DE2656663C3 - Condemnation - Google Patents

Description

The invention relates to a method for the joint fermentation of lactose-containing residual solutions Dairies with ground products of grain, pulses and / or other raw materials with one Content of sugars and polysaccharides with the addition of ammonia as the only inorganic substance.

For the production of protein and baker's yeast z. B. Lactose-containing dairy solutions such as sour whey, Rennet whey, permeates of the filtration of whey and skimmed milk and dialysates, and is milling products z. B. soy flour and / or other raw materials with a content of sugars and polysaccharides such as potatoes, Tapioca. and cellulosic materials are subjected to cohesion.

The lactose-containing residual solutions from dairies are difficult to use because large amounts of the solution have to be processed with a low dry matter. Complete recycling can be achieved by drying the untreated or kneaded whey, whereby apart from the Brüdendämpl'e no waste water is created. In the case of Verhefung (comparative report on technically implemented whey fermentation process, see L. Forman et al .. Kvasny prumysl, 21, 1975, Vol. 12, pp. 283-285), lactose and acids after the addition of simple nitrogen compounds such as ammonia and Ammonium sulphate biomass is formed and thus the protein content of the end product is increased compared to the untreated material. The ash content of the hacked material obtained by total drying is undesirably high compared to the untreated product, which is due to the weight loss during yeasting (about 40% of the lactose) and the addition of sulfuric acid or ammonium sulfate (corresponds to an addition of Sulfuric acid, since the ammonia of these compounds is assimilated by the yeasts and sulfuric acid remains in solution), combined with an increase in the ash content by neutralizing the acids with lye after the fermentation is complete. Et / terc is important, as otherwise concentrated acids are formed through the evaporation process (concentration effect is about 500 times the original / iijresrt / tcn acids, 1 ton of whey contains 940 kg of water and after fermentation approx. 40 kg of product with 4-5 % Water are obtained, the end product only contains 1.5-2 kg of the original amount of water). The addition of an acid which has been used up again during the fermentation is advantageous. According to the Polyvit process, nitric acid is used, which also serves as a nitrogen source (B. Waeser, Chemikerzeitung 7, 1944, pp. 120-125). However, this method has the major disadvantage that the

ίο Nitrite arising spontaneously from nitrate due to lack of oxygen in the presence of microorganisms with secondary amines with the formation of carcinogenic nitrosamines can react (J. Sander, Hoppe-Seyler's Z. PhysioLChem. Vol. 349, 1968 S. 429-432).

Lactic acid has proven to be more favorable for regulating the pH value in aerobic fermentation batches with mixed cultures of yeast and lactic acid bacteria (O. Moebus and P. Kiesbye, DE-OS 24 03 306, 24 10 349 and 2 50 323). The yeasts assimilate lactic acid as a carbon source; Lactic acid bacteria growing in mixed culture with the yeast form the lactic acid required to adjust the pH value even under aerobic conditions. The only addition to the whey is ammonia, which is bound as ammonium lactate by lactic acid. In addition to whey, solutions containing carbohydrates, starch and cellulose are generally given as substrates. According to more recent processes, the whey is treated with additional concentrated products in view of the high drying costs

JO trated carbon sources quantitatively enriched. L. Forman et al. achieve a significant increase in Dry matter by adding ethanol to the whey, which is only of economic interest if it is cheap synthetic ethanol is available. Does this have to be made from raw materials containing starch? it is better to put these together directly after appropriate enzymatic digestion for the fermentation use with whey (H. Müller, DE-OS 25 48 641). Due to their ability to assimilate lactose, the

■ Ό types of yeast used for whey fermentation Kluyveromyces fragilis (syn.Saccharomyces fragilis) and Candida kefir (syn.Candida pseudotropicalis) cannot assimilate maltose (J. Lodder, 1970, North Holland Publishing Company, Amsterdam et al.

London).

The yeasts like Saccharomyces cerevisiae are excellent on maltose-containing vegetable substrates customized. O. Moebus and P. Kiesbye (1974) for this reason have mixed cultures of yeast and lactic acid bacteria with suitable assimilation properties Used in the fermentation of whey in combination with raw materials containing polysaccharides. The use of the mixed cultures of lactic acid producers and yeasts starts because of the same temperature

5 ^r > more or less common temperature range of growth, which means that the process is subject to considerable restrictions, also with regard to the end product that can be obtained.

The invention is based on the object

w) Process for the joint fermentation of lactosehal term residual solutions from dairies with ground products of grain, pulses and / or other raw materials with a content of sugars and polysaccharides with the addition of ammonia as the only one

^h "> to provide an inorganic substance for the production of baker's yeast Saccharomyces cerevisiae, which allows for a practically wastewater-free utilization of these substrates with acceptable ash emissions in the end product.

let and to an end product with the highest possible yeast protein content and high yield Yeast dry matter leads.

