Method of producing apple cider vinegar
Patent Information
- Authority / Receiving Office
- PL · PL
- Patent Type
- Patents
- Current Assignee / Owner
- UNIV ZIELONOGORSKI
- Filing Date
- 2023-05-14
- Publication Date
- 2026-07-27
AI Technical Summary
Current methods for producing apple cider vinegar are primarily batch processes, lacking efficient continuous processes and suitable beds for continuous production, which limits scalability and productivity.
A method utilizing a tubular bioreactor filled with a porous carbon-apple extrudate bed, created by drying apple pomace, mixing it with charcoal and other components, and extruding it into a specific form, allows for continuous acetic fermentation with controlled oxygen flow and nutrient injection, enabling immobilization of Acetobacter bacteria for sustained fermentation.
This approach enables continuous production of apple cider vinegar with high acetic acid content and efficient fermentation dynamics, achieving a maximum productivity of 3.6-3.9% acetic acid and maintaining a favorable taste, overcoming the limitations of batch methods.
Abstract
Description
[0001] The present invention relates to a method for producing apple cider vinegar using a bed based on apple pomace.
[0002] Apple cider vinegar is a traditional product of the culinary arts, known since ancient historical times, which is traditionally obtained as an oxidation product of apple cider, i.e. a low-alcohol drink resulting from the alcoholic fermentation of apple juice. Apple cider vinegar is produced by the aerobic bacteria Acetobacter, which form a characteristic dross on the surface of the solution. For a proper acetic fermentation process, three factors must be met: a sufficiently high concentration of oxygen available to the bacteria, alcohol content and, advantageously, the presence of a source of simple sugars in the environment.
[0003] Chinese patent application CN105018384A describes an Acetobacter strain belonging to the field of industrial microorganisms and its use in fermenting apple cider vinegar. The Acetobacter strain is Acetobacter pasteurianus strain CYD1S9, which was deposited in the China Center for Type Culture Collection on 30 June 2015. The address of the collection is Wuhan University, Wuhan, PRC, and the collection number is CCTCC NO: 2015418. The strain has a higher acid production capacity (up to 110 g / l or more). Apple cider vinegar fermented with the Acetobacter strain is obtained with high yield and has a favourable taste, making Acetobacter pasteurianus strain CYD159 a suitable Acetobacter strain for obtaining apple cider vinegar.
[0004] Korean patent publication KR102263129B1 relates to a method of making apple cider vinegar and apple cider vinegar produced by said method. The method includes: (1) the step of preparing apple concentrate by concentrating apple juice; (2) the step of preparing concentrated apple wine by inoculating a culture solution of Saccharomyces cerevisiae strain into the prepared apple concentrate from step (1) and culturing it; (3) the step of preparing an acetic starter in the prepared concentrated apple wine of step (2) by inoculating the mixture with a culture of the strain Acetobacter pasteurianus, to which the prepared apple concentrate of step (1) and its culture are added; and (4) the step of acetic fermentation of the mixture, in which the prepared acetic starter of step (3) is added to the prepared concentrated apple wine of step (2).
[0005] Traditionally, cider vinegars are made by exposing the cider to oxygen over as large a surface area as possible, thus increasing the surface area in contact with oxygen. The methods used by some wineries also use coarsely cut oak chips to increase the surface area as well as to impart sensory characteristics. However, each of the methods mentioned is a batch method, meaning that the vessel in which the process is carried out is periodically filled with substrate and the product is removed at the end of the process.
[0006] There is still a need in the field for new methods of obtaining apple cider vinegar, especially in a continuous process, as well as new beds that can be used to produce apple cider vinegar especially in a continuous process.
[0007] The aim of the present invention was to develop a method for obtaining apple cider vinegar by fermentation using aerobic Acetobacter bacteria in a column lined with a suitable bed - a carbon-apple extrudate.
[0008] This objective has been achieved by the method of the present invention.
