RU2615145C1 - Method of treating liquid food product - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: liquid food products, such as water, wine, beer, juice, milk, are treated by removing oxidiants therefrom by means of saturation by hydrogen with the excess relative to oxygen of more than 1.2 times while bubbling. The product saturated with hydrogen is passed through the filter with a palladium catalyst. To ensure the binding of oxidants, the product passed through the filter with a palladium catalyst is brought into contact with the palladium catalyst placed in the container for the product storage.

EFFECT: increasing the shelf life due to deoxygenation, reducing the redox potential of the liquid product after treatment to negative values.

2 cl, 3 dwg

Description

The invention relates to the food industry, to the field of conservation, conservation of food products, and especially liquid. The duration of storage of products is largely determined by the suppression of the processes of their oxidation, fermentation. Therefore, methods of preserving food products are mainly aimed at removing oxidizing agents from them: oxygen, peroxides, and oxidizing radicals.

Removing or preventing the penetration of oxidizing agents into food products is carried out in various ways.

Oxygen scavengers are becoming increasingly popular as they allow plastic packaging to compete with glass and metal packaging that have excellent oxygen impermeability. The increase in the number of servings of packaged meat, cheese and other products for one person and sensitive to the effects of oxygen also plays into the hands of absorbers. The additives introduced into the walls of single-layer polyethylene terephthalate (PET) bottles absorb enough oxygen to turn such single-layer bottles into a competitive beer packaging that quickly deteriorates when exposed to oxygen. (In order to prevent oxygen from entering the PET beer tank, multilayer bottles or special coatings are usually required.)

Oxygen scavengers, also called oxygen sorbents, are an example of packaging in a modified gas environment that physically and chemically configures plastic containers in order to create the optimal balance of gases and humidity to maximize food freshness. Unlike barrier layers, such as a copolymer of ethylene and vinyl alcohol (EVOH), polyvinylidene chloride and polyamides, where there are passive gas exchange restrictors, absorbers are considered as “active” protective components, since they react chemically with oxygen inside the package. Many packaging manufacturers use combinations of passive and active systems to achieve the highest levels of oxygen tightness.

Absorbing oxygen inside a container with a food product or drink, absorbers prevent the growth of aerobic bacteria, mold and other organisms that cause spoilage of the product. Their use can also reduce or completely eliminate the use of chemical preservatives, such as butylhydroxytoluene (BHT), butylhydroanisole (BHA), sorbates and benzoates. Polyunsaturated fats do not become rancid in an atmosphere with a low oxygen content, vitamins C, A and E do not decompose, as is usually the case when they are exposed to oxygen. Absorbing all excess oxygen, absorbers significantly slow down the spoilage of fruits and vegetables and help preserve the aromas of freshly roasted nuts and coffee beans.

The action of the scavengers complements oxygen removal operations such as filling the packaging with an inert gas or vacuum packaging, ensuring quick removal of oxygen from the top of the packaging contents. After sealing the packaging, absorbers can reduce the oxygen concentration to less than 0.1% in just a few days; without an absorber, oxygen concentration can reach 0.5% or more in a few days.

A common scavenger is iron oxide, which is usually packaged. Other absorbent chemicals that are packaged include unsaturated fatty acid salts or metal / polyamide complexes.

Low molecular weight organics, especially ascorbic acid and its sodium salt, are often added to bottle caps to absorb oxygen. Other small organic molecules used as oxygen scavengers include squalene and unsaturated fatty acids. Oxidizable polymers, such as layers of cobalt-catalyzed MXD6 nylon, can be used as the oxygen-absorbing layer inside polyester bottles. Other scavenger systems use readily oxidizable unsaturated polymer compositions such as 1,2-polybutadiene.

Some oxygen absorption layers present in packaging structures release small molecules that create organoleptic problems (associated with taste and smell) that arise when these layers interact with oxygen. The formulation, known as OSP, from Chevron Phillips Chemical, is designed to minimize this problem. The OSP system, consisting of an oxidizable copolymer of ethylene methyl acrylate and cyclohexene methyl acrylate (EMC), which absorbs oxygen together with a photoinitiator and catalyst (cobalt), is activated by ultraviolet radiation. Typically, an oxygen absorbing layer is coextruded with a passive oxygen barrier, such as EVOH, nylon, or PET, and an inner sealant layer, such as high pressure polyethylene (HDPE), linear high pressure polyethylene (LLDPE), or an ionomer. The system is suitable for packaging products such as juices, beer, various types of meat and cheese.

Another UV-activated system is the Cryovac OS oxygen scavenger film, which is sold by Sealed Air Corp. The main component of the Cryovac OS system is an oxidizable polymer with a transition metal salt catalyst and a photoinitiator. The transition metal salt may be at least one metal salt selected from the group consisting of ferrous salt, nickel salt, copper salt, manganese salt, cobalt salt, and combinations thereof. The active film layer is coextruded with a sealing layer and a base layer, which gives the packaging mechanical strength. The oxygen barrier film may also be laminated to various outer layers. The Cryovac system can be used to extend the shelf life of various foods, including fresh pasta, dehydrated and smoked meat, prepared meat dishes, grated cheese, dried fruits and nuts, animal feed and cereal. According to reports, films can reduce the oxygen concentration in sealed packages to 0.1% over a period of 3 to 10 days.

