US2192212A - Method of manufacturing articles of food from indian corn - Google Patents

Description

T. B. WAGNER March 5, 1940.

METHOD 0F MRNUFACTURING ARTICLES 0F FOOD FROM INDIAN CORN Filed Oct. l 29, 1936 3 Sheets-Sheet 1 omlmtumn ZKQU n.0 Jmzdwv. T

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T/EODORE W/YE/. BY

@Ofc-w ATTQRNEY.

Mal'Ch 5, 1940. C T B, WAGNER .2,192,212

METHOD CF MANUFACTURING ARTICLES oF Foon FROM INDIAN CoRN Filed ocr. 29.. 195e' l s sheets-sheet 2 ZL/@.3 v covlzN en@ *C A, ALKALINE;

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ATr'oRNE.4 l

March 5, 1940. T. B. WAGNER KETHOD 0F MANUFACTURING ARTILES 0F FOODl FROM INDIAN CORN 5 Sheets- Sheet 3 Filed oct. 29. 195s THEOORE B. WHG/VER BY G. ATTORNEY.

Patented Mar. 5, 1940 UNITED sTArEs Theodore B. Wagner, Brooklyn, N. Y,

Application October 29, 1936, Serial No. 108,195

Claims.

This invention relates to a new method of manufacturing from Indian corn articles of food, commonly designated as white goods and comprising hominy, grits and meal, and, more par- 5 ticularly, relates to an improved method of decorticating, decapping and degerminating shelled Indian corn.

It is well known that heretofore the conventional metho'd of milling corn for the production of white goods has been employed for almost one hundred years and did not permit of obtaining constituents of corn, especially the germ and the cap, in an isolated state or in a state of r greatest purity, because the milling process depended wholly upon machinery for the mechanical separation of the cortex and the germ from the endosperm and such machinery did not permit of an even approximately quantitative separation of the cortex, the germ and the endo- 20 sperm from each other. This l conventional method was known as the dry milling process and has been described in many prior publications.

The art of manufacturing corn products; particularly of the White goods type, as formerly practiced, had no means of eliminating therefrom outstanding objectionable features, the more serious of which are (l) unsatisfactory yield of primary products and of germs, both far below 30 the achievable amount; (2) excessive yield of undesirable and unprotable secondary products;

(3) excessive'content of Yoil in hominy, grits,

meal and other finished products; (4) rancidity;

(5) inefcient decortication andy degermination; 35 and (6) troublesome and involved decapping.

Although many attempts and proposals have been made to' solve the vexatious problem confronting the art, none, as far as I am aware, has been wholly satisfactory and successful, espelo cially when carrledinto practice on an industrial scale for tle production of commercial products.

An object of my present invention Iis to replace the "dry milling of corn with a practical proc- 45 ess permitting of milling it in a wet state and of conducting the operation efficiently and satisfactorily.

It is another object of my invention to increase the yield of commercially valuable primary prod- 50 ucts, such as hominy and grits, to increase the yield of germs and oil, to decrease the yield of ,N less valuable secondary products, such as meal, and to decrease, if not eliminate altogether, the yield of inferior by-products, such as the hominy feed.

It is a further object of my invention to 1m-y prove the quality of the nished primary products, especially with respect to freedom from corn oil, and, as a consequence thereof, freedom from 60 rancidity while in storage.

(c1. zza- 42) The invention also contemplates the provision of a method of recovering the soluble constituents of the corn, leached from the latter during the steeping period and using them for human food or animal feedstuis.

It is also within the contemplation of my invention to simplify the milling process and to effect a saving in the cost of production by eliminating a large amount of machinery heretofore considered necessary, such as tempering devices, degerminating mills, reducing mills, and a large portion of the grading reels, aspirators nad sifters; and, to effect a substantial saving in power and steam. l l

Other objects and advantages of my invention will become apparent from the following description of a preferred procedure of carrying my invention into practice on an industrial scale, taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a diagrammatic cross sectional view of an ordinary, i. e, untreated, kernel of corn and clearly shows the placement of (a) the hull (cortex), (b) the tip cap, (c) the gluten, (d) the endosperm or starch, and (e) the germ, with the embryo root and the embryo stem;

Fig, 2 illustrates a cross section, somewhat diagrammatic, of a kernel of corn decorticated, decapped and degerminated by my method; and

Fig. 3 depicts a flow sheet of a method embodying the present invention.

