RU98001U1 - DEVICE FOR REPRODUCING SEED BEER YEAST - Google Patents

Abstract

 A device for breeding seed brewer's yeast, which is a cylindrical-conical digestion tank, which is equipped with a jacket that serves to supply steam and a cooling medium, means of periodic aeration of the wort and, in addition to vacuum and safety valves, is equipped with washing heads and an aeration nozzle for supplying sterile air, characterized in that the digestion tank is equipped with a microprocessor, functionally interconnected with dispensers of nutritional supplements to the wort, as well as means of automation support the composition of the breeding medium, temperature, and air supply rate necessary to optimize the growth of yeast biomass to the residual amount of basic fermentation and to keep the yeast in suspension, and the aeration nozzle is placed at the bottom of the tank and made in the form of a series of nozzles.

Description

The invention relates to the brewing industry, and in particular to devices for breeding seed brewer's yeast for introducing yeast into the fermentation apparatus at the main fermentation stage.

TI 18-6-47-85 [Technological instruction for the production of malt and beer, M.: 1985, P.102-103] prescribes the growth and increase in the volume of seed yeast by repeated reseeding from container to container with doubling the volume of added sterile wort used as a culture medium.

The procedure is very lengthy and time-consuming, requiring sterilization of the wort by boiling, followed by cooling in special devices - propagators, retrofitted with air sterilization devices. In order to propagate seed yeast to the volume necessary for introduction into the fermentation apparatus, the brewery needs to use several devices of increasing volume in turn.

Of the known technical solutions, the closest is the brewing yeast breeding apparatus proposed by Wackerbauer [Wackerbauer, K., Zufall, C: Dresdner Brauertag, 17.4.1998, ref. Briforum 5 (1998 s.133-134)], comprising a cylinder-conical tank (CKT), equipped with a jacket for supplying steam and a cooling medium, and in addition to vacuum and safety valves, equipped with washing heads, while sterile air is supplied through an aeration nozzle. At the same time, a pure culture from the preliminary dilution flask is transferred to the Carlsberg flask at a dilution of 1: 200; then from the Carlsberg flask - to the propagator at a dilution of 1: 300; then transferred to a pure culture tank in a ratio of 1:20 for subsequent application to the CCT for every 500 hl. wort. Thus, in 2.5-3 days, the volume of yeast is increased, sufficient for one cooking, which is pumped into a digestion tank. Prior to this, the tank is half filled with wort; the wort is sterilized for 15 minutes and cooled to + 20 ° C. In this case, the breeding yeast is actively aerated with sterile air in the digestion tank: on the first day - 1 minute after an interval of 15 minutes; on the second day - 1 minute after an interval of 5 minutes. Only after that the obtained biomass of yeast is transferred to the main fermentation apparatus, which differs in capacity for different enterprises.

The disadvantage of this device is the need for pumping portions of breeding yeast through several devices. In addition, the disadvantage of this device is the use of wort as an inferior culture medium and the non-use of specially adapted media. Under these conditions, at each stage of yeast breeding, the number of cells can correspond only to the upper boundary of the possible maximum [Manger, H.J., Annemuller. G.: Speed of Yeast Propagation in Breweries-Basis for Planning and Sizing a Yeast Propagatin Plant. Brauwelt Internat. 19.2001, 117-123]. In this case, the so-called "Grabtree effect." The Grabtree effect is the reason that when breeding yeast in wort, it is impossible to prevent the formation of ethanol, which blocks the growth of yeast by destroying young budding cells [Magner. H.J., Annemuller.G .; Speed of Yeast Propagation in Breweries-Basis for Planning and Sizing a Yeast Propagation Plant. Brauwelt Internat. 19, 2001, 117-123; Gavin Millar et al. “CCT of the Velke Popovice Brewery, Beer and Life, 2003 From 17-21 // www.propivo.ru Beer @ Life magazine]. In addition, the disadvantage of the device is the need for repeated reseeding of seed brewer's yeast and introducing them into the main fermentation apparatus from the “digestion” tank in a ratio of 1:20 to the volume required for main fermentation. This corresponds to the practice of brewing, in which only part of the required volume of yeast is introduced into the CCT, which multiplies in the first two days of the main fermentation to the required volume of residual amount. So Maltsev P.M. [Technology of malt and beer, M .: Publishing house "Food Industry", 1964, S.499-500] believes that when inoculated with 0.5 l of liquid yeast per 1 hl of wort, a four-fold increase in yeast is usually obtained, taking into account that each yeast cell will have time to produce up to 40 divisions before the start of autolysis due to an imbalance in the carbohydrate and nitrogen components of the wort and under the influence of the Grabtree effect.

