CA1056200A - Dough-improver tablets containing strong oxidizing agents - Google Patents

Abstract

Abstract of the Disclosure A multi-layer tablet for improvement of dough comprising a layer comprised of strong oxidizing agent, a layer comprised of flour and dough additive of an organic material, and interposed between said layers and separating same, a layer comprised of insert salt.

Description

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This invention relates to a tablet containing a strong oxidizing agent useful as a flour additive for improving the handling properties of dough and the quality of bread and other bakery pro-ducts prepared therefrom. More particularly, this invention con-cerns a multi-layer tablet composed of a layer comprised of strong oxidizing agent (a flour and dough improver), a layer comprised of a conventional flour and dough additive of an organic chemical nature, and interposed between said layers and separating same, a layer comprised of a salt which is inert with respect to the mat-erials in the layers separated thereby and is edibly acceptable as a filler for flour additive compositions.
Combinations of strong oxidizing agents with dough add-itives of organic chemical nature have a long history of use in the baking industries. There are a number of advantages in having the combination of ingredients in a unitized form such as a tablet;
for instance, only a single addition by the baker is required, simplifying the operation; accurate and reliable dosage is assured;
and weighing of separate ingredients or multiple additions of single ingredient tablets is eliminated.
It has been noted in the flour additives art that com-positions comprised of concentrated powdery or granular mixtures of a strong oxidizing agents with an organic material additive may present some hazard when subjected to impact and possible heat generated when the mixtures are compacted into a tablet (a tablet is the physical form of flour and dough additives preferred for use in the bread-making process). This invention provides a safer tablet comprised of said ingredients with regard to reduction of any fire and/or explosive decomposition potential. The article of

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this invention is a multi-layer tablet in which a layer of inert salt is interposed between the layer comprised of strong oxidizing agent and the layer comprised of organic additive, thereby effect-ively separating such flour improving substances and eliminating their coaction during manufacture and storage. Advantageously, the inclusion of the salt barrier layer in the tableted article em-bodied herein does not diminish the efficacy of the active ingred-ients in carryin~ out their improving and maturing functions in the flour and resultant dough. Further details of the invention are presented hereinbelow.
Materials illustrative of the strong oxidizing agent portion of the novel tablet include the alkali metal and alkaline earth metal bromates, iodates, chlorites, periodates and peroxides, for example, potassium bromate, potassium iodate, sodium bromate, sodium iodate, calcium bromate, calcium iodate, magnesium bromate, magnesium iodate, sodium peroxide, calcium peroxide, sodium chlorite, potassium periodate, and the like. The most widely-used oxidizing agents for flour and dough are potassium bromate, potassium iodate, calcium iodate and calcium peroxide. There may be mixed with the oxidizing agent various particulate additives (powdery or granular) known in the flour additives and tableting arts; for instance, tableting aids such as microcrystalline cellulose or magnesium stearate (up to about 10% by weight based on the weight of oxidizing agent); materials that cause disintegration of the tablet when contacted with water in the baking process, for example, a mixture of sodium carbonate and sodium acid pyrophosphate, sodium aluminum phosphate or monocalcium phospate (up to about 5% of each); and one or more inert fillers, such as dicalcium phosphate, monocalcium :
-' - i056ZC~0 phosphate, tricalcium phosphate, sodium sulfate, calcium sulfate, magnesium sulfate, sodium chloride, magnesium chloride, magnesium carbonate and the like. Generally there is on the order of 5 to 10% of filler in the oxidizing agent layer. It is understood, however, that the upper limit of filler is one only of practicality because even though the inert filler provides an extra safety factor, it will also contribute to the si7e of the tablet; it is desirable to produce a safe tablet which is as small as possible for convenience in manufacturing, packaging and distribution.
The interposed or barrier layer of the tablet, that is, a protective layer separating the layer comprised ofoxidizing aqent and the layer co~prised of organic additive, is comprised of at least one inert salt, that is, inert with respect to the active flour treating ingredients and other tablet additives, and which is, of course, edibly acceptable in food products. The inert salt may be the alkali metal or alkaline earth metal salt of an in-organic or organic acid, and may be anhydrous or hydrated. Re-presentative inert salts are Ca3(PO4)2; CaHPO4; A12(SO4)3; Na2HPO4;

