid absorbed on a dry starch basis. The cake is made up to a water content of 20% or less using a draw dryer or other common dryer dried. The dried cake is then heated to a temperature of 110 to 170 ° C to carry out the dehydration and esterification reaction therein.

It is possible to have the properties of the above products within one remarkably wide range depending on temperature and duration carrying out the heat treatment when the temperature is 110 to 170 ° C, to regulate. When using a lower temperature and shorter duration prevail the properties of the diester starch divaso te relatively before, # that the products in terms of the property of acid resistance and electrolyte resistance are superior and have low temperature stability. When the heating temperature is increased and the heating time is lengthened, the diester bond formed first becomes slowly decomposed thermally and at the same time a monoester formation reaction between the absorbed phosphoric acid and starch promoted. Because of these reactions Almost mono-ester derivatives are formed, which form a transparent liquid paste (Xerber) with the property of acid resistance, electrolyte resistance and have excellent low temperature stability.

Due to the regulation of the heating conditions, it is easily possible To obtain starch derivatives that have superior acid resistance property and electrolyte resistance and at the same time have excellent low temperature stability.

The method according to the invention is further characterized in that that the absorbed phosphoric acid in comparison with the phosphoric acid according to the prior art technology is more responsive. When heating continued for 5 to 8 hours take only about 20% of the absorbed phosphoric acid in the formation of the Ester bond in the prior art belongs to the ancestors part while found was that in the process according to the invention about 45 to 55 wt .-% phosphoric acid be associated with strength.

The starch derivatives obtained as above, the superior acid resistance property and electrolyte resistance as well as excellent resistance in the freeze-thaw tests are excellent as viscosity enhancers and humectants For @auce, mayonnaise, ice cream and the like. And also as a stabilizer for canned and chilled foods. Disregard these applications on there In the food industry it is possible to use the starch derivatives as molding agents for medical tablets, paste for printing, separators for the dry cell and Use sizing agents for paper and textiles.

Figure 1 gives an amylogram of typical crosslinked starches in comparison with an untreated starch again, the typical crosslinked starches according to the prior art and which have the characteristic curves thereof in the amylogram as indices for assessing the formation of a crosslinking bond be used.

Figure 2 gives a paste photogram of typical crosslinked starches compared with an untreated starch again, with the typical crosslinked Strengths are manufactured according to the state of the art and their characteristic Curves in the paste photogram as indices for assessing the formation of a crosslink bond be used.

FIG. 3 gives an amylogram of highly crosslinked starches ii comparison with an untreated starch in acidic areas again, being the highly networked Starches are manufactured according to the state of the art.

Figure 4 illustrates the relationship between the variation of Reaction time and the variation in phosphoric acid content in the case of Example 1.

Figures 5 and 6 show a paste photogram and an amylogram, where each shows the variation in the degree of crosslinking in the PaUe of example b is.

FIG. 7 gives a graphic representation of the curves of swelling and the solubility, where the variation in crosslinking @ degree in the case of Biespiel 1 is shown.

FIG. 8 gives an amylogram of a starch derivative prepared according to Example 4 again, wherein the variations in viscosity in the neutralized area and in the acidic area of pH 3 are indicated.

Figure 9 is a graphical representation of curves corresponding to the To illustrate properties of different starch derivatives in a freeze-thaw test.

FIG. 10 gives an amylogram of one produced according to Example 5 Starch derivative again.

The following embodiments are the preferred embodiments illustrate methods of practicing the present invention.

Example 1 12 moles (dry weight 1,944 g) of commercially available corn starch are in 2.4 ltr. suspended in deionized water. 2.4 moles (254.5 g) g) sodium carbonate @ are added. 1.2 mol (170.7 g) of phosphoric anhydride are dissolved in 500 ml of water dissolved while chilling with ice to give a solution that is compatible with the oil Suspension is given. After about 15 minutes of stirring, the suspension will pass through an aqueous sodium hydroxide solution using a glass electrode pIi knife adjusted to pH 11.0. Water is added to the suspension to make up the total volume to bring to 6 liters, in which. a reaction at a temperature of 60 to 700C while the reagent is running at a constant speed of 80 rpm * The resulting product is neutralized with hydrochloric acid, resulting in a precipitate which is washed with deionized water. The washing is repeated until no phosphoric acid and chlorine ions in the excess *) single aliquot volume is withdrawn after every hour. going Liquid can be found. The precipitate is then air-dried in a hood, whereby a crosslinking type starch phosphate is obtained.