Broadly stated, my present invention contemplates the elimination of the dry method of milling corn and its replacement with a wet milling process, easily capable of industrial application and resulting in increased yields of primary products of a quality superior to those obtainable by the dry milling method.

I have discovered that in order to effect a substantially complete and practical'separation of the main constituents of corn,-including the hull and tip cap, germ, and endosperm, and in order to obtain increased yields and improved quality of these same constituents, it is necessary to condition the shelled corn for a prolonged period .by completely immersing it in water, at a moderate elevated temperature preferably ranging be-A tween about 100 and about 125 F. and to add to the wateran alkaline agent in such a manner and -to such an extent as to liberate the cortex (hull),

the tip cap, and the germ from the kernels of' tex and the germ, but, in particular, to insure the removal of the tip cap. The removal of the tip cap is of special importance for the reason` that the tip cap has a naturally dark color, and the presence of such dark colored tip caps in the finished product, particularly white goods, including hominy, grits, or meal, adversely affects its quality and contaminates it to such a degree as to reduce its value or to render it wholly unmerchantable.

The removal of the tip cap is also one of the most difficult features of the conventional dry milling process and requires an amount of machinery entirely out of proportion with the service performed, i. e. the amount of tip caps contained in a bushel of corn usually amounts to approximately 2% which is about 1.12 pounds. My new method of milling corn in a wet state completely eliminates the diculties attending the dry process and dispenses with the aforesaid excessive amount of machinery.

-I have found that the quantity of the alkaline agent necessary to effect the removal of the h-ull, the tip cap and the germ, the latter including the germ stem and germ embryo, approximates, for example in the ca se of sodium hydroxide, one and six-tenths pounds per pounds of commercial corn. This amount is usually sufficient to maintain the steeping liquor in an alkaline condition until the steeping period is finished and to keep its pH value above about 7.0.

Generally speaking, I have found that a charge of about 1,000 pounds of corn requires about 16 pounds of caustic soda of 76% strength and I consider it preferable to dissolve this amount of caustic soda in about 4,000 pounds of water, so that the alkalinity of the steep liquor will practically be equal to 0.4%, by weight, expressed as commercial 76% NaOH on about 0.3% expressed as chemically pure sodium hydroxide (about 0.24% NazO). I prefer to keep the temperature of the steep liquor between about 100 and about Fahrenheit. 'I'he effect of the alkaline steep liquor will be increased -by circulating the same vigorously in the steep tanks, and this effect will be still further accentuated by circulating it under pressure. I have found that a pressure (gauge) of about 8 to about 15 pounds per square inch gives satisfactory results.

Circulation and pressure, alone or in conjunction, tend 'to reduce the time required for steeping the corn and tend to reduce the quantity of the alkaline agent, which I use for decorticating, decapping and degerminating the kernels of corn.

I have found that in order properly to condition the corn for practical and satisfactory separation of the cortex, the tip cap and the germ from the endosperm, a steeping period of about 48 to about 60 hours usually suflices, though in the case of extremely well seasoned corn a longer period may occasionally be required. I use for effecting the steeping operation the customary tanks or vats which are provided with cone-shaped bottoms and strainers, which arrangement permits of automatically draining the steep liquor from the steeped corn. The steep tanksmay be operated singly, or in tandem, or in series, and/ or under the counter-current principle.

At the end of the steeping period, II drain the steep liquor from the .corn. 'I'he color of the latter, whether originally White or yellow, will have darkened considerably and, in order to restore its original color, I have found that it is preferable to immerse the corn in water containing about 1/3 of one percent of dissolved sulfur doxide (by weight) and to allow it to remain therein until the original color has substantially returned. This usually requires less than about one hour or so. I then wash the corn with water until the latter no longer shows an acid reaction to litmus, or only faintly so.