Oxygen scavengers allow plastic packaging to conquer part of the market that glass and metal packaging has long occupied. The demand for absorbers is increasing due to an increase in the need for packaging of packaged products, ready to eat and designed for one serving. Numerous physical and chemical systems have been developed to take advantage of the technology provided by absorbers. Absorbers can reduce the number of barrier layers required for packaging, such as EVOH, nylon or polyvinylidene chloride, which allows the packaging to be thinner than would otherwise be possible. Probably, the wider use of oxygen scavengers due to the expansion of the scope of application of packaging systems in a modified gas environment.

Wine production is not complete without artificial additives. One of them is the preservative E220. E220, or sulfur dioxide, is a gas that has no color, but has a sharp specific odor. It is used in the food industry as a preservative, although it is listed as a health hazard supplement. Other names of this preservative are also placed on wine labels: sulfite, sulphurous acid, sulphurous anhydride, sulphurous gas. The introduction of these additives (sulfite, sulphurous acid, sulphurous anhydride, sulphurous gas) leads to the appearance of sulfite ion SO ₃ ^2- in wine, which is a reducing agent and can bind oxygen to form sulfate ion SO ₄ ^2- ,

Despite the potential harm that the supplement can cause to health, wine production cannot do without it. The fact is that even packaged wine continues to ferment and oxidize. If the process is not stopped, the drink that reaches the consumer will have a terrible taste. That is why manufacturers use the E220 preservative, since they have not yet come up with an analogue of this substance, absolutely safe for human health. It is believed that if the manufacturer has complied with the standard restricting the use of E220 at the rate of not more than 330 mg per 1 liter of wine, then such a drink is safe for humans.

Sulfur dioxide is a toxic chemical and is assigned a third hazard class. Some people are sensitive to this preservative, which can result in side effects such as headache, nausea and even vomiting, dizziness, diarrhea, speech impairment, runny nose and cough. The biggest harm of this preservative is manifested in the fact that it destroys vitamins B1 and H, as well as protein compounds. With the constant use of products containing E220, the condition of the skin, hair, nails, etc. worsens. Special care should be taken for people with asthma and lung diseases, since sulfur dioxide can cause a severe allergic reaction, even leading to pulmonary edema.

Chemicals having incompletely oxidized or reduced hydrocarbon molecules can be fermented. These include amino acids, alcohols, organic acids, etc. As a result of fermentation, several products are usually formed. By the type of products formed and accumulated in the process, alcohol fermentation, butyric acid, lactic acid, propionic acid, and other types are distinguished.

The removal of oxygen from champagne wine materials and wines of a slightly oxidized type is carried out in various ways: biological, bubbling with inert gases, prolonged anaerobic aging (Collection of technological instructions, rules and regulatory materials for the wine industry / Edited by G.G. Valuyko, A.V. Trofimchenko. - 7th ed. - Moscow, 1998; Avakyants SP Biochemical principles of champagne technology. - Moscow, 2000; Novikova VN and others. Biological deoxygenation of sulfitated wine materials. - Wine making and viticulture С NG, 1995, No. 8).

When bottling, a big problem can be the penetration of air into the bottle, leading to an increase in the content of dissolved oxygen and oxidative degradation of the wine. Pre-filling the bottle with nitrogen helps eliminate this problem.

Solutions aimed at reducing the content of oxidizing agents are known from the patent literature, see Patent No. 2411519, “DEVICE FOR PROCESSING WINE AND MEASURING ITS SUSPENSION AGING”. The device contains a support element and a calibrated oxidizing element for contact with wine, made of an alloy comprising from 60 to 99.9% copper, from 0.05 to 20% silver and from 0.05 to 20% gold. SU 737447 discloses a method for ripening drinks based on the use of copper plates of certain sizes as a catalyst for oxidation-reduction processes of wine while transmitting oxygen.

A known method of preservation of wine using an inert gas (nitrogen, hydrogen) for deoxygenation of oxygen-enriched wine materials, which leads to the removal of oxygen, reduce the redox potential. (Nilov V.I., Tyurin S.T. Ripening and storage of wine materials in large tanks. - Moscow, 2002 - prototype). In the process of gas sparging, wine is saturated with small gas bubbles supplied to it in pipelines, or already in storage tanks. During the movement of bubbles through the wine layer, oxygen molecules diffuse into gas bubbles, and then the resulting gas mixture is discharged into the atmosphere through a sterile ventilation filter.

Bubbling efficiency depends on:

- bubble size

- contact time (from 5 to 30 seconds)

- wine temperature (from 15 to 20ºС)

- pressure (from 1 to 2 bar)

- gas flow

- the number of bubble stages

Typically, the nitrogen flow rate is from 0.1 to 0.3 volume of the storage capacity, but in some cases it is higher, up to 0.8 ... 1.2 volumes. As a rule, bottled wine contains about 7-10 cm ³ / l of nitrogen. A single-stage sparging can reduce this nitrogen content to 2-3 cm ³ / l, and a two-stage sparging to 1-2 cm ³ / l.