The technical result of the claimed utility model is the development of a device for a single tank of fermentation, which automatically optimizes breeding conditions of brewer's yeast, both in terms of the composition of the culture medium for breeding brewer's yeast, and in terms of ensuring, without reseeding from tank to tank, the optimal rate of biomass growth to the required volumes of “residual quantities. "

The technical problem is solved in that in the known device for breeding seed brewer's yeast, which is a cylindrical-conical tank for digestion, which is equipped with a jacket for supplying steam and a cooling medium, means for periodic aeration of the wort and, in addition to vacuum and safety valves, is equipped with washing heads and an aeration nozzle for supplying sterile air, according to a utility model, the digestion tank is equipped with a microprocessor functionally interconnected with batchers of nutrient add Wok to the wort, as well as automation tools to maintain the composition of the breeding medium, temperature and air supply rate necessary to optimize the growth of yeast biomass to the residual amount of basic fermentation and to maintain the yeast in suspension, the aeration nozzle placed at the bottom of the tank and made in the form of a series nozzles.

A useful model of the device is shown in the drawing, while the device for propagating seed brewer's yeast includes: the body of the digestion tank 1; mixer constituting the culture fluid 2; brewer's yeast plasmolysate dispenser 3; wort dispenser 4; Carlsberg flask 5; boiler - instantaneous water heater 6; remote float level gauge 7; temperature sensors 8; dissolved oxygen meters 9; blower 10; spiral distribution device for supplying air 11 with air supply nozzles 12; a control device for the air supply nozzles 13; microprocessor 14.

According to the claimed utility model, all procedures for propagating seed yeast to the required “residual amount” are carried out in a single digestion tank 1, into which fractionally necessary portions of plasmolysate are dispensed with plasmolizate 3 dispenser, and wort is dispensed with wort 4 through a mixer 2 located in the upper part of the digestion tank 1 and portions of seminal yeast by extrusion from a Carlsberg flask 5. In this case, water heated to 40 ° C is supplied to the mixer 2 from the flow-type boiler 6 at a rate of 0.3 liters per minute throughout the breeding period zhzhey. Moreover, before introducing seed yeast into the digestion tank 1, one fourth of the volume is filled with water and culture liquid, as evidenced by its appearance in the remote float level gauge 7. This level corresponds to the level of the start of immersion of the temperature sensor 8 and the sensor for measuring dissolved oxygen 9 into the liquid , which corresponds to the beginning of fluid monitoring. According to the readings of the dissolved oxygen meter 9, a blower 10 is turned on, which supplies air to the spiral switchgear 11 at the bottom of the digestion tank 1. At the same time, the air supply, which ensures a constant suspended state of breeding yeast, is carried out by switching on the air supply nozzles 12 one by one, through the control device 13 through the principle of "traveling wave". Moreover, for the efficiency of mixing the yeast and homogenizing the temperature of the liquid (up to 32 ± 2 ° C) throughout the whole digestion tank 1, the air supply rate in the initial period of propagation of yeast is at least one volume of supplied air per volume of culture liquid. Subsequently, the amount of air supplied by the blower 10 is determined by the microprocessor 14 according to the readings of the dissolved oxygen meter 9, and the amount of dissolved oxygen should not be lower than 5 mg O ₂ / L.

