RU2804537C1 - Method for obtaining dietary fibre from beet pulp (embodiments) - Google Patents

Abstract

FIELD: dietary products.

SUBSTANCE: production of powdered dietary fibre from beet sugar production pulp. In the first embodiment, the method for producing powdered dietary beet fibre from beet pulp includes deodorizing the pulp by steam treatment, then preserving it by irrigation through nozzles with a 10% solution of citric acid until the pH value on the surface of the beet pulp is 4.0-4.5. After that, it is sealed in pressed form without access to air, the resulting product is stored for up to 10 months. After which it is unpacked, dried in a rotary air separation flash dryer, and ground in an air sorting mill to obtain final product particles with a size of 75-150 microns. In the second embodiment, the method for producing powdered dietary beet fibre from beet pulp includes canning the pulp using bacterial starters based on a mixture of strains of lactic acid and propionic acid bacteria with the acidity of the pulp reaching pH values of 3.8 and below, then the raw material is sealed in a pressed form without access to air, and stored for up to 10 months. After which the pulp is unpacked, deodorize by steam treatment, dried in a rotary air-separation flash dryer, ground in an air sorting mill to obtain particles of the final product with a size of 75-150 microns.

EFFECT: invention provides a product with a high content of soluble fractions, high moisture and oil retention capacity, and neutral flavour and aromatic properties.

6 cl, 1 tbl

Description

The group of inventions relates to the food industry, namely to the production of powdered dietary fiber from beet sugar production pulp, and can be used for year-round production of dietary fiber with improved characteristics: increased content of soluble fiber, neutral flavor, whiteness above 60%, high moisture-retaining and oil holding capacity. The invention also relates to a product obtained by this method.

Dietary fiber in powder form, including beet fiber, has two main uses:

1. As a technological food additive, they are used to save expensive basic raw materials (meat, dairy, flour, etc.), obtain and stabilize the desired structure of meat products, confectionery and dairy products by absorbing and reducing water activity, emulsifying fats and oils, and also as an anti-caking agent.

2. Use as a functional food ingredient. When they are included in food products, or when consumed independently, the calorie content of the diet decreases, and the biological value increases due to an increase in the content of dietary plant fiber.

For these applications of beet dietary fiber, critical characteristics are high adsorption capacity, effective moisture binding, neutral taste and aroma (no unpleasant beet odor), and white (or close to white) color.

When producing dietary fiber from a by-product of sugar production - beet pulp (desugared beet chips), to achieve such characteristics it is necessary:

• Ensuring correct storage conditions for pulp before processing to avoid the development of putrefactive or butyric acid fermentation. Taking into account the seasonality of beet processing, the required storage time for beet pulp can be up to 9-10 months.

• Effective deodorization of raw materials - removal of beetroot flavor.

• Suppression of enzymatic darkening of raw materials by inactivating the tyrosinase enzyme and limiting contact with air. Or effective pulp bleaching.

• Use of drying methods that do not lead to thermal destruction of the material, which begins at temperatures above 120°C. Destruction leads primarily to the loss of soluble fractions of beet raw material polysaccharides (pectin, some hemicelluloses), as well as to additional darkening.

The standard technology for the production of fiber from beet pulp, described, for example, in RF patent No. 2175844, includes pressing of fresh pulp and treatment with saturated steam at a temperature above 115°C. The resulting mass is treated with a bleaching agent (3-5% hydrogen peroxide solution), pressed to a dry matter content of 15-16%, dried and ground to a powder. High-temperature processing and the use of such a highly active reagent as peroxide can eliminate the odor of the feedstock and solve the problem of microbiological purity of the product, but lead to the destruction of pectin, a decrease in moisture retention by the resulting fibers, and the accumulation of free radical compounds in the finished product.

The same disadvantages characterize the method according to patent CS 270967, A23L 1/21, 1991, which involves extracting sugar and other soluble substances from fresh pulp by washing with water, disinfection and bleaching with a solution of hydrogen peroxide or ozonation, or irradiation.

The method in accordance with patent RU2340678 involves separation of mechanical impurities from fresh beet chips, pressing, treatment with saturated steam, extraction with sulfite water, re-steaming, drying, and final grinding.

Another disadvantage of this method is the use of sulfated water for extracting pressed pulp. The presence of sulfites in food has a negative impact on human health - it can cause breathing problems, stomach irritation, asthmatic and allergic reactions.

There is a known method for obtaining dietary fiber from beet pulp, which includes heating to 90 - 100°C, grinding to 40 - 45 mesh, immersion in an aqueous-alcohol solution, then in an aqueous solution of sodium hydroxide, drying. The method ensures the production of a product of high nutritional value (CN 110419744 A, 08.11.2019). The disadvantage of this method is the need for wet grinding of raw materials in a colloid mill, which makes the technological processing of finely ground mass difficult in subsequent stages. The use of an alcohol solution significantly increases the cost of processing, and the resulting fibers have low moisture retention due to a decrease in the solubility of pectin fractions after alcohol treatment.

