CA1193131A - Freeze concentration of aqueous wood smoke flavor solutions and use thereof - Google Patents

Abstract

Abstract of the Disclosure Aqueous smoke flavorings are freeze concentrated to derive concentrates with the same relative quantities of acids, phenols and carbonyls, but with more stability and less water, than the stock solutions. The freeze concen-trates are used with or without dilution to flavor foodstuffs by atomization, spraying, dipping or injection.

Description

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This invention relates to aqueous solutions of wood smoke flavors. More particularly, this invention is concerned with a process of concentrating aqueous solutions of wood smoke 1avors and the use of the concentrates in smoke flavoring foodstuffsO

Background of the Invention Aqueous based smoke flavorings made by direc~
water absorption and condensation of natural vaporous smoke components under Hollenbeck U.S. patent 3,106,473 are well established, improved substitutes for vaporous smoking.
Meat items appropriately treated with these solutions take on the color and flavor characteristics of direct natural vaporous smoked products without the well documented drawbacks of the latter. Since the commercial introduction of aqueous smoke flavorings, the trend has been one of demand for more concentrated products. Chief among the reasons for this are a desire for a more intense brown color on meat surfaces and lower packaging and shipping costs of the smoke flavorings.
To meet this demand, smoke flavoring manuEacturers have had to rely upon more extensive extraction conditions Eor direct absorption and condensation of the vaporous smoke~
The result of this is the evolution of processes which operate at the edge of practicality and economy due to physical and chemical limitationsO
Although the phenolic and carbonyl components are equally of major importance, the potency of aqueous smoke flavorings is generally expressed as a function of the concentration of acids in the solution. As used herein, including the claims, acids concentration means titratable acidity expressed as grams of acetic acid per 100 ml of ~3~
sample (%w/v). The titratable acidity comprises the combined effect of both acidic substances and phenolic substances in the aqueous smoke solutionO Commercially available products range from a low of about 2.5% acids to a high of 12.5~, but rarely exceed this upper limit for a number of reasons.
One reason is the flavor becomes harsh and phenolic due to increased solubility of phenols and tar polymers as the percentage of acicls increases. Normally insoluble polycyclic aromatic hydrocarbons/ some of which are carcinogenic, become more soluble in the higher acids solution. Presumably this is because solution polarity is decreased since more organic compounds and less water are present. Undesirable tars are substantially more soluble for the same reason, Efficiency of acids uptake by the recirculating solution decreases above 10% acids as will be shown here. In part this is due to the fact that water, as well as the desirable smoke components, is produced and condensed. This water condensation causes continual dilution which, although not a problem below 10~ acids; imposes an upper maximum limit of about ~0 14% acids. Moreover~ serious production inefficiency occurs between 10 and 14% so that for practical reasons 12~ acids is a realistic limit.
As shown in Figure l of the attached drawings, when an aqueous solution of natural wood smoke flavors is produced by contacting water in countercurrent flow to upward flow of vaporous smoke according to Hollenbeck U.S~ patent 3,106,473l the percent of acids in the product increases proportionally with the smoke solution production time until the solution contains about 10% acids~ Subsequently, the uptake of acids does not continue in proportion with production time. Instead of following the projected identical proportional increase in acids content with increased production time ~3~3~

along the dashed line, the acids concentration uptake with production time follows the curved part of the solid line above 10% acids. Accordingly, -there is a decrease in production efficiency above 10~ acids. This limits commercial production by the process as a practical matter, to solutions having about 12~ acids. The reason for this will be clear by reference to Figure 1 which shows tha-t it would take 15.6 hours to produce a 14% acids product instead of the theoretical 14 hours. The additional 1.6 hours represents uptake efficiency.
Prior art has shown that it is possible to first produce an aqueous smoke flavoring, then concentra-te it by evaporating water. While physically feasible, due to substantial losses of desirable smoke components as well as the water, the process is not done commercially. U.S.
patent 4,278,694 teaches that it is advantageous to concentrate aqueous smoke solu-tions by evaporation specifically for application to food casings for two main reasons. First, the concentrate is useful in producing food casings with a greater density of smoke components per unit area. Second, the evaporation process removes acids which are detrimen-tal to the integrity of the food casings. However, in evaporative concentration, loss of important color forming and flavoring compounds also occurs. By using the method of freeze concen-tra-tion herein described, the loss of -these functional components is avoided.
The following U.S. patents disclose freeze concentration methods and apparatus: Ashley et al 3,070,969; Ashley 3,477,241; Ashley 3,501,924; Ganiaris 3,620,034; Johnson 3,664,145; Ogman 4,091,635; and Engdahl 4,314,455. The ice crystals are coa-ted with concen-tra-te which can be recovered by means of wash columns or centrifuga-tion. None of the references discloses or suggests freeze concentrating a solution of smoke flavors or use of the resulting concentrate on and in foodstuffs.

