CA1052170A

CA1052170A - Process for removing solvent from proteinaceous material

Info

Publication number: CA1052170A
Application number: CA209,214A
Authority: CA
Inventors: Tryggve L. Knutsen; Sven-Olof Osterman
Original assignee: Astra Protein Products AB
Current assignee: Astra Protein Products AB
Priority date: 1973-09-14
Filing date: 1974-09-13
Publication date: 1979-04-10
Also published as: NO743296L; AU7312274A; AR201967A1; CH596776A5; JPS5623568B2; NO139461B; NL7411466A; SE381977B; OA04776A; FR2243647B1; DD113434A5; SU562171A3; JPS5053548A; IE40518L; DE2439233A1; FR2243647A1; BE819925A; GB1479172A; SE7312533L; DK481074A

Abstract

ABSTRACT
It is known to rapidly and almost completely remove solvents from protein material using direct steam. This process subjects the protein to temperatures at which it becomes denatured, resulting in change of colouration and texture, and loss of coagulation and water retention properties. These changes make the resulting material unusable in foodstuffs. The present invention relates to a method of treating protein material with air, saturated with water, having a sufficient energy to evaporate the solvent while at the same time water condenses from the air replacing the evaporated solvent, thus overcoming the drawbacks of the prior methods.

Description

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The present invention relates to a process for removing solvent from proteinaceous material.
The objec~ of the present invention is to remove rcsidual solvent from a protein material having been extracted with a solvent or containing a solvent, possibly after a mechanical separation of excess of solvent, to very low residual amounts without heating the protein material so that a heat denaturation is caused resulting in a loss of important functional properties of the protein material, such as coagulability, swellability, water- and oil binding capacity.
A further object of the present invention is to obtain a coagulable and swellable, solvent-freed-protein, as animal protein from fiSh or vegetable protein from soya beans and rape.
A further object of the present invention is to remove solvent from a protein material, even if it should have been heat denaturated by a prior treatment, without greatly influencing the colour of the end product.
It is known to almost completely remove a solvent using direct ~;
steam. This process res~lts in ~he protein being subjected to temperatures in the range of 100C. A resulting drawback is that the protein is denatur-ated and loses it functional properties such as coagulation and water binding `~
capacity. Furthermore, the protein material may undergo a colour change so `: 5 that it can not be mixed with lightly coloured foodstuffs.
Protein material thus tTeated gives, after drying, a "sandy" feeling when it is eaten which makes it unsuitable and in most cases unusable as an additive to water containing foodstuffs as fish and meat products.
! It has now been found possible~ by means of the present invention, -to elimina~e these drawbacks while at the same time obtaining almost complete evaporation o solvent. The invention is characterized in that the protein material is treated with air at a temperature between 40 and 90C and having ~` at least 5% actuation with water whereby the temperature and the relative humidity of the air are such that enough energy is added for B

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vaporisation of the solvent. At the same time water is condensed from the air and replaces the amount of solvent being vaporized.
~ ccording to the present invention the protein material, containing solvent is treated with air having a tem~erature of 40-90C and being at least 50% saturated with water. The volume of air usedjin the ~reatment is from 1.0-5.0 mJ per kg of material to be treated.
~ In the preferred embodiment of the invention the tre~tment is carried out continuously in a verti~al column. The air used for the treatment flo~ contercurrent to the material. The column is indirectly heated to a temperature 10-30 C, preferably 10-15C, below that of the air. Air may be introduced in the upper part of the column at a temperature higher than that at which it is introduced in the lower part of the column. The air is intro-duced~in the upper part of the column at such as rate that, due to the cooling effect of the evaporation of solvent, the temperature of the material being ~, treated remains substantially uniform throughout the column at-a temperature 10-30 C below that of the air introduced in the lower part of the column. In the preferred embodiment the air temperature is in the range of 45-65 C, pre-ferably 45-55C, and the dègree of sc~turation with water is at least 70% pre-ferably 100%. The amount of air used in the preferred embodiment is in the range of 2.0-3.0 m3 per kg of protein material treated.