This object is achieved by the method according to the claims, in which the starch and sugar-containing raw materials are added to the lactose-containing solution and the lactose after gelatinization and dextrination of the starch with the addition of ammonia by the Yogurt bacteria Lactobacillus bulgaricus and Streptococcus thermophilus fermented to lactic acid, which Dextrins hydrolyzed by amylases and the resulting lactic acid suspension with aeration and more Add ammonia with Saccharomyces cerevisiae. The hydrolysis of the dextrins can also only take place can be carried out during the deepening, with an enrichment through the metered addition of the amylase suppressed by maltese and isomaltose and alcohol formation can be switched off.

Instead of starch or together with starch, after appropriate grinding, cellulose- containing raw materials can be tacked with the additional use of cellulase, i. H. the process is generally applicable to raw materials containing sugar and polysaccharides.

The plant used to carry out the process for the production of protein and baker's yeast can initially produce a protein-rich animal feed. By simply switching the system, baker's yeast can also be produced and the rest of the processed raw material can be dried as animal feed with practically no waste water.

The invention achieves that by adding starchy raw materials to the whey and other lactose-containing residual solutions, a practically waste-water-free utilization of these substrates with acceptable ash contents in the end product can be achieved. The product obtained after deepening is a valuable source of protein and vitamins for animal nutrition. Since cultured yeast can be used, these products can be used in the food sector as there are no toxicological concerns. The process can be easily adapted to the raw materials currently available and can be varied in many ways in terms of equipment and application to possible end products. The method of the invention ^; In contrast to the older method with mixed cultures of lactic acid producers and yeasts (O. M ο ebu s and P. K iesbye, 1974), it is designed in two stages, in that first the lactic acid bacteria and then the yeasts are used. In the first stage, lactic acid is formed by using thermophilic lactic acid bacteria, whereby the temperature - unlike the fermentation temperature - can be set so high that the growth of harmful microorganisms is suppressed and the amylases used can work in the optimal temperature range. In the following stage, the well can be operated at a lower operating temperature in order to obtain an end product with the highest possible content of yeast protein and a high yield of yeast dry matter.

To the height of the invention it is stated that, deviating from the method of working when using mixed cultures, according to the invention, the wastewater-free yeasting of lactose-containing residual solutions from dairies with milled products of grain, pulses and / or other raw materials with a content of sugars and polysaccharides is carried out in / white stages, so that different working temperatures can be used. Surprisingly , this process leads to the achievement of an optimal end product. In the exemplary embodiment (follows) a temperature of 50 ° C. is selected for the first stage when using the yoghurt bacteria , at which the growth of harmful microorganisms is switched off and at the same time an optimal temperature is set for the activity of the amylases. This temperature is above the maximum growth temperature of Saccharo myces cerevisiae. The temperature for the fermentation is then given as 32 ° C, at which an end product with the highest possible protein content is produced. If a common temperature range of growth is used for lactic acid producers and yeasts, z. B.

with increasing temperature, the final yield of dry yeast mass per unit weight of sugar. According to the invention, the fermentation process achieves a maximum yield of crude protein in the end product so that it can compete with other protein feedstuffs (soy meal, fish meal). ^ nn.

The invention is hereinafter referred to as one Embodiment described.

example

2j 4 t of Izen flour with 63.3% starch, 13.3% crude protein (Kjeldahl-N χ 6.25), 1.6% ash and 11.6% water (air-dry substance) are mixed cold with 201 whey, with one sufficient for dextrination Amount of thermostable bacterial α-amylase (e.g.

jo 900 ml of commercially available amylase I) were added and brought ^{to 75 ° C. by introducing steam with stirring.} (At 65'C the cladding sets in, the suspension becomes thin again due to the action of amylase). The suspension is 30 minutes at 70-8O ⁰ C

j5 held, then brought to 50 ° C., 80 l of yoghurt culture were added and the pH was adjusted to 6.2 with 25% aqueous ammonia solution and kept at pH 6.2 until 200 l of NHj solution had been consumed. After about lOStdn. Fermentation at 50 ⁰ C becomes a pH of

■ to 4.3 reached, which no longer changes significantly (Vei orauch of the lactose). The suspension is now ^{unified at 32 5} C with aeration after adding 100 kg of compressed yeast and further addition of ammonia. Initially, a pH of around 5.0 is maintained. Towards the end of the fermentation, the pH slowly rises above 5.0. After 20h Culture, the pH is 6.7. A total of 4001 aqueous ammonia is consumed. The entire harvest suspension is dried. 3200 kg of dry matter are obtained. The material contains 7.66% water, the dried substance contains 41.66% crude protein, 1.60% crude fat, 0.61% crude fiber, 48.46% N-free extra, 92.33% org. Tuibstanz and 7.67% ash. A fungal amylase is added to hydrolyze the dextrins (e.g. 500 ml

ι '· commercially available An.ylase II). The addition of the ^r . The enzyme can take place at the end of the lactic acid fermentation, but even at the temperature of the fermentation the reaction rate is still sufficiently high that in the latter case the formation of maltose can be controlled

wi possible according to the maltose consumption by the yeast is.