Summary of the Invention According to one aspect of the invention there is provided a method of concentrating an aqueous solution of wood smoke flavors which comprises cooling an aqueous solution of wood smoke flavors containing up to about 12~
acids until enough ice crystals form in the cooled solution to produce a solution having a desired increase in acids concentration upon removal of the ice; and separating the ice from the smoke flavor solution.
The starting or stock solutions desirably contain about 6 to 12~, more suitably about 6 to 11%, and preferably 6 to 10~, acids.
It is generally desirable to cool the solution until enough ice is formed and removed to produce a product containing at least ]5% acids, but usually not above 35~, since this is the approximate limit (completely dewatered)~
The product obtained by freeze concentration as described is highly dilutable with water asr for example~
it can be diluted with water back to the starting concentration with little to no precipitation of tar.
According to a second aspect of the invention the freeze concen-trated aqueous solution of wood smoke Elavors is applied, with or without dilution, to a foodstuffO

The concentrate, diluted or undiluted, can be applied to the foodstuff by atomization, spraying, dipping, drenching, injection, by incorporating it into the foodstuff -- 4 ~

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by mixing or by coating a casing for the foodstuff with the solution. The amount used will be governed by the usual standards of desirable taste, aroma, flavor and color.
When appropriatel the foodstuff can be heated or cooked before, during or after application of the smoke solution.
The concentrates and aqueous dilutions thereof are especially useful in flavorlng meat products such as ham, bacon and sausage, poultry, seafood, cheese and snack foods. When applied to the surface of sausage, the concentrates produce a very appealing medium brown color on the sausage.

Detailed Description of the Invention In practicing the freeze concentration process of the invention, any suitable aqueous solution of wood smoke flavors can be used. However, the products produced by the process disclosed in the Hollenbeck U.S. patent 3~106,473 :a and marketed by Red Arrow Products Company as C~A~-SO ~are preferably employed because they possess the desired high quality flavoring properties.
Smoke solutions containing about 6 to 12% acids are desirably employed in the process. Starting or stock solutions containing less than about 6~ acids are not as desirably used because (1) much more water would have to be removed as ice from the solutions containing less than 6% acids with added energy use for refrigeration and product pumping and (2) stock solutions with less than 6% acids produce concentrates with higher amounts o phenols which impart a stronger often harsh and undesirable flavor than solutions with lower amounts oE phenols. Figure 2 of the attached drawings shows that stock solutions having about 6 to 12~ acids, and especially to about 11~ acids, are low ~ r~L~ c.~/~