The supply of 1 component of the culture fluid to the digestion tank is carried out in fractional portions through dispensers 3 and 4 according to commands from microprocessor 14 programmed to maintain compliance: one volume of plasmolysate and three volumes of wort per three volumes of water. Dilution is considered completed when about 150 cells · 10 ⁶ / cm ^{3 are} detected in the yeast culture sample. The microprocessor program 14 includes the use of a dispenser resource 3-4, necessary for growing every 100 l of yeast culture, which is calculated to be added to the fermentation apparatus at the stage of main fermentation. When the dispenser resources are exhausted or when the filling level of the sprinkler tank 1 is reached, with a design capacity of 5000 l, the microprocessor switches off the dispensers and the water supply, while maintaining only the control of sparging the entire contents of the sprinkler tank.

A device for supplying air to breeding yeast biomass is essential. Breeding yeast requires at least 0.03 mg O ₂ / liter of yeast to ensure tissue respiration. Below this value, the reproduction of yeast stops. The optimum oxygen supply is more than 5.0 mg O ₂ / liter of medium.

A device for supplying oxygen to a yeast propagation medium is known, in which air is supplied through a semipermeable membrane made in the form of tubes [Fedorenko B.N. Brewing Engineering. - St. Petersburg, Publishing House Profession, 2009, P.152]. In this case, only rapidly dissolving oxygen passes into the wort through the membrane wall. This state-of-the-art device eliminates the need for both air sterilization and the supply of pure oxygen sources to the line propagator.

The disadvantage of this device is the inevitability of biofouling of the air supply tubes and the lack of required bubbling of the growing biomass of yeast. To optimize reproduction, maintaining the yeast in suspension is required. A device for supplying air to the yeast mass in the form of thin jets or through special candles meets this requirement [Gavin Millar et al. CCT of the Velke Popovice brewery, Beer and Life, 2003 C 17-21 // www.propivo.ru Beer @ Life magazine]. However, small-bubble devices for supplying air to the wort carry the risk of developing cavitation processes when the bubbles rupture, which can be detrimental to yeast cells. In the device adopted for the prototype, the air supply is carried out portionwise: on the first day - 1 minute after an interval of 15 minutes; on the second day - 1 minute after an interval of 5 minutes.

The indicated problem: the need for aeration to enrich the reproduction environment with oxygen and to maintain the yeast biomass in suspension in the claimed utility model is solved by the fact that the blower 10, which pumps air into the air supply nozzles 12, along the spiral nozzle 11, distributed in the lower part of the tank 1, included alternately by command from the control device 13 at a speed determined by the readings of the sensors 9 of the amount of dissolved oxygen in the environment of propagation of yeast. The jet air supply by nozzles 12 alternately from bottom to top provides active mixing of the growing yeast biomass. In this case, the inevitable foaming is blocked by a defoamer located in the upper part of the tank 1 below the mixer 2 constituting the culture medium (not shown in the drawing).

An example of a specific application.

To create an optimized breeding culture medium, the plasmolysate of spent brewer's yeast was used. The composition of the culture medium based on plasmolysate is shown in the table.

The ideology of the device is to maximize the biological resources of spent brewer's yeast to propagate a new batch of seed yeast. Moreover, in order to avoid the process of technological purification of the autolysate obtained by lysis of whole cells with inevitable side inclusions accumulated by the shells of yeast cells, which can affect the taste of beer, we preferred to use only plasmolysate of yeast cells. At the same time, the cell membranes destroyed by ultrasound are removed from the solution by centrifugation, and the plasmolysate itself is treated with proteolytic enzymes to break down proteins into amino acids and nitrogen-containing components, suitable for assimilation by the yeast to grow biomass. Each new sowing begins with the sowing of a standardized (pure seed culture) batch, and after the wort is fermented and the main fermentation is complete, the entire yeast biomass is disintegrated and the beer is pasteurized. This made it possible to abandon the bubbling of yeast biomass with sterile air, which, along with the refusal to boil the wort with subsequent cooling to a temperature optimum for the reproduction of yeast, significantly reduced energy consumption. The wort, supplied as part of the culture medium of the propagation of yeast, in the inventive industrial model is produced by a remote microwave pasteurizer (not shown).

