DE2704743C2 - Procedure for detoxifying rapeseed meal - Google Patents

Description

The invention relates to a method for detoxifying rapeseed meal. In particular, the invention provides an economical method of detoxifying rapeseed meal (rapeseed meal), so that more of this too

Can be added to compound feed than before.

The residues left in the production of edible oils have been the most important for decades Source of vegetable proteins for animal nutrition. However, there are big changes in the protein content present in the digestibility and energy value of these residues. Steamed or toasted soy flour plays a leading role in the animal feed sector due to the high quality of the protein it contains; the. ever growing protein demand for animal feed and the expected competition for soy protein for human consumption, however, calls for as much as possible of the other oilseed residues to animal Diet to use. The greatest interest is in rapeseed meal because it contains a high quality protein and because rapeseed is obtained in ever increasing quantities, the expected world yield for 1980 being around six million tons

Based on the amount of the most important essential amino acids in rapeseed meal, this comes first in the List of oilseed residues in terms of protein quality: Its lysine content is only slightly lower than that of soy protein and considerably higher than that of other oilseed residues, and it will Also highly rated for the amount of sulfur-containing amino acids, this being a limiting one Have an effect in the case of soy protein. However, untreated rapeseed meal usually contains certain substances zen that prevent or restrict its use as a feed component, whereby from The most important of these substances are the thioglucosides. These compounds are found in the rapeseed meal the extraction of the oil are left behind and become natural by water and thioglucosidase or others occurring enzymes present in the flour hydrolyzed. During hydrolysis, several compounds with thyrotoxic effects are released from the thioglucosinolates, e.g. B. Isothiocyanates, formed The main rapeseed or turnip rape thioglucosinolate is progoitrin, and a hydrolysis product of progoitrin is (S) -5-vinyloxazolidin-2-thione, a product with a strong thyrotoxic effect.

(S) -5-Vinyloxazolidin-2-thione and other isothiocyanates therefore set the degree of feed utilization in the animal body. Apart from the fact that the meal has a pungent or pungent taste do not make it appetizing or desirable for pigs and cattle.

A known method for detoxifying rapeseed meal (US-PS 33 92 026) consists essentially in one Heating of the rapeseed meal with steam to inactivate the thioglucosidase in it, a subsequent treatment of the meal with gaseous or aqueous ammonia and direct steam and a final drying under vacuum. The first level of attenuation according to the US-PS is considered essential considered, since it is assumed that the otherwise released 2-hydroxy-3-butenyl isothiocyanate in the enzyma Table hydrolysis immediately undergoes cyclization to give (S) -5-VinyIoxyzolidin-2-thione, which does not Reacts enough with ammonia in the next stage to ensure adequate detoxification.

This detoxification process comprises three stages, apart from the drying of the detoxified meal, and takes at least 75 minutes and possibly even longer. This prolonged treatment is detrimental to protein quality in addition to the fact that the procedure is not actually is economical and, in fact, has not found practical application.

In another known method for detoxifying rapeseed meal (GB-PS 6 90 597) the meal is only treated with water vapor (i.e. without added chemicals) at an elevated temperature, but the Treatment time is necessarily so long here that the protein quality suffers again here too. In US-PS 33 91 000 is a detoxification process for another oil fruit containing thioglucosides, the Crambe abyssinica, which also belongs to the cruciferous vegetables, is described, with exemplary embodiments both are given for de-oiled as well as for non-oiled seeds. This process consists of four stages:

a) dry heating to at least 180 ⁰ F = 102 ° C;

b) addition of 2 wt .-% Na2CO3 or NaOH (if necessary even before the start of the first stage) and so much water that the water content of the mixture is increased to approx. 22%;

c) then heating to 104 * -110 ° C for 40 minutes;

d) finally drying with indirect steam.

The total time of the treatment at elevated temperature is also not much shorter with this method (according to some examples even longer) than the first mentioned, and the economy of the process as well as the Accordingly, the protein quality is unsatisfactory.

The invention represents a substantial improvement on the latter method, thereby making it much better Made more economical and at the same time the protein quality is less than that of the starting material is impaired than in the known method.

It has surprisingly been found that a completely adequate detoxification of the rapeseed meal with very improved protection of its protein content by steam treatment at elevated temperature in the presence of a solid, non-volatile alkaline substance and water can be achieved without prior inactivation of the thioglucosidase if the solid, non-volatile alkaline Substance calcium oxide or hydroxide is used and that, moreover, this surprising effect is retained even if the duration of treatment and the water content of the mixture are reduced not insignificantly below the minimum values specified as necessary according to known processes.

According to the invention, the water content of the .Mixture of rapeseed meal with calcium oxide or hydroxide to 12 to 18%, preferably about 15%, and the duration of treatment with steam to a maximum of 30 Minutes, preferably 15 to 20 minutes.

Although it is known (J Am. Oil Chemists Soc 45 (1968), 53-57), in that after a previous 25 to 29minütigen dry heating of Crambe abyssinica, a reduction of the water content of their mixture with sodium carbonate in the subsequent 40-minute heating at 110 ⁰ C from 30.0 to 16.0% does not affect the detoxification, but a shortening of the steaming time from 40 to 20 minutes, even after 34 minutes of dry heating, allows the residual thiooxazoIidone content of the treated goods to rise significantly.