The variation in the content of phosphoric acid in this product and variations in the paste photogram, amylogram, in the swell curve and the solubility curve, the former Accompanying variation are illustrated in FIGS. 4, 5, 6 and 7. How from these Graphical representations is evident with the increase, the networking ability the swelling and solubility of the starch are remarkably smaller and the viscosity curve assumes a shape that reflects stability at the elevated temperatures.

Example 2 12 moles of corn starch (2 260 g material containing 13.9% water) are suspended in 1.2 mol of aqueous phosphoric acid solution, which by dissolving of 174 g of phosphoric anhydride in water is made. The pH of the suspension is adjusted to 11.0 by adding sodium hydroxide. The suspension will reacted at a temperature of 6000 for 3 hours, leaving a suspension a strength of crosslinking @@ p is obtained that contains a very small amount of phosphorus contains, but has superior swelling inhibition and ii amylograms lesser Shows decomposition. The crosslinking type starch suspension becomes pH adjusted by orthophosphoric acid. After standing up for one night, the snapension will be filtered, the cake thus obtained on the filter paper is in a fume cupboard air-dried at a temperature of 50 to 6000. When its water level is lower when it has become 20%, the cake is heated to a temperature of i5000 esterified.

The variations in water content and in phosphoric acid content caused by Samples have been obtained every two hours during the reaction period, shown in Table 1.

- Table 1 Reaction time for the esterification (hours) 0 2 4 6 8 Was @ erhalt (*) 12.4 2.4 0.6 0.4 0.2 Bound phosphorus content (%) 0.023 0.23 0.50 0.60 0.63 ratio of esterification of absorbed phosphorus (%) * - 16.1 35.0 42.3 43.8 * The ratio of the esterification of the absorbed phosphorus gives the ratio au phosphorus, which is bound to the starch by means of the esterification reaction The phospher reabsorbed in the cake on the filter paper.

Example 3 12 moles of corn starch (2 260 g material containing 13.9% water contains) are suspended in 0.6 mol of aqueous phosphoric acid solution, which by Dissolving 8.7 g of phosphoric anhydride in water has been prepared. The pH the suspension is adjusted to 10.5 by adding sodium hydroxide.

The suspension is at a temperature below the gelatinization temperature the starch left to react for 5 hours.

After completion of the reaction, the reagent is added by adding Hydrochloric acid neutralized, us lower the pH to 6.50 in. To Standing still for 10 hours, the reagent is filtered to obtain a cake, which is dried. The dried cake is subjected to its esterification on a Heated to a temperature of 125 ° C. The variation in phosphorus content is shown in Table II illustrated.

Table II Reaction time for the esterification (hours) 0 2 4 6 8 Water content (%) 8.4 0.9 0.0 0.0 0.0 Content of bound 0.020 0.17 0.35 0.42 0.44 phosphorus (%) Ratio of esterification of absorbed phosphorus (%) * - 17.9 36.5 43.9 45.6 * The meanings are the same as in Table 1.

Example 4 12 moles of corn starch (2 260 g material containing 13.9% water contains) are in 3 ltr. suspended aqueous phosphoric acid solution, di.

Contains 1.0 mole (142 g) of phosphoric anhydride. The pH of the suspension is adjusted to 11.0 by adding sodium hydroxide. The suspension will left to react at a temperature of 60 ° C for 10 hours, then the reagent neutralized by the addition of hydrochloric acid to bring the pH to 6.80 'humiliate. After standing still for 20 hours, the reagent is filtered, whereby a Cake which is dried. The dried cake turns out sweet Esterification heated, resulting in a phosphoric acid derivative, wherein the monoester-forming Bond is mixed with the diester-forming bond. The characteristics of this Derivatives are illustrated in Table III and Pigur 8 and 9.

Table III Reaction time for the esterification (hours) 0 2 4 6 8 Water content (%) 7.8 1.2 0.7 0.3 0.2 Content of bound 0.055 0.26 0.48 0.60 0.68 phosphorus (%) Ratio of esterification * - 22.6 40.8 51.3 57.8 of the absorbed phosphorus (%) * The meaning is the same as in Table 1.