The removal of the cortex, the tip cap, and the germ is effected, in part, mechanically and automatically while the corn is being discharged from the4 steep tanks. The shearing action, caused by the friction created within the downward motion of the corn, serves to liberate a large amount of the cortex, the tip cap, and the germ. These are separated from the kernels of corn by conveying the latter, together with a sufficiently large amount of water, to reels, covered with metal sheathing, the perforations of which are of such size and shape as Will permitv the passage of the cortex, the tip cap and the germ, while retaining the kernels of corn. As regards that portion of the cortex, tip caps and germs which may still adhereto the kernels, I remove the same hydraulically, i. e. by forcing, under pressure, a copious stream of water upon the steeped corn, in any suitable apparatus, a conveyor-like device, for instance. After having thus liberated the hulls, the tip caps4 and the germs from the kernels (endosperm) I convey the mass to and through a reel, of the type described above, and thereby practically complete the separation of the cortex, tip caps, and germs from the kernels of corn. It is not necessary, of course, to complete the separation in two'stages, as herein described, for they may readily be consolidated into one single o-peration. Also, I may pass the steeped corn through roller mills, scourers, or

other suitable appliances, so arranged as to exto smaller fragments by applying a stream of water, preferably in considerable volume and under pressure. In this manner it is possible to conduct the grading of the particles of decorticated, decapped and degerminated corn in a Wet state attended by a very substantial elimination of reducing mills, grading reels, and aspirators. However, I may employ the conventional system lof grading which is used in the dry system, in which case, the whole or fragmented kernels are subjected to heat, in a suitable apparatus, until their moisture content has been reduced to approximately 13%. I prefer to do the grading in a wet state and then dry the graded and finished products until, likewise, their moisture content approximate 13%.

I may, of course, separate the germs, hulls and veyor or reel, hereinbefore referred to, and in` tended for the removal of the liberated germs. I eliminate any adhering brine or starch mllk, as the case may be, by washing with water.

I process the mixture of germs, hulls, and tip caps for the extraction of the oil and, likewise, I recover and utilize the spent steep liquor in substantially the same manner as is practiced in the manufacture of starch from vIndian corn. The spent steep liquor contains, in combined form, the

caustic soda used in the preparation of the original steep liquor, which I thus recover in its entirety and this bears favorably upon the economic feature of'my invention. The spent steep liquor may or may not contain dissolved cellulose, the amount depending upon the character of the alkaline steeping agent and varying with its concentration. The greater the alkaline strength of the steeping liquor, the greater is usually the amount of dissolved cellulose and vice versa.

In Fig. 1, the constitution of a kernel of corn may be clearly seen. In the center of the kernel, the embryo stem I and the embryo root II are located. Surrounding these parts is the germ I2. Extending from the germ outwardly is starch. In the upper part is crown starch I3 and in the sides horny starch I 4. Towards the lower part, tip starch I5 occurs just above tip cap I6. Between the starch and hull I'I, a layer of horny gluten I8 is found.

After a kernel of corn is treated by my process, it is converted to a new structure such as illustrated in Fig. 2. From this view, it will be observed that a lhollow product is produced having a starchy portion constituted of crown starch I3,

` horny starch I4, and tip starch I5. Around the outside of the starchy portion, the layer of horny gluten I8 remains. From the central region, the embryo stem and root and germ are removed whereas from the outside, not only the hull but also the tip cap are removed. As far as I am aware, this is a novel product which has never been produced in the trade and made available as an article of manufacture. Due to the practically complete elimination of the hull, the embryo stem and root, the germ and also the tip cap, a superior corn product has been made available to the art. Thus, for brewing of beer and other beverages, my novel product offers many advantages and produces superior hominy. As this hominy is substantially free from corn oil, tip caps, etc., it is better than conventional hominy for the brewing of beer, etc.

Among the advantages resulting from my invention are the following:

. Increased yield of pure germs.

. Increased yield of corn oil.

. Increased yield of hominy and grits.

. Improved quality of valuable primary products.