NaCl; CaHPO4-2H2O; A12(So4)3-9H2o; A12( 4 3 2 4 2 g 2 2 ; 2 4 2 ; ( 2 4)2 2 ; 2 3- 2 ; 2 4 lOH2O; Na2HPO4.7H2O; KNa tartrate; 4H2O; sodium citrate.2H2O;
calcium citrate.4H2O; calcium lactate.5H2O; and the like. The preferred barrier layer salts are hydrated because of the added protection against fire afforded by the water of hydration. Pre-ferred hydrated salts are CaHPO4.2H2O and Ca(H2PO4)2.H2O. This barrier or so-called "buffer" layer composition may have admixed therein other ingredients such as the various tableting aids and disintegration substances mentioned earlier (up to about 5% of each) 1~56~0(~

,ll~d ~) to ~O~It 70'(, 0~ othcr fil]er~ such as silicon dioxide and talc.
The orc3anic l.ayer of the multi-layered tablet èmbodied herein is comprised of at least one organic material used in flour and dough treatment, which may be in admixture with the f-il.l.crs, additi.ves, tabletinc~ aids, and tablet disintegration materials previously mentioned as compatible with the oxidiziny agellt layer and the bu~fer layer. A widely-used organic substance for flour additi.on is a flour ma-turinc~ agent in par-~iculate form, fully described in U.S. Patellt 2,903,361, seleeted from the class of amides, amidines and mixed ester-amides of azodicarbonic acid, which compounds may be represented by the structural formula Rl-C-N=N-C-R

where in the case of amides, R3 and R are each an oxygen atom, and R1 and R are each NH2 groups, either substituted or unsub-stituted; in the case of amidines, Rl and R2 are as above and R
and R4 are each an N~l radical; i.n the case of the mixed ester-amides, R3 and R are each oxygen, R is NH2, substituted or un-substituted, and R is alkoxy. The preferred flour maturing agentfrom this class is azodicarbonamide.
Other organi.c flour additives includeglutha-thione and L-cysteine, either in the form of the I~C1 hydrate or cysteine-N-carbamide, which serve as dough conditioning aids to reduce flour mixing requirements; enzymes such as protease, amylase and lipoxi-dase; ascorbic acid which serves as a dough conditioning agent or flour maturing agent; and organic peroxides, for example, acetone peroxide and benzoyl peroxide, which serve as maturing and bleach-ing agents.

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The multi-layered tablets of this invention may be prepared using conventional tableting machinery, such as, for example, the Stokes "566"* Series multi-layer tableting presses (product of Pennwalt Corporation).
The size of the tablets are generally designed for the convenience of the baker to provide from about 5 to about 100 ppm of oxidizing agent per 100 pounds of flour. Consequently, -the total weigh-t of the tablets will in general range from about 1 gram to about 10 grams; their size will, accordingly, be on the order to about 0.25 to 1 inch in thickness with a diameter ranging from about 15/32 to about 5/8 inch. It is of course understood that the size of the tablets may vary, nonetheless, over a wide range depending on their partlcular constituencies and the dosage of ingredients desired in the particular baking operation. In general, however, the proportion of oxidizing agent layer of the tablet will be in the range of about 40% to about 60% based on the weight of the tablet and the organic substance layer will comprise from about 35 to 50% of the tablet. The buffer (barrier) layer may vary in weight and thickness according to the diameter and thickness of the tablet. Although the weight of this layer will generally be from about 1 to 10~ of the tablet weight, there is no critical limitation on the amount of the barrier layer, but one of practical-ity consistent with fabricating a tablet of reasonable thickness and bulk; the lower limit is that which will effectively separate the active agent oxidizing layer and the organic layer.
When the various constituents comprising the individual layers of the tablet, that is, the oxidizing agent, the inert salt, * Trade Mark ....

