Abstract:
With a process for manufacturing compostible thin-walled molded articles such as cups, plates, fast-food packagings, trays, flat sheets and the like, by applying a starch-based baking composition on the lower part of a multipart, preferably bipartite mold, to obtain a tough, durable article of high mechanical stability by using an essentially fat-free baking composition composed of water, a starch product, a release agent, and optionally further conventional additives, by baking the baking composition filling the mold, and by conditioning the resulting product to establish a moisture content of 6-22% by weight, the invention proposes the use, in addition to or instead of starch, of at least one modified starch selected from the group comprising starch esterified with organic acids or phosphoric acid, etherified starch, cross-linked starch and starch capable of being modified by ionic interaction.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a process for manufacturing compostible thin-walled molded articles such as cups, plates, fast-food packagings, trays, flat sheets and the like, by applying a starch-based baking composition on the lower part of a multipart, preferably bipartite mold, to obtain a tough, durable article of high mechanical stability 
     1) by using an essentially fat-free baking composition that is composed of 
     a) 42.0-60.0% by weight, preferably 45.0-56.0% by weight, water, 
     b) 36.0-56.5% by weight, preferably 38.0-52.0% by weight, of a starch product 
     c) 0.04-11% by weight, preferably 0.2-4.5% by weight, of one or more medium- or long-chain, optionally substituted fatty acids and/or salts thereof and/or acid derivatives thereof, e.g. acid amides, as a release agent--optionally using 0.5-6.5% by weight, preferably 0.1-4.2% by weight, of polymethylhydrogen siloxanes in combination with said compounds, or as a partial or occasionally as a complete substitute thereof, such that, when both groups of compounds are used and the concentrations of fatty acids and derivatives thereof are high, normally the concentration of polymethylhydrogen siloxanes is best not allowed to exceed 3% by weight, and optionally thickening agents such as swell-starch, pregelatinized starch or baking wastes, and/or guar gum, pectin, carob gum, carboxymethylcellulose and/or gum arabic; fibrous materials such as high-cellulose raw materials, vegetable raw materials, fibers of plastics, glass, metal and carbon; non-fibrous fillers such as calcium carbonate, carbon, talc, titanium dioxide, silica gel, alumina, shellac, soybean protein powder, wheat gluten powder, chicken egg protein powder, casein powder, and caseinate powder; colorants; preservatives and antioxidants; 
     2) by baking the baking composition filling the mold, and 
     3) by conditioning the resulting product to establish a moisture content of 6-22% by weight. 
     Such a process is described in our U.S. Pat. No. 5,376,320. Various starches and/or flours and flour mixtures are used as starch products there. 
     SUMMARY OF THE INVENTION 
     The type of starch used to produce the molded articles together with the co-use of additives and the manufacturing conditions determine the properties (weight, density, mechanical properties and the like) of the resulting product. 
     It has surprisingly been found that the molded articles show significantly increased stability when in addition to or in lieu of starch at least one modified starch chosen from the group comprising starch esterified with organic acids or phosphoric acid, etherified starch, cross-linked starch and starch capable of being modified by ionic interaction is used. 
     While the starch derivatives used to date in the known formulations have been employed mainly because of their thickening action, e.g. pregelatinized starch, thereby keeping a check on sedimentation of individual ingredients of the baking composition, the additives of the invention are found to have an effect on structure formation and stability. 
     Starch, most important natural starches consisting of amylose (17-31%) and amylopectin (69-83%), is organized in granular structure, one grain consisting of a large number of amylose and amylopectin molecules of high chain length (greater than 1000 glucose units). Per glucose unit 3 OH groups of amylose are available for substitution, equally so with amylopectin, with the exception of the branching positions, here 2 free OH. 
     Starch derivatives are characterized by several important indicators: 
     DS (degree of substitution) average number of substituted positions per glucose unit Maximum=3, frequently used from less than 0.001 to 0.2, i.e. less than 1 to 200 substituted positions per 1000 glucose units % substitution (% by weight substituents in total dry substance) 
     Indication of DS or % substitution is depending on method of derivatization and determinability. 
     The said starch derivatives (esterified starch, etherified starch and cross-linked starch) are outwardly (microscopically) unchanged granules of starch. They must show two mutually balanced activities. 
     1. Facilitation of swelling of the grain by monofunctional esterification, etherification i.e. water binding and gelatinization at lower temperatures. Consequence: faster, further-reaching gelatinization during the baking process, thus better exploitation of the &#34;binding force&#34; of starch. 
     2. Cross-linking of grain structures limiting swelling, water is absorbed and retained, but no unlimited swelling and thus bursting of the grain. A denser and more stable structure as a result. 
     1a) esterification with organic acids: ##STR1## 
     R=CH 3  acetylation, DS up to 0.12 
     R=CH 2  --CH 2  --COOR 1  succinylation, max. 4% succinic anhydride 
     R 1  =H, Na or other counterion, depending on pH and salts/bases used 
     R=CHR 2  --CHR 3  --COOR 1 , alkenyl succinylation, max. 3% alkenyl succinic anhydride 
     R 2  =H and R 3  =alkenyl or 
     R 2  =alkenyl and R 3  =H 
     Alkenyl=Octenyl, decenyl for example 
     