Example 5 12 moles of potato starch (2,371 g of material containing 18.0% of water contains) are suspended in an aqueous phosphoric acid solution, dte by dissolving of 0.6 moles (85 g) of phosphoric anhydride in water. The pH the suspension is adjusted to 11.0 by adding sodium hydroxide.

Diester formation takes place at a temperature of 50 ° C for 24 hours carried out with slow stirring in the aqueous suspension. Then the reagent neutralized by adding sulfuric acid to lower the pH to 7.0 in. After standing for 20 hours, the resagen is filtered to give a cake which is then dried.

The dried cake becomes his up to a temperature of 145 ° C Esterification heated. The esterified product is washed three times with 50% methanol and dried. Every 2 hours a sample is taken in the form of an aliquot volume drawn. The variation in phosphoric acid content in these samples and an amylogram are illustrated in Table IV and Figure 10, respectively.

Table IV Reaction time for esterification (hours) 0 2 4 6 8 Phosphoric acid content (%), (based on the dry basis of the product) 0.076 0.33 0.51 0.60 0.64 example 6 0.3 mol of phosphoric anhydride (42.6 g) are in 5 1tr. deionized water dissolved and left to stand for 20 minutes and there are 10 moles of sweet potato starch (1,976 g of material containing 18% water) suspended. The pH of the suspension is adjusted to 10.70 by adding potassium hydroxide.

The suspension is subjected to the crosslinking reaction, while it is stirred at a speed of 80 rpm for 8 hours while at a Temperature of 550C is maintained.

The resulting reaction product is adjusted to pH with the addition of Hydrochloric acid decreased to 6.50 and stand at room temperature for 15 hours left to allow the rehydration of the phosphoric acid and its absorption into the starch granules progresses. The product is then filtered under reduced pressure, whereby a cake is obtained which is up to a water content of 10% in a rotary hot air dryer is dried. The dried cake is then dehydrated and kept at a temperature of 165 ° C in a reaction vessel equipped with a stirrer at 40 rpm, transferred to the monoester. Table V shows the variation in phosphoric acid content, which follows the progress of the reaction. The phosphoric acid content is 0.017 % when the diester formation has ended.

Table V Reaction time for monoester formation (hours) 0 2 4 6 8 Phosphoric acid content (%), based on the dry basis of the product 0.017 0.18 0e52 0264 0.69 Through the In response, the properties of sweet potato starch paste are remarkably improved. In particular, it is possible to make a paste with high viscosity that will enhance the character after "short" is, high transparency and high stability during storage in receive the cold su.

Numerous modifications of the present invention will be apparent to those skilled in the art Invention at hand without leaving the scope of the invention see below. The described specific embodiments are intended only to illustrate the invention to serve.

Claims (5)

Claims 1. A process for the production of starch phosphates of the inhibited-swelling crosslinking type by means of phosphoric anhydride, thereby marked that @an a) suspends starch in water, b) the pH of the suspension medium the aqueous starch suspension by adding an alkali metal hydroxide and / or Alkaline earth metal hydroxide, c) phosphoric anhydride in the aqueous Starch suspension hydrated to several types of phosphoric acids with different Degree of hydration to form, bringing the starch at a temperature below the gelatinization temperature of the starch and at a pH above 8.0, and d) a starch phosphate of the inhibited-swelling crosslinking type from the suspension. 2. The method according to claim 1, characterized in that in the suspension a puff @@ ittel is given to keep it alkaline for a long time. 3. The method according to claim 2, characterized in that the buffer means is an alkali metal carbonate. 4. The method according to any one of the preceding claims, characterized in, that the pH of the suspension is maintained at 8.0 to 12.0 by regulation. 5. A process for the production of a starch derivative, characterized in that that a) an alkaline suspension of a starch phosphate according to one of the preceding Manufactures claims, b) the alkalinity of the suspension by adding an acid neutralized, c) the neutralized suspension is left to stand until it has a sufficient amount of orthophosphate is formed, d) from the orthophosphate Suspension obtained by filtering off a cake, e) the cake is dried, f) the Heat the cake to a temperature of 110 to 170 ° C, to the To promote esterification, and g) the starch derivative wins that simultaneously from Monoesters and diesters of the crosslinking type. R e r s e i t e