` Protein materic~l containing solvent is such protein material to whihh . .
one ha~ added solvent for preserving purposes or which contains solvent after an extraction. Solvents used for extraction are usually isopropanol, n-butanol, sec-butanol, isobutanol, ethanol, ethyl acetate, acetone, chlorinated hydro-3epQ,~te /y carbons~ and hexane. These solvents are used each ~Pu~LL~ or in combination. ~;
The protein material can be of animal or ~egetabilic origin as protein from slaughter offal, fish, crustaceans, or in water living mammals, or pro-tein from soya beans and rape or protein from a cultivation of microorganisms on hydrocarbons.

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:, l ~05'~70 Protein materi~ hich has been treated at a temperature exceeding the denaturation point of the protein, usually 60-70C, will rapidly lose its functional properties, i.e. inter alia its capability to absorb and bind water. This property is very valua~le and necessary when the addition of the protein as a substitute-protein in products of animal origin a~ meat stuffing, sausages, and fish is concerned in order to maintain the texture and the binding capacity of these foodstuffs. Using larger amounts of denaturated protein does not increase the binding effect and the products uill fall apart.
Further, denaturated protein has a sandy character, which leads to a coarse taste of the products when eating them. When the functional properties are left in the protein this sandy character does not exist and the products have ` a natural texture. ~ ~
`, The present invention will be described more in detail with refer- ` `
ence to the Examples below.
Example 1 In a column for evaporation of solvent which column is provided with a stirrer in the shape of a helical having interruptions along its periphery and having a diameter of 100 mm and a height of 200 mm solvent extracted fish ~` material was introduced in an amount of 200 g. The composition of the protein material was 61.5% dry substance, 25.5~ isppropanol and 13.0% water.
In the bottom of the evaporator air containing water was introduced in an amount of 2.0 m3 per hour during efficient stirring.
The water saturated air was obtained by introducing air in the bottom of a closed vessel containing water of~a certain temperature, whereafter the ~?~
air was introduced directly into the bottom of the evaporator.
~ The test was carried out using water saturated air of four different temperatures, The evaporation capacity is directly dependent on the amount of `~ energy added and is thereby controlled, within a certain apparatus volume, by the amount and temperature of the water saturated air. According to a table ~ ,~

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of the properties of moistened air the heat contents of water saturated air calculated per kg air at 40 c is 39.6 kcal/kg, while the energy contents of 50, 60, 70~ 80 and 90 air is 6s.3, log, 190, 363 and 912 kcal/kg respect-ively.
In the table below the dry substance (DS) and remaining isopropanol (IPA) in the material is given after different time. The evaporator column, -which was provided with a jacket, had a temperature which was 10 below that of the water saturated air.

~` 10 Air 40 C Air 50 c Air 60 c Air 70 C
, Time (min) DS % IPA ~ DS % IPA % DS % IPA % DS % IPA %
; lo 68.8 11.9 69.o 0.062 68.5 0.044 68.2 0.047 ~`
71.2 2.95 67.5 0.049 66.7 0.032 64.2 0.017 69.0 o.o64 63.9 0.025 61.1 0.014 54.7 o.oo~
, 45 67.6 0.048 58.4 0.005 56.2 0.003 ....
64.2 o .027 55.2 o .003 46. o o .002 As is evident from the above results almost complete evaporation of solvent is very rapidly obtained. After 60 min or earlier the evaporation has reached the point that only 20-270 ppm of the solvent are left in the moistened material.

