US2503241A - Method of producing light-colored sirups - Google Patents

Description

Patented Apr. 11, 1950 METHOD OF PRODUCING LIGHT-COLORED SIRUPS Leo M. Christensen, Lincoln, Nebn, assignor to National Agrol Company, Washington, D. C., a

corporation of Michigan No Drawing. Application May 24, 1946,

Serial No. 672,169

11 Claims. 1

This invention relates to a method of producing light-colored syrups from starchy material, more particularly to a novel method of producing syrups of a highly desirable light color from starchy material by enzymatic conversion.

As is known, at the present time, there are two general methods employed for the manufacture not. The original hydrolysate generally contains only about of sugars and in commercial practice it must be evaporated to a concentration of about 60 to about 65% sugars. This concentration may be effected at atmospheric pressures or at lower temperatures under reduced presof sugar or sugar syrups from starch or starchcontaining materials. The process most generally employed comprises the separation of the starch from the other grain constituents, by suitable mechanical means, and its subsequent conversion,

by cooking with dilute mineral acids, to a mixture of sugars including dextrose and maltose. The second process involves the use of saccharifying enzymes such as the amylases of malt, mold bran and certain bacteria. These amylases serve to convert the cooked starch to sugars. The products produced from the described process are generally designated acid converted or enzyme converted syrups respectively. Dextrose and maltose may be recovered from these syrups in crystalline form by methods well-known in the art.

Enzyme converted syrups possess a distinct inherent advantage as compared to acid converted syrups. Such enzyme converted syrups contain about the same amount of dextrose, about twice the amount of maltose and only about half of sures; in either case'the color begins to develop when the sugar concentration reaches about,40%, by weight, and the color intensifies as the concentration progresses. In the past, efforts have been made to reduce this undesired color of the enzyme converted syrups. Treatment of the original hydrolysate with a good quality of decolorizing carbon reduces the color somewhat, and the concentrated or partially concentrated syrup may be somewhat decolorized by such methods. However, these methods are expensive and are performed with difliculty when applied to the viscous syrups.

As a result of intensive experimentation in this field it has been foundthat the color and much of-the flavor of the enzyme converted syrups does not derive from proteins, as had previously been supposed, but from other constituents of the grain. Thus, when pure starch, such as is made by a very careful mechanical separation from other grain constituents is employed, the color and flavor, generally speaking, are just as pronounced as though large amounts of protein had the amount of dextrins as are produced by acid been originally present. It has been ascertained conversion. Since the dextrins have no sweetas a result of intensive investigation that the imening power, the enzyme syrups are thus sweeter purity in the starting material which ultimately than the acid converted syrups. However, this gives rise to the color in the syrup, and to some advantage, while recognized in the past, has been extent, the flavor, was derived from some conoffset considerably by reason of the fact that the stituent of mechanically purified starch, and not, enzyme converted syrups are brown in color and strictly considered, a protein. have certain flavors that makes their use objec- It has long been known that starches contain ,tionable in many products. For these reasons the in their cell walls certain sterols, waxes and phosenzyme converted syrups have found but a lim-- pholipids. These products are water insoluble ited commercial use even though, as noted, they 40 and are not solubilized by acid conversion. Howare superior in sweetening power. ever, it has been determined that the common It has commonly been assumed or postulated amylase preparations hydrolyze these constituthat the color and much of the flavor of the enents to water soluble forms, furthermore, it has zyme converted syrups are due to some type of been ascertained that these compounds readily chemical combination of sugar and proteins. lose water on heating and the dehydrated deriva- These proteins are present because of the fact tives thus produced are highly colored. that the enzymatic saccharifying agents used It was then found that if these color-forming contain proteases as well as amylases, and thus bodies could be removed from the starting mabring into, solution larger amounts of amino acids terial the undesired color of enzyme converted and polypeptides than are derived when acid consyrups could be substantially eliminated. To esversion is used. This is particularly true when tablish this fact a quantity of purev corn starch the enzyme conversion is applied to ground whole was extracted with a solvent for the sterols, grain as is not infrequently done. waxes and phospholipids and the extracted This color, typical of enzyme converted syrups, starch was subsequently converted to syrup. For develops during the concentration of the prodthis purpose grams of pure starch was ex- 3 tracted with petroleum ether. By reason of this extraction 0.25 gram of an oily impurity was recovered. The extracted starch was then converted by enzymatic conversion and was found to have the composition generally obtained by other methods of saccharification and was practically water whitein color. Further experimentation demonstrated that to obtain such water white enzyme converted syrups it was not necessary to use starch but that ground whole grain could be employed and that if such grain is extracted with a good fat solvent it also could be converted by enzymatic agents to yield a syrup of very low color without decolorizing or bleaching. Obviously, any readily available eilective fat solvent may be employed such, for example, as chlorinated hydrocarbons and the like.