         ______________________________________Example:                   Gelatinization                   temperature______________________________________Corn starch             62-72° C.acetylation at DS            0.04   56-63° C.            0.08   48-56° C.(R = COCH.sub.3) 0.12   41-51° C.______________________________________ (Leach et. al, Cer. Chem 36, 564, 1959) 
    
     
         Example: succinic acid ester         Gelatinization                    Swelling         temp.      at room temp.% substitution         degrees C. ml/25 g______________________________________0             72         341             67         352             65         403             63         474             58         49______________________________________ (O. B. Wurzburg, Modified starches, CRC Press, 1986, p. 133) 
    
     The esters are not stable under alkaline conditions, therefore etherification is preferable. 
     1b) Monofunctional esterification with phosphoric acid: ##STR2## 
     R=H, Na or other counterion, depending on pH and salts/bases used 
     DS=0.005-0.1, preferably less than 0.05, max. 0.5% P in the derivative; from approximately DS 0.07 upwards gelatinization at room temperature. 
     1c) Etherification: starch--OH→starch--O--R 
     R=CH 2  --CH 2  --OH hydroxyethyl ether 
     R=(CH 2 ) 3  --OH hydroxypropyl ether 
     DS=0.01-0.2, preferably 0.02 to 0.1 
     The substitution effects described apply in principle to all important types of starch (corn, potato, tapioca, wheat) as well as to cationic starches. 
     The influence of cross-linking is of particular importance with potato starch, as it shows extreme swelling and dissolution of the granular structure. 
     
         ______________________________________  water      mean aggregate  absorption volume     packing  g/g starch ml/g       density______________________________________corn     15.1         35.5       0.45potato   115.0        405.0      0.24tapioca  21.9         59.5       0.38______________________________________ (Evans, Haisman, J. Texture Studies 10, 347, 1979) 
    
     2) Cross-linking: 
     1. Phosphate cross-linking with sodium trimetaphosphate or phosphorus oxychloride ##STR3## R=H, Na or other counterion, depending on conditions DS=1.10 -4  to 1.10 -2 , preferably 5.10 -4  to 5.10 -3 , max. phosphorus content 0.14% (0.04% from cross-linking) 
     2. Dicarboxylic acid cross-linking 2 starch--OH→starch--O--CO--(CH 2 ) n  --CO--O--starch e.g. n=4: adipic acid cross-linking, max. 0.12% adipic anhydride 
     3. Glycerol cross-linking 2 starch--OH→starch--O--CH 2  --CHOH--CH 2  --O--starch max. 0.3% epichlorohydrin or 0.6% acrolein 
     The importance of cross-linking becomes apparent when observing the processes related to increasing swelling and gelatinization. 
     The water absorption, reversible up to approximately 50° C., and swelling of starch granules increases as the temperature rises. Partly crystalline structures are dissolved and viscosity increases strongly, as the increasingly swelling starch granules increasingly bind the free water. Parts of the starch, especially amylose, are released and serve as glue. As swelling continues, the swollen granules are destroyed and viscosity decreases markedly, especially in the case of potato starch. 
     This excessive swelling is to be prevented by slight structural cross-linking. 
     The preferable derivative according to the invention is: 
     1. a starch ether (hydroxypropyl ether): thereby swelling and gelatinization at lower temperatures and simultaneously 
     2. a cross-linked starch (phosphate-ester linkages): limiting and slowing down swelling, water being better bound, no bursting of the granular structure. 
     Other derivatives with similar characteristics are: 
     1) Starch esters for example with a) acetic acid, b) succinic acid, c) phosphoric acid, or d) alkenyl succinic acid; thereby earlier swelling and gelatinization. 
     2a) Cross-linking via dicarboxylic acid, phosphate and glycerin groups to limit swelling and bursting 
     2b, c) No chemical cross-linking, but free carboxylic groups, native or by substitution, such as from succinic acid, octenyl succinic acid. These groups also lead to products with greater density and strength due to coordination compounds with bivalent and trivalent ions (Ca, Mg, Al) and with silicates. 
     The degree of substitution of the starch derivatives should be less than 0.2. 
     Generally speaking, the gelatinization temperature should be lowered by at least 2° C., preferably 5° C., by derivatization to observe an effect. 
     With starch modified by ionic interaction, a &#34;bridge function&#34; similar to cross-linking may be assumed with the ionic groups stated below. 
     With the following substances an intensifying effect may be observed: 
     1. Aluminum sulfate An influence of aluminum ions was observed in the concentration range 0.05-0.15 g Al 2  (SO 4 ) 3  per 100 g starch. There is no analogy to the seizing of paper, as the batter pH is about neutral or above, conditions where aluminum hydroxide starts precipitating. 
     2. Alkali silicates Addition of water glass solutions in the range of 0.1-1.0% of starch leads to a significant structure consolidation. This happens despite the high pH of 7.5-9.0 in the batter, which normally causes an opposite effect. 
     3. Dicalcium phosphate, calcium silicate Dicalcium phosphate and calcium silicate also lead to a consolidation of the structure when added at 0.1-2.0% of starch. The little soluble salts have only a minor influence on the pH of the batter. 
     With other phosphates, such as monocalcium phosphate, tricalcium phosphate or pyrophosphates as well as other calcium salts no such effect can be observed. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     EXAMPLE 1 
     Production of trays; 235×175×14 mm addition of potato starch succinic acid ester derivative 
     