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in phenols. This indicates that stock solutions having less than about 6% acids are far less suitable for use in the process, especially when conslderation is given to point (1~ above. The stock solutlons having a higher phenols level are undesirable because high phenols is associated with a high tar content which can settle out, especially from a concentrate made from a stock solution having less than about 6% acids.
~ny suitable equipment can be used to freeze concen-trate the stock solution on a batch or continuous basisu However, the preferred process is indirect freezing as with a scraped surface heat exchanger as opposed to other methods employing direct contact of refrigerant with the process solution. The latter leads to losses of important, volatile smoke components. After the ice is formedl the concentrate can be separated from it by ei~her centrifugation or wash columns. When adequately separated from the concentrate, the ice can be discarded, since it contains an insignificant quantity of useul smoke constituents.
Because the stock solution is altered only in that water is removed as ice, the freeze concentrate can be d.iluted, such as back to the exact starting concentration, without signiEicantly affecting its composition, especially when a 6 to 10% acids stock solution is used. By starting with a sufficiently dilute stock solution, 6% acids for example, freeze concentrates of up to about 35% acids can be produced wh.ich are dilutable to any degree, such as back to 6%, without precipitation of tarry substances. By contrast, stock aqueous solutions of smoke flavors produced by d.irect absorption and condensation of smoke vapors and having above 10% acids, for example, cannot be diluted with ~ater without ~3~3~
experiencing precipitation of tars. Further, evaporatlve concentrates can be diluted only to a limited extent since organic acids, which help solubility, are volatllized and lost during evaporationO
Also of benefit in freeze concentrates is their reduced potential for tar precipitation as the product ages.
The same principle applies in this phenomenon as it does in the dilutability concept. 8y removing water and increasing the concentration of tar solubilizing organic compounds, greater resistance to tar precîpitation results. Tar solu-bilizing agents, such as polysorbates, need not be added to the concentrates before dilution with water to avoid tar precipitation although such agents are needed if stock solutions with high acids content are diluted. No effect upon the rate of reaction in formation of tar polymers is presumed; merely a profound and beneficial solubilization is realized.
It has been found that the pH of the freeze concen-trated solutions can be adjusted without causing the usual precipitation incurred when the pH of regular smoke solutions is adjustedO With freeze concentrates, the pH can be adjusted with some limitations without requiring a solubilizing aid.
This is possible as long as water added by causticizing solutions is restricted according to the pH.
As an extension of products produced by the direct absorption and condensation of smoke vapors~ the range of practical and economical products i5 increased to about 35% acids by weight. Gains in production efficiency are made possible by being able to produce lower acids stock solutions, and then freeze concentrating to generate higher acids productsO

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In the application of freeze concentrated smoke flavor solutions to food, meat or meat products, the major benefit found is that less ~ater is available Eor interference with color formation on the meat surface. When smoked appear-ance is desired, aqueous smoke flavorings can be applied to the surface of food items by any of several methodsO
In this way dehydration dependent color forming reactions between smoke components and proteins at the meat surface which result in characteristic brown smoked color can take place and sufficient smoke flavor likewise will be imparted.
Typically, food, including meat or meat products, are flavored by exposing them to an atomized aqueous smoke flavoring solution or they are showered with, or dipped in, the solution. For meat items which are placed in food casings, another method of application is possible. ~hus, casings can be used to which the aqueous smoke flavoring solution has been applied. U.S. patent 3,894,158 teaches that casings may be manufac-tured in such a way as to include smoke flavorings as an integral part of edible casings.
Chiu U.S. patent 4,278,694 teaches that aqueous smoke flavorings may be modified to be made suitable or application to the surface of ood casingsn The smoke solids depos ted on the casing are subsequently transferred to the meat item during processing. The casing is then removed and discarded.
Foods, particularly meat products, placed in these casings and then appropriately heat processed~ will take on the flavor and appearance of smoke products.
Only limited success has been realized in applying smoke flavorings to food casings. The major problem is that it is difficult to obtain a sufficient density of smoke solids per unit area of casing which will give sufficiently smoke flavored and colored products. Chiu has shown it 3~
to be necessary to modify the smoke flavorings by various combinations of smoke solution concentration~ pH adjustment and solubilization with additives. The methods of concentration used employ evaporation, primarily of water and acids.
Chiu claims a casing stability benefit by avoiding acid hydrolysis of cellulose casings by evaporating unneeded acids.
By use of freeze concentrated wood smoke flavor solutions, a greater density of smoke solids per casing unit area can be obtained. Also, the freeze concentrated solutions made as specified herein are pH adjustable within some limitations without use of solubilizing agents, thus making the products more useful since they do not adversely affect the casing~
In atomi~ation, the product surface must have been properly conditioned before atomization and smokehouse atomization parameters of temperature, humidity, time and cloud density must be appropriate. Even when the product surface has been properly conditioned and temperature and humidity are optimized, atomized cloud density will limit the amount of color forming constituents in the smoke which come in contact with the meat sur~ace. It is desirable to increase the quantity of smoke constituents contac~ing the product surface and U.S. patent 4,250,804 is evidence of the intention to enhance the extent of this contact by employing the principle of electrostatic precipitation.
It is claimed that by transferring a negative charge to the smoke particles, they become selectively attracted to relatively more positive meat. With concentrates made as specified in the present inventionl a greater density of color forming components in the atomized cloud is possible thus allowing more smoke constituents to con~act the product surface.
The maximum attainable density of smoke components in the smokehouse is reduced by the amount of water concom~
mitantly atomizedO The water increases the relative humidity which in turn limits the maximum density of smoke components in the atomized cloud. Above this limit, condensation on the walls, ceiling and floor of the smokehouse occursO
In theory, if it were possible to atomize only the desirable smoke components without the water, relative humidity would be minimally affected, and a higher density of desirable smoke components would result, thus causing a more intense brown colored product to be produced. By freeze concentrating, it is possible to approach this ideal state by removing much of the water present in aqueous smoke flavorings without affecting the relative composition of the other componentsO
A second benefit of lowering the relative humidity is that the smoke color forming reactions on the product surface take place to a greater extent in a dryer atmosphere. This results in darker products which are usually desirable.
Generally, when ~he smoke solution is applied by showering the product or by dipping, because the contact between the solution and ~he product is intimate, the solution can be more dilute than with atomization. The concentrated solution of this invention usually can be diluted without the problems caused by tar formation with the regular smoke solutions.

