IL32687A - Steam conversion process for producing degraded cereal products - Google Patents

Description

6/29/24 32687/2/3 STEAl'l CGTOBSIOH BOCB30 ¾R ½ODOO:TO liBGRABSD OEBSAL SODUCfS This invention relates to a method for the in situ degradation of tissue polymers contained in raw grains.

Many methods have been proposed for the treatment of starch after it has been removed from the grain to provide conversion for various applications in industry, such as paper or textile . finishing, sizings, adhesives. United States patent ^specifications Nos.2,698,819 and 2,698,936 relate to methods* for providing; respectively, dextriniza- tion and condensation products of starch, the final steps in each of the processes ,of these patent specifications consisting of torrefying (roasting) a starc product by heating under a vacuum, the prior processes being directed to the production of starch conversion and condensation products.

Other previously proposed starch degradation processes include the treatment of starch with heated rollers as disclosed in United States patent specification 1,979» 57, and the use of a controlled extrusion-cooking operation after the raw material has been subjected to steam and high temperatures as disclosed in United States patent specification 3»159,505· The use of heated rollers is slow, involves expensive equipment and results in products varying widely in uniformity of degradation and flake thickness. The starch conversion and condensation processes are directed -to the production of' special products, and they are relatively expensive.

Prior processes have been directed mainly to the degradation of starch after it has been removed from the grain kernel, these processes being ineffective for degradation within the kernel structure. Previous1 gelatinization pro- ■ X. water which is expensive to add and remove, and the processes do not., provide a high percentage degradation. Moreover, none ^ of these processes are directed to or are suitable for in situ polymer degradatio within the kernel.

The problem (to be solved by this invention is to provide an effective' process -for the degradation of cereal tissue polymers. The problem is solved by the process in accordance with the invention which* provides a process for treating a farinaceous material comprising the steps of treating the farinaceous material with at least one gas, the gas comprising at least one of the gases sulphur dioxide, hydrogen chloride, ammonia and chlorine, so that the gas is absorbed into the kernel structure of the farinaceous material and subjecting the farinaceous material to steam under pressure within' a pressure container.

As used herein the term "grain" includes farinaceous materials in general, and particularly, cereal feed grains, such as corn, grain sorghums, wheat, rice, barley, rye, oats, triticale, millet, and other feed grains for which" the term "cereal grains" is. generic. The term "raw grain" means grain which has been chemically untreated, and includes whole grain as well as grain which has been ground. The term grain further includes mixtures of individual grains. .

The term "absorption" is used herein to mean the assimilatioi of gas into the inner kernel structure of the grain. The term "liquid water" is used herein to distinguish the term "water" from gaseous water, or steam. The term "gas" ;as used herein includes either a single gas or a mixture of gases. ' The majority of examples hereinafter described were performed on whole grain into which sulphur dioxide had been absorbed by the absorption process disclosed in our copending . application 32686 filed 23rd July 1969, but the process is also to those with "as is" moisture but only increase handlin problems and costs. "As is" moisture content, normally present in mature warehouse cereal grains, is usually present in the range of 7 to 16 per cent; 12 to 14 per cent moisture being ordinary.

During the steam conversion step, high quality steam is introduced into the autoclave containing the grain at a rate such that a maximum pressure of 10.5 Kg. per square centimeter gauge is reached Within about one minute after start. Pressures ranging from 1.76 to 17.6 Kg. per square can be used/ centimeter gauged however, generally, those much below . 5 Kg. per square centimeter gauge are not satisfactory if the desired degree of degradation of the tissue polymers in the grain is high; for some uses lower pressures may be useful as set forth above. All of the examples belo were carried out at pressure between 10.5 and 17.6 Kg. per square centimeter gauge, a range which is considerably higher than th'at normally used ' in the industry. A preferred pressure range is 6 to 17.6 Kg. per square oentimeter gauge. Peak pressures as low as 2.8 Kg. ar square, .5 Kg. per square centimeter gauge is from about three to five minutes. Temperatures used correspond to that for. ^ steam at- the peak pressures..

An optional improvement consists in flashing the steam into an at least partially evacuated autoclave containing the grain. Upon charging the autoclave with grain, preferably grain containing adsorbed gas therein,, a vacuum is drawn. The higher the vaouum the better, but 610 to 660 mm. of vacuum is adequate, and can be readily and economically accomplished with a single stage steam ejector. The purpose of the vacuum is to remove interfering air molecules so as to cause greater and more rapid gaseous water adsorption from the steam under reduced pressure, and, therefore, greater adsorption during the low prevailing temperatures. The steam is introduced into the autoclave preferably at a rate such that peak pressure is attained one minute after start of introduction. This is desirable in order to exceed the period of relaxation of the grain.

This may be increased somewhat if necessary, but the total time required will be diminished, roughly, by the amount · of additional time stretched out to attain maximum pressure.