         ______________________________________Ingredient/recipe no.             1        2        3______________________________________Starch (1)        100      80       50Water             100      100      100Starch derivative (4)             --       20       50Thickening agent (2)             0,5      0,5      0,5Release agent (3) 2        2        2Viscosity, mPas, 24° C.             1400     1500     3100Baking time, sec. 155      160      190Baking temperature, °C.             190      190      190Weight, g         16,1     21,4     22,0Weight, %         100      133      137______________________________________ 
    
     pH value 7,4; conditioning 70% r.h., 27° C., 24 hours. (1) potato starch; (2) guar; (3) magnesium stearate; (4) succinic acid ester of potato starch, 4% substitution 
     Resistance to compression test: testing the maximum force required to compress the specimens by 30% according to a relative method has shown the following results. Number of specimens per trial: 
     
         ______________________________________  Weight     Maximum forceRecipe no.    g         N      %       s(1) s, %______________________________________1        16,1       95    100     31   332        21,4      337    355     45   133        22,0      468    493     51   11______________________________________ (1) Standard deviation N, n = 10 (n = 9 with no. 3) 
    
     A bending test showed no significant differences in the force required to break the specimens. 
     EXAMPLE 2 
     Production of ampoule tray, 80×65×13 mm; addition of starch ether derivativ with phosphate cross-linking 
     
         ______________________________________Ingredient/recipe no.           4       5        6     7______________________________________Starch (1)      100     90       70    --Water           100     100      100   100Starch derivative (4)           --      10       30    100Thickening agent (2)           0,5     0,5      0,5   0,5Release agent (3)           2       2        2     2Baking time, sec.           32      33       36    44Baking temperature, °C.           185     185      185   185Weight, g       1,78    1,85     2,00  2,88Weight, %       100     104      112   162______________________________________ conditioning 72% r.h., 26° C., 24 hours. (1) potato starch; (2) guar; (3) magnesium stearate; (4) hydroxypropyl ether, crosslinked 
    
     EXAMPLE 3a 
     Rectangular cup, 110×120×48 mm; addition of alkali silicates 
     
         ______________________________________recipe no.     8       9       10    11    12    13______________________________________IngredientStarch (1)     100     100     100   100   100   100Water     120     120     120   120   120   120Fiber (4) 10      10      10    10    10    10Thickening     0,5     0,5     0,5   0,5   0,5   0,5agent (2)Release   2       2       2     2     2     2agent (3)Soda      --      0,3     0,5   0,7   1     2waterglassViscosity,     1500    1400    1300  1300  1200  --mPas, 22° C.pH value  7,6     8,9     9,0   9,4   9,5   &gt;10Baking    90      90      90    90    90    90time, sec.Baking    200     200     200   200   200   200temperature °C.Weight, g,     8,5     9,0     10,3  12,1  14    16without cond.Weight, % 100     106     121   142   (165) (188)                                 (5)   (5)______________________________________ conditioning 70% r.h., 27° C., 24 hours. (1) potato starch; (2) guar; (3) magnesium stearate; (4) cellulose; (5) partly formation of cracks 
    