The closest to the claimed technical solution in terms of technical essence and achieved technical result is the method known from patent RU 2555790, according to which the technical result is achieved by washing the raw materials with water at a temperature of 70-90°C, crushing to a certain fraction size with simultaneous irrigation shavings with a 30% solution of citric acid, ensuring the pH of the squeezed juice is in the range of 4.0-4.5, squeezed to a pulp moisture content of 70-80%, dried in a drying unit combining infrared and convective processes, at the temperature of the product during the process the entire drying period is within 32-40°C, the humidity of the blown air when drying the product is 10-15%. In accordance with this method, no toxic reagents are used in production; drying is carried out at low temperatures.

The disadvantage of this method is drying using an infrared dryer with hot air. Drying using this type of dryer at the specified temperatures is characterized by low efficiency and a significant drying time due to the low intensity of heat and mass transfer. Long-term drying causes a significant overall duration of the technological cycle, high specific energy consumption, and reduces the quality of the finished product.

The disadvantages of the above known methods, each separately or all together, cause a low level of technological efficiency, an increase in the level of technological and investment costs, difficulty in scaling production, and do not allow obtaining a product with the declared properties.

At the same time, in the above-discussed and other known methods for obtaining food-grade beet fibers, the use of other types of raw materials other than freshly squeezed beet pulp after pressing is not specified.

Due to the short shelf life of undried and uncanned beet pulp, this approach does not solve the problem of seasonal availability of raw materials and seasonal cyclicality of production.

The seasonality of production significantly affects the organization of the production process and the use of resources, the uniformity of material and financial flows, the increase in costs associated with the creation of special conditions for storing large stocks of raw materials, conservation of equipment, employee compensation, etc.

To solve the above technical problems, two options are proposed for the method of obtaining powdered food beet fiber from beet pulp.

According to the first option, the pulp is first deodorized by steam treatment, then preserved with a food preservative solution, after which it is sealed in a pressed form without access to air, the resulting product is stored for up to 10 months, after which it is unpacked, dried in a rotary air-separation flash dryer, and crushed at an air classification mill.

In particular cases, a solution of citric acid is used as a food preservative, which is processed until the pH value on the surface of the beet chips is 4.0-4.5.

In a particular case, the residence time of the raw materials in the drying chamber is 1-2 s.

In a particular case, grinding is carried out to obtain particles of the final product of 75-150 microns.

In a particular case, the final product contains at least 25 wt.% pectin.

According to the second option, the pulp is first processed using starter cultures, then it is hermetically packaged in a pressed form without access to air, stored for up to 10 months, after which it is unpacked, the pulp is deodorized by steam treatment, dried in a rotary air-separation flash dryer, and crushed by air - classification mill.

In particular cases, starter cultures based on lactic acid and/or propionic acid bacteria are used.

In a particular case, the residence time of the raw materials in the drying chamber is 1-2 s.

In a particular case, grinding is carried out to obtain particles of the final product of 75-150 microns.

In a particular case, the final product contains at least 25 wt.% pectin.

The technical result is to obtain a product with a high content of soluble fractions, high moisture and oil retention capacity, and neutral flavor and aromatic properties.

As our own research and analysis of available information sources have shown, it is impossible to obtain dietary fiber with the required technological and consumer characteristics from dry beet pulp, dried by methods well known from the existing state of the art, namely, in pulp drying drums, in which drying is carried out by combustion products of liquid or gaseous fuel at drying agent temperatures at the dryer inlet of 400-800 ^o C.

A better quality product (uniformly dried, with a moisture mass fraction of no more than 10%, without foreign odors, without the presence of charred particles that are formed during drying with flue gases) can be obtained by using more gentle methods, for example, when drying in a fluidized bed with superheated steam temperature 150-155°C with programmed steam supply to the layer of dried pulp. This drying method is described, for example, in patent RU 2346988.

However, even when drying in steam dryers, it is not possible to obtain dry pulp suitable for processing into highly functional fibers of food quality. This was confirmed by the results of our own studies comparing the functionality of dietary fiber samples obtained from pulp dried in a steam dryer (Danish company EnerDry) and from freshly squeezed pulp.

Thermal exposure during high-temperature drying leads to critical degradation of non-cellulosic polysaccharides of pulp, which in turn significantly reduces the functionality of the resulting dietary fiber, in particular, moisture-binding capacity, as well as sorption capacity in relation to toxic substances such as heavy metals, etc.