UNIQUE QUALITIES OF FREEZE CONCENTRATES
30 1. DILUTABILITY
Because the product composition is altered only in that water is removed, a stock smoke solution can be ~3~3.~
freeze concentrated, and then diluted back to the identical starting composition without affecting its properties.
Evapora~ively concentrated smoke flavorings can be diluted only to a lesser extent.

2. NO PRECIPITATION OF WOOD TARS
Because the amount of acids is higher in the concen-trates and because these acids act as organic solvents, precipitation of tars from solution is greatly reduced in freeze concentrated aqueous smoke flavor solutions.

3. _NO LOSSES OF IMPORTANT FIJNCTIONAL COMPOUNDS
Since the process of freeze concentration selectively removes water, the relative composition of desirable components is unchanged. For example, ratios of phenols and carbonyls to acids in the freeze concentrates are very much the same as in the stock or unconcentrated solutions.

4. pH ADJUSTABLE
The p~ of freeze concentrated smoke solutions can be adjusted without causing significant tar precipi-tation, especially when water is not added to the product.

5. POLYCYCLIC AROMATIC HYDROCARBON (PAH) FREE
~ . _ Typically, during production of smoke flavorings by the absorption concentration of various wood smoke components into an aqueous medium, when the concentration of smoke components in solution exceeds a certain level~ solubilization of PAHs occurs. This occurs for benzo(a~pyrene at about 10% acids. Much longer aging is required for stock solutiorls having above 10% acids to remove trace levels of benzo(a)pyrene~

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6. EXTENDS THE RANGE OF SMOKE ELAVORING CONCENTRATIONS
The practical upper limit of acids in solutions formed by direct absorption of smoke in water is about 12~
acids. Above 12% the 1avor becomes harsh, production efficien-cy falls and tarring potential becomes much greater. By making, for examplel a product with ~ acids by absorption of smoke vapors in water, concentrates having 15, 18, 24, 30% or greater acids can be produced by freeze concentration with the same desirable flavor, minimal tarring potential, etc- as in the 8% stock product.

7. PRODUCTS WITH DIFFERENT CHARACTERISTICS ARE POSSIBLE
BY CONCENTRATING MORE DILUTE FLAVORINGS _ _ An unexpected minimum tar and phenol solubility has been found to exist in the 6 to 10% acids range. By freeze concentrating products in ~his acid range to 13%
acids, for example/ a product is obtained which has much lower tar potential and a significantly lower phenols concen-tration than would be found in a 13% acids product produced by direct absorption of smoke vapors in water.

UTILITY OF FREEZE CONCENTRATES
1. NO LOSSES OF PRODUCT AS TAR
As aqueous smoke flavorings age, tar precipitates and it must be separated from usable liquid and discarded.
In freeze concentrates, no tar precipitates form during normal storage and cause loss of usable volume.