The pressure is maintained preferably for a period of from three to five minutes and the steam then discharged at about the same rate as it was charged into the autoclave. When the steam is released, the water in the grain vaporizes and the desorbed steam is vented.- As soon as the prevailing pressure is sufficiently low, the grain is discharged from the autoclave. The complete steaming cycle may be repeated every ten minutes with another batch of prepared grain; the cycle may be less than eight minutes when using pressures around 17.6 Kg. per square centimeter gauge. water added through steam may be removed by simple cooling.

Thus, a rapid and efficient process has been devised to introduce water into the grain through steam, gelatinize and energize the consequent reaction, and remove the water, all in one short operation. With conventional procedures, such accomplishments are comparatively expensive. When it is necessary. to grind the farinaceous converted product, lower condensation; final moistures are desirable to prevent( oondon&€b¾o» and subsequent reagglomeration of the adhesive ma erial during the process of. comminution.

In conventional treatmen processes, as stated above, a moisture content from 30 to 50 per cent is used. Normally in these processes, heat is provided to increase the energy level to that sufficient to gelatinize the starch; higher pressures being used only to inorease the rate and extent of gelatinization. In thepresent process, however, the steam is relied upon to furnish both water and energy and permit simultaneous gelatinization and degradation, a unique feature for several reasons. At peak pressure in the !, i present process the grain adsorbs sufficient moisture from j the steam to reach 30 to 35 per cent moisture oontent, but the water adsorbed is sustained at a very high energy level and tends to attain the same temperature as the steam, the ■ I high energy contributing to the degradation and gelatinization. j The degradation and gelatinization process will work even | if the moisture level has been increased to. a higher value, i but the resulting product is usually not as economically j attractive and would not be used unless a high moisture was > I required to carry out a previous treatment. 1 . I · · ■ i When the process is applied to SOg impregnated grain, and as the temperature and moisture are increased during the ' to sulphur trioxide. Simultaneously, as the water level is increased, the sulphur trioxide combines with water to beoome sulphuric acid, whose mode of action is that of hydrolysis. Thus, during the early stages, it is probable that both reduction and hydrolysis take place with the likelihood that the latter takes place preferentially where the former has taken place, due to location.

There is almost certainly chemical reduction taking place with S02 oxidized to The addition of water during steaming certainly causes the following: Not so apparent, however, is the pyrolysis which takes place at the same time. For instance, in one experiment in which no chemicals were used, the steaming step was carried out with grain sorghum (14 per cent moisture) at 10.5 Kg. per square centimeter gauge for four minutes. The cold water solubles were just under. 50 per cent. With another experiment in which identical, untrea'ted grain sorghum was steamed for 1.5 minutes at 17.6 Kg. per square centimeter gauge, the resulting cold water solubles were 65.20 per cent. Thus, it is quite plain that pyrolysis had taken place. The temperature achieved with such relatively low moisture is high; however, with a water content of 32 per cent, for example, the maximum temperatures are not as high and less pyrolysis results.

Primarily, however, the additional water protects the primary bonds f om destruction to the extent that the water is present.

With a peak pressure between zero and 2.1 Kg. per square centimeter gauge. (for four minutes), the extent of degradation is nil, as evidenced by such criteria as low and virtually unchanged reducing sugar content, low hot and cold water solubility, and low alkali number. Even at .2 Kg. per square centimeter gauge (four minutes) the degree of degradation is low, with resulting hot water solubility barely exceeding that of a conventionally cooked grain sorghum. When the time. element is significantly increased,, the results are essentially the same. With 6.0 Kg. per square centimeter gauge peak pressure, the preferred lower peak pressure, the degree of degradation is only moderate. From 6.0 Kg. per square centimeter gauge upward, the degree of degradation progresses well and the time element required is more closely !related to the pressure used. At 10.5 Kg. per square cm. gauge the extent of desired reaction is excellent. At any pressure of about 7.35 Kg. per square centimeter gauge or higher, the time at which pressure is maintained is a function of the pressure and vice versa. At 10.5 Kg. per square centimeter gauge three to five minutes is adequate; less time results in insufficient degradation for most purposes and additional time is not helpful, may cause undes rable handling problems, and is less desirable economically. At pressures above 10.5 Kg. per square centimeter gauge the time ismerely decreased. Thus, by controlling the peak pressure, and the time at that peak pressure, excellent control over the degree of degradation is possible.

When HCi, impregnated grain is used in conjunction with the conversion process in accordance with the invention, the basic mode of reaction is somewhat different than that for S02 , impregnated grains, and a somewhat different range of products is produced. Hydrogen chloride is neither ' oxidative nor reductive but is hydrolytic and may react and extensive than that encountered with sulphuric acid.

Historically, it has "been found that HCJt reactions are difficult to control and have a tendency to break down an increasing proportion of constituents into primary and simple repeating units of which the various polymers are comprised. With the present process, and using whole grain, the solubles are slightly higher and reducing groups somewhat greater, compared to S02 impregnated grain, exhibiting excellent control. As the degree of particle subdivision is increased, the water solubles increase, and hydrolysis to repeating units is increased markedly. Thus, a wide variety of products are readily available.