[0009] Thus, the subject matter of the invention is a method of producing acetic acid by acetic fermentation, wherein the fermentation medium, which is cider containing 5.2 % w / w ethanol and 20 g / dm 3< glucose, is fed from above into a tubular bioreactor at a volume rate of 30 cm 3< / h, using a retention time of 66.6 h for the fermentation medium in the reactor; oxygen is fed from the bottom of the bioreactor at a pressure of 110 000 Pa and a volume intensity of 480 cm 3< / h; characterised in that the tubular bioreactor is filled with a porous bed obtained by a method comprising the steps of: (a) the apple pomace shall be vacuum dried at a temperature of 40 to 80°C, preferably 50 to 70°C, more preferably at 60°C and under pressure of 60 000Pa to give a product with a moisture content of 40%; (b) the material obtained is subjected to further drying, preferably in a convection dryer, at a temperature of 100 to 110°C, preferably 105°C, until a product with a moisture content of 20% is obtained; (c) the apple pomace with a moisture content of 20% is mixed with charcoal, preferably apple charcoal, silicon oxide, calcium carbonate and calcium sulphate and crushed, followed by the addition of an aqueous glass solution and the whole is mixed, the quantities of the individual components being as follows: apple pomace with a moisture content of 20% (61.82%), charcoal (30.91%), silicon oxide SiOi (0.46%), aqueous glass, solution of 10% by weight in water (6.18%), calcium carbonate anhydrous (0.31%), calcium sulphate anhydrous (0.31%); (d) the resulting mass is extruded in an extruder operating at a screw speed of 200 rpm, a compression ratio of 1.75 and a heating power of 2kW to produce extrudates with a diameter of 20-30 mm, preferably 25 mm; (e) extrudates are allowed to rest for 24 h; whereby, prior to the acetic fermentation process, the bed is subjected to conditioning, in which the extrudates are crushed, washed with distilled water at room temperature, and poured over a solution of the following composition: water (62.28%), apple juice (31.14%), ethanol 70% v / v (6.23%), magnesium sulphate (VI) (0.05%), lyophilised cultures of Acetobacter (0.31%); and left for 48 h using a pure oxygen flow rate of 10 ml / min
[0010] In the present invention, a specially prepared bed consisting of a porous material, such as carbon-apple extrudate, is used as the filling of a tubular bioreactor in which the apple cider vinegar production process is carried out continuously, i.e. the nutrient solution is fed into the bed at the same time, as well as the product in the form of fermentation fluid containing acetic acid is collected.
[0011] The object of the invention is illustrated in the figures of the drawing, where: Fig. 1 shows the fermentation system, bioreactor and equipment; Fig. 2 illustrates the fermentation dynamics for a continuous process in a bioreactor. EXAMPLESExample 1 - the method of production of a porous bed
[0012] The bed for filling the tubular bioreactor was produced by extrusion. The components of the bed and their proportions are shown in Table 1. The apple pomace, representing 61.82% of the mixture by weight, was pre-dried according to the following scheme: 100 kg of apple pomace was vacuum dried in an evaporator (temperature 60°C, vacuum pressure 60 000 Pa) to obtain products in the form of cellular water and aromatic fraction. Evaporator drying was carried out until a product with a moisture content of 40% was obtained. The material was then transferred to a convection dryer, where it was dried at 105°C until a moisture content of 20% was obtained. The apple pomace together with charcoal, silicon oxide, calcium carbonate and calcium sulphate were transferred to a beater mill for grinding. An aqueous glass solution was then added in the mixer in the amount provided in the recipe below. After mixing, the mass was transferred to an extruder operating at a screw speed of 200 rpm, a compression ratio of 1.75 and a heating power of 2 kW. The resulting extrudates had a diameter of 25 mm and were aged for 24 h after the process.
[0013] Bed preparation also included crushing the resulting porous mass of extrudates to grind them to a size that would fit into the tubular reactor cylinder. After crushing, the bed was poured into the reactor and washed twice with 5 l of distilled water at room temperature (20°C). The bioreactor was then flooded with a solution of the composition shown in Table 2 and left to condition for 48 h. During bed conditioning, a pure oxygen flow rate of 10 ml / min was applied. After this time, the conditioning solution was collected via a peristaltic pump.