It will thus be seen that the broad concept of the invention comprehends the defatting of the starchy material at any suitable stage before the development of color. For obvious reasons this defatting is carried out on the dry raw material but in view of the availability of effective water immiscible fat solvents it is apparent that defatting may be carried out at any desirable stage in the process. As will be seen hereinafter the defatting of the starchy material presents other advantages of prime economic importance in respect to the filtration of the saccharified mash.

In carrying out the invention it is preferred to start with whole ground grain or with starch rich in grain fractions although it will be appreciated that any starchy substrate may be employed. The dry starting material is extracted, as previously noted, with an effective water immiscible fat solvent, such as petroleum ether, trichlorethylene and the like, and such extraction is continued until substantially 95% of the fat content is extracted. Such extraction may require from about one-half hour to as long as 8 hours more or less, depending upon the physical character of the material, the solvent and the type of equipment used. Preferably the grain is ground to mesh or finer and is treated in an efiicient extraction unit. With effective separating conditions the fat-like constituents are substantially completely removed within a period of about an hour. The solvent, as will be appreciated, is passed through an evaporation and recovery system and the denuded solvent is recycited to the extractor. The recovered fats may be utilized for any desired purpose.

The defatted starchy fraction is then mixed with from 2 to 3 parts of water and cooked. If the starchy material is substantially pure starch about 3 parts of water are employed such amount being less if the starting material contains less starch. In the preferred operation the starchy material is first moistened with about one-half the amount of water and this slurry is introduced into the balance of the water, the latter being at a temperature high enough to insure substantially instantaneous gelation. When corn is the starting material employed this temperature should be above 65 C.

The aqueous starch slurry is then cooked for suitable period of time as, for example, for a period of about 5 minutesat 150 C. or, if desired, for a longer time and at a commensurately lower temperature.

As is known and as scribed in U. S. Patent curred in cooling cooked mash down to the saccharification temperature when normal methods of slow cooling are employed. These losses ap- 2,342,330, losses are inpear to be due to I from which the data of Table is more particularly deeconomic significance an irreversible hydration of the starch during the orthodox step of slow cooling of cooked starch from a temperature of about C. down to the optimum saccharification temperatures, which latter are about 60 C. for malt and about 55 C. for mold bran. In the present process therefore this quick cooling with consequent avoidance of starch retrogradation is recommended to thereby insure higher sugar yields.

The cooked starch may be preliminarily cooled by evaporation at reduced pressure after which it is added with instantaneous mixing to a volume of cold water containing approximately 10 pounds of malt or approximately 3 pounds of mold bran, or their equivalent in amylase content, per 100 pounds of the original grain. .The volume and temperature or the cold water is ad- Justed so as to practically instantaneously reduce the temperature of the mixture to the optimum saccharification temperature which in the case 0; mold bran, as noted above, is substantially 5 C.

This saccharifying mash is then maintained at a temperature of from 45 C. to 55 C. for a period move larger fiber particles and is thereafter filtered to remove suspended matter. The filtrate may be treated with decolorizing carbon if the malt or mold bran have yielded any appreciable color to the solution. Such colors, if present, are the carbon. Thereafter the clarified filtrate is evaporated, preferabl at reduced pressures, to a syrup of the desired concentration. Thereaction throughout the process should be pH 4.8 to pH 5.5.

As noted previously, the preliminary step of defatting the grain, or other starchy substrate, results not only in the production of light-colored syrup but also insures marked economies in the filtration step. As is known, the filtration of the saccharified mash, prior to evaporation, is the most diificult operation in the whole enzymatic syrup process. It has been ascertained that when defatted starchy material is employed not only is the amount of suspended matter to be resuch preliminary defatting is not carried out.

