Abstract: The invention relates to the synthesis of aspartame involving enzymatic deformylation of an N-formyl-&agr;-L-aspartyl-L-phenylalanine compound by treatment with an enzyme having formylmethionyl peptide deformylase activity and having as a co-factor group 5 to 11 bivalent metal ions. The invention also relates to selective preparation and recovery of aspartame from a mixture of N-formyl-&agr;- and &bgr;-L-aspartyl-L-phenylalanine compounds by treatment with such enzyme. And finally, the invention relates to one-pot enzymatic synthesis of aspartame from N-formyl-L-aspartic acid and L- or D,L-phenylalanine methyl ester involving an enzymatic deformylation reaction simultaneously with an enzymatic coupling reaction, as well as to one-pot di- or oligopeptide synthesis by simultaneous enzymatic coupling and deformylation reactions in general.

Abstract: The invention relates to soft drinks, concentrates and syrups sweetened with a dipeptide sweetener and containing a fructosyl saccharide. The sweetening power of these products is maintained for longer during storage if the fructosyl saccharide therein is a fructan with fructosyl units linked mainly via a &bgr;-2,1 bond, and a chain length of 3 to 100 units, with the modal and the mean chain length each being at least 4.75, and with the pH of the products being 2.5 to 4. The invention also relates to a method of maintaining the sweetening power of soft drinks, concentrates or syrups sweetened with a dipeptide sweetener, during storage, by adding a fructosyl saccharide with the abovementioned characteristics, before the products are put into storage, and adjusting the pH to between 2.5 and 4.

Abstract: The invention makes available, by means of an increased provision of intracellular metabolic intermediates, in particular of erythrose 4-phosphate, alternative processes for the microbial preparation of substances, in particular of aromatic amino acids such as L-phenylalanine, in which processes the activity of a transaldolase is increased in a microorganism producing these substances. In preferred embodiments of the invention, the activity of a transketolase or the activity of a transport protein for the PEP-independent uptake of a sugar and/or the activity of a kinase which phosporylates the relevant sugar are/is additionally increased. The invention also relates to gene structures, and to transformed cells carrying these gene structures, which make it possible to implement these processes in a particularly successful manner.

Abstract: The invention relates to stable, liquid suspensions containing a dipeptide sweetener in water as well as an agent which keeps the suspension liquid, the dipeptide sweetener being a sweetening salt of an aspartic acid-based dipeptide sweetener and a derivative of a sweetening acid, and the agent used to keep the suspension liquid a component chosen from the group of water-soluble, modified or non-modified polysaccharides or proteins, lipids, sulphonates and phosph(on)ates with surfactant properties at a pH of 3.5 or lower. The invention also relates to a process for the preparation of such suspensions, the sweetening salt, prepared in situ or otherwise, and the other component being mixed thoroughly and intensively.

Abstract: Aspartame powder for application in instant powder mixtures and instant desserts and consisting entirely or practically entirely of aspartame with a narrow particle size distribution with a d.sub.50 value in the range of from 40 to 80 .mu.m, with max. 10 wt %<20 .mu.m and max. 10 wt %>150 .mu.m; and process for the preparation, from dry or wet aspartame granules, of aspartame powder consisting entirely or practically entirely of aspartame, for application in instant powder mixtures and instant desserts, wherein granular aspartame having a moisture content of max. about 40 wt % is crushed, in dry or drying conditions at a temperature of 0-60.degree. C., or while supplying drying air having a temperature of 100-180.degree. C., in a first step in an impact mill while air is being supplied for discharging the crushed product from the mill, with drying if necessary to achieve a moisture content of less than 4 wt %, to a product in which at least 70 wt % of the particles is smaller than 150 .mu.

Abstract: Aspartame having particles smaller than 100 .mu.m can be deposited on an edible supporting material, by mixing in a dry form, in amounts that clearly exceed 10 wt. %, if the aspartame has a free bulk density of 350 kg/m.sup.3 or lower, and is obtained through, successively, crystallisation from an aqueous medium with forced convection, granulation and subsequent mechanical reduction, the mixing being effected in a weight ratio of aspartame and supporting material of at most 1:1, but not less than 1:30.

Abstract: An enzymatic method for producing N-formyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester by a condensation reaction between N-formyl-L-aspartic acid and L-phenylalanine methyl ester or D,L-phenylalanine methyl ester, which comprises: supplying an organic phase comprising a water-immiscible solvent containing N-formyl-L-aspartic acid and L- or D,L-phenylalanine methyl ester onto an aqueous phase comprising a thermolysin-like metalloprotease; proceeding the condensation reaction in the aqueous phase to produce N-formyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester; and extracting the N-formyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester thus produced from the aqueous phase to the organic phase.