     EXAMPLE 3b 
     Rectangular cup, 110×120×48 mm; addition of alkali silicates 
     
         ______________________________________Ingredient/recipe no.           14      15      15a   16______________________________________Starch (1)      100     100     100   100Water           130     130     130   130Fiber (4)       10      10      10    10Thickening agent (2)           0,3     0,3     0,3   0,3Release agent (3)           2       2       2     2Potassium waterglass           --      0,5     1     0,5(5)Calcium silicate           5       --      --Viscosity, mPas, 22° C.           1300    1200    1400  1300pH value        7,6     9,1     9,7   7,5Baking time, sec.           90      90      90    90Baking temperature, °C.           200     200     200   200Weight, g, without cond.           9,5     9,7     11,0  8,7______________________________________ conditioning 70% r.h., 27° C., 24 hours. (1) potato starch; (2) guar; (3) magnesium stearate; (4) cellulose; (5) neutralized with 12 ml 0,1 N hydrochloric acid 
    
     EXAMPLE 4 
     Production of flat tray, 235×175×12 mm, wall thickness 4 mm, different additions of potato starch derivatives 
     
         ______________________________________Ingredient/recipe no.           17       18      19    20______________________________________Starch (1)      100      90      80    70Water           100      100     100   100Starch derivative (4)           --       10      20    30Thickening agent (2)           0,5      0,5     0,5   0,5Release agent (3)           2        2       2     2Viscosity, mPas, 22° C.           2000     2200    2000  2000Baking time, sec.           150      155     160   160Baking temperature, °C.           190      190     190   190Weight, g, without cond.           15,3     16,3    17,3  18,8Weight, %       100      107     113   123______________________________________ conditioning 72% r.h., 25° C., 24 hours (1) potato starch; (2) guar; (3) magnesium stearate; (4) potato starch, hydroxypropylated, crosslinked 
    
     EXAMPLE 5 
     Production of a basket-like container, 115×80×38 mm, different additions of hydroxypropylated potato starch 
     
         ______________________________________Ingredient/recipe no.           21      22      23    24______________________________________Starch (1)      100     80      50    --Water           100     100     100   100Starch derivative (4)           --      20      50    100Thickening agent (2)           0,5     0,5     0,5   0,5Release agent (3)           2       2       2     2Viscosity, mPas, 22° C.           1450    1800    3300  &gt;10000Baking time, sec.           60      55      55    55Baking temperature, °C.           185     185     185   185Weight, g       4,3     4,6     4,9   5,3Weight, %       100     108     113   123______________________________________ conditioning 72% r.h., 25° C., 24 hours (1) potato starch; (2) guar; (3) magnesium stearate; (4) propoxylated potato starch 
    
     Resistance to compression test: testing the maximum force required to compress the specimens by 30% according to a relative method has shown the following results. Number of specimens per trial: 
     
         ______________________________________  Weight of           Maximum forceRecipe no.    tray, g    N      %      s(1) s, %______________________________________21       4,3        128    100    17   1322       4,6        155    121    17   1123       4,9        160    125    22   1424       5,3        173    135    35   20______________________________________ (1) Standard deviation N, n = 12 
    
     EXAMPLE 6 
     Production of rectangular conical container, 145×90×50 mm; different additions of an octenyl succinate ester 
     
         ______________________________________Ingredient/recipe no.           25      26      27    28______________________________________Starch (1)      100     90      80    60Water           110     110     110   110Starch derivative (4)           0       10      20    40Thickening agent (2)           0,5     0,5     0,5   0,5Release agent (3)           2       2       2     2Viscosity, mPas, 22° C.           1500    1480    1520  1700pH value        8,0     7,7     7,4   7,0Baking time, sec.           70      68      60    58Baking temperature, °C.           190     190     190   190Weight, g       6,2     6,8     7,5   8,8______________________________________ conditioning 70% r.h., 10° C., 10 hours (1) potato starch; (2) guar; (3) magnesium stearate; (4) corn starch, octenyl succinate 
    