2 SOLUBILIZING AGENTS NOT_N ESSARY
Additives such as polysorbates are frequently added to aqueous smoke flavorings to eliminate tar precipitates.

This can increase product cost up to 20%. With freeze concen-trates made from 6 to 10~ acids stock solutions, the need for polysorbate solubilization is unnecessary.

3 . ATOMI ZATION
Moisture is an inhibitor of the color forming reaction between smoke components and meat proteins. By atomizing a freeze concentrated smoke solution into a smoke-house, the same or greater density of color forming compounds can be obtained at a lower relative humidity, thus increasing the intensity of brown color.

4. LOWER SHIPPING COSTS
A significant part of the cost o~ a smoke solution product received by a customer is freight~ By using a freeze concentrated smoke solution, these costs can be reduced considerably, with the magnitude depending upon product concentration.

20 5. APPLIGATION TO FOOD CASINGS
The major advantage in application oE smoke solution concentrates to food casings is that a greater density of smoke solids per unit area can be obtained. A further advan-tage is that by virtue of having less water in the smoke solution, milder drying conditions can be used which reduce volatilization and/or degradation of desirable components.
Both of these advantages are possible with evaporative concen-trates and freeze concentrates, however, with freeze concen-trates greater quantities of desirable components remain in the concentrate and are available for casing application and subsequent transfer to the meat surface.

- ~3 A third significant advantage in freeze concentrating is that the pH is adjustable without use of solubili~ing agents such as water soluble alcohols. This pH adjustment is important in application of the product to cellulose casings to avoid acid hydrolysis of cellulose which is mani-fested in brittleness of the casings.

This e~ample demonstrates that freeze concentration is done by freezing water and separation of the ice from the concentrate.
A freeze concentrate was produced by placiny CharSol C-10 (commercially available; made by the process of U.S.
patent 3,106,473) aqueous wood smoke flavoring, having 11.4%
acids by weight, in a conventional freezer at -20F for about 18 hours. The free liquid was allowed to drain away from the ice. The acids concentration in the liquid was found to be 20.6%.

This example illustrates the tar-free nature of freeze concentrates.
The freeze concentrate from Example 1 was stored with the C-10 stock solution from which it was prepared.
The amount of precipitated tar was measured periodically over a seven week duration. The results are reported in Table 1.

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~ Tars Precipitation~ Tars Precipitation Weeks at 40CFrom C-10 From Freeze Concentrate _ _ O .()0 0 1 .50 0 ~ .86 4 1.29 7 2.02 0 This example demonstrates that the freeze concentra~
tion process does not alter the relative composition of desirable smoke components. It functions only as a means of water removal.
An aqueous solution of wood smoke flavors (CharSol C-12~ with 12~ acids was freeze concentrated to 18.9~, 24.4%
and 26.9% acids. The freeze concentrates were subsequen~-ly diluted with water to approximately 12~2% acids, the starting concentration. Samples were analyzed for acids, phenolics/ carbonyls and colorO The phenolics are the mos~
important flavoring substances in smoke flavorings. The carbonyls are responsible mainly for the characteristic brown color formation on a meat surface. rrhe color is a measurement of the intensity oE solution color. The results are reported in Table 2.

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TAsLE 2 Acids Phenols Carbonyls Color (%) ~/ml) (%~ Number Control 12 16.2 12~5 10.5 Diluted 13.9%
Concentrate 12 16.2 12.4 10~5 Diluted 24.4%
Concentrate 12 16.8 12.5 ll.0 Diluted 26~9~
Concentrate 12 17.4 12.4 10.5 All results are within experimental error, i.e. there are no significant differences between the samples for any of the analytical parameters. It can be concluded that the freeze concentration process did not significantly alter the smoke flavoring composition other than by water removal.

The example shows that it is possible to further free~e concentrate to produce even more concentrated smoke flavorings.
A freeze concentrate with 24% acids was placed in a dry ice-acetone bath and frozen to a semi-solid state.
Free liquid was drained and the percent acids was found to be 30.6~. With commercially available equipment it is anticipated even more concentrated smoke Elavorinys can be produced. In theory, it is possible to produce a completely dehydrated flavoring, the percent acids in which may reach 35% or so.