Abstract: The process of the present invention is conducted in a liquid medium and concerns the preparation of a sweetening salt as the reaction product from two sweetener components in which one component is a sweetener derived from aspartic acid and the other is an intense sweetener not derived from aspartic acid. The process steps include adding to a liquid medium, in any order, a sweetener derived from aspartic acid, a derivative, such as a salt, of a sweetening acid not derived from aspartic acid, and a strong acid whereby a liquid system is obtained, allowing the components then present in the liquid system to react for at least one minute such that the sweetening salt formed, and isolating the sweetening salt. Novel sweetening salts having a good thermal stability and a low moisture content, as well as a new crystal modification of the sweetening salt from aspartame and acesulfamic acid are also disclosed. The sweetening salts can be used in foodstuff and the like.

Abstract: A method for making a stabilized neutral metalloprotease enzyme composition is described in which a neutral metalloprotease and an aqueous solution are combined to obtain a solution or slurry thereof, whereby the stabilized neutral metalloprotease enzyme composition is obtained. The aqueous solution contains an N-protected amino acid, or an N-protected amino acid is added thereto. The invention also provides a stabilized neutral metalloprotease composition, and a method of transporting the stabilized neutral metalloprotease composition.

Abstract: Improved method for crystallization of .alpha.-L-aspartyl-L-phenylalanine methyl ester (aspartame) from an aqueous solution by conductive cooling while avoiding turbulence in the crystallizing system wherein crystallization is carried out with cooling to a temperature level not lower than 10.degree. C. in the presence of at least 0.1% by weight of a C.sub.3-8 ketone, the amount of ketone and the temperature level being chosen for each individual ketone so that a homogeneous solvent system is present at the start of crystallization and an open drainable network of aspartame crystals is obtained.

Abstract: The invention relates to a process for the preparation of N-protected-L-aspartyl-L-phenylalanine methyl ester by enzymatic coupling of an N-protected-L-aspartic acid and L- or DL-phenylalanine methyl ester in an aqueous solution with formation of a precipitate using a thermolysin-like protease enzyme, wherein a water-immiscible organic solvent is added to and blended with the reaction system during the formation of the precipitate in the course of the coupling reaction, which organic solvent has a relatively high affinity for the precipitate. The process is particularly suitable as a continuous process. The method results in lower enzyme deactivation during and after the enzymatic coupling reaction and in larger and thicker precipitated crystals.

Abstract: The invention relates to a process for the preparation of N-benzyloxycarbonyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester by enzymatic coupling of N-benzyloxycarbonyl-L-aspartic acid and L-phenylalanine methyl ester in an aqueous medium with formation of a precipitate, the coupling reaction being effected with (virtually) equimolar quantities of N-benzyloxycarbonyl-L-aspartic acid and L-phenylalanine methyl ester under the influence of a neutral protease at an initial pH of from 4.5 to 6.0 and in the presence of from 3 to 25%, calculated as per cent by weight based on the total reaction mixture, of an alkali metal salt, alkaline earth metal salt or ammonium salt.

Abstract: A process is described for the recovery of raw materials in the aspartame preparation process from aqueous process streams which also contain dissolved salt. The process comprises subjecting the streams to nanofiltration with the aid of a composite membrane having specified retention values to obtain a retentate. The raw materials present in the retentate are recovered or the retentate is returned to the aspartame preparation process without any further processing. An apparatus for carrying out the process is also described.

Abstract: The invention relates to a process for the crystallisation of aspartame by neutralising an aqueous solution of aspartame, having a pH of less than 3, with a base and homogenising the solution by means of forced convection, characterised in that the solution is neutralised, and homogenised, in such a manner that the solution obtained is substantially homogeneous and has a pH higher than 3, with the solution no longer being mechanically stirred at least from the beginning of the last second before crystallisation is visually perceptible.

Abstract: The invention relates to a process for the drying and granulation of aspartame through the thermal treatment of a wet mass of aspartame crystals using a hot carrier gas, characterized in that a wet mass of aspartame crystals is supplied, in a continuous process, to a high-speed paddle dryer fitted with a jacket heated to a temperature of 80.degree.-190.degree. C. and with paddles, mounted on a central shaft with a controllable speed of rotation, at an adjustable distance from and angle to the jacket, which are positioned so that the required particle size of the granules is realized, the speed of rotation being chosen so that the Froude number is higher than 1, and the supplied product is treated in the paddle dryer for 15-600 seconds, with the simultaneous presence of a carrier gas having an inlet temperature of 100.degree.-200.degree. C.

Abstract: The invention relates to a process for the treatment of dried aspartame characterised in that, in a first separation step, particles smaller than 50 .mu.m are removed, with the aid of a stream of air, from aspartame having a particle size distribution with which more than 5 wt. % of the aspartame has a particle size of less than 20 .mu.m and more than 10 wt. % of the aspartame has a particle size of more than 400 .mu.m, and that in a second separation step the product resulting from the first step is subjected to a screening step using a screen that separates at a value between 150 and 250 .mu.m, after which the fraction of the smaller particles thus obtained is recovered as a first product and the fraction of the larger particles is recovered as a second product or is optionally subjected to a further separation step using a screen that separates at a value between 400 and 1000 .mu.m, the fraction of smaller particles thus obtained being recovered as the second product.