     Resistance to compression test: testing the maximum force required to compress the specimens by 30% according to a relative method has shown the following results. Number of specimens per trial: 
     
         ______________________________________  Weight of           Maximum forceRecipe no.    tray, g    N      %      s(1) s, %______________________________________25       6,2         74    100    16   2226       6,8        114    154    16   1427       7,5        156    211    16   1028       8,7        219    296    40   18______________________________________ (1) Standard deviation N, n = 10 
    
     EXAMPLE 7 
     Production of rectangular conical container, 145×90×50 mm 
     
         ______________________________________Ingredient/recipe no.           29      30      31    32______________________________________Starch (1)      100     75      75    75Water           110     110     110   110Starch derivative (4)           --      25      --    --Starch derivative (5)           --      --      25    --Starch derivative (6)           --      --      --    25Thickening agent (2)           0,5     0,5     0,5   0,5Release agent (3)           2       2       2     2Viscosity, mPas, 25° C.           1750    1250    1800  3500Baking time, sec.           75      67      63    63Baking temperature, °C.           190     190     190   190Weight, g       6,6     7,3     8,3   6,9______________________________________ conditioning 75% r.h., 12 hours, room temperature. (1) potato starch; (2) guar; (3) magnesium stearate; (4) corn starch, hydroxypropyl ether; (5) corn starch, octenyl succinate; (6) corn starch, cationic, hydrophobic 
    
     EXAMPLE 8 
     Production of round plate, diameter 155 mm, 12 mm high 
     
         ______________________________________Ingredient/recipe no.            33       34       35______________________________________Starch (1)       100      --       --Water            100      100      100Starch derivative (4)            --       100      --Starch derivative (5)            --       --       100Thickening agent (2)            0,5      0,5      0,5Release agent (3)            2,0      2,0      2,0Baking time, sec.            60       70       75Weight, g, without            6,0      9,5      10,5conditioning______________________________________ conditioning 70% r.h., 27° C., 24 hours. (1) potato starch; (2) guar; (3) magnesium stearate; (4) corn starch, cationic, hydrophobic; (5) corn starch, octenyl succinate 
    
     EXAMPLE 9 
     Production of packaging trays, 130×105×30 mm 
     
         ______________________________________Ingredient/recipe no.          36      37      38     39______________________________________Starch (1)     100     --      --     100Water          100     100     110    100Starch derivative (4)          --      --      100    --Starch derivative (5)          --      100     --     --Starch derivative (6)          --      --      --     10Thickening agent (2)          0,5     0,5     0,5    --Release agent (3)          2       2       3      2Baking time, sec          90      90      115    90Weight, g, without          8,9     13,0    18,0(7)                                 12,0conditioning______________________________________ (1) potato starch; (2) guar; (3) magnesium stearate; (4) rice flour; (5) corn starch, cationic, DS = 0,04; (6) corn starch, propoxylated, pregelatinized; (7) isolated partial formation of cracks 
    
     EXAMPLE 10 
     Production of a tray, 135×220×19 mm; addition of different concentrations of Al ions 
     
         ______________________________________Ingredient/recipe no.            40      41      42    43______________________________________Starch (1)       100     100     100   100Water            100     100     100   100Thickening agent (2)            0,5     0,5     0,5   0,5Release agent (3)            2       2       2     2Aluminum sulfate.xH.sub.2 O            --      0,11    0,22  0,4455% Al.sub.2 (SO.sub.4).sub.3corresponding to Al.sup.3+            0       0,01    0,02  0,04Batter volume, ml            30      32      34    37Batter temperature, °C.            25      25      25    25Viscosity, mPas, ± 100 mPas            1500    1500    1500  1500Baking time, sec., ± 5 sek.            145     145     145   145Baking temperature, °C.            190     190     190   190Weight, g (average)            15,2    16,2    17,4  18,8Weight, % (relative)            100     107     114   124______________________________________ conditioning 72% r.h., 12 hours, room temperature (1) potato starch; (2) guar; (3) magnesium stearate 
    
