Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/16—Oxyacids of phosphorus; Salts thereof
  • C01B25/26—Phosphates
  • C01B25/38—Condensed phosphates
  • C01B25/40—Polyphosphates
  • C01B25/41—Polyphosphates of alkali metals
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING OR TREATMENT THEREOF
  • A23C19/00—Cheese; Cheese preparations; Making thereof
  • A23C19/06—Treating cheese curd after whey separation; Products obtained thereby
  • A23C19/068—Particular types of cheese
  • A23C19/08—Process cheese preparations; Making thereof, e.g. melting, emulsifying, sterilizing
  • A23C19/082—Adding substances to the curd before or during melting; Melting salts

Definitions

• the present invention relates to readily soluble, acidic polyphosphates with a high P 2 O 5 content and processes for their preparation and furthermore describes a suitable device which permits continuous operation.
• Acidic polyphosphates are understood by those skilled in the art to be those which have a sodium / phosphorus molar ratio of ⁇ 1, in particular ⁇ 0.9, corresponding to an Na 2 O content of ⁇ 30% by weight, and in the solid state usually 2- Contain 10% by weight of water.
• the water content is essentially based on the presence of free phosphoric acid hydroxyl groups.
• the degree of polymerization also serves to characterize these phosphates, which are characterized by chain and ring-shaped structures. Due to the high content of free hydroxyl groups, the solutions of these phosphates are very acidic.
• Another crystalline form corresponds to the formula Na 3 H (P0 3 ) 4 , which can be obtained in 12 hours by heating to 600 ° C. and tempering at 350 ° C. This product is also insoluble in water (Griffith.ACS 1956, pp. 3867-3870 and US-P 2,774,672).
• DE 4128124 C2 describes acidic polyphosphates as an additive or as a molten salt for the preparation of cheese. These polyphosphates are produced from monosodium phosphate and phosphoric acid or sodium hydroxide solution and phosphoric acid in suitable mixing ratios directly by melting at 400 ° C to 500 ° C, with residence times of 20 min to 2 hours, the composition of the end product being determined by melting temperature, residence time and Na / P- Ratio is determined. For the general manufacturing conditions, reference is made to the above US Pat. No. 2,774,672. These polyphosphates are said to have stabilizing and preserving properties.
• the P 2 O 5 content is between 73 and 77% by weight, the Na 2 O content is between 20 and 25% and the residual water content is 2 to 3% by weight.
• the Na / P ratio is therefore between 0.6 and 0.8.
• the solubility of such products is about 90 minutes, which is necessary for the intended use as a molten salt and stabilizing agent. tel in the cheese industry is too slow. Because of the necessary processing times, dissolving times of less than 30 minutes, preferably less than 20 minutes, would be desirable.
• polyphosphates For use as food phosphates, including for processed cheese production, such polyphosphates must have a number of properties and functions:
• a) there must be solid, easy-to-handle powders which b) have a high solubility, in particular a time to dissolution in water of less than 30, preferably less than 20 minutes, c) a good complexing ability for alkaline earth metals, in particular calcium and magnesium, d ) a good buffering effect in the acidic range, especially for use in salad dressings and mayonnaises, for example, e) a preserving effect (expressed in the reduction in the number of germs per volume and amount) even during the storage time of the finished cheese, f) a stabilizing effect compared to other additives, in particular Show vitamin C.
• These medium-length chains surprisingly have a very high dissolution rate, with dissolution times for 10% by weight of about 10 minutes being achieved in favorable cases.
• a large part of the acidic groups is blocked by the chain-like structure, so that these polymers are significantly less acidic than the analytical content of phosphoric acid.
• the compounds are able to hydrolyze slowly and to this extent exert a strong buffering effect.
• the polymeric structure is capable of complexing divalent ions, especially magnesium and calcium ions, and thus preventing their precipitation as poorly soluble phosphates.
• these polyphosphates have proven to be surprisingly good stabilizers. They also show a slightly microbiocidal effect on bacteria and especially fungi
• chain lengths and the degree of crosslinking of polyphosphates can be determined very easily with modern 31 P-NMR methods by dissolving the polyphosphate in deuterium oxide and during or briefly after the dissolution process, ie before a noticeable hydrolysis begins and the result is falsified, picks up the resonance signals of the different phosphate groups.
• Terminal phosphate groups have a resonance at -6 to -12 ppm
• medium-sized phosphate groups in the chain have a resonance frequency of -18 to -24 ppm
• cyclic phosphates have a resonance at -23 (trimetaphosphate) or -21 ppm (Tetrametaphosphate).
• the signal of the free orthophosphates is found under these circumstances at 0 ⁇ 2 ppm, depending on the acidity.
• the water content of the products which in this case determines predominantly bound water, is usually determined by determining the loss on ignition at 600 to 800 ° C., zinc oxide being added to the determinations in order to avoid P 2 O 5 losses in the case of acidic polyphosphates.
• the measured turbidity in TE / F is assessed visually according to the following scheme:
• the products according to the invention are prepared by predrying an aqueous solution of phosphoric acid and sodium phosphate or sodium hydroxide solution in a sodium / phosphorus ratio of 0.3 to 0.6 to a water content of approximately 20% and melting by slowly heating this mixture in a suitable oven at temperatures of 400 to 600 °, for a period of 60 to 120 minutes.
• a suitable oven at temperatures of 400 to 600 °, for a period of 60 to 120 minutes.
• the water vapor pressure above the melt is set to 0.1-0.5 bar as a further parameter.
• the melt After a short cooling phase, the melt is cooled to room temperature in an anhydrous atmosphere and ground to fineness of powder. Products with a Na / P ratio of less than 0.3 can no longer be ground or solidify at room temperature.
• Table 3 shows that with a very long residence time at temperatures of 500 ° or with shorter residence times at even higher temperatures, the average chain length increases significantly, which is also shown by the decrease in the loss on ignition. The corresponding, more crosslinked products are no longer sufficiently soluble to be used according to the invention.
• the aforementioned phosphate solution is continuously introduced into a melting furnace according to FIG. 1 via a diaphragm metering pump, whose stroke volume and cycle frequency can be adjusted.
• a tube furnace 1 in the current case a type F 500 from Gero, with a total length of 750 cm and a heating zone of 500 cm was used
• a quartz tube 3 with a length of 880 cm and a diameter of 55 cm.
• a slightly inclined melting tank 2 which is milled out of a graphite rod, which has an area of 256 cm 2 and a volume of 1024 cm 3 , which can be reduced to 256 cm 3 by inserting an insert wedge if necessary
• silicon carbide can also be used as the material; other ceramic materials are partially attacked by the phosphate melts.
• the Phosphate solution is fed in at a metering rate of 300 g / h via line 4, the melt produced runs continuously via line 5 due to the inclination at the end of the melting tank 2 and is solidified in a glass-like manner via a cooled roller 6.
• the phosphate glass obtained is broken with the exclusion of atmospheric moisture with a scraper 7 and ground to powder after being stored temporarily in container 8.
• the inlet zone of the quartz tube 1a is preheated to 100 °, the actual reaction zone 1b is set to 650 to 675 °, resulting in melt temperatures of 515 to 560 °.
• the apparatus is continuously flowed through with a 10 l / min nitrogen stream via line 9, which is set to 150 mbar water vapor pressure by passing through 60 ° warm water in the scrubber 10.
• Table 5 It is shown that optimal solubilities corresponding to chain lengths of approximately 20 to 30 can be achieved at melt temperatures of up to 530 °.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Polymers & Plastics (AREA)
• Glass Compositions (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Dairy Products (AREA)