In the examples given below illustrating the steam conversion process, whole grain is used in all but one, and the procedure for adsorption of gas into the grain structure precedes the steam conversion step. Accordingly, all of the examples of the process were performed on grain containing adsorbed gas, this being the product to which the process is peculiarly applicable.

When the grain is transferred from the vacuum chamber to the autoclave for steaming it is desirable, in order to prevent condensation, that the autoclave be preheated to a temperature higher than that which would be obtained with the anticipated peak pressure. In commercial practice such procedure would be inherent in that the equipment would be used repetitiously.

In the examples and elsewhere in the specification, all percentages stated are percentages by weight. The percentages of gas and moisture are based on the dry weight of the grain. The weight of the gas adsorbed in all examples-was calculated by weight differential, before and after "basis of glucose but actually are a measure of terminal reducing groups. "As is" moisture content usually varies from '7 to 16 per cent of the weight of the grain, and in most of the examples a moisture adjusted to per cent was used for the sake of uniformity and comparison.

Example 1 14-9«3 grams with 10.7 per cent moisture of whole grain sorghum were mixed with 5.7 grams of water to increase the moisture content to about 14 per cent. The tempered grain was then placed in a reaction chamber, the chamber hermetically sealed, and subjected to a vacuum (less than 25.4 mm. of absolute pressure). After equilibrium conditions were established, 0.625 grams of sulphur dioxide (0.5 ) was flashed into the nearly filled chamber increasing the chamber pressure to atmospheric, requiring 4.0 seconds, after which the flow of gas was stopped. The pressure started to decrease immediately, regaining 77 per cent of the original vacuum within one minute and 91 per cent of said vacuum within five minutes and approximating the original > vacuum (within 2.5 cm.) at the end of an hour. The colour of the grain became lighter as the gas was added. The grain remained in the hermetically-sealed chamber for a total of 9.75 hours afterthe chemical addition, all at a prevailing 24°C room temperature; then the vacuum was released and the sample transferred to the preheated autoclave. The autoclave was hermetically sealed and a vacuum established (ca 585 mm. Hg) , followed by the injection of steam at such a rate that the peak pressure of 17.6 Kg. per square centimeter gauge was attained within 2.5 minutes. This pressure was maintained for an additional .minute, and then the steam was exhausted to atmosphere in 1.17 minutes.

After air drying (75°C) to about six per cent moisture, the grain was easily and finely ground by a hammermill.

The resulting whole grain product has a reducing sugar content of 1.93 per cent-, cold water solubles of 83.49 per · cent, all based on the final 5.74· per cent moisture basis.

Example 2 155.0 grams of whole grain dent corn with an adjusted moisture content of 14· per cent was used. 0.55 grams of sulphur dioxide (0.4125 per cent) was flashed into the grain-bearing chamber for 5.7 seconds and the flow of gas terminated. The . pressure, atmospheric at the instant the gas was shut off, decreased rapidly and the grain colour became lighter and brighter. Within one minute, 70 per cent of the original vacuum was recovered and 97 per cent was recovered within the first hour. After 11.75 hours the vacuum was released and the grain transferred to the preheated autoclave which was hermetically sealed and a vacuum of about 635 mm. Hg was imposed thereon followed by the introduction of steam at a rate that the peak pressure of 17.6 Kg. per square centimeter gauge was attained in 1.25 minutes, this peak pressure being maintained for an additional two minutes. The steam was discharged to atmosphere within 4-5 seconds leaving the grain sample slightly sticky but generally free flowing when it was removed from the autoclave. The moisture content was reduced from 9.5 to 5.5 per cent by air drying (75°0) , the product cooled, and finely ground with ease in a hammermill. The resultant product had a reducing sugar level of 3.4-5 per cent and cold and hot water solubles content of 81.03 and 84.10 per cent, respectively, based on the, final 5.37 per cent moisture content.

Example 3 155.0 grams of dehulled whole rice grain having a moisture content adjusted to 14 per cent was used and 0.5 grams of sulphur dioxide was flashed into the chamber, increasing the pressure to atmospheric in a period of 3.0 seconds, and the flow of gas terminated. The pressure started to decrease immediately and the grain lightened somewhat in colour. After one minute the pressure decreased to 71 per cent of the original vacuum and at the end of one hour had decreased to 97 per cent of the original vacuum.

After 1.8 hours with the vacuum being 98 per cent of that originally established, sulphur dioxide was introduced into the chamber again, this time for 1.8 seconds, increasing the pressure from vacuum to 860 gm. per square centimeter absolute, and the flow of gas terminated. .During the second addition 0.3 grams of S02 was introduced into the chamber making a total of 0.8 grams (0.6 per cent) of gas. No colour change occurred during the second addition of sulphur dioxide. Within one minute after the cessation of the second addition, 74 per cent of the original vacuum was restored, and 97 per cent was reestablished after one hour. The vacuum was released at the end of 12.4 hours after the second SO^ adsorption and the treated grain transferred to the preheated autoclave which was hermetically sealed and a vacuum of about 660 mm. Hg drawn in the autoclave. Steam was fed into the autoclave at such a rate that a peak pressure, of 10.5 Kg. per square cm. gauge was attained in one minute and the peak pressure was held for an additional four minutes after which the steam was released to atmosphere at about i a moisture content of about 14 per cent which was reduced by air (75°C) to about five per cent and then easily ground finely with a hammermill. The resulting product had a reducing sugar value of 1.13 per cent and cold and hot water solubles content of 85.15 and 90.86, respectively, based on the final 4.83 per cent moisture content.