, .
~ 20 At subsequent drying this residue is further reduced and is in dry material . ~ !
only 10-30 ppm. The evaporation can ~or this reason be interrupted after 15 min using air temperatures of 50, 60, and 70-degrees or after about 30 min ~ using air temperatures of 40-degrees, as the .:, $
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material then obtained contains 20-40 ppm isopropanol after drying, which is extremely low. The drying is carried out a~ 35 C by means of blowing with dry air.
15 min blowing with water saturated air in accordance with above corresponds to an amount of air of 2.5 m3 per kg protein material.
Example 2 A solvent evaporation in accordance with Example 1 was carried out on unground and ground products respectively, using water saturated air having a ;
temperature of 50 C. The jacket ~emperature was 40 C. The unground product -~
had a particle si~e according to the distribution 18 % <5-3 mm, 13 % <3->2 mm `~
and 69 ~ ~ 2 mm. The ground material had a particle size of s 2 mm. The `~
result is given in table 2 below. The amount of protein material introduced was 400 g containing 68.7 % dry substance, 15.8 % isopropanol and 15.5 % water.
TABLE 2 j~
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Unground product Ground product Time DS % IPA % DS % IPA %
75.5 2.83 76.4 2.66 75.6 0.898 76.4 1.03 -74.1 0.084 74.6 0.053 ~, 45 71.1l 0.027 72.0 0.008 _ 68.4 0.018 68.4 0.002 1 .
As is evident from the table a satisfactory result is obtained also with the unground product, which shows that extracted fish material does not need to be further divided before evaporation. The differences shown in residual amounts of solvent are such that a further equality is obtained at the final ` 20 drying of the material.
The products obtained according to Examples 1 and 2 had their -~-` functional properties left and showed good swellability in water except for ; -' the test with 70 C air temperature, where a certain beginning coagulation.i : .~':
was observed. ;~
Example 3 In a vertic~l column provided with a stirrer in the shape of a :
peripherical, interrupted helix and having a diameter of 300 mm a solvent extracted fish pro~ein was introduced to a height of 3200 mm. The stirrer was rotated with a speed of 15 rpm. The column ~ 5 ~ l `

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which was pro~ided with a jacket which had a te~perature o~ 40~.
The protein material introduced in the column consisted of herring, extracted with isopropanol containing 55.6 % dry substance, 38.2 % isopropanol and 6.2 % water. The temperature of the material when introduced was 20 c.
The test was concerned about continuous evaporation with an amount of 18 kg/hour of protein material fed out. The height of material in the column was kept constant. The test was divided into two su~bsequent parts, namely 1) treatment with water saturated air obtained in accordance with Example 1 having a temperature of 53 G and in an amount of 60 m3/hollr introduced in the bottom of the column and 2) after I45 min; treatment using water saturated air having a temperature of 55 C and in an amount or 30 m3/hour introduced in the bottom of the column and usin~ water saturated air with a temperature of 80 C and in an amount of 30m3/hour introduced in the upper part of the col~
umn, The result is given in Table 3 below.

T~me DS ~ IPA %
"' 62.7 ' 22.2 62.2 21.4 105 61.7 18.6 ;~ 20 145 64-9 15.6 ` 155 63-4 12.83 175 65-7 9.28 195 67.2 4-64 205 67.o 1.91 ; `
~ , -- - -As is evident from Table 3 a bett~r result is obtained in a contin-~ uous process if water saturated air is introduced also in the upper part of ;~ the material packing, ~hereby this air has a temperature which exceeds that introduced in the bottom of the evaporation column, whereby, h~wever, the temperature of the material in the upper part did not exceed the temperature ~ - 6 of the water satura~ed air in the lower part of the column in accordance with Table 3 below.

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Time Top of column Upper half Middle of Lower half Bottom of of column column of column column o C C C C C

205 53 50 48 46 43 ~ -When the test was continued the following results were obtained in accordance with Table 3 B after further ~ -Time DS % IPA %
min 66.2 0.5 :~
65.8 0.2 ~ :
65.4 0.06 65.0 <0.025 :~
The capacity of the column can thus be utilized completely by distributing the air containing water introduced on different levels in the column, whereby the air in the upper parts of the column can be given a -temperature which is higher than that of the air introduced in the lower part, whereby, however, at treatment of non-denaturated protein the temperature ~ :~
should not exceed the denaturation point of the material. The temperature and the amo~lt of air shall thus be selected that the temperature of the :~ :
material in the upper part does not exceed the temperature of the water saturated air in the lower part of the column. By distribution on different - , ~
. levels the energy added can be increased, which of course gives higher ` -~
B capacities.
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- Example 4 ~
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The effect of the final drying on the residual amount of solvent -~- _ 7 _ 1 '' -' ~05'~
in a material having been evaporated with water saturated air in accordance wi~h the invention and in a directly dried material, which had not been evaporated, is given in Table 4 below, in which different materials with different amounts of dry substance and isopropanol are given before and after drying after evaporation with water saturated air and a basic material which is not evaporated but directly dried. The drying was carried out at 35 C

using sweeplng alr.