     EXAMPLE 11 
     Production of rectangular conical container, 145×90×50 mm 
     
         ______________________________________Ingredient/recipe no.         44      45     46    47    48______________________________________Starch (1)    100     100    90    90    90Starch (4)    --      --     --    --    10Starch derivative (5)         --      --     10    10    --Water         110     110    110   110   110Thickening agent (2)         0,5     0,5    0,5   0,5   0,5Release agent (3)         2       2      2     2     2Aluminum sulfate.xH.sub.2 O         --      0,15   --    0,15  --55% Al.sub.2 (SO.sub.4).sub.3 cor-responding to Al.sup.3+         --      0,013  --    0,013 --Viscosity, mPas, 22° C.         800     800    850   1000  600pH value      7,3     6,7    7,1   6,6   7,3Batter volume, ml         15      15     17    17    16Baking time, sec.         70      74     70    63    70Weight, g (average)         6,83    7,17   7,31  7,38  6,92Weight, % (relative)         100     105    107   108   101______________________________________ Baking temperature 180/185° C., conditioning 72% r.h., 6 hours, 26° C. (1) potato starch; (2) guar; (3) magnesium stearate; (4) corn starch; (5) corn starch derivative, octenyl succinate 
    
     EXAMPLE 12 
     Production of packaging tray, 130×105×30 mm 
     
         ______________________________________Ingredient/recipe no.         49     50      51    52    53______________________________________Starch (1)    100    100     100   100   100Water         110    110     110   110   110Thickening agent (2)         0,5    0,5     0,5   0,5   0,25Release agent (3)         2      2       2     2     2Aluminum sulfate,         --     0,05    0,1   0,15  0,15anhydrousViscosity, mPas, 22° C.         1400   1700    1800  1900  900pH value      7,7    7,1     6,7   6,5   6,3Baking time, sec.         65     65      70    70    73Baking temperature, °C.         180    180     180   180   180Weight, g (average)         8,3    8,7     9,6   9,0   9,8Weight, % (relative)         100    105     116   118   118______________________________________ conditioning 72% r.h., 3 hours, 29° C. (1) potato starch; (2) guar; (3) magnesium stearate 
    
     Resistance to compression test: testing the maximum force required to compress the specimens by 30% according to a relative method has shown the following results. Number of specimens per trial: 
     
         ______________________________________Recipe Weight   specimen Al sulfate                            Maximum forceno.   of g     %        g/100 g starch                            N      %______________________________________49    8,25     100      0        98     10050    8,70     105      0,05     118    12051    9,62     117      0,1      133    13652    9,70     118      0,15     153    156______________________________________ (1) Standard deviation N, n = 10 
    
     EXAMPLE 13 
     Production of packaging tray, 130×105×30 mm (as in example 12) 
     
         ______________________________________Ingredient/recipe no.             54       55       56______________________________________Starch (1)        100      100      100Water             100      100      100Thickening agent (2)             0,5      0,5      0,5Release agent (3) 2        2        2Calcium carbonat  --       2        --Calcium hydrogen phosphate             --       --       1Viscosity, mPas, 22° C.             1500     1900     1300pH value          7,6      8,9      7,3Baking time, sec. 65       65       70Baking temperature,conditioning as in example 12Weight, g         9,03     8,61     9,57Weight, Relativ-% 100      95       106Maximum force, N (4)             11,8     12,3     14,2Maximum force, % (relative)             100      104      120______________________________________ (1) potato starch; (2) guar; (3) magnesium stearate; (4) measured at punched disc, 30 mm diameter 
    
     EXAMPLE 14 
     Production of a sorting insert, 195×65×16 mm 
     
         ______________________________________Ingredient/recipe no.            57      58      59    60______________________________________Starch (1)       100     100     100   100Water            120     120     120   120Thickening agent (2)            0,3     0,3     0,3   0,3Release agent (3)            2       2       2     2Calcium hydrogen phosphate            --      1,2     --    --Calcium phosphate            --      --      1,25  --Calcium dihydrogen phosphate            --      --      --    0,9pH value         7,4     7,1     7,0   6,6Baking time, sec.            28-30   28-30   28-30 28-30Baking temperature, conditioningas in example 13Weight, g        5,01    5,55    5,45  5,37Weight, % (relative)            100     111     109   107______________________________________ 
    
     EXAMPLE 15 
     Production of trays, 235×175×14 mm, addition of starch ester derivative 
     
         ______________________________________Ingredient/recipe no.             61       62       63______________________________________Starch (1)        100      50       0Water             100      105      110Starch derivative (4)             --       50       100Thickening agent (2)             0,5      0,5      0,5Release agent (3) 2        2        2Baking time, sec. 170      180(5)Baking temperature, °C.             190      190      190______________________________________ pH value 7,2; conditioning 73% r.h., 24° C.; 24 hours (1) potato starch; (2) guar;. (3) magnesium stearate; (4) acetylated potato starch, E1422; (5) no longer properly shaped