UNITED STATES PATENT OFFICE 2,261,926 PROCESS for PRODUCING LACTIC ACD Arthur J
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Patented Nov. 4, 1941 2,261,926 UNITED STATES PATENT OFFICE 2,261,926 PROCESS FOR PRODUCING LACTIC ACD Arthur J. Nolte and Harry W. von Loesecke, Winter Haven, Fla.; dedicated to the free use of the People of the United States No Drawing. Application March 15, 1940, Serial No. 324,07 2 Claims. (C. 195-48) (Granted under the act of March 3, 1883, as amended April 30, 1928; 30 O. G. 5) This application is made under the act of March added until the liquor is alkaline to phenolphtha 3, 1883, as amended by the act of April 30, 1928, lein. The precipitate of calcium citrate, here and the invention herein described and claimed inabove mentioned, in the case of Orange or may be used by or for the Government for gov grapefruit juice, is now removed by any suitable ernmental purposes without payment to us of means, and about 93 percent of the calculated any royalty thereon. amount of citric acid present in the juice may be | We hereby dedicate the invention herein de recovered as calcium citrate. scribed to the free use of the people of the United The filtrate and washings from the calcium States to take effect on the granting of the pat citrate should be treated while hot preferably ent to us. 10 with activated charcoal (2 percent based on the In present commercial practice, lactic acid and Weight of the liquor) and filtered, preferably by calcium lactate may be produced from starch, means of any type of plate and frame press, using molasses, and dextrose by fermenting with lac a filter aid. tic acid bacterial of the Lactobacillus delbrickii This filtered liquor is light amber in color, and type. Or these chemicals may be obtained from 5 from which calcium lactate may be obtained in whey. any manner now already known to the art, Such Our invention differs from these well-known as by concentration and crystallization. Lactic methods, and relates, to the production of lactic acid may be obtained from this calcium lactate acid and calcium lactate from sacchariferous fruit by methods already known, such as by acidifica juices, and particularly grapefruit juice, by means 20 tion. With H2SO4 and concentration. of micro-organisms naturally found present in Having thus described our invention, what we such juices, the control of said Organisms being claim for Letters Patent is: accomplished by maintaining the pH and tem 1. The method for producing lactic acid from perature of the fermenting liquor most Suitable sacchariferous fruit juices by fermentation, which for their growth, while unsuitable for the growth 25 comprises neutralizing the natural fruit acid pres and maintenance of all other organisms not con ent in the juices and permitting the insoluble cal ducive to the production of lactic acid. cium salts to settle, thence adding to the juices In our process sacchariferous fruit juices, and a starter containing lactic acid forming bacteria particularly grapefruit juice, are screened by any normally present in such juices, maintaining the well-known method, and to the Screened juice 30 said juices at a temperature of at least 52 C. is added sufficient calcium carbonate (free from throughout fermentation, the while maintaining iron and low in magnesium) to completely neu the pH of the juices between 4.0 and 6.5 by peri tralize the acid present. We have found that by odically neutralizing the lactic acid thus formed, neutralizing the acid present more optimum con thence recovering the insoluble calcium salts, ditions for the growth of these lactic acid bac 35 and thence recovering the actic acid. teria are obtained. In the case of grapefruit 2. The method of producing actic acid from juice this neutralization will give a precipitate of grapefruit juices, which comprises subjecting calcium citrate, which it is not necessary to re-. Screened grapefruit juice to the action of cal move at this stage of our process. cium carbonate that is free from iron and low The neutralized liquid is rapidly Warned to at 40 in magnesium, thereby neutralizing the grape least 52 C. and maintained Substantially at this fruit juice and giving a precipitate of calcium temperature during fermentation. During this citrate; thence rapidly heating the neutralized period of fermentation, periodic neutralization liquid to a temperature of at least 52 C., main with calcium carbonate is necessary in order to tained during fermentation, the while adding maintain the pH between 4.0 and 6.5. 45 calcium carbonate in amounts sufficient to main It is advantageous to prepare starters, where tain a pH between 4.0 and 6.5; thence adding cal large volumes of juice are to be fermented. This cium hydroxide until the liquor is alkaline; thence saves time and aids in acclimating the organisms removing the precipitated calcium citrate, and to the medium. The starter is prepared by main the While recovering substantially 93% of the cal taining the juice (previously neutralized with cal 50 culated amount of citric acid present in the juice cium carbonate) at 50° C. for two or three dayS. as calcium citrate; thence washing and filtering We may add the proportion of about five per the calcium citrate; thence subjecting the fil cent by volume of such a starter to the main tered liquor to concentration and crystallization, batch of juice. thereby obtaining calcium lactate; and, thence After fermentation has been completed, judged 55 acidifying the lactate and obtaining lactic acid. by the fact reducing sugars are less than one per ARTHUR, J. NOLE, cent, calcium oxide or calcium hydroxide may be HARRY W. von LOESECKE, .