Table The mineral composition of plasmolysate and culture medium, μg / g ash residue (own data) Mineral Plasmolysate yeast race 34 must water one 2 3 four Sa 666.0 66.12 23.98 Mg 272.0 108,0 7.96

Table continuation

one 2 3 four R 2619,0 243.0 0,033 Si 8.88 47.7 5.05 Na 75.62 50.12 48.71 TO 1564.0 367.0 2.91 Li 0.007 0.0053 0.00359 Al 0.16 0.09 0.009 Fe 12.1 0.40 0.05 J 0,03 0.018 0.003 Zn 26.26 0.40 0,03 Se 0,0536 0,0208 0,00161 Cu 1,56 0.1 0,01097 Cr 0,0244 0.056 0.0012 Mn 1.18 0.14 0,001957 As 0.013 0.0014 0,00043 AT 0.13 0.15 0,066823 Cd 0.01848 0.000138 0.000012 Co 0,03748 0.00117 0,000071 Hg 0,00054 0,00054 0,000635 Ni 0.28 0,00036 0.001455 Pb 0,00485 0.00015 0,000809 Sn 0.01231 0,00203 0.000015 Sr 1.55 0.13 0.20 V 0.0024 0.002 0,00077 ∑ 5,248.92 mcg / g 882.83 mcg / g 83.975 kg / g

Under normal production conditions, when preparing 1 hl of young beer, about 1 kg of residual yeast is obtained, which we propose to use to obtain plasmolizate. In our experiments, the mineral component of plasmolysate of brewer's yeast race 34 did not exceed 30% of the dry residue. The data in the table show that the plasmolysate of spent brewer's yeast is the main supplier of calcium, magnesium, zinc, phosphorus, potassium, necessary to increase the biomass of brewer's yeast. On this basis, we consider it unnecessary to saturate the optimized culture medium developed by us with minerals or microelements. In this, our technical solution differs from the essential features of analogues of nutritional supplements for breeding yeast biomass.