. Substantial elimination of cheap secondary products, such as hominy feed.

Elimination of degerminating mills.

. Appreciable saving of milling equipment.

. Appreciable saving in power and steam.

. Elimination of potential rancidity ofcarbohydrate products.

In certain instances, an increase of about 200% inthe yield of pure germs and of corn oil was obtained and an increase of about 50 to about 100% in the yield of hominy and grits was effected.

For the purpose of giving those skilled in the art a better understanding of my invention, the following description of an illustrative example of carrying my invention into practice will now be given:

I introduce about 500 bushels of white or yellow corn from corn bins C into a steeping bank T (see Fig. 3) previously filled with about 13,500

vgallons of water, in which I have dissolved about 450 pounds of commercial caustic soda, of 76% strength. The water containing. caustic soda, termed herein alkaline steep liquor, may be supplied from tank A. With the aid of a steam coil, or otherwise, I raise the temperature of the Water to about 110 F. and maintain such temperature throughout the steeping period. Operating the steeping tank as a single unit, I preferably maintain therein a pressure of about 10 pounds per square inch (gauge) and circulate the steep liquor constantly and vigorously. I test it frequently with litmus paper to determine whether its reaction is alkaline or acid; if it be acid, I add such an amount of caustic soda, in solution, as may be necessary to restore a distinct alkalinity of the steep liquor asshown by litmus. This is of importance as an unchecked acidity at an early stage of the steeping period may impair the ciciency of my invention. The acidity may have been produced by several factors: for instance, the presence of organic acids, such as. lactic, produced by bacterial action, or of amino acids naturally occurring in corn, or by an inorganic acid, such as phosphoric, produced by a decomposition ofthe organic phosphorus compounds of corn, such as the magnesium-calcium salt of the phosphoric acid ester of inositol, which is naturally present in Indian corn, in substantial quantities. The sodium hydroxide of my alkaline steep liquor promptly combines with the liberated or generated acids and if the latter are present in excessive quantities, the steeping liquor changes its character; it may lose its alkalinity and turn acid.v At the end of the steeping period, usually between 48 and 60 hours, I drain the steep liquor from the corn, immerse the latter in water, containing about one third of one percent (by weight) of dissolved sulfur dioxide, allow the corn to remain therein until the original color of the corn has been restored, and then withdraw the corn into a suitable receiving vessel.

Du'ring the exit from the steep tank tothe receiving vessel a large volume of germs is set free, and these I recover readily by passing the steeped and washed corn through a perforated reel or reels R, provided withopenings which permit of the passage of the germs, hulls, and tip caps G, while the partly decorticated, decapped, and degerminated kernels of corn, X, tail off. In the case of germs which still adhere to some of the kernels, although but loosely, I transfer the tails to a suitable vessel,such as aconveyor,rolling mill, or scourer, Y. Where a conveyor is the alternative` selected, I use one which has a solid bottom at the head for about 2/3' of. the length of the conveyor, and a perforated bottom for about 1/3 of its length. Into the upper portion I inject, under pressure, a copious stream of water for the purpose of freeing the germs. The material then passes through a perforated reel again or is run into a liquid flotation tank Z to separate out the germs.

the apparatus Y, pass directly to the driers or, should I choose to getsmaller particles, may pass, still wet, to other scourers or disintegrators N, or any other suitable apparatus to effect such reduction of the kernels. They are then graded in graders J, in a wet state, and are then transferred to dryer D--3 in which their moisture content is reduced to about 13% and nally are conveyed to packers P. It is understood, of course, that I may dry the decorticated, decapped, and degerminated kernels of corn, reduce their moisture content to about 13%, and then reduce and grade them in the manner customary in the dry milling of white goods and well known to those skilled in the art.

I next collect the germs, which have been thoroughly washed with water before their separation, and dry them in standard dryer D-l until their moisture content has been reduced to approximately 2%, whereupon I convey them to the customary expellers herein called oil extractors O, for the extraction of oil K, and the separation of foots F and residue M. I prefer to commingle the hulls and tip caps with the germs before delivery to the expellers, wholly or in part, as the added roghage tends to facilitate the extraction of the oil. The residue M is dried in dryer -D--2 and forms a valuable feedstuff B, which may be used as an absorbent of the spent steep liquor, hereinbefore described, or may be utilized otherwise.