An alternative way to store beet pulp for a long time is to can it. However, the preservation of beet pulp by traditional methods (silage in trenches or in sleeves) practically eliminates the possibility of obtaining raw materials that meet the requirements for food-grade materials. Due to the high content of water in the pulp and the insufficiently effective displacement of air during the silage process, in the absence of lactic acid starters, rapid microbial contamination occurs, which provokes rapid fermentation of the raw material according to the acetic acid type, significantly deteriorating its quality, loss of nutritional materials, and further development of butyric acid and putrefactive bacteria.

An additional increase in the quality of ensiled pulp due to targeted regulation of fermentation processes can be achieved by introducing starter cultures based on cultures, primarily lactic acid and propionic acid bacteria. This ensures selectivity of the fermentation process and reduction of losses due to unwanted fermentation. The rapid accumulation of lactic acid reduces the acidity of the pulp to the required pH values - 3.8 and below, and prevents the proliferation of colibacteria, listeria, clostridia and yeast.

The optimal option for preserving pulp is the addition of food-grade preservatives or starter cultures into the pulp immediately after deep (not less than 25% dry matter) pressing, followed by film packaging into bales using a compactor - press-wrapper, which presses out the excess preservative solution, forming compact bales, and hermetically their packer. When using starter cultures, the pulp steaming operation is preferably carried out after unpacking the pulp from storage immediately before drying.

As was unexpectedly found as a result of our own research, a dietary fiber preparation with high functional and consumer properties, corresponding in sorption capacity, VUS, MUS, color and organoleptic characteristics to fibers obtained from fresh (freshly pressed) beet pulp, can be produced using the methods described below technological methods from raw materials treated with a food preservative and hermetically packaged, even after long-term storage of such raw materials.

Table 1 shows the characteristics of the final product - powdered beet fibers, produced using the same technology from: A) fresh beet pulp, B) dry beet pulp, dried in an EnerDry steam pulp drying unit, and C) canned pulp, treated with citric acid, pressed and packaged in film packaging using the LT Master wrapping press from GÖWEIL, after storage for 8 months.

Table 1

Sample A Sample B Sample C Whiteness according to ISO, % 73 56 68 Smell Absent Characteristic, pronounced Absent Taste Neutral Characteristic with a bitter aftertaste Neutral Mass fraction of dry substances, % 93 92 93 Ash,% 3.3 3.0 2.8 Cellulose content, % 23.2 36.5 22.0 Pectin content, % 37.5 12.6 35.9 Moisture holding capacity,% 770 580 800 Oil holding capacity, % 230 210 210 KMAFAnM, CFU/g 5*10 ² 2.5*10 ⁶ 2*10 ⁴ Mold, CFU/g Not detected 410 Not detected Yeast, CFU/g 20 550 160

The inventions ensure the production of powdered dietary fiber with improved characteristics - increased content of soluble fractions, neutral flavor, as well as high moisture and oil retention capacity.

This goal is achieved by the fact that, in contrast to known technical solutions, a combination of technological methods is used that has not previously been used for the production of beet dietary fiber:

1. Deep-pressed beet pulp is used as a raw material, which eliminates additional pressing of the raw material after steaming and treatment with a preservative;

2. A solution of citric acid or a preparation of lactic acid bacteria is used as a preservative agent, which eliminates processing using reagents whose presence in food materials is undesirable or is standardized (sulfated water or hydrogen peroxide). Also, a preparation of lactic acid bacteria, or a complex preparation containing cultures of lactic acid and propionic acid bacteria, can be used as a preservative;

3. After treatment with a preservative, the pulp is additionally pressed, then hermetically packaged in big bags and stored until processing begins;

4. The pulp is dried in a rotary-type vortex separation flash dryer, due to which the residence time of the raw material in the drying chamber does not exceed 1-2 seconds;

5. Final grinding is carried out to a powder fineness of 75-150 microns (200 - 100 mesh) on an air classification mill or another that provides the required grinding fineness and effective heat removal from the crushed material.

To achieve the stated goal, the claimed method is carried out in the following way. The pressed pulp with a moisture content of 70-72% is fed at an adjustable speed by a scraper conveyor to a disk separator, on which mechanical impurities are separated. Next, the raw material enters the conveyor steamer-blancher. Steam treatment for deodorization and removal of beet taste is carried out at a temperature of 98-100°C for 20 minutes in a thin layer. This treatment also has a sterilizing effect.

The steamed pulp is unloaded onto a screw conveyor and, while moving, is irrigated through nozzles with a 10% solution of citric acid until the pH value on the surface of the beet chips is 4.0-4.5. If bacterial starters are used, they are applied in accordance with the manufacturer's instructions. The pulp conveyor is fed into the receiving hopper of the compactor - a press-wrapper, which presses out excess steam condensate and preservative solution, squeezes out the air, forms compact bales and hermetically packs them in an air-tight stretchable film with an adjustable degree of layer overlap.