However, it has been found that using calcium oxide or hydroxide as the alkaline substance does not only an inactivation of thioglucosidase is completely dispensed with, but also a certain residual content undestroyed isothiocyanates such as (S) -5-VinyloxazoIidin-2-thione can be accepted, know! that in Product remaining calcium hydroxide these toxins or their formation in the digestive tract of the animals the enzyme required from the actually harmless glucosides originally contained in the starting material Thioglucosidase blocked to such an extent that the product can be used both by ruminants and cattle as well as by Poultry can be tolerated without damage.

The invention made it possible to dispense with dry heating for the purpose of enzyme inactivation, as well as the shortening the steaming time and the reduction in the water content during steaming result together both a significant reduction in protein coagulation and the breakdown of essential amino acids and thus a significant improvement in quality, as well as considerable savings in energy (heating) costs and an improvement in the throughput of the plant.

Untreated rapeseed meal usually contains about 1.0 to 13% of (S) -5-vinyloxazoIidin-2-thione, and so can it can only be added to poultry feed in limited quantities,

Rapeseed rape, which has been detoxified according to the invention, contains less of this compound, so that much more of this meal - about 2 to 3 times as much - can be added to the compound feed. This has been established by extensive feeding trials with ordinary rapeseed meal and rapeseed meal detoxified according to the method according to the invention. Feeding experiments with groups of one-day-old broiler chickens (Table I) show after 8 weeks the influence of rapeseed meal, which was _{detoxified with 2% Ca (OH) 2} (Example 2), and untreated rapeseed meal on the average body weight in comparison with a soy meal. Corn control diet.

Table I.

Broiler chicken feeding trials with treated and untreated rapeseed meal

Soybean corn control group 12.5% untreated rapeseed meal in the diet 25% untreated rapeseed meal in the diet. 12.5% treated rapeseed meal in the diet 25% treated rapeseed meal in the diet

Average body weight relative Feed utilization after 8 weeks % after 8 weeks absolutely 100.0 relative kg 90.6 % 1.621 75.1 100.0 1.468 98.4 103.9 1,217 90.6 103 ^ 1495 994 1.469 100.5

Feeding experiments with groups of laying hens in 59 weeks (Table II) show the influence of rapeseed meal _{detoxified with 2% Ca (OH) 2} (Example 2) and 4% Ca (OH) ₂ (Example 1) and of untreated rapeseed meal with regard to specific factors of laying hens compared to a soy-corn control diet:

Table II

Feeding experiments in laying hens with treated and untreated rapeseed meal

25th 30th 35 40 45

Sets of Lining Lay Egg weight E- Feed supply Rapeseed meal recording power per hen blows more per kg in the diet and day Egg weight % % reL % reL % reL % reL % reL

Soy Corn - 100 100 100 100 100

Control group

Rapeseed meal, with 7.5 98 100 98 98 99

4% Ca (OH) ₂ detoxified

Rapeseed meal, with 15 96 97 96 99 100

4% Ca (OH) ₂ detoxified

Rapeseed meal, with 7.5 96 98 97 99 99

2% Ca (OH) ₂ detoxified

Rapeseed meal, with 15 93 93 91 99 103

2% Ca (OH) ₂ detoxified
Untreated rapeseed meal 15 82 76 74 99 114

The invention is explained in more detail below with the aid of examples. Rapeseed meal was used for all experiments used, which had been dried to a residual water content of less than 10% for the purpose of preservation.

example 1

20 kg of rapeseed meal were mixed with 4% Ca (OH) ₂ at 65 ° C. This mixture was fed to a container which was provided with a steam jacket for heating, a stirrer and direct steam supply.

First, such an amount of water was added that the water content of the meal was 15% resulted, followed by the direct addition of steam, with a temperature of the shot of 100 ° C revealed. The temperature in the steam jacket was 105 ° C.

The direct addition of steam and the indirect heating ended after 18 minutes treated rapeseed meal was then cooled to a temperature of 25 ° C 60% of (S) -5-VinyIoxazoIidin-2-thione had been decomposed.

Example! 2

20 kg of rapeseed meal were mixed with 2% Ca (OH) ₂ at 65 ° C. This mixture was fed to a container which was equipped with a steam jacket for heating, a stirrer and a direct supply of steam.

First, an amount of water was added such that the shot had a water content of 15%, followed by the direct supply of steam, resulting in a temperature of the shot of 100 ° C. The temperature in the jacket was 105 ^° C.

The direct addition of steam and the indirect heating ended after 20 minutes treated raccoon meal was then cooled to a temperature of 25 ° C. 40% of the (S) -5-vinyloxazoIidin-2-thione had been decomposed.

50 55 60 · 65

Claims (4)

Patent claims: 1. Process for detoxifying rapeseed meal, in which the meal is mixed with 1 to 8% by weight of a solid, non-volatile alkaline substance and water and mixes with steam at a temperature of min treated at least 90 ⁰ C, characterized in that the alkaline substance calcium oxide or Calcium hydroxide is, the water content of the mixture is adjusted to 12 to 18 wt .-% and the duration of the subsequent steam treatment does not exceed 30 minutes 2. The method according to claim 1, characterized in that the steam treatment at 100 to 105 "C he follows. 3. The method according to claim 1 or 2, characterized in that the duration of the steam treatment 15 to 20 mismatches. 4. The method according to any one of claims 1 to 3, characterized in that the water content of the Mixture in the steam treatment is about 15 wt .-%