If the steep water (light) L, which I have drained from the corn, gives an alkaline reaction,

I add a suflicient quantity of an acid, sulfurous or hydrochloric for instance, to render it neutral or faintly acid to litmus, and I thereupon concentrate it in an evaporator E, preferably in vacuo, until it has reached a density equal to about 23 Baum. This'concentrated steep water (heavy) H consists mainly of so-called corn solubles, which include the mineral salts which salts, especially phosphorus,

naturally occur lin corn and nitrogenous substances largely of an amide character. Due to the high nutritional value of both, the mineral as Well as the nitrogenous substances, I may use the concentrated steep-liquor for the enrichment of animal 'feedstuffs, decient therein, or, because of the large amount of readily assimilable amino-acids contained therein, I may use the steep liquor, concentrated or at its original gravity, as a yeast stimulant in the manufacture of compressed bakers yeast, or I may use it for culinary purposes in a variety of food products, or in some other manner.

Using my present invention, I have obtained the yields shown in the following table:

Expressed in pounds per bushel of corn, based' upon a total weight of fifty-six pounds, which, as those skilled in the art know, .is the approximate weight of a bushel of corn, the results are shown in the following table:

Table 'I I Pounds Hominy, grits and mea1 approximately 44.80

Feed 5.60 Oil 1.65 Corn solubles, dry 1.81 shrinkage 2.13

A typical chemical analysis of hominy, grits or meal products obtained by my new method is given in the following table:

The laboratory yield of extract obtained from hominy, grits or meal produced according to my new method, are shown in the following table:

Table IV Per cent Moisture approximately 11.24 Extract 83.20 Extract, on dry basis 92.69

yIt is obvious that means of. mechanically separating the hulls, the tip caps and the germs from the kernels of corn, other than those described by me may be used and I mean to include all such mechanical devices as within the scope of my present invention.

It is to' be observed that my new method of decorticating, decapping and degerminating Indiari corn is not limited in its application to the production of white goods, but may readily be applied to the manufacture of corn starch, corn syrups and corn sugars. The principal advantages derivable from its usel in this instance, would lie in a simplification of the manufacturing process and in increased yields-of corn oil, starch and gluten. Yellow corn is principally used in the manufacture of. starch and it is obvious, therefore, that my new method lends itself equally well to the milling of both, white and yellow corn.

My invention should not be confused with prior attempts of thek art to .dehull or degerrninateV shelled Indian corn; such as the method described in U. S. Letters Patent No. 563,859 to Hopkins,

according to which corn can be dehulled by mere spraying potash lye upon the grain. While the lye has a minor corroding effect upon a portion of the hulls, it does not effect a removal of the germ. The Hopkins process is unsuited to the needs of the dry miller because no provision is made for the removalof the sprayed potash lye. It remains adhering to the grain and thus exerts a deleterious influence in several ways. For instance, the lye causeslthe feed, obtained as a byproduct, to acquire a greenish color, which makes it unsalable, or the grits, obtained as a primary product, cannot be employed for the` principal use for which it is intended, namely in the manufacture of fermented malted beverages, for the reason that its alkalinity, caused bythe potash lye,

has an inhibiting e'ect uponthe fermentation of the Wort, etc. Other attempts similar to that of Hopkins are described in U. S. Letters Patent mercially. U. S. Letters Patent No. 1,045,490 to Wulkan is typical of these attempts. Rejecting the use of alkali (page 1, lines 36-40) Wulkan describes a process calling for the employment of a steeping liquor, containing 2% per.` cent of hydrochloric acid. This meansthe employment of a steeping liquor containing 10% of commercial 18 hydrochloric acid. Aside from the fact that my process would exercise no such corrosive effect as would the use of such strong concentrations of acid and hence would not require equipment of prohibitive cost, there are other disad- .lio

