CA1091085A

CA1091085A - Process for the detoxification of rapeseed meal

Info

Publication number: CA1091085A
Application number: CA271,031A
Authority: CA
Inventors: Ernst W.W. Trautschold
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1976-02-06
Filing date: 1977-02-03
Publication date: 1980-12-09
Also published as: IT1072899B; IE44519B1; DE2704743C2; DE2704743A1; FR2340059A1; NO770385L; BE850943A; GB1575506A; FR2340059B1; FI62618C; FI62618B; DK43677A; LU76708A1; FI770310A7; NL7701124A; SE7701269L; SE424691B; PL195819A1; IE44519L

Abstract

ABSTRACT OF THE DISCLOSURE

The content of repossed meal is reduced by treating the meal immediately after it leaves the extractor with 1-8%, preferably 2-4%, of an at ambient temperature non-volatile, alkaline substance;
raising the moisture content of the meal to 8-25% and thereafter steaming the meal less than 30 minutes.
The described treatment allows the incorporation of greater amounts of repossed meal in animal feedstuffs without thyrotoxic effects occurring.

Description

10~ 5 A 516 tR) The invention relates to a process for detoxicating rapeseed meal. In particular the invention provides an economical process for detoxicating rapeseed meal, so that more of it can be added to compound feeds than before.
The residues left behind in the production of edible oils have for decades been the most important source of vegetable protein for animal nutrition. However, there are great variations in the protein content, digestibility and energy value of these residues. Steamed or toasted soya meal plays a leading role in the feedstuff sector, owing to the high quality of the protein therein, but the ever increasing protein demand for feedstuffs and the expected competition for soya protein for human consumption urge one to use as much of the other oilseed residues for animal nutrition as possible. he greatest interest lies in rapeseedmeal, because it contains a high-grade protein and because rapeseed is obtained in ever increasing amounts, the expected global yield for 1980 being about six million tons.
On the basis of the amount of the most important essential amino acids therein, rapeseed meal comes high - on the list of oilseed residues as regards protein quality: its lysine content is only slightly below that Or soya protein and considerably higher than that of other oilseed residues, and it also scores high as regardæ the amount of sulphur-containing amino acids therein, these ~ ~ having a limiting effect in the case of soya protein.
; ~ However, ordinary, untreated rapeseed meal contains ~ .

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certain substances that oppose or restrict its use as a feed component, the most important being thioglucosides.
These compounds are lert behind in the rapeseed meal after the extraction of the oil and are hydrolysed by water and thioglucosidase or other naturally occu~ing enzymes present in the meal. During hydrolysis several compounds with thyrotoxic effects are ~ormed from thioglucosinolates, e.g.
isothiocyanates. The main thioglucosinolate of rape is ~-progoitrin and a product of hydrolysis of progoitrin is (S)-5-Vinyl-oxazolidine-2-thione, a product with a strong thyrotoxic effect.
Therefore (S~-5-Vinyl-oxazolidine-2-thione and other isothiocyanates lower the degree of food utilization in the animal body. Besides they give the meal an acric ~' taste, making it unappetizin~ for pigs and cattle.
A known process for detoxicating rapeseed meal (US
! Patent No. 3,392,026) egsentially consists in heating the rapeseed meal with steam to inactivate the thioglucosidase therein, treating the meal successively with gaseous or aqueous ammonia and live steam, and finally drying it ~ 20 under vacuum. The first steaming step in this US-Patent - i~ considered essential, since it is assumed that the

2-hydroxy-3-butenyl-isothiocyanate otherwise liberated in the enzymatic hydrolysis immediately undergoes cyclization to give (S~-5-vinyl-oxazolidine-2-thione, which does not react suf~iciently with ammonia in the next step to ensure adequate detoxication.
This detoxicating process comprises three steps -

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dpart from the drying of the detoxicated meal - and takes at least 75 min and possibly even longer. This prolonged treatment is detrimental to the protein quality, in addition to which the process i9 not really economical and has not in fact gained practical application.
In another known process for detoxicating rapeseed meal (British Patent No. 690,597) the meal is treated only with steam (i.e. without added chemicals) at an elevated temperature, but the time of treatment is necessarily so long here that the protein quality again suffers.