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This example illustrates the loss of desirable components occurring in evaporative concentration of smoke flavoring.
A 12.0~ acids, aqueous smoke flavoring was subjected to 90C and 28" vacuum until two thirds of the original volume was evaporated. The sample was analyzed for classes of compounds and the analytical values were compared with theoretical values. If only water was lost, analysis should have revealed three times more of the original values in the concentrate than in the stock solution. The results are reported in Table 3.

Acids Phenols Carbonyls Color _~3(m~/ml3 (%) Stock Solution 12.017.0 13.2 11.0 Theoretical Concentrate 20 (three times stock values) 36.051.0 39.6 33.0 Evaporative Concentrate19.8 40.6 32.5 32.0 ~ Loss 45.020.4 17.9 3 The data show the greatest loss to be of acids. Substantial losses of the phenols, the important flavoring compounds, and of the color forming carbonyls, are realized. No signifi-cant change in solution color is seen.

This example shows that aqueous products down to at least 1.1% acids are of use in making freeze concentratesO

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Aqueous smoke flavorings having from 1.1 to 11.8 acids were freeze concentrated to 13.0% acids. Dissolved solids, dilution tar and phenols were measured. The results are reported in Table 4.

Starting Solutions DissolvedDilution Acids Solids Tar Phenols 1 0 ( % ~ ? ( ~ ) (m~/ml ) 1.1 16.6 0 26.2 3.~ 15.6 0 21.9 6.8 16.0 0 20.B

8.9 17.8 .33 20.9 10.~ 19.2 .54 21.0 11.8 ~0.6 .87 22.2 13.0 (control3 23.0 1.2 23~7 The data show optimum benefit by using 6.B~ acids stock solution, but all samples have lower dissolved solids and dilution tar than the control. Due to the higher phenols content of very dilute stock solutions (1.1~ and 3.4~ acids), these have a more intense phenolic flavor since they have a greater phenols level per unit of acid. This is often undesirable.

This example demonstrates the dilution tar-free advantage of freeze concentrates made from stock solutions in the 6 to 10% acids range co~pared to higher acids stock solutions.

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An 11.7%, and a 6.5%, acids aqueous smoke ~lavoring were separately freeze concentrated to 14.4% acids. Several dilutions of the concentrates were made and the percent tar which precipitated due to the dilution was measured.
The results are reported in Table 5.

Freeze Concentrate from Freeze Concentrate from 11.7% Acids Stock Solution6.5% Acids Stock Solution ~ Acids i~ Dilution % Tar % Acids in Dilution ~ Tar 13.2 o 9 0 0 11.0 .83 702 0 8.8 1.31 6.6 0 6.6 1.75 505 0 3.3 1.73 4.R 0 The diluted solutions can be applied to foodstuffs to produce smoke flavored products. The solutions which have no, or a minimum, tar are preferably used.

EXAMPI,E 8 This example shows that in producing smoke flavorings of greater than 10% acids concentration, absorption efEiciency .LS reduced below that which is experienced up to 10~ acids.
Hardwood sawdust was burned on a commercial scale generator as per the Hollenbeck U.S. patent No. 3,106,473 and the vaporous smoke was absorbed into water. Titratable acidity was used as an indicator of solution strength.
The percent acids was measured periodically over a 16 hour period. The data in Figure 1 show that at about 10% acids, the actual production efficiency is below that which would be expected. It took 11% more time to reach 14~ acids than ~3~3~
would have been expected. This corresponds direc~ly to 11% higher production costs per gallon of smoke flavoring.

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Benzpyrene reduction was established in freeze concentrated wood smoke solutions by use o~ less concentrated stock solutions~
CharSol C-10 (11.5% acids) and C~6 (7~ acids) were obtained within two days of production, chilled to precipitate tar, filtered and analyzed immediately for benzo~a)-pyrene. Portions of both samples were freeze concentrated to a 16~ acids level. The stock solution and the freeze concentrates were analyzed for benzo(a)pyrene.
This study resulted in the following levels of benzo(a)pyrene:

Fresh C-10 = 7.0 ppb benzo(a)pyrene Freeæe Conc. C-10 (16% acids) = 12.0 ppb benzo(a)pyrene Fresh C-6 = 0.2 ppb benzo(a)pyrene Freeze Conc. C-6 (16% acids) - 0.1 ppb benzo(a)pyrene From a benæo(a)pyrene concentration standpoint, it would clear]y be better to freeze concentrate 7% acids material rather than 11.5~ acids material.

