by weight preferably 20 percent with an acid concentration of 0 5 45 n normal preferably 6 n in the case of hydrochloric acid and and 45 n in the case of phosphoric acid at a pressure of 1 3 atmospheres preferably 1 atmosphere and under continuous stirring optionally solid matter which results after hydrolysis may be removed before employing the solution of amino acids to produce the desired flavors this is however not mandatory the solid matter the insoluble cell residues of the biomass may alternatively be left in the mixture and also be subjected to the maillard reaction in such a case it is preferable to evaporate to dryness the solution which results after the hydrolysis in order to obtain the necessary concentration for the maillard reaction it is most preferred in this invention to use a process wherein the amino acids are isolated from the hydrolyzed solution prior to the maillard reaction this is appropriately done through isolation of the amino acid mixture contained in the solution by means of chromatographic adsorption and through subsequent evaporation to dryness the maillard reaction is appropriate performed under conditions as specified hereafter at a ph value of 3 12 preferably 6 7 with the ph value being adjusted by the use of ammonium hydroxide or potassium hydroxide or phosphoric acid with a duration of the treatment of 1 200 hours preferably 70 140 hours at a temperature of 20 u00b0 180 u00b0 c preferably 90 u00b0 140 u00b0 c with a molar ratio of the amino acids to the reducing sugar added between 4 1 and 1 4 preferably between 1 1 and 2 1 in aqueous solution with a solids content of 20 70 percent by weight preferably 45 55 percent by weight at a pressure of 1 5.