The present invention is an improvement of the first of the above-mentioned known processes, whereby the latter is made much more economical without the protein quality being affected. It has now been found in fact that the meal can be extensively detoxicated without having to inactivate the thioglucosidase before heating the rapeseed meal with an alkali, if prior to steaming the meal is treated at an elevated temperature with a sufficient amount of alkaline or acidic substances not volatile at ambient temperatures and enough water to bring its moisture content to 8 - 25g and preferably to about 12 - 18%.
Accordingly, the invention provides a process for detoxicating rapeseed meal after the extraction of the oil therefrom in which after leaving the extractor the meal is admixed with 1 to 8% by weight of an alkaline or acidic substance which is non-volatile at ambient temperatures, and with a sufficient amount of water to increase the water content of the meal to 8 to 25% and immedia$ely thereafter the meal is steamed for at most 30 minutes at a temperature of 90 to 130C.
In contrast to the U.S. patent no. 3,392,026 there is no ~B

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"eed to deactivate the enzyme thioglucosidase by a separate heat-treatment, one process step becoming superfluous. In fact, the meal can be heated straight away to the temperature of the treatment, i.e. to 90 - 130C and preferably to 100 - 105C. Of course, this does not mean that other treatments such as partial desolventizing cannot ~B 4a -,,.. ,............. , ~ . .
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- 1091~S A 51& (R) be interposed between theextractor and the detoxicator. In the process of the invention, the meal is treated with 1 -8%
and preferably 2 - 4% of alkaline or acidic substance, and preferably calcium oxide or calcium hydroxide, which not only have the desirable effect of enriching the feedstuff in calcium, but also, and more importantly, ensure rapid and efficient detoxication without adversely affecting the protein quality; however, e.g. NH4HC03, H3P04 and Na2C03 are also suitable.
Untreated rapeseed meal normally contains about 1.0 -1.3% of (S)-5-vinyl-oxazolidine-2-thione, and so it can be added to poultry feed only in a limited amount.
Rapeseed meal detoxicated according to the present invention contains much less of this compound, so much more of it - about 2-3 times as much - can be admixed to compound feeds. This has been borne out by extensive feeding trials with ordinary rapeseed meal and rapeseed meal detoxicated by the process of the present invention.
Feeding tests on groups Ofday-Old broilers (table 1) show after 8 weeks the influence of rapeseed meal detoxicated with 2% Ca(OH)2 (example 2) and untreated rapeseed meal on the average body weight in comparison to a soy-corn-control diet.

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1 0 9 i V 8 5 A 516 (R) Table 1 /
Broiler reeding te~ts with treated and untreated rapeseed meals:
Average body weight Fodder utilization after 8 weeks after 8 weeks absolutely relative relative grams % % , soy-corn control group 1,621 loo.o loo.o 2.5% untreated rapeseed . 10meal in the diet 1,468 90.6 103.9 25% untreated rapeseed meal in the diet 1,217 75.1 103.5 12.5% treated rapeseed ~ meal in the diet 1,595 98.4 99.5 ,, .
1525~ treated rapeseed meal in the diet 1,469 90.6 100.5 Feeding tests 021 groups of laying hens in 59 weeks (table 2) show the influence of rapeseed meal detoxicated with 2%
Ca(OH)2 (example 2) and 4% Ca(OH)2 (example 1) and untreated rapeseed meal on some specif`ic factors of laying hens in comparison to a soy-corn-control diet:
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lV~ 5 A 516 (R) Table 2 Feeding tests on laying hens with treated and untreated rape seed meal s:
E~g Feed con-Arnount of ~ying weight s~nption rapeseed meal Feed per- per hen E~g per kg egg in the diet `intake forrnance andday weight weight % % rel. % rel. %rel. % rel. % rel.
soy-corn control-group - 100 100100100 100 rapeseed meal detoxicated with

4% CatC~1)27.5 98 100 98 98 99 rapeseed meal de-toxicated with 4% Ca(OH)2 15 96~ 9796 99 100 rapeseed meal de-toxicated with 2 % Ca(C~)27-5 96 98 97 99 99 rapeseed meal de-toxicated with 2% Ca(CH)2 15 93 93 91 99 103 untreated rapeseed meal 15 82 76 74 99 114 The invention is further illustrated, but not restricted by the following Examples.
Example I
20 kg rapeseed meal were mixed at 65C with 4%
Ca(OH)2. This mixture was fed to a container equipped with steam jacket heating, stirrer and direct addition of steam.
First, such an amount was added as to give the meal a water content of 15%, followed by the direct addition of steam, resulting in a temperature of the meal of 100C.
The temperature in the jacket was 105C.
The direct addition of steam and the indirect heating , . . :.