Example 4 155.0 grams of whole grain triticale having an adjusted moisture content of 14 per cent was used. 0.6 gram of sulphur dioxide was flashed into the grain-bearing chamber in 3.8 seconds, increasing the pressure to atmospheric, after which the flow of gas was terminated. The colour of the kernels of grain lightened immediately. The rate of adsorption was about that described for previous examples. Upon release of the vacuum after 1.8 hours, 99 per cent of the original vacuum was attained, and sulphur dioxide was again introduced into the chamber, this time for 2.7 seconds, increasing the pressure from vacuum to atmospheric, and the flow of gas was terminated. During the second addition of-sulphur dioxide, 0.45 grams of gas was introduced making a total of 1.05 grams (0.787 per cent). Within one minute after the cessation of the second addition of gas, 56 per cent of the original vacuum was restored and 95 per cent was restored after one hour. At the end of 11.25 hours, the vacuum was released andthe sample transferred to the preheated autoclave. After sealing, a vacuum of about 660 mm. Hg was drawn in the autoclave and the steam was introduced at such a rate that a peak pressure of 10.5 Kg. per. square cm. gauge was attained within 1.2 minutes and that peak pressure maintained for an .additional four minutes, after s a w s x us a s grain exhibited the usual medium tan colour, was uniform, free flowing and had a moisture content of about 17.7 per cent. After drying to approximately 5.25 per cent moisture (75°C.air), the grain was finely ground through a hammermill. The resultant product had a reducing sugar valve of 2.53 per cent and cold and hot water solubles content of 75.29 and -82.55 per cent, respectively, all based on the final moisture content of 5.18 per cent.

Example 5 14-9.3 grams of whole grain sorghum having a moisture content of 10.7 per cent was mixed with 9.05 grams of sodium chloride solution which contained 2.667 grams of sodium chloride (2.00 per cent) and 8.08 grams of water and which increased the moisture content to about.15.3 per cent. After tempering the sodium chloride solution, the grain was placed in the reaction chamber which was hermetically sealed and evacuated. 0.6 grams of preweighed sulphur dioxide (0.45 per cent) was flashed into the chamber, increasing the pressure from vacuum to about 355 mm. Hg and requiring .6' seconds. The grain lightened in colour immediately and the sulphur dioxide was adsorbed rapidly, 90 per cent of the original vacuum being attained within five minutes and 98 per cent of the original vacuum being attained within one hour. The vacuum was released after some 40 hours of conditioning and the sample transferred to a preheated autoclave which was hermetically sealed and evacuated to about 660 mm. Hg. Steam was introduced into the autoclave at such a rate that the peak pressure of 10.5 Kg. per square cm. gauge was attained in 60 seconds, this peak pressure being maintained for an additional four minutes. Upon converted grain had a moisture content of 17.6 per cent, was free flowing and relatively dark in colour. After drying to about 7.5 per cent moisture (75°C air) the grain was finely and easily ground with a hammermill. The converted product had a moisture content of 7.4-7 per cent, a reducing sugar value of 2.35 per cent and cold and hot water solubles of 76.81 and 84·.18 per cent, respectively, based on the moisture content of the ground product.

„ Example 6 151.4· grams of grain sorghum offal containing 11.93 per cent moisture was used. The sample was a byproduct from the production of grain sorghum brewer's grits and contained all the fractions of the berry, not. included in the grits, which were essentially small and coherent portions of low-fat endosperm. The moisture content of the offal fraction was adjusted to 14 per cent, and after complete mois.ture adsorption, the unground and highly cellulosic material was placed in the glass reaction chamber, hermetically sealed, and evacuated. 3.Q grams of sulphur dioxide (2.2 per. cent) was flashed into the chamber in a period of 9.9 seconds with the pressure increasing to about 590 gm. per square cm. gauge (4-30 mm. Hg) , and the flow of gas terminated. The colour of the cereal tissue was lightened somewhat instantaneously and the rate of adsorption was extremely rapid. Within an hour after the gas injection, 86 per cent of the original vacuum was restored, due to adsorption,, and 90 per cent of the vacuum was reestablished after 15.25 hours at which time the vacuum was released. The sample was transferred to a preheated autoclave which was sealed and evacuated to about 660 mm. Hg. Steam was then introduced into the autoclave at a rate such as to attain a peak pressure of 10.5 Kg. per square cm. gauge after 75 seconds, this peak pressure being maintained for four additional minutes, at which time the steam was released to atmosphere at about the same rate it was introduced. The resulting product contained 16.8 per cent moisture, was. free flowing, slightly lumpy, easily handled and uniformly converted. The sample was dried to about 4.0 per cent moisture, cooled, and finely, ground through a hammermill. The final product exhibited a reducing sugar value of 4.00 per cent and cold and hot water solubles content of 60.23 and 68.54 per cent, respectively, all based on the final moisture content of 3.75 per cent.