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After evaporation After final drying -DS % IPA % H20 % DS % IPA % H20 %
65.1 3.91 31.0 93.8 0.233 5.97 65.8 1.91 32.3 93.6 0.083 6.32 65.6 1.25 33.1 93.6 0.053 6.35 ~ ~
65.6 0.98 33.4 93.4 0.040 6.56 ~ `

Before drying After drying - 55.6 38.2 6.2 92.0 6.86 1.14 - ! As is evident from Table 4 an extremely improved result is ob-~ 10 tained at the final drying, if the material has been evaporated first using ;~
i water saturated air.

Example 5 : :.
The importance of the water in the evaporation air is evident from the test below, wherein 200 g of test material with 65.1 % of dry substance, 25.8 % of isopropanol and 9.1 % of water was treated on one hand with water saturated air and on the other with non-water saturated air ~max 35 % relative hunidity~ in an amount of 2 m3/hour during 45 min and having an evaporation - ;~
temperature of the air of 30, 40, 50, and 60 C. The jacket temperature was ;~
' in each test kept 10 below the temperature of the air containing water. The ~ `
result after 45 min is given in Table 5 below. ~`

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Type of air Evaporation DS IPA H20 temperature % % %

80.4 0.91 18.7 Water 40 78.0 0.21 21.8 saturated 50 76.4 0.053 23.5 air 60 74.5 0.036 25.5 ... . . .
Non-water 30 87.7 5.06 7.2 saturated 40 90.7 5.10 4.2 ; air S0 93.9 6.09 + 0 94.2 6.~4 + 0 The results show a remarkable difference between the two different evaporation methods, whereby the second method must be regarded more or less as drying method.
Example 6 A series of test was carried out in order to show the validity of the process for different solvents and materials. In Table 6A an evaporation test on presscake flour from sardinella extracted with isopropanol is given having 65.1 % dry substance, 25.8 % isopropanol and 9.1 % water. 350 g of ` `
test material were treated with water saturated air having inlet temperature , of 50C and in an amount of 2 m3/hour in a column provided with a jacket, the jacket temperature being 40C.
; TABLE 6 A
--Evaporation time Outlet gas DS IPA H20 min tempeTature %

2.5 32 64.1 24.4 9.5 68.3 19.1 12.6 36 71.8 7.6 20.6 i 15 39 73.7 1.81 24.5 `, 20 42 72.0 0.389 27.6 43 70.8 0.162 29.0 44 69.0 0.082 30.9 44 64.0 0.030 36.0 44 57.8 0.013 42.2 ,` _ 9 _ ,` ' l~S'~

The same test using presscake fLour extracted with sec-butanol was carried out, the extracted material containing 56.8 % dry substance, 18.7 % sec-butanol and 24.5 % water. The result is given in Table 6 B below.

Evaporation time Outlet gas DS SBA H20 min temperature % % %
- -2.5 35 56.9 18.2 24.9 - :: .- ~
38 58.1 14.5 27.4 -39 60.6 6.56 32.8 ~
` 15 40 60.7 1.81 37.5 `
.:, , 41 60.4 0.77 38.8 `~
44 59.2 0.24 40.6 44 57.3 0.075 42.6 -44 52.3 0.022 47.7 44 47.1 0.007 52.9 `~
The same test was carried out on presscake flour extracted with hexane? the extracted material containing 70.4 % dry substance, 21.5 % hexane -and 8.1 % water. The result is given in Table 6 C below. ~
::. ~.-Evaporation time Outlet gas DS Hexane H20 " min temperature % % %
:.: C
2.5 23 80.4 10.7 8.9 24 88.1 0.85 11.0 41 ~4.8 0.095 15.1 ;~
43 83.0 0.060 16.9 44 81.4 0.025 18.6 `;
44 79.1 0.021 20.9 44 77.7 0.015 22.3 ~ ~
` 45 44 72.8 0.013 27.2 ~ ; -`' 60 44 67.4 0.010 32.6 ;
The same test was carried out on soya beans extracted with hexane, ~
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the extracted material containing 79.5 % dry substance, 11.4 % hexane, and `
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9.1 % water. The result is given in Table 6 D below.
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Evaporation time Outlet gas DS Hexane H20 min temperature % % %
C
2.5 2~ 88.6 0.515 10.9 32 87.0 0.178 12.8 85.3 0.120 14.6 42 83.8 0.095 16.1 43 82.2 0.075 17.7 44 80.3 0.050 19.6 44 78.5 0.030 21.5 44 71.6 0.018 28.4 44 64.5 0.011 35.5 . :
The results show that the choice of solvent or the choice of ; material has no influence on the evaporation effect, but a satisfactory result ., is obtained with different types of solvent and material.
Example 7 A test was carried out in order to show the effect of the amount `
-~ of water present in the air containing water. Thereby evaporation of iso- ;~
propanol was carried out in accordance with that in Table 6 A given with that difference that the air being 50 C and saturated to 100 % was heated to 60 C before introduction into the evaporation column, whereby the degree of ~ -~, saturation was decreased to 57 %. The result of the evaporation is evident , from Table 7 below.