X~MPLE 10 This example shows that the pH of a freeze concen~
trate can be increased to any point by addition of alkali without causing precipitation of tar polymers.

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A 12~0~ acids aqueous smoke flavoring was freeze concentra~ed to 24.0~ acids and solid NaOH was added to raise the pH several points. Then the amount of water which could be added to bring the sample just to the point where precipitation occurred, herein referred to as cloud point, was measured. The results are reported in Table 60 % Added Water pH at Cloud Point 2.2 50 2.5 26 3.0 2~

4.0 19 5.0 12 5.5 3 6.0 7.0 trace 10.0 trace 11.5 50 12.0 This example shows that freeze concentrates can be used to treat food casings and that more smoke solids per unit area can be achieved.
Duplicate sections of fibrous cellulose, non~Eibrous cellulose and collagen casings were dipped in 12~ acids ~3~
aqueous wood smoke Elavor stock solution or a 24~ acids freeze concentrate thereof. The cas~ngs were allowed to drain and the excess liquid was shaken of. After further drying and weighing, the smoke solids retained per unit areas were determined and averaged~ ~he results are reported in Table 7.

MgO Smoke Solids Per Square Inch 12% Acids 24% Acids _ Casing Type _tock Solution Freeze Concentrate Fibrous Cellulose5.48 9.33 Non-Fibrous Cellulose.84 5.70 Collagen 10.02 15.61 The data show significant benefit in use of the freeze concen-trate for all three types of casings. The greatest improvement is with the non-fibrous cellulose, while the highest total retention is by the collagen.

This example shows that direct application of freeze concentrate to meat suraces produces darker brown products than by application of the stock solution.
Beef and pork wieners in non-fibrous ce]lulose casings were dipped in smoke flavoring solutions for 5 or 10 seconds according to the following treatment matrix:

5 seconds 10 seconds 12% Acids Stock Solution ~1 ~3 24% Acids Freeze Concentrate ~2 ~4 ~3~3~
The wieners were placed in a smokehouse and cooked to an internal temperature of 160~'. After cooling, the wieners were evaluated for color formation by six panelists who were asked to place the wieners in an order of color from darkest to lightest. All six panelists rated the wieners from the ~4 treatment the darkest followed by those from the #2 treatment. The #1 treatment wieners were rated darker than the wieners Erom #3 by four panelists while two panelists thought the wieners from ~3 were darker.
The results indicate that darker products can be produced with freeze concentrated smoke flavorings.
It can be concluded that doubling the concentration is more effective in producing a darker product than doubling -the exposure time.

This example shows that with freeze concentrates the same or greater quantities of desirable smoke components can be atomized into a smokehouse with less effect on relative humidity than by atomization of a stock solution.
Into a four cage smokehouse containing 32 lbs.
of wieners was atomized 64 oz. of 12~ acids aqueous wood smoke flavoring stock solution. The relative humidity was determined before atomization, immediately after atomization, and again after 10 min. This was repeated with 32 ozO of 24% acids freeze concentrate and with a second atomization of 32 oz. of 24~ acids freeze concentrate. The results are reported in Table 8.

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64 oz. of 12% Acids 32 oz. of 24~ Additional 32 oz.
Stock Acids Freeze of 24~ Acids Freeze SolutionConcentrateConcentrate Relative Humidity Initial 24~ 19% 31%

Relative Humidity after Atomization 39% 31% 31 Relative 10 Humidity after 10 min. 44% 32% 31%

The data show that in the case of 32 oz. of 24~ acids freeze concentrate a smaller increase in relative humidity with the same quantity of desirable smoke components available for interaction with product was achieved. Upon further atomization of freeze concentrated solution, no rise in relative humidity occurred.