Example 7 149.3 grams with 10.7 per cent moisture whole grain sorghum, were mixed with 19· 5 grams of water to increase the moisture content to approximately.21 per cent. The tempered grain was placed in a glass reaction chamber, , hermetically sealed, and a vacuum imposed on the half-filled chamber. After equilibrium conditions were established, 1.0 gram of sulphur dioxide (0.75 per cent) was flashed into the chamber, increasing the pressure to atmospheric, and requiring 3.7 seconds after which the flow of gas was terminated. The pressure started to decrease instantly with the simultaneous and characteristic bleaching. The rapid · adsorption of the gas by the grain exhibited a rate about the same as previous examples, and the chamber had regained about 95 per cent of its original vacuum at the end of the first hour. After 11.4 hours the vacuum was released and the sample was transferred to the preheated autoclave. was drawn (about 660 mm. Hg) , followed by injection of steam at such a rate that the peak pressure of 10.5 Kg. per square cm. gauge was attained in about 50 seconds. The peak pressure of 10.5 Kg. per square centimeter gauge was maintained for four additional minutes and then the steam was discharged to atmosphere at about the same rate it was introduced. The discharged grain was free flowing, slightly lumpy and had a moisture content of about 20 per cent. The sample was then air dried (at 75°C) to about 6.5 per cent moisture, cooled, and easily reduced in a hammermill. The' resulting adhesive product possessed a reducing sugar value of 2.28 per cent, cold and hot water solubles of 70.77 and 83.08 per cent, respectively, all- on the final moisture basis of 6.31 per cent.

Example 8 155.0 grams of whole grain sorghum having an adjusted moisture content of 14 per cent was used. 0.85 gram (0.638 per cent) of sulphur dioxide was flashed into the reaction chamber in 6.3 seconds and the flow of gas terminated. The pressure began to drop instantly and the grain colour was lightened significantly. 68 per cent of the original vacuum was restored within 60 seconds due to adsorption of sulphur dioxide by the grain and 95 per cent of the original vacuum was reestablished within one hour. After 17.5 hours the vacuum was released and the grain transferred to a preheated autoclave which was hermetically sealed, and a vacuum of about 585 mm. Hg was established in the autoclave. Steam was introduced into the evacuated autoclave at such a rate that the intended peak pressure of 10.5 Kg. per square centimeter gauge was established within only six seconds and that peak pressure was maintained for five minutes thereafter. The steam was exhausted in 3 seconds and the grain discharged. The converted product, having a 20.5 per cent moisture content, was free flowing, uniform, and slightly sticky. It was dried to about 5.5 per cent moisture content and easily ground to a. fine condition in a hammer-mill. The resultant product, at 5.62 per cent moisture, had a reducing sugar value' of 2.15 per cent and cold and hot water solubles content of 72.66 and .84.08 per cent, respect-ively, based on the "as is" moisture basis.

Example 9 209.3 grams with 1 per cent moisture whole grain sorghum was used. 1.00 gram of hydrogen chloride (0.556 per cent) was flashed into the evacuated chamber in 2.0 seconds. After termination of gas. flow, the pressure started to decrease instantly and rapidly. No significant colour change was noted. Within 30 seconds, over 87 per cent of the original vacuum had been recovered and 89 per cent of that vacuum was restored 15 minutes after termination of gas flow. The pressure remained essentially the. same for ¾ie duration of the 20 hours allotted for total gas adsorption. At the end of the adsorption time the vacuum was released and the sample transferred to the preheated autoclave which was sealed hermetically and a vacuum of 635 mm. Hg was drawn. Steam was then injected at such a rate that the peak pressure of 10.5 Kg. per square centimeter gauge was attained in about one minute, and this pressure was maintained' for four additional minutes, after which the steam was exhausted to atmosphere at about the same rate it was introduced. The discharged grain was dark coloured, uniform, free flowing, and had a "sweet" odour. The converted grain was then air dried at 75°C from about 19 to nearly per cent. The grain was easily ground through a hammermill. The resulting adhesive product was cold water soluble to the extent of 66.38 per cent, based on the final moisture content of 3.59 per cent.