,: ': , ' ', ' lU910~S A 516 (R) were finished after 18 minutes. The rapeseed meal thus treated was then cooled to a temperature of 25C. 60% of (S)-5-vinyl-oxazolidine-2-thione had been decomposed.
Example II
20 ~g rapeseed meal were mixed at 65C with 2%
Ca(OH)2. This mixture was fed to a container equipped with steam jacket heating, stirrer and direct addition o~
steam.
First, such an amount of water was added as to give the meal a water content of 15%, followed by the direct addition of steam, resulting in a temperature of the meal of 100C. The temperature in the jacket was 105C.
The direct addition of steam and the indirect heating were finished after 20 minutes. The rapeseed meal thus treated was then cooled to a temperature of 25C.
40% of (S)-~-vinyl-oxazolidine-2-thione had been decomposed.
; ~ Example III
, 20 kg rapeseed meal were mixed at 65C with 6%
NH4H C03. This mixture was fed to the container described in Example I.
The meal was brought to a water content of 14~ and, as described in Example I, heated directly and indirectly i with steam. In this case, too, the meal reached a temperature of 100C. The temperature in the jacket was again 105C.
The direct addition of steam and the indirect heating were finished after 20 minutes. The meal was cooled to ~, . ~

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20C. 45% of (S)-5-vinyl-oxazolidine-2-thione had been decomposed.
Example IV
20 kg rapeseed meal were mixed at 60C with 4%
Na2C03. This mixture was fed to the container described in Example I.
The meal was brought to a water content of 18~ and, as described in Example I, heated directly and indirectly with steam. Here, too, the meal reached a temperature of 100C.
The temperature in the jacket was also 105C. The direct addition of steam and the indirect heating were finished after 30 minutes.
The meal was cooled to 20C. 60% of (S~-5-vinyl-oxazolidine-2-thione had been decomposed.
Example V
20 kg rapeseed meal were mixed at 60C with 2%
H3P04 (20%). The mixture was fed to a container as described in Example I.
The meal was brought to a water content of 17% and, as described in Example I, heated directly and indirectly with steam.
However, in this case the operation was carried out at a pressure of 0,4 atm. The meal temperature was 105C;
the temperature in the jacket 110C.
The direct addition of steam and the indirect heating were finished after 25 minutes.
The meal was cooled to 20C. 50% of (S)-5-vinyl-oxazolidine-2-thione had been decomposed.

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Example YI lO9~Ll~t~S
20 kg rapeseed meal were mixed at 65C with 7.3% NiS04.7H20.
This mixture was fed to a container equipped with steam jacket heating, a stirrer and direct addition of steam.
First, such an amount of water was added as to give to the meal a water content of 17%, followed by the direct addition of steam at a pressure of 3 atm (2.94 bar), resulting in a temperature of the meal of 130C.
The temperature in the jacket was 135C. The direct addition of steam and the indirect heating were finished after 6 minutes.
The rapeseed meal thus treated was cooled to a temperature of 20C.
55% of (5)-5-vinyl-oxazolidine-2-thione had been decomposed.

Example VII
20 kg rapeseed meal were mixed at 65C with 8% A12(S04)3.18 H20.
This mixture was fed to a container equippped with steam jacket heating, a stirrer and direct addition of steam.
First, such an amount of water was added as to give the meal a water content of 17X, followed by the direct addition of steam, resulting in a temperature of 120C. The temperature in the jacket ; was 125C. The process was carried out at a pressure of 2.1 atm (~ 2.06 bar).
The direct addition of steam and the indirect heating were finished after 10 minutes.The rapeseed meal thus treated was cooled to a temperature of 20C. 45% of (S)-5-vinyl-oxazolidine-2-thione ,I had been decomposed.
.,1 I Example VIII
20 kg rapeseed meal were mixed at 60C with 6% MgO. This mixture was fed to a container eguipped with steam jacket heating, a stirrer and direct addition of steam. First, such an amount of water was i added as to give the meal a water content of 16%, followed by the direct addition of steam, resulting in a temperature of the meal of 110C. The temperature in the jacket was 115C. The process was ' 35 carried out at a pressure of 1.8 atm ~ 1.76 bar). The direct addition of steam and the indirect heating were finished after 15 minutes. The rapeseed meal thus treated was cooled to a temperature of 20C.
50% of (S)-5-vinyl-oxazolidine-2-thione had been decomposed.