- lOS6;~00 and orgallic material, and optionall~ t:l-e sundry tablet additives ancl fillers as aforementioned, were ulliform]y mixed together and attempts made to form the pulverulent mixture into a homogenous tablet, i.e., a "single-layer" -tablet, serious shortcomings re-sulted. The powc~er blend had inadequate flowability and would not properly feed to the tableting machine. When in the machine, there was binding and sticking oE the plunger face and die wall, and tablet capping and laminations. The dispersion or disintegration time of the homogenous tablet was also -Eormed to be beyond practical limits; more specifically, the safe multi-layered tablet of the invention will disperse in the yeast broth (i.e., aqueous yeast suspension) within 15 -to 60 seconds. In contrast, a single-layer tablet requires from 3 to ]5 minutes or more for dispersal. More-over, the shelf life of the single-layer tablet was found to be only two to three days compared to greater than 120 days for the tablet of the invention.
Several standard tests which have been developed to gauge the fire hazards and explosive (decomposition) tendencies of substances are useful in evaluating the tablets of this invention.
The first of these is the Modified Trauzl Block Test which measures the sensitivity of the test sample to a blasting cap shock and the potential energy released under these conditions. Quantitative measurement is made by measuring the degree of expansion of a lead block into which 6 grams of substance in a sample vial is placed in contact with a No. 8 electric blasting cap. The volume of the lead block is measured before and after detonation to the nearest halfmilliliter using water as a reference medium. The increase in the volume of the block is reported as the "Trauzl number". The ~ - ~
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10~6~'00 minimum expansion is the result obtained using water as the test material, which gives an expansion of 7.0 ml., or a Trauzl number of 7. The maximum expansion which can be sustained by the lead block, before rupturing, is llS ml. or a Trauzl number of 115.
For the kind of compositions involved herein, Trauzl numbers of 25 and below are regarded as designating safe tablets and materials.
Another test for gauging safety of the tablets is the "Impact Sensitivity" test in which the test apparatus, a DuPont Impact testing machine, is set at a desired height. A 30 milli-gram sample is placed in the center of the drop test cup. Thecup is placed on the anvil, under the plunger pin assembly and the weight dropped. This operation is repeated at several different heights. A report and/or smoke and obvious decomposition of the sample is considered a positive result. If none of these properties is observed, the result is considered negative.
Another means for measuring relative proneness to fire and explosion is the "Hot Plate" test in which a 5 g sample is weighed into a 2-1/2" diameter x 5/8" deep aluminum dish, which is placed on the hot plate maintained at 500 or 600F. The behavior of the sample is observed and recorded.
Yet another test for evaluating safety of the tablets is the flame test in which the flame of a Bunsen burner is held to the test tablet for five seconds, then withdrawn, and observations noted.
The following examples present illustrative articles of the invention and comparisons with single-layer tablets and powder mixtures. In the examples the weight of the tablets range from

3 to 3.3 grams and their sizes are 5/8 inch in diameter with thick-ness varying from 5/8 to 3/4 inch. All proportions of ingredients are given in percents by weight.

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Example 1 A single-layer tablet is prepared from a mixture of pulverulent materials as follows:

Potassium bromate ~95%) 56.6 %
Azodicarbonamide 27,45%
Dicalcium phosphate.2H2O 14.5 %
Microcrystalline cellulose *
("Avicel") 1.0 %
Sodium Carbonate 0.2 %
Sodium acid pyrophosphate 0.25%
The results from hazard tests for the blend are as follows:

6 g Sample Powder Trauzl number - 115 Powder Impact Sensitivity - Explosion at 18 inches Hot plate test at 600F.
Fire - None Decomposition - Very violent; propagation to complete decomposition in 15 seconds Smoke - Yes; in 5 seconds Residue - White Tablet flame test: violent decomposition, pro-pagation of decomposition, ignition and smoke.
Example 2 A single layer tablet containing a significant amount of highly hydrated inorganic salt is prepared having the following composition.