Example 10 209.3 grams of whole grain sorghum having an adjusted moisture content of 14 per cent was used. Sulphur dioxide and ammonia were flashed into the evacuated grain-bearing chamber, in that order, all at room temperature. 0.9 gram of sulphur dioxide was flashed into the container over a period of 24.4 seconds at the end of which time the pressure began to decrease, 43 per cent of the original vacuum being restored within one minute, 93 per cent after one hour, and 98 per cent re-established at the end of the 11.3 hour adsorption period. 0.4 gram of ammonia was flashed into the evacuated chamber in 3.7 seconds, increasing the pressure to atmospheric. Seven minutes after the gas was shut off,- 99 per cent of the vacuum had. been recovered and at the end of that short adsorption time ammonia was flashed into the container again, this time for 6.0 seconds delivering 0.42 gram (a total of 0.455 per cent) of ammonia. 81 per cent of the starting vacuum had been recovered within one minute and; 102 per cent of that vacuum at the end of the 2.8 hour, adsorption period. The final vacuum was 99· per cent of the original vacuum, prior to the introduction of sulphur dixoide. At the end of the 2.8 hour adsorption period, after the second ammonia exposure, the vacuum was released and the sample transferred to the preheated autoclave.

Immediately after iransfer the autoclave was evacuated and . steam directed into the autoclave at such a rate that the peak pressure of 10.5 Kg.per square centimeter gauge was reached in 1.25 minutes, and this pressure was maintained for an additional four minutes. The steam was then exhausted to atmosphere at about the same rate it was introduced. The discharged sample was relatively light in colour, free flowing, and uniform. The moisture was reduced from 16.9 to about 4 per cent by air drying at 75°C The converted grain was easily ground in a hammermill. The resulting product was 55.95 per cent soluble in cold water, based on the final 3.49 per cent moisture.

Example 11 209.3 grams of whole grain sorghum, containing an adjusted moisture content of 14 per cent was used. Sulphur dioxide, ammonia, and hydrogen chloride were used, in that order, all. at room- temperature. 0.9 gram of sulphur dioxide (0.5 per cent) was flashed into, the evacuated and hermetically sealed container in 23.8 seconds, increasing the pressure to atmospheric, then the supply of gas was shut off. The pressure started to drop instantly, reaching 49 per cent of, the original vacuum within 60 seconds, and 93 per cent of the original vacuum within an hour. At the end of the 14.1 hour adsorption time, 98 per cent of the vacuum had been restored. 0.68 gram of ammonia (0.378 per cent) was flashed into 1he evacuated chamber, increasing the pressure to atmospheric after 22.1 seconds, at which time the gas flow was terminated. The pressure commenced to. decrease, recovering 2 per cent of the starting vacuum after 10 minutes at which time the sample was subjected to another ■ - ammonia exposure, this time 0.30 gram "being added in 9.2 seconds.. A total of 0.98 gram of ammonia was adsorbed (0.54-4· per cent total). The pressure started to decrease simultaneous with gas flow cessation, 82 per cent of the starting vacuum being re-established within one minute and 99.6 per cent of the starting vacuum within 15 minutes. The gas adsorption period was 28.8 hours, and at the end of this time 1.0 gram of hydrogen chloride was flashed into the evacuated chamber in 9.8 seconds, then the gas flow was shut off. The vacuum was 85 per cent recovered after 1 minutes at which time the second exposure of hydrogen chloride was made. 0.55 grams of hydrogen chloride was flashed into the container in ·8 seconds (1.55 grams, or 0.861 per cent in all). Again, at the instant the gas supply was shut off the pressure began to drop. After 18.1 hours adsorption time the starting vacuum was 70 per cent recovered after which time the vacuum was released and .the grain transferred to the preheated autoclave. Immediately, ■ the pressure in the autoclave was reduced to about 660 mm.

Hg, then steam was introduced at such a rate that the peak pressure of 10.5 Kg. per square centimeter gauge was attained within 1.17 minutes. The 10.5 Kg. per square centimeter gauge pressure was maintained for four minutes and then exhausted to atmosphere at about the same rate it was introduced. The converted grain was free flowing and very dark in. colour. At.75°C the sample was air dried from 16.7 to 4.0 per cent moisture. The resulting product, easily ground through a hammermill, was 59.4-6 per cent cold water soluble, based on the final 3.28 per cent moisture content.

Example 12 . moisture content of 14 per cent, was used. Both sulphur dioxide and hydrogen chloride, in that order, were used.

The grain was placed in a container, hermetically sealed, and evacuated. After equilibrium conditions were established, 0.89 gram of sulphur dioxide (0.49 per cent) was flashed into the container in 24.1 seconds, after which the flow of gas was stopped. The pressure started to decrease immediately and rapidly so that within one minute 53 per cent of the vacuum had been restored and 96 per cent of the vacuum had been recovered by the end of the 19.1 hours adsorption time. Hydrogen chloride was flashed into the evacuated chamber (0.61 grams,- or 0.33 per cent) for 4.6 seconds, then the gas flows terminated. The following adsorption was very rapid with 87 per cent of the starting vacuum recovered in .60 seconds and 95 per cent regained within one hour.' After an 18.3 hour adsorption time, and with the vacuum . 94 per cent of that just prior to the hydrogen chloride exposure, the vacuum was released. The grain was transferred to the preheated autoclave, the autoclave evacuated to about 635 mm. Hg, steam was introduced into the autoclave at a rate such that the peak pressure of 10.5 Kg. per square centimeter gauge was attained within 1.33 minutes and that pressure maintained for four additional minutes. The steam was then exhausted to atmosphere at about the same rate it was introduced, and the grain removed. The discharged sample- was free flowing, relatively dark in colour, and uniform. After drying from about 13 to about 4- per cent moisture by air at 75°C, the sample was cooled:, and easily ground through a hammermill. The adhesive product was 78.40, per cent cold water spluble, based on the final 3.70 per cent moisture content.