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Evaporation time Outlet gas DS IPA H20 ~ -min temperature % % %
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2.5 35 65.1 22.1 12.8 ~-! 5 37 67.7 16.3 16.0 73.0 3.60 23.4 44 73.1 0.471 26.~ `~
72.6 0.153 27.2 .
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71.3 0.097 28.6 ~
69.8 0.049 30.2 -~-67.1 0.031 32.9 63.3 0.016 36.7 . .

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As the outlet gas temperature has increased just 1 C ~cf Table 6 A above) compared with evaporation using water saturated air at 50 C
this indicates, that the excess heat in the non-water saturated air is consumed during the passage through the material packing. This is also shown by a somewhat more rapid evaporation of residual isopropanol in the beginning of the evaporation course and a somewhat lower condensation of water in the product. The requirement for an efficient evaporation is that enough energy is added to evaporate the solvent at the same time as a certain amount of water has to condense in the material in exchange to the solvent evaporated.
If these requirements are fulfilled the low temperature evaporation can be -carried out within wide limits for the relative humidity of the air, but it is evident that one having a maximal upper temperature limit has highest evaporation capacity with 100 % relative humidity, i.e. water saturated air.
The materials evaporated according to the present invention, ~
which materials have been treated before this treatment so that they are not - `;~i denaturated, have their functional proper~ies left after evaporation, as ;
water swellability.

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Claims

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

1. A process for the evaporation of solvent from proteinaceous material, extracted with solvent, characterized in that the protein material is treated with air at a temperature between 40 and 90°C and having at least 50% saturation with water whereby the temperature and the relative humidity of the air are such that enough energy is added for vaporization of the solvent at the same time as water is condensed from the air and replaces the amount of solvent being vaporized.

2. A process according to claim 1, characterized in that the protein material is solvent extracted fish protein.

3. A process according to claim 1 characterized in that non-denaturated protein material is treated with air containing water having a temperature of 40-70°C.

4. A process according to claim 2, characterized in that the air has a temperature of between 45 and 65°C.

5. A process according to claim 4, characterized in that the air has a temperature of between 45 and 55°C.

6. A process according to claim 1, characterized in that the protein material is heated with air in an amount of 1.0 to 5.0 m3 per kg of treated protein material.

7. A process according to claim 6, characterized in that the protein material is treated with air in an amount of 2.0-3.0 m3 per kg of treated protein material.

8. A process according to claim 7, characterized in that the air containing water is water saturated to at least 70%.

9. A process according to claim 8, characterized in that the air containing water is water saturated to 100%.

10. A process according to claim 1, characterized in that the treatment of the protein material is carried out continuously in a vertical column by means of air containing water countercurrent to the material flow, the column being indirectly heated to a temperature which is below the temper-ature of the air introduced.

11. A process according to claim 10, characterized in that the column is heated to a temperature which is 10-30°C below the temperature of the air introduced.

12. A process according to claim 11 characterized in that the column is heated to a temperature which is 10-15°C below the temperature of the air introduced.

13. A process according to claim 11, characterized in that the treatment of the protein material is carried out continuously in a vertical column by means of air containing water countercurrent to the flow of material, the air containing water being introduced at some different levels in the column.

14. A process according to claim 13, characterized in that the tempera-ture of the air containing water introduced in the upperapart of the column exceeds the temperature of air containing water introduced in the lower part of the column.

15. A process according to claim 14, characterized in that the air con-taining water, which is introduced in the upperapart of the column, is intro-duced in such an amount and of such a temperature that the temperature of the material in this part of the column by means of vaporisation of solvent is substantially the same as the temperature of the material in the lower part of the column.