In the case of using bacterial starters, steam treatment of the pulp is preferably carried out after unpacking the pulp from storage immediately before drying. This will avoid wasting time on pulp cooling after steaming and provide optimal conditions for the work of bacterial strains.

Hermetically packaged pulp treated with preservative solutions can be stored for 10 months, even in open areas, provided that the integrity of the packaging is maintained and there is no contact with air.

Before further processing, bales with pulp are unpacked and the film packaging is removed. The compressed pulp mass is broken down using appropriate technical means and fed into the receiving hopper of the dosing conveyor.

The flow of raw materials at a controlled speed enters the receiving hopper of the dryer. For drying pulp, a vortex separation rotary dryer for rapid drying is used.

In the drying chamber, the raw materials come into contact with a coolant having a predetermined temperature. The optimal drying speed is achieved at a drying air temperature of 160-200°C. The required temperature is achieved by mixing hot air from the heat generator and cold atmospheric air in the required proportion. The raw material is crushed by the working elements of the rotating rotor, and at the same time dried, rising to the dynamic separator in the head section of the dryer. Rapid reduction in particle size and drying them in a fluidized state ensures optimal heat transfer and instant evaporation of moisture. The separator, whose rotation speed is controlled, passes fine and dry raw materials, returning large and wet particles to the grinding rotor. The process is repeated until the required degree of moisture is obtained and the material is crushed. The crushed and dried raw materials (grains) are carried into cyclones.

From the cyclones, the grits are unloaded through a sluice gate onto a screw conveyor and then fed into the receiving hopper of the mill. Inside the hopper there is a mixing device that prevents the material from caking. From the hopper, the material is fed by a feeder at an adjustable speed into the feed neck of the air classification mill. Due to the centrifugal classification of particles, the mill output produces a powder with a fairly narrow range of particle sizes. The powder, crushed to 75-150 microns, is carried into cyclones due to the air flow created by the mill rotor.

From the cyclones, through a sluice gate, the powder is unloaded onto a bucket elevator, then into a finished product hopper, and then onto a packaging device.

The resulting powder has a color from white to light beige, a neutral flavor with a weakly expressed vegetable taste, a pectin content measured photometrically of not less than 25%, a moisture-holding capacity in the range from 1 to 7 to 1 to 12, and an oil-holding capacity from 1 to 4 up to 1 to 6.

The alleged invention satisfies the criteria of novelty, since when determining the level of technology it was shown that the claimed set of operations was not previously known, and no method was discovered that has all the features identical to the features listed in the claims, namely: obtaining dietary fiber powder with a high content soluble fiber from deep-pressed beet pulp through steam treatment, preservation with a food preservative, hermetically sealed packaging, drying using “instant” drying technology and fine grinding of the dried material.

The method has an inventive step, since the level of technology has not identified technical solutions that have features that coincide with the distinctive features of this invention, and the influence of the distinctive features on the specified technical result has not been established.

The claimed technical solution can be implemented in the industrial production of complex forms (soluble and insoluble) of dietary fiber in powder form. This meets the “industrial applicability” criterion for inventions.

The inventions provide a product: dietary fiber in powder form with a high content of soluble fiber and improved functionality.

Claims (6)

1. A method for producing powdered food beet fiber from beet pulp, including drying, grinding, characterized in that the pulp is first deodorized by steam treatment, then preserved by irrigation through nozzles with a 10% solution of citric acid until the pH value on the surface of the beet pulp is ensured 4 ,0-4.5, after which the product is sealed in a pressed form without access to air, the resulting product is stored for up to 10 months, after which it is unpacked, dried in a rotary air-separation flash dryer, crushed in an air-classification mill to obtain final particles product size 75-150 microns. 2. The method according to claim 1, characterized in that the residence time of the dried material in the drying chamber does not exceed 1-2 s. 3. The method according to claim 1, characterized in that the final product contains at least 25 wt.% pectin. 4. A method for producing powdered food beet fiber from beet pulp, including drying, grinding, characterized in that the pulp is first preserved using bacterial starters based on a mixture of strains of lactic acid and propionic acid bacteria with the acidity of the pulp reaching pH values of 3.8 and below, then the raw materials are hermetically packaged in a pressed form without access to air, stored for up to 10 months, after which they are unpacked, the pulp is deodorized by steam treatment, dried in a rotary air-separation flash dryer, crushed in an air classification mill to obtain particles of the final product with a size of 75-150 µm. 5. The method according to claim 4, characterized in that the residence time of the dried material in the drying chamber does not exceed 1-2 s. 6. The method according to claim 4, characterized in that the final product contains at least 25 wt.% pectin.