The figure shows the practical implementation of a system for carrying out the method. she consists from an inlet (1) for the lactose-containing residual solution

ι- 1 gene and an addition of the starchy raw materials (2) in a heatable and coolable tank (3) for gelatinization and dextrination of the starch, a fermentation tank (4) with temperature regulation and addition of ammonia (5), one

sclbsten'schlammcenden centrifuge (8) / for the separation of the solids and lactic acid bacteria and "drying in the spray tower (7), an I ermenter (6) for the fermentation of the lactic acid solutions with added ammonia (5), a self-cleaning centrifuge (9) for possible complete or partial preconcentration of the yeast hernia (K)), whereby for a new batch the centrifugal pump is pumped into the fermentation tank (4), a coolable stacking tank (II) for receiving centrifugal, fermentation and solidification suspensions. steam system (12) for concentrating the harvest suspension, a spray tower (7) and a bagging system for the finished product (13), heat exchangers, fryer, cooler and measuring and control systems are not shown - and Tmckniingssyslenie aus triUMIU WCI UCII.

To produce a feed, the lactose-containing residual solvents (I) are used together with the starchy raw materials (2) placed in a tank (3), in which the starch is gelatinized and dextrinated after adding thermostable amylase, the lactose in the Tank 4 fermented by yoghurt bacteria after adding ammonia (5) to lactic acid and the dextrins hydrolyzed by amylases; the one produced in tank 4 Suspension is, after any separation of the solids by the centrifuge (8) and separately Drying in the spray tower (7), pumped into the fermenter (6) and there with ventilation and more Adding ammonia and the entire product, after possible pre-concentration with the centrifuge 9 and return of the centrifugate to the fermentation tank (4). dried (evaporator I2. spray tower 7). if in addition to animal feed, baker's yeast is also produced. the grain residues and lactic acid bacteria get there after the lactic acid fermentation not in the fermenter 6, but are separated by the centrifuge 8 and dried (7); the baker's yeast 10 separated off with the centrifuge 9 is washed and further processed as usual; the centrifugal from 9 and washing water of the baker's yeast (not shown) are in the findampfer (12] concentrated and dried together with the residue from centrifuge 8 (7).

If a water-soluble lactic acid dry acid with Fiweiß / u'.at / is produced in addition to feed, it becomes a suitable raw material. / B. bran, in a lactose-containing substrate, e.g. B. whey, gelatinized and dextrinated (3) and then fed into tank 4 together with prepared yeast *; During the lactic acid fermentation, the yeast is autolyzed and, after the process is complete, lactic acid bacteria, grain residues and egg cell walls are separated off with the centrifuge 8 and dried (7); the lactic acid eiwciui cicnc

wiiu n.ici

yi ι f

Findampfen (12) also dried. In addition to feed, it becomes a water-soluble protein-rich protein concentrate produced, a protein-containing raw material z. B. a final meal, in a lactose-containing substrate e.g. whey, gelatinized and dextrinated (J) and dam together with baker's yeast already produced in lank 4; during the micahic acid fermentation the handle becomes autolyzed. and after the process is complete, lactic acid,: bacteria. Grain residues and I lefezell walls separated with the centrifuge 8 and dried (7) and the lactic acid protein-rich solution in the fermenter 6 guided: and there ur.ter aeration uric: The addition of ammonia was a problem. while the baker's yeast (10) separated with the centrifuge 9, without washing Process for the next lactic acid fermentation in the fermentation tank 4 is pumped, the centrifugal 9 with the Concentrated evaporator 12 and then dried wire (7).

1 sheet of drawings

Claims (1)

Claim: A method for the joint fermentation of lactose-containing residual solutions from dairies with ground products of grain, legumes and / or other raw materials with a content of sugars and polysaccharides with the addition of ammonia as the only inorganic substance, characterized in that the lactose after gelatinization and dextrination of the starch by the Yoghurt bacteria Lactobacillus bulgaricus and Streptococcus thermophilus is fermented to lactic acid, the dextrins are hydrolyzed by amylases and the lactic acid suspension obtained in this way with aeration and further addition of ammonia is agitated with Saccharomyces cerevisiae, the hydrolysis of the dextrins also only through metered addition during the fermentation Amylase can be done.