The grains used in the examples included grain sorghum, rice, triticale, and grain sorghum offal. The process is effective on all cereals without exception. The moisture content of the grains used varied from 11.93 to ■ '21 per cent before steam conversion, and the moisture content of the converted product varied from 9.5 to 20.5 per cent.

Peak pressures ranged from 10.5 Kg. to 17.6 Kg. per square centimeter gauge; the time used to attain these peak pressures varied from 6 seconds to 2.5 minutes. The time for maintenance of peak pressure ranged from one to five minutes and the time used for exhaustion of steam varied from 4-5 seconds to 1.33 minutes. The reducing sugar values, cold water solubles content, hot water solubles content of the final products, based on their final moisture content after drying and cooling, varied, respectively, from 1.13 to 4.00, 55.95 to 85.15 and 68.5 to 90.86 per cent. In all but four of the examples, the cold water solubles content of the product exceeded 70$, and in all of the examples except one in which the hot water solubles content, was I available it exceeded 80 per cent.

The' gases with which the treated grains were impregnated were sulphur dioxide, hydrogen chloride, sulphur dioxide and ammonia, sulphur dioxide with ammonia and hydrogen chloride, and sulphur dioxide with hydrogen. chloride. Other gases may be used, . such as, ammonia,, hydrogen sulphide, chlorine, ethylene, ethylene oxide, and combinations of these gases with each other and with sulphur dioxide and hydrogen chloride.

Examples 10, 11 and 12 illustrate the application of the conversion process to grains which have adsorbed two or more gases, the cold water solubles content of the products illustrating the efficacy of the process in this application. These examples illustrate the application- of the process for promoting a chemical reaction in situ between two or more gases adsorbed into the kernel structure to provide an end product in the grain kernel. For example, if the desired reaction is primarily reduction, in lieu of reduction and subsequent hydrolysis as encountered with sulphur dioxide, ammonium sulphite may be substituted by adsorbing ammonia first, then sulphur dioxide. For slightly varied results, the chemicals may- be reversed in their order of adsorption. .As another example, hydrogen sulphide may be adsorbed if there are reasons to employ the reduced form of sulphur instead o the oxidized form, sulphur dioxide. Both are reducing agents; both exhibit a bleaching effect on whole grain. · As an illustration of overall cereal tissue degradation, consider Example 6 wherei grain sorghum offal was used.

The raw material, a by-product from the production of grain sorghum brewers' grits, is principally bran with some germ and minor proportions of endosperm. The cold and hot water solubles were over 60 per cent and while not quite so high as the other examples, the values are higher than can be accounted for by the starch content. The reducing sugar values were still quite low at 4.00 per cent, indicating the presence of large polymers and relatively few small or short polymers.

Among the .advantages of the process is that it improved, utilization of the inherent nutritive value of the treated grain is realized over that for the untreated grain. For example, in the case of the whole grain sorghum treated with sulphur dioxide and then subjected to steam conversion, after the grain had dried to a storable level of about 12 per cent moisture, samples were placed in the rumen (ruminant's first stomach) of a fistulated steer, using the nylon bag technique. Unlike ordinary whole kernels, where about four to seven per cent disappearance was noted in 4-8 hours, 9 per cent disappearance was observed for the treated grain in 24· hours. The various cereal tissue polymers are in a state of significantly greater and more rapid availability. The feasibility of direct, animal feeding thus becomes self-evident and is greatly enhanced by the economy or production mandatory in such a competitive endeavor.

After, the grain is discharged from the autoclave, it must be cooled; or, in the case of grain with substantially more than 16 per cent moisture content, dried and then cooled. Following that procedure there is no urgency whatever to perform any additional processing steps since the product is extremely stable and may- be stored indefinitely. It may be shipped as processed grain in bulk, or it may be ground and packaged before shipment. Due to the chemical degradation many internal vector forces have been relieved or eliminated; the response to practically every type of conventional grinding is excellent illustrating a significant improvement over that encountered with untreated grain and a substantial improvement as compared to grain which is simply gelatinized.

The product odours are interesting and useful. With^ steam converted cereal grains, having first been impregnated with sulphur dioxide, the odours have a striking likeness to cereal grains having been coated with molasses. The odours are molasses- like whether in whole grain form farinaceous form or ground whole converted grain. When sulphur dioxide and ammonia combinations are used, the odour is unmistakably that of fresh roasted peanuts, the degree apparently depending on the amounts and proportions of those gases used. With' HO1 the odour is frequently "sweet" and somewhat "acid", the degree depending upon the amount of gas used and degree of degradation which is dependent on the. numerous controlling factors. While such pleasant Odours may not be particularly useful for some purposes it is a well-established fact that molasses is attractive to animals, especially ruminants. Moreover, the readily available, energy of the product in accordance with this invention is considerably greater than the same weight of molasses.