Potassium bromate (95%) 56.90%
Azodicarbonamide 27.55%
Aluminum sulfate.l8H2O 7.00%
Disodium orthophosphate.l2H2O 8.55%

6 g Sample Powder Trauzl number - 88 Powder Impact Sensitivity - Negative at 20 inches Hot Plate Test at 500F.:
Fire - None Decomposition - Moderate; did not propagate Smoke - Light Residue - White The tableting characteristics of this composition are inadequate as evidenced by poor flowability and sticking of material g * trade mark ., . .

~S6~100 to the plunger face and die wall. Storage stability characteristics of these tablets are also deficient as noted by their disintegration in storage containers after 3 to 5 days.
Example 3 Another single-layer tablet, containing a hydrated salt in a significant amount, is prepared as follows:

Potassium bromate 40.0%
Azodicarbonamide 20.0%
Dicalcium phosphate.2H20 36.3%
Sodium Carbonate 0.7%
Sodium acid pyrophosphate 1.0%
Magnesium stearate 1.0%
Silica ("Cabosil")* 1.0%
6 g Sample Powder Trauzl number - 20 Powder Impact Sensitivity - Negative at 35 inches Hot Plate Test at 500~F.:
Fire - None Smoke - Yes; 10 seconds Residue - gray Tablet Decomposition - Rapid; propagation; complete decomposition in 25 seconds.
Tableting characteristics are poor because of insufficient flow-ability and difficulty in filling the die chamber.
Tablet Disintegration Test - Slight dispersion after 16 minutes;
tablet mostly solid, but soft.
(In this test tablets are placed in a beaker of water and observed until they have completely lost their original form. Due to the relative insolubility of the ingredients, a granular mass remains on the beaker bottom. The disintegration time is measured, from the moment of tablet immersion until it has crumbled completely and all motion within the granular mass has ceased).
Example 4 A single-layer tablet containing no hydrated salt is prepared composed of:

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- Potassium bromate (95%) 40.0%
Azodicarbonamide 20.0%
Salt(NaCl) ~ -38.3%
Sodium Carbonate 0.7%
Sodium acid pyrophosphate 1.0%

6 g Sample Powder Trauzl number - 50 Powder Impact Sensitivity - Postive at 35 inches Hot Plate Test at 500F.:
Fire - None Smoke - Yes; 5 seconds Residue - White Tablet Decomposition - Very rapid; propagation; complete decom-position in 15 seconds.
Tablet Disintegration Test - Completely dispersed after 3 minutes.
Example 5 Another single-layer tablet containing significant pro-portions of other hydrated salts has the following composition and properties:

Potassium bromate (95%) 40.0%
Azodicarbonamide20.0%
Salt (NaCl) 12.3%
Calcium lactate.5H2O12.0%
Magnesium chloride.6H2O 12.0%
Sodium carbonate 0.7%
Sodium acid pyrophosphate 1.0%
Magnesium stearate1.0%
Silicone Dioxide (Cobosil) 1.0%

6 g Sample Powder Trauzl number - 19 Impact Sensitivity - Negative at 35 inches Hot Plate Test at 500F.:
Fire - None Smoke - Yes; 20 seconds Residue - Black Tablet Decomposition - slow; propagation; complete decomposition in 85 seconds.
Tablet Disintegration Test - No dispersion after 18 minutes; tablet still hard and solid.
This composition also tableted poorly because of lack of flow-ability and excessive stickiness.
_ample 6 A three-layer tablet comprised of the following layers is prepared:

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1056Z~0 oxidizing Laye _(50.1% of Tablet) Potassium bromate (95%) 90. 06 Dicalcium phosphate.2H~O(unmilled) 5.0%
Microcrystalline celluIose 2. 5~6 Sodium carbonate 1.0%
Sodium acid pyrophosphate 1.5%

Buffer (Middle) Layer ~6.7% of Tablet) _ _ _ _ Dicalcium phosphate 80.0%
Salt(NaCl) 10.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate3.0%
Tricalcium phosphate 5.0%

Organic Layer (43.2% of Tablet) Azodicarbonamide 50.0%
Dicalcium phosphate.2H20(unmilled) 35.0%
Salt(NaCl) 5.0%
Microcrystalline cellulose 5.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate 3.0%
Tablet Disintegration Test - Completely dispersed after 25 seconds.
Tablet Flame Test: Slight, mild decomposition; no propagation; no ignition.
Hot Plate Test at 500F :
Fire - None Smoke - Yes; 5 seconds Residue - White Tablet Decomposition - Light to moderate; no propagation.
5.3 g Powder Sample of Oxidizing Layer,(a) Trauzl number - 18 5.3 g Powder Sample of Organic Layer( ), Trauzl number - 9 10.6 g Powder Sample of Mixture of All Layers(b), Trauzl number - 75 10.6 g Sample of eight-1/2" diameter Tablets(C), Trauzl number - 20 Notes: (a) The composition and weight of these powder samples was equivalent to combining the respective layers of eight of the 3-layer tablets.
(b) The composition and weight of this powder sample was equivalent to a mixture of'eight of the tablets. The reduced Trauzl number for the tablets(C) demonstrates their improved properties.

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i~S6'~0 Example 7 _ _ three-layer tablet is formed, composed of the following:
Oxidizing Layer (0 62 gram Potassium bromate (95%) 90.0%
Dlcalcium phosphate.2H O(unmilled) 5.0%
Microcrystalline cellu~ose 2.5%
Sodium carbonate 1.0%
Sodium acid pyrophosphate 1.5%
Barrier Layer (0.1 gram) Dicalcium phosphate.2H2O(unmilled) 80.0%
Salt(NaCl) 10.0%
Sodium carbona-te 2.0%
Sodium acid pyrophosphate 3.0%
Tricalcium phosphate5.0%
Organic Layer (0.79 gram) Ascorbic acid 50.0%
Dicalcium phosphate.2H O(unmilled) 40.0%
Microcrys-talline cellu~ose 5.0%
Sodium Carbonate 2.0%
Sodium acid pyrophosphate 3.0%
Tablet Flame Test ~ slight and slow decomposition; no ignition;
no smoke.
Example 8 A three-layer tablet is prepared, composed of the following:

Oxidizing Layer (0.88 gram) -- -- --Calcium peroxide 50.0%
Dicalcium phosphate.2H 0(unmilled) 40.0%
Microcrystalline cellu~ose 5.0%
Sodium Carbonate 2.0%
Sodium acid pyrophosphate 3.0%
_rrier Layer (0.1 gram)_ _ _ Dicalcium phosphate.2H20(unrnilled) 80.0%
Salt(NaCl) 10.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate3.0%
Tricalcium phosphate 5.0%