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Citations (9)

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• 1997
  • 1997-06-26 DE DE19727144A patent/DE19727144A1/de not_active Ceased
• 1998
  • 1998-06-23 BR BR9811271-6A patent/BR9811271A/pt not_active IP Right Cessation
  • 1998-06-23 AU AU87281/98A patent/AU734894B2/en not_active Ceased
  • 1998-06-23 CN CNB988065851A patent/CN1161273C/zh not_active Expired - Fee Related
  • 1998-06-23 CA CA002295687A patent/CA2295687C/en not_active Expired - Fee Related
  • 1998-06-23 PL PL337655A patent/PL192090B1/pl unknown
  • 1998-06-23 EP EP98938627A patent/EP0991589A1/de not_active Ceased
  • 1998-06-23 JP JP50526999A patent/JP2002507957A/ja not_active Ceased
  • 1998-06-23 HU HU0003050A patent/HUP0003050A3/hu unknown
  • 1998-06-23 SK SK1768-99A patent/SK286395B6/sk not_active IP Right Cessation
  • 1998-06-23 CZ CZ0451099A patent/CZ300062B6/cs not_active IP Right Cessation
  • 1998-06-23 WO PCT/EP1998/003823 patent/WO1999000324A1/de not_active Ceased
  • 1998-06-23 KR KR10-1999-7012306A patent/KR100522290B1/ko not_active Expired - Fee Related

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