The protein component of the plasmolysate reached 70% of the total composition, while the concentration of amino acids in the yeast plasmolysate was 54.5 g / L. The total nitrogen in the plasmolysate was 1750 mg%, with residual nitrogen 32.25 mg%. The determinations were made in the accredited testing laboratory of VNIIMS (Orenburg) according to the method of G.A. Uzbekov in the modification of Z. S. Chulkova [K. G. Kolb, B. C. Kamyshnikov. Handbook of clinical chemistry. Minsk. Belarus, 1982]. In this case, the wort contained only 0.2 g / l of amine nitrogen. Thus, barley wort cannot provide even part of the nitrogen requirements of growing yeast biomass. Considering the fact that ordinary brewer's yeast does not contain proteolytic enzymes, therefore, cannot independently utilize protein and polypeptide nitrogen, it became necessary to add a proteolytic enzyme to the plasmolysate, for example, the available bacterial preparation Protosubtilin G20x, which has proteolytic activity (TU 9152- 031-34588571-99). The drug was used in concentrations up to 1% by weight of plasmolysate. The use of enzymes in the production of yeast autolysate is justified only by enzymatic cytolysis of the whole cell [Patent RU No. 2125992, published 04/27/1999], and the introduction of amylolytic enzyme amilorizin P10X inevitably provokes an acceleration of the fermentation of sugars and the development of Grabtree syndrome (ethanol death of young budding cells) . It is known that autolysis (self-digestion) of a yeast cell inevitably occurs without the addition of enzymes under adverse environmental conditions, for example, when carbon reserves in a nutrient medium are exhausted. It is also known that up to 40% of the protein component of the cell consists precisely of enzymes, including proteolytic ones, which is the basis for obtaining vitamin-enzyme mixtures from yeast. However, the process of spontaneous autolysis is lengthy. So, during technological hydrolysis, the microbial biomass is subjected to heat shock (15-17 s), after which it is exposed for 2 hours at a temperature of 45-50 ° C and 1 hour at 55-60 ° C, followed by salting out of the protein component [Smotraeva I.V. "The use of secondary material resources of brewing in the baking industry, diss. Ph.D., St. Petersburg 2003. - 120 s]. In the claimed technical solution, we used a proteolytic enzyme (but not amylolytic) to simplify and accelerate the low-temperature decomposition of complex proteins into fragments suitable for assimilation by the biomass of breeding yeast. The wort used for the preparation of the culture mixture (11% extractability) contained 20 g / l of sugars, while only 0.5 g / l was found in the centrifuged sugar plasmolysate. The determination was carried out in accordance with GOST R 51135-98 (clause 5.5.3.2.2). The fact we discovered is consistent with the existing theoretical concepts that functionally active yeast accumulate polysaccharides and glycogen in the cell wall [Krueger, Lin. Yeast metabolism and its effect on the taste and aroma of beer / Lin Krueger // Sputnik Brewer. - 1999. - Spring. - S. 39]. We sensibly approached the removal of cell membranes (and other suspensions) by centrifugation and, accordingly, the reduction in the content of the carbon component of the nutrient medium in favor of a significant simplification of the technology for producing plasmolizate. At the same time, the proportion of wort in the composition of the culture medium was compensated three times. At the same time, we took into account that the accumulation of biomass depends on the concentration of carbohydrates in the medium: the larger it is, the more intensively the yeast mass grows. Moreover, with a lack of sugars as a carbon source, the yeast mass cannot absorb nitrogen, begins to degrade as a result of self-digestion of starving yeast with a lack of carbohydrates [Gracheva, I.М. The effect of the concentration of dry substances in the initial wort on the dynamics of the accumulation of fermentation products / I.M. Gracheva, Yu.A. Atrushkevich, V.N. Romanenko // Anthology of alcoholic fermentation, distillation and rectification of ethyl alcohol. Vodka production / Sturgeons SB - [B. m.], 1998. - Access mode: http: // sergey-osetrov. narod.ru/Projects/Fermentation/influence_to_ concentration_dry_ material_ with_source_mash_on_fermentation.htm. - Date of treatment 10.11.2009]. This fact served as the basis for the use of wort as a carbon source in a culture fluid composed of yeast plasmolysate. When calculating the necessary balance of sources of nitrogen, carbon and minerals to obtain biomass in a digestion tank for every 100 liters of seed yeast, the following ratios are adopted for setting the dispensers: one volume of plasmolysate and three volumes of wort for three volumes of water.

Thus, a device was developed with automated control in the form of a single digestion tank, ensuring optimal conditions for propagation of brewing yeast seed breeding, providing optimal conditions for the growth of yeast biomass maintained in suspension, under conditions optimally adapted for brewing yeast breeding in terms of temperature (from +30 to + 35 ° С), oxygenation of the medium (not less than 5.0 mg О ₂ / l) and according to the balance of nitrogen sources, carbohydrates and minerals. The device contains commercially available automation tools in the form of a microprocessor, typical sensors, measuring devices and actuators. Each of them is used for its intended purpose, but when used together, they give a new positive effect. Moreover, the device is economical, environmentally friendly, easy to implement, contributes to the efficient disposal of spent yeast and can be used in any brewery.

Claims (1)

A device for breeding seed brewer's yeast, which is a cylindrical-conical tank for digestion, which is equipped with a jacket that serves to supply steam and cooling medium, means of periodic aeration of the wort and, in addition to vacuum and safety valves, is equipped with washing heads and an aeration nozzle for supplying sterile air, characterized in that the digestion tank is equipped with a microprocessor, functionally interconnected with dispensers of nutritional supplements to the wort, as well as means of automation support the composition of the breeding medium, temperature, and air supply rate necessary to optimize the growth of yeast biomass to the residual amount of the main fermentation and to keep the yeast in suspension, and the aeration nozzle is placed at the bottom of the tank and made in the form of a series of nozzles.