These major benefits are apparent from the data in the following table. In the operation I is derived, the saccharified mash was first screened, then centrifuged, in a solid bowl centrifuge, and filtered on a suction filter through paper.

Table I Deiatlcd corn meal Corn meal Suspended matter in centritugate, Filtration rate of centrifugate, Ga

sq. it., without filter aid Filtration rate of centriiugate, Gallons/minute/ sq. in, with filter aid From an inspection of the data in the table it -will be observed that by removing the fat content equally with and without a filter aid. This rapid filtration, as will be appreciated, is of profound since for the same thruput the filtration area required for processing deiatted corn is but one-fifth of that necessary for the undefatted corn. Furthermore, it has been found that when defatting is invoked the filters can be operated substantially twice as long between cleanings as when undefatted grain is used.

It will be appreciated that utilization of the principles of the present invention insures not only marked economies in the production of enzyme converted syrup but also results in a novel product, i. e., a syrup having the desired sweetening power of the enzyme converted syrups coupled with the low color value characteristic of the acid converted syrups.

While a preferred method of efiectuating the principles of the invention have been described it will be understood that this is given didactically as one illustrative method of achieving the advantages of the novel basic concept, namely, 01 the discovery of the essential color imparting factor in the source material and its removal at any suitable stage in the operation by any appropriate procedure.

I claim:

1. A method of producing syrups of high sweetening power and low color which comprises, ex-

tracting a starchy substrate with a solvent for sterols and waxes until a substantial proportion of the sterols and waxes are removed, heating an aqueous slurry of the extracted starch to effect gelation thereof, cooking the starch at elevated temperatures, then cooling the cooked mash to optimum saccharification temperatures and inoculating the cooled mash with an amylase-containing saccharifying material.

2. A method in accordance with claim 1 in which the amylase-containing material is a vegetable amylase.

3. A method in accordance with claim 1 in which the amylase-containing material is a iungal amylase.

4. A method in accordance with claim 1 in which the amylase-containing material is barley malt.

5. A method in accordance with claim 1 in which the amylase-containing material is mold ,bran.

6. A method in accordance with claim 1 in which the amylase-containing material is a mixture of barley malt and mold bran.

'1. A method of producing syrups of. high sweetening power and low color which comprises, extracting a starchy substrate with a water immiscible fat solvent, heating an aqueous suspension of the extracted starchy material to effect gelation of the material, cooking the material at cooking temperatures, rapidly cooling the cooked mash to optimum saccharification temperatures and without substantial retrogradation of starch and saccharifying the cooked mash with enzymatic saccharifyin'g material.

' .8. A method of producing syrups of high sweetening power and low color which comprises, extracting a starchy substrate with a water immiscible fat solvent, heating an aqueous suspension of the extracted starchy material to effect gelation thereof, cooking the material at suitable cooking temperatures, rapidly cooling the cooked mash to optimum saccharification temperature by quickly mixing the cooked starch with the requisite amount of cold water containing an enzymatic saccharifying agent, maintaining the saccharifying mash at such optimum temperature for a period of time sufilcient to insure the desired saccharification, screening the saccharified mash, filtering out suspended matter and evaporating the filtrate to the desired sugar concentration.

9. A method according to claim 8 in which the converting agent is barley malt.

10. A method according to claim 8 in which the converting agent is mold bran.

11. A method according to claim 8 in which the converting agent is a mixture of barley malt and mold bran.

LEO M. CHRISTENSEN.

REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS 7 Date

Claims (1)

1. A METHOD OF PRODUCING SYRUPS OF HIGH SWEETENIGN POWER AND LOW COLOR WHICH COMPRISES, EXTRACTING A STARCHY SUBSTRATE WITH A SOLVENT FOR STEROLS AND WAXES UNTIL A SUBSTANTIAL PROPORTION OF THE STEROLS AND WAXES ARE REMOVED, HEATING AN AQUEOUS SLURRY OF THE EXTRACTED STARCH TO EFFECT GELATION THEREOF, COOKING THE STARCH AT ELEVATED TEMPERATURES, THEN COOLING THE COOKED MASH TO OPTIMUM SACCHARIFICATION TEMPERATURES AND INOCULATING THE COOLED MASH WITH AN AMYLASE-CONTAINING SACCHARIFYING MATERIAL.