[0014] The bed thus prepared was ready for the fermentation process.Example 2 - carrying out of the acetic fermentation process and its effects
[0015] A fermentation system was prepared according to the scheme shown in Fig. 1. The fermentation medium was cider containing 5.2 by weight ethanol and 20 g / dm 3< glucose. The fermentation medium was fed into the bioreactor at a volume rate of 30 cm 3< / h, the working volume of the reactor was 2 dm 3< , the retention time of the medium in the reactor was 66.6 h. The nutrient solution was injected into the bed from the top and flowed freely down the reactor. Technical oxygen was injected from the bottom of the reactor, oxygen pressure 110 000 Pa, oxygen volume intensity 480 cm 3< / h. At the top of the bioreactor was a pressure equalisation valve, in the form of a tube plugged with a movable glass ball. The valve allowed the fermentation gases to escape freely from the bioreactor. The fermentation product was collected at the bottom of the tube and transported by a peristaltic pump to the product tank.
[0016] Fig. 1 shows the fermentation system, a bioreactor with equipment.
[0017] The use of a porous bed in a tubular bioreactor allowed the multiplication of Acetobacter and their immobilisation. Feeding the medium and oxygen in a countercurrent manner significantly increased the fermentation dynamics. The fermentation product, apple cider vinegar, was obtained using a continuous method, i.e. the volume intensity of the nutrient solution fed was equal to the volume intensity of the fermentation product (apple cider vinegar) received.Example 3 - Process flow and end results of fermentation
[0018] Fig. 2 shows the dynamics of fermentation changes in the apple cider vinegar received from the bioreactor during the continuous process. It can be observed that the first 24 hours of the process were a period of gradual increase in the concentration of acetic acid in the receiving fermentation medium. This was related to the biomass multiplication period and the need for the dynamic equilibrium in the reactor to establish itself.
[0019] After 24 hours, the maximum productivity of the bioreactor was reached, which allowed receiving continuous digested substrate containing between 3.6 and 3.9% acetic acid. In the receiving medium, 1 to 2.3 g / dm 3< glucose and 0.2 to 0.55% ethanol were determined.
[0020] The resulting product after biomass centrifugation was ready-to-eat apple cider vinegar.
[0021] Fig. 2 shows the fermentation dynamics for a continuous process in a bioreactor.
Claims
1. A method of producing acetic acid by acetic fermentation, wherein - the fermentation medium, which is cider containing 5.2 % w / w ethanol and 20 g / dm3 glucose, is fed from above into a tubular bioreactor at a volume rate of 30 cm3 / h, using a retention time of 66.6 h for the fermentation medium in the reactor; - oxygen is fed from the bottom of the bioreactor at a pressure of 110 000 Pa and a volume intensity of 480 cm3 / h; characterised in that the tubular bioreactor is filled with a porous bed obtained by a method comprising the steps of: (a) the apple pomace shall be vacuum dried at a temperature of 40 to 80°C, preferably 50 to 70°C, more preferably at 60°C and under pressure of 60 000Pa to give a product with a moisture content of 40%; (b) the material obtained is subjected to further drying, preferably in a convection dryer, at a temperature of 100 to 110°C, preferably 105°C, until a product with a moisture content of 20% is obtained; (c) the apple pomace with a moisture content of 20% is mixed with charcoal, preferably apple charcoal, silicon oxide, calcium carbonate and calcium sulphate and crushed, followed by the addition of an aqueous glass solution and the whole is mixed, the quantities of the individual components being as follows: (d) the resulting mass is extruded in an extruder operating at a screw speed of 200 rpm, a compression ratio of 1.75 and a heating power of 2kW to produce extrudates with a diameter of 20-30 mm, preferably 25 mm; (e) extrudates are allowed to rest for 24 h; whereby, prior to the acetic fermentation process, the bed is subjected to conditioning, in which the extrudates are crushed, washed with distilled water at room temperature, and poured over a solution of the following composition: and left for 48 h using a pure oxygen flow rate of 10 ml / min.