The uniform and appropriate physical properties of the product, along with the low cost of production, heretofore not possible, combine into a fortuitous set of circumstances which provide markets previously unavailable. Products made by prior, art processing, which are degraded to about the same extent as the present product, are available, but are prohibitively expensive for certain markets because of the lengthy time elements involved, cost of pure polymers, high moisture requirements necessary, uniformity difficulties, and the like.

■ One such. market is for a nutritive binder for animal feed pellets. Generally, a pellet binder is desirable for many feedstuffs mixtures to provide tough pellets, resistance to crumbling, and to increase the through-put per pellet machine. Ideally, a pellet binder should be effective (as stated), inexpensive, nutritive, and readily available. Thus far, no product has been offered which has satisfied all requirement and most products offered for the purpose have enjoyed no significant portion of the potential market whatever. Calcium lignosulphonate, a paper manufacturing byproduct, is probably the most efficient binder currently marketed, but it is considered to be of little nutritional value by most authorities, and is not allowed to be used in feedstuffs in excess of four per cent. According to numerous tests conducted, the product from the present process satisfies all requirements, can.be used in any proportion, including 100 per cent, and is at least as efficient and more economical than calcium lignosulphonate. The fact that the product is not hygroscopic, yet imbibes water very rapidly and is largely water soluble makes it attractive as a nutritive pellet binder, because during the process of feed pelleting, the product has only about six seconds to adsorb sufficient moisture to become effectively adhesive.

Feeding tests, using rats, have indicated strongly that when supplemented with protein the product produced significantly better growth rates than the same grain which had not been processed but which. as protein supplemented in like manner.' Another use for the products of the steam conversion process in accordance with:the present invention are as a . replacement for molasses used as a carrier in liquid fed supplements. Other uses for the product are as an adjunct in the manufacture of gypsum wallboard, and as a binder for various products, such as foundry cores, charcoal "briquettes, taconite pellets, and other related and similar uses.

In gypsum wallboard production, a modified raw starch or dextrinized raw flour is commonly added to the wet gypsum stucco mix just prior to casting to improve the adhesion of paper to the core as the starch migrates toward the surface of the core during drying. It is also believed that the farinaceous materials aid in controlling the rate of gypsum crystal formation. Further, there is evidence to support the belief that a material with cold water solubles higher than the 10 to 35 per cent range currently being supplied would enhance the rate of wallboard production.

The product in accordance with the invention has been tested forthis use and has demonstrated an efficacy which is very promising. Should a manufacturer desire somewhat different \ properties to suit individual plant manufacturing operations, produc characteristics may be altered to satisfy the requirements because of inherent flexibility and utility.

Claims (3)

1. 32687/2/3 WHAT V/E CLAIM IS: 1. A process for'< treating a farinaceous material comprising the steps of treating the farinaceous material with at least one gas, 'the gas. comprising at least one of the gases sulphur dioxide, hydrogen chloride, ammonia and chlorine, so that' the gas is absorbed into the kernel structure of the farinaceous material and subjecting the farinaceous material to steam under pressure v/ithin a pressure container.

2. A process according to claim 1 in which the pressure container is at least partially evacuated prior to the introduction of the steam.

3. A process according to claim 1 performed without the addition of liquid water. k, A process according to any one of the preceding claims in which the steam is brought to peak pressure of at least 1.76 Kg. per square centimetre gauge. 5. A process according to any one of the preceding claims in which the steam is brought to peak pressure in a period of from six seconds to 2.5 minutes after steam introduction has been initiated and the steam is maintained at peak pressure for a period of from one to five minutes, whereby the grain is brought to a desired reducing sugar value and cold and hot water solubles content. 6. A process according to any one of the preceding claims wherein at least 0.1 per cent by weight of said at 32687/2/3 7β A process according to any one of the preceding ,'t claims, in which the gas is a mixture of sulphur dioxide and ammonia/ i -' ■! &. ; < A, process, according to any one of claims 1 to 6, '·■ ' ' /' ' , ' ' . in which the gas is a mixture of sulphur dioxide, ammonia and hydrogen chloride. 9. A process according to any one of claims 1 to 6, in which the gas is a mixture of sulphur dioxide and hydrogen chloride. 10. A process according to. claim wherein the peak steam pressure lies between 10.5 and 17.6 Kg. per square centimetre gauge, is attained in from 6 seconds to 2.5 minutes, and said peak pressure is held for a period of from one to five minutes. 11. A process according to any one of the preceding claims in which the product of the treatment has a reducing sugar. value, cold and hot water solubles content, respectively, of from about 0.93 to 4.00, 55.95 to 85.15 and 75.00 to 90.86 per cent. 12. A process for creating a farinaceous material substantially as described in the herein Examples. 13. Farinaceous material whenever treated by the process claimed in any one of claims 1 to 12.