vantages to such acid'treatment to which my process is not subject. In the rst place, neutralization of excess acid results in the production of large amounts of sodium chloride (common salt) dissolved in the steep liquor. Since the only commercial outlet for the steep .liquor is the gluten feed, a highly valued concentrated animal feedstuff, obtained as a by-product, and since the presence of considerable salt would render this unmarketable, the advantage which my process enjoys economically over an acid process is apparent. Secondly, as 125 F., the usual steeping temperature, a large amount of hydrochloric acid necessarily hydrolyzes a not inconsiderable portion of the starch, a loss from which my process does not suiier and for which an increased yield of oil would not compensate. Also, it is to be noted that the acid process, as exemplified by Wulkan, does not separate and remove the tip caps-indeed, it is not aimed to do so-and under present conditions this is essential to the successful production of white goods, as the tip caps, being dark in color, would render the finished milled products (grits, for example) unmarketable.

I claim:

1. The process of manufacturing .decorticated, decapped and degerminated Indian corn substantially free from corn oil, which comprises imm'ersing whole Indian corn in an aqueous solution of sodium hydroxide at a temperature between about 100 F. and about 125 F., said solution containing sodium hydroxide o1l about 76% strength in an amount equal to about 1.6% of the weight of the corn land said solution having a concentration of about 0.24% NazO; continu- .ing the immersion of said corn in said aqueous 2. The process of. manufacturing decorticated,

decapped and degerminated Indian corn substan'- tially free from corn oil, which comprises establishing a mass of Indian corn in an aqueous pool of sodium hydroxide weighing about 4 times the weight of said corn and containing an amount of soluble alkali equivalent to about 1 to about 2% of the weight of said corn calculated as NazO at -a temperature above 100 F. and below the gelatinization temperature of corn starch; circulating said aqueous pool through said mass of Indian corn until the germs, tip caps and hulls are loosened; discontinuing the circulation of said aqueous pool; sub-jecting said Indian corn to slight pressure to detach hulls, germs and tip caps from the endosperm and gluten; and separating said detached germs, hulls and tip vcaps from said endosperms and gluten whereby decorticated, degerminated and decapped Indian corn is obtained as whole kernels in substantially their original form and practically free from corn oil.

3. The process of manufacturing decorticated, decapped and degerminated Indian corn substantially free from corn oil, which comprises treating Indian corn with about 4 times its weight of an aqueous solution containing sodium hydroxide in an amount equal to about 1 to about 2% of the Weight of the corn and having a temperature above 100 F. and below the temperature of gelatinization of corn starch until the germs, tip caps and hulls become loosened; subjecting said treated corn to slight pressure to detach said germs, hulls and tip caps from the endosperms and gluten; and separating said detached germs, hulls and tip caps from said endosperms and gluten whereby decorticated, degerminated and decapped Indian corn is obtained, as whole kernels substantially in their original form and substantially free from corn oil.

4. The process of manufacturing decorticated,

vdecapped and degerminated Indian corn substantially free from corn oil, which comprises treating Indian corn with about 4 times its weight of an aqueous solution containing a soluble alkali in concentration of about 0.24% calculated as NazO at a temperature above 100 F. and below the temperature of gelatinization of corn starch at a gauge pressure of, about 8 to about 15 pounds per square inch until the germs, tip' caps and hulls are loosened; detaching said germs, tip caps and hullsfrom the endosperms and gluten; and separating said germs', tip caps and hulls from said endosperms l whereby `decorticated, degerminated and decapped Indian corn is obtained as whole kernels substantially in their original form and substantially free from corn oil.

5. In the alkaline steeping process of manufacturing decorticated, decapped and degerminated Indian corn by steeping, applying pressure or attrition, and separating kernels of said corn from hulls, tip caps and germs thereof, the improvement of steeping said corn in an aqueous solution vcontaining an amount of soluble alkali equivalent to about 1 to? about 2 percent of the weight of the corn and having a concentration of about 0.24%'calculatedas NaaO, at a temperature of above about 100 F. to below the ltemperature of gelatinization of starch. l Y

'rHnoDoRE B. WAGNER.

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