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Organic Layer ~0.54 gram) Ascorbic Acid 50.0%
Dicalcium phosphate.2H 0(unmilled) 40.0%
Microcrystalline cellu~ose 5.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate 3.0%
Tablet Flame Test - slight and slow decomposition; no ignition;
no smoke.
_xample 9 A three-layer tablet is made of the following constituents:
Oxidizing Layer (0.7 grams) Potassium iodate (granular) 50.0%
Dicalcium phosphate.2H O(unmilled) 40.0%
Microcrystalline cellu~ose 5.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate 3.0%
Barrier Layer (0.1 gram) Dicalcium phosphate.2H2O(unmilled) 80.0%
Salt (NaCl) 10.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate 3.0%
Tricalcium phosphate 5.0%
Organic Layer (0.7 gram) Azodicarbonamide 50.0%
Dicalcium phosphate.2H2O(unmilled) 40.0%
Microcrystalline`cellulose 5.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate 3.0%
Tablet Flame Test - even less decomposition than Examples 7 and 8.
Example 10 A three layer tablet is made of the following components:
Oxidizing Layer (0.33 gram) Potassium bromate (95%) 90.0%
Dicalcium phosphate.2H2O(unmilled) 5.0%
Microcrystalline cellulose 2.5%
Sodium carbonate 1.0%
Sodium acid pyrophosphate 1.5%

5620~) _rrier Layer (0.l qram)__ _ _ _ _ Dicalcium phosphate.2l~20(unmilled) 80~0~
Salt(NaCl) 10.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate3.0%
Tricalcium phosphate 5.0%

Organic Layer(l.l grams) _ _ _ . _ _ _ L-cysteine.~ICl hydrate50.0%
Dicalcium phosphate.2H~O(unmilled) 40.0%
Microcrystalline cellu~ose 5.0%
Sodium carbonate 2.0%
Sodium acid pyrophosphate 3.0%

Tablet Elame Test - Somewhat more vigorous decomposition than Examples 7 and 8; slight smoke; no ignition.

In the Bunsen burner test, a hazard evaluation rating system has been devised for comparative purposes. In the numbering system of l through 10, the best flame rating (most resistant to decomposition and ignition) is assigned the number 1; the poorest rating (least resistant to decomposition and ignition) is assigned the number 10. The following table summarizes the flame rating comparisons of overall powder mixtures, i.e., as a single layer tablet, with the three layer tablets described in Examples 7-10.

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Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A multi-layer tablet for improving flour and dough comprising a layer comprised of strong oxidizing agent, a layer comprised of organic chemical flour and dough additive, and inter-posed between said layers a barrier layer comprised of a salt which is inert to said other layers and is edibly acceptable as a filler for flour additive compositions.

2. A tablet according to claim 1 in which the strong oxidizing agent is an alkali metal or alkaline earth metal bromate, iodate, chlorite, periodate or peroxide; the organic chemical flour and dough additive is selected from the group consisting of amides, amidines and mixed esteramides of azodicarbonic acid, glutathione, L-cysteine.HCl hydrate, cysteine-N-carbamide, ascorbic acid, organic peroxide, and enzymes; and the inert salt is an alkali metal or alkaline earth metal salt of an inorganic or organic acid.

3. A tablet according to claim 2 in which the oxidizing agent is selected from the group consisting of potassium bromate, potassium iodate, sodium bromate, sodium iodate, calcium bromate, calcium iodate, magnesium bromate, magnesium iodate, sodium pero-xide, calcium peroxide, sodium chlorite and potassium periodate.

4. A tablet according to claim 2 in which the inert salt is selected from the group consisting of Ca3(PO4)2, CaHPO4, Al2(SO4)3, Na2HPO4, NaCl, CaHPO4.2H2O, Al2(SO4)3.9H2O, Al2(SO4)3.18H2O, MgSO4.
7H2O, MgCl2.6H2O, Na2HPO4.12H2O, Ca(H2PO4)2.H2O, Na2CO3.10H2O, Na2 SO4.10H2O, Na2HPO4.7H2O, KNa tartrate.4H2O, sodium citrate.2H2O, calcium citrate.4H2O, and calcium lactate.5H2O.

5. A tablet according to claim 2 in which the strong oxidizing agent is selected from the group consisting of potassium bromate, potassium iodate, calcium iodate and calcium peroxide.

6. A tablet according to claim 2 in which the organic flour and dough additive is azodicarbonamide.

7. A tablet according to claim 5 in which the organic flour and dough additive is azodicarbonamide.