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Example IX
20 kg of rapeseed meal were mixed at 60C with 8~ MgCl2.6H20.
This mixture was fed to a container equipped with steam jacket heating, a stirrer and direct addition of steam. First, such an amount of water was added as to give the meal a water content of 17X, followed by the direct addition of steam, resulting in a temperature of the meal of 110C. The temperature in the jacket was 115C. The process was carried out at a pressure of 1.8 atm (1.76 bar).The direct addition of steam and the indirect heating were finished after 19 minutes. The rapeseed meal thus treated was cooled to a temperature of 20C.
45~ of (S)-5-vinyl-oxazolidine-2-thione had been decomposed.

Example X
20 kg of rapeseed meal were mixed at 60C with 6% tartaric acid.
This mixture was fed to a container equipped with steam jacket heating, a stirrer and direct addition of steam. First, such an amount of water was added as to give the meal a water content of 18~, followed by the direct addition of steam, resulting in a temperature of the meal of 130C. The temperature in the jacket was 135C. The process was carried out at a pressure of 3 atm (2.94 bar).
The direct addition of steam and the indirect heating were finished after 9 minutes. The rapeseed meal thus treated was cooled to a temper-ature of 25C. 55% of (S)-5-vinyl-oxazolidine-2-thione had been decomposed.
Example XI
20 kg of rapeseed meal were mixed at 60C with citric acid C6H807.1H20.
This mixture was fed to a container equipped with steam jacket heating, a stirrer and direct addition of steam. First, such an amount of water was added as to give the meal a water content of 18%, followed by the direct addition of steam, resulting in a temperature of the meal of 118C. The temperature in the jacket was 123C. The process was carried out at a pressure of 2 atm (1.96 bar).

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Example XII
20 kg of rapeseed meal were mixed at 63C with 8X MgS04.7H20.
This mixture was fed to a container equipped with steam ~jacket heating, a stirrer and direct addition of steam. First, such an amount of water was added as to give the meal a water content of 15%, followed by the direct addition of steam, resulting in a temperature of the meal of 100C. The temperature in the jacket was 105C. The direct addition of steam and the indirect heating were finished after 30 minutes. The rapeseed meal thus treated was cooled to a temperature of 25C. 50% of (S)-5-vinyl-oxazoli-dine-2-thione had been decomposed.

Example XIII
20 kg of rapeseed meal were mixed at 60C with 4X KHC03.
This mixture was fed to a container equipped with steam jacket heating, a stirrer and direct addition of steam. First, such an amount of water was added as to give the meal a water content of 18%, followed by the dir~ct addition of steam, resulting in a temperature of the meal of 90C. The temperature in the jacket was 95C. The direct addition of steam and the indirect heating were finished after 25 minutes. ~he rapeseed meal thus treated was cooled to 20C. 45% of (S)-5-vinyl-oxazolidine-2-thione had been decomposed.

Example XIV
20 kg of rapeseed meal were mixed at 60C with 3X Na2C03. This mixture was fed to a container equipped with steam jacket heating, a stirrer and direct addition of steam. First, such an amount of ; water was added as to give the meal a water content of 18X, followed by the direct addition of steam, resulting in a temperature of the meal of 90C. The temperature in the jacket was 95C. The direct ad-dition of steam and the indirect heating were finished after 30 min.
The rapeseed meal thus treated was cooled to a temperature of 25C.
55X of (5)-5-vinyl-oxazolidine-2-thione had been decomposed.
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Claims

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

1. Process for detoxicating rapeseed meal after the extraction of the oil therefrom in which after leaving the extractor the meal is admixed with 1 to 8% by weight of an alkaline or acidic substance which is non-volatile at ambient temperatures, and with a sufficient amount of water to increase the water content of the meal to 8 to 25% and immediately thereafter the meal is steamed for at most 30 minutes at a temperature of 90 to 130°C.

2. Process according to claim 1, in which the meal is admixed with 2 to 4% by weight of the alkaline or acidic substance.

3. Process according to claim 1, in which the meal is admixed with a solid alkaline substance.

4. Process according to claim 3, in which CaO or Ca(OH)2 is used as the solid alkaline substance.

5. Process according to claim 4, in which about 4% of calcium, calculated as Ca(OH)2 is used.

6. Process according to claim 1, 2, or 3, in which a sufficient amount of water is added to increase the water content of the meal to 12 to 18% by weight, preferably about 15% by weight.

7. Process according to claim 1, 2, or 3, in which the steaming is conducted at a temperature of the meal of 100 to 105°C.

8. Process according to claim 1,2, or 3, in which the meal is steamed for 15 to 20 minutes.

9. Rapeseed meal whenever treated according to a process claimed in claim 1, 2, or 3.