EX~MPLE lA

This example shows that atomized freeæe concentrates can be used to produce darker colored products than with stock smoke flavorings or natural vaporous smoke.
The wieners in Example 13 were shower-cooled, chilled, then packaged and evaluated for intensity of brown color development 24 hours later. Nine panelists were asked to put the samples in an order, which included a non~smoked control and a natural vaporous smoked sample, from lightest to darkest colored.

All nine panelists found the 64 oz. of 24~ acids freeze concentrate treated product to be the darkest colored.
Seven of nine panelists thought the wieners which were treated ~3~3~L

with 32 oz. of the 24~ acids concentrate were lighter than ~he wieners treated with vaporous smoke but darker ~han the wieners which were treated with 64 oz. of 12% acids stock solution. All nine panelists thought the no-smoke control wieners were the lightest colored and that the wieners which received the 64 oz. of 12% acids were darker than the control but lighter colored than the wieners treated with the freeze concentrated solution and the wieners which received natural vaporous smoke.
On a numerical scale ~7ith a rating of 5 assigned for the darkest colored product and 1 for the lightest colored product a weighted average ranking was determined. The results are reported in Table 9.

64 oz. of 64 02. of 12% 32 oz. of 24~ Natural 24~ Acids Acids Stock Acids Freeze Vaporous Freeze Control _ Solution Concentrate Smoke Concentrate 1.0 2.0 3.~ 3.8 5.0 The data show that by use of freeze concentrates, darker brown products can be produced than wlth either natural vaporous smoke or with wood smoke flavor stock solution.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art.

Claims (21)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of concentrating an aqueous solution of wood smoke flavors which comprises:
cooling an aqueous solution of wood smoke flavors containing up to about 12% acids until enough ice crystals form in the cooled solution to produce a solution having a desired increase in acids concentration upon removal of the ice; and separating the ice from the smoke flavor solution.

2. A method according to claim 1 in which the starting solution has at least 6% acids.

3. A method of concentrating an aqueous solution of wood smoke flavors which comprises:
indirectly cooling an aqueous solution of wood smoke flavors containing about 6 to 12% acids until enough ice crystals form in the cooled solution to produce a solution having a desired increase in acids concentration upon removal of the ice; and separating the ice from the smoke flavor solution.

4. A method according to claim 3 in which the starting solution has 6 to 11% acids.

5. A method according to claim 3 in which the starting solution has 6 to 10% acids.

6. A method according to claim 3, 4 or 5 in which enough ice is formed and removed to produce a product containing at least 15% acids.

7. A method according to claim 3, 4 or 5 in which enough ice is formed and removed to produce a product containing about 15 to 35% acids.

8. A method according to claim 1 or 3 which comprises adjusting the pH of the freeze concentrate by adding a basic material to it.

9. An aqueous solution of wood smoke flavors containing at least 15% and up to about 35% acids and dilutable with water to a 6% acids product with little to no precipitation of tar, when produced by the process of claim 1 or 3.

10. A method of smoke flavoring a foodstuff which comprises applying a freeze concentrated aqueous solution of wood smoke flavors to a foodstuff.

11. A method according to claim 10 in which the concentrate contains at least 15% acids.

12. A method according to claim 10 in which the concentrate is applied to the foodstuff by atomization, spraying, dipping or injection.

13. A method according to claim 10 in which the freeze concentrated aqueous solution is undiluted with water after concentration before it is applied to a foodstuff.

14. A method according to claim 10 in which the freeze concentrated aqueous solution is diluted with water and subsequently applied to the foodstuff.

15. A method according to claim 10 or 11 in which the foodstuff is a meat.

16. A method according to claim 10 or 11 in which the foodstuff is a sausage meat.

17. A method which comprises contacting the internal, external, or both, surfaces of a sausage casing with a freeze concentrated aqueous solution of wood smoke flavors and then stuffing the casing with a sausage meat formulation.

18. A method according to claim 17 in which the solution contains about 15 to 35% acids and the ratios of phenols, carbonyls and acids therein are substantially similar to those of the solution before freeze concentration.

19. A method according to claim 17 in which the concentrated solution is diluted with water before it contacts the casing.

20. A method according to claim 17 in which the solution pH is adjusted to decrease the acidity prior to incorporating it into the casing.

21. A method according to claim 17 in which the casing is dried after application of the solution and before being stuffed with the meat.