The deoxidation of wine with inert gases is based on bubbling the wine with hydrogen, nitrogen - separately or in a mixture; while oxygen from the wine diffuses into small bubbles of inert gas and is removed into the atmosphere. Inert gases are introduced into wine in a highly dispersed state with the help of bubblers, the atomizing, dispersing gases of which are made of finely porous materials (ceramics, titanium, etc.). The wine in the tank is treated with hydrogen or nitrogen, which is dosed for 15 minutes at a rate of 1 dm ³ / dal (decalitre). A mixture of gases is carried out of the slide space through a water seal. After removal of dissolved oxygen, 50 dm ³ / L of ascorbic acid is metered into wine to restore peroxides.

Deoxygenation of wine by long anaerobic aging is based on the chemisorption of oxygen by the components of the wine during its sufficiently long exposure. Canteen and champagne wine materials do not need an excess of oxygen, so they should be stored under anaerobic conditions, and technological operations should be carried out with the least access of atmospheric oxygen. The wine is kept in a stream in a system of series-connected sealed tanks for at least 1 month. The redox potential, which is an objective indicator of the presence of oxidizing agents in the medium, decreases very slowly with this method of deoxygenation, and only by 40-45 mV. The redox potential of them:

Barrel dining room, young 360-410 mV Tableware, Mature 150-250 mV Champagne 200-350 mV

To accelerate the deoxygenation of wine, yeast (1.5-2%) is periodically introduced into the system, which quickly autolizes and provokes the development of lactic acid bacteria, which can lead to wine disease.

Thus, the task of processing liquid food products is to reduce the redox potential of the liquid product after processing to negative values (to -700 mV and below).

The technical result of the proposed method is to increase the shelf life of the liquid food product.

To achieve this result, a method is proposed for treating liquid food products by removing oxidizing agents from them by saturation with hydrogen while sparging, while the hydrogenated product is brought into contact with a palladium catalyst.

Besides,

- the hydrogenated product is passed through a filter with a palladium catalyst.

- the product passed through a filter with a palladium catalyst is brought into contact with a palladium catalyst located in a container for storing the product.

- as liquid products use water, or wine, or beer, or juice, or milk.

- water passed through a filter with a palladium catalyst is sent to the conservation of solid-phase food products.

- saturation of liquid food products with hydrogen is carried out in excess with respect to oxygen, not less than 1.2-1.3 times.

The figure 1 gives a General scheme of the method, where

1 - hydrogen generator;

2 - ejector;

3 - bubble column;

4 - filter with a palladium catalyst;

5 - separation column;

6 - compressor (ejector).

The implementation of the method is carried out by saturation with hydrogen of liquid food products such as water, beer, wine, juices, dairy products with hydrogen, followed by their contact with a palladium catalyst. This can be accomplished by passing liquid food products, for example, through a filter with a palladium catalyst, on which even at room temperature there is a complete binding of oxygen, hydrogen peroxide and other oxidizing agents with hydrogen to form a small amount of water. Calculations show that when the oxygen content in wine is up to 8.6 mg / l, when it is transferred with hydrogen to water, 9.6 mg / l of water is formed. With a wine density of at least 960 g / l (960,000 mg / l), we get a share of water in the wine of 0.00001 (0.001%), which is incommensurably lower than fluctuations in the water content in wine (and other products) in their production. Those. this process does not impair product quality.

Excess hydrogen creates a reducing atmosphere in the volume of preservation of liquid products: bottles, banks, packaging. After the removal of oxygen and other oxidizing agents, the processing product is poured into cans, bottles of glass, metal or a multilayer polymer with a metal, usually aluminum, layer, which is a diffusion barrier for hydrogen, which ensures the conservation of hydrogen in the package. It is also possible to introduce a palladium catalyst into these containers in the form of, for example, a sprayed layer on a part of the internal surface of the preservation volume for guaranteed binding of oxidizing agents during the storage of products.

Also, deoxygenated water treated in this way can be used to preserve solid products. It can be used to make pickles and syrups for preserving vegetables and fruits with a low content of salt and sugar.

It can be used to make ice for storing and transporting freshly caught fish without deep freezing at a temperature of about zero degrees Celsius. At this temperature, the solubility of hydrogen in ice-water is 22.2 ml per liter of ice-water.

Studies show that to guarantee the binding of oxidizing agents, an excess of hydrogen is required for 20-30% more than the stoichiometric ratio, i.e. hydrogen should be 1.2-1.3 times more.

Here are examples of the implementation of the method on an installation with a capacity of 2000 l / h, which is equivalent to a bottling rate of 0.5 liter bottles of 4000 pcs / h. The experiments were carried out with water and beer. Moreover, these examples do not limit the implementation of the method for other liquids: juices, milk, etc.

Hydrogen was fed into the liquid to be treated (for example, water, beer) from hydrogen generator 1, for example, using the TsvetKhrom hydrogen generator, for example. After that, the liquid with hydrogen was sent to the bubbler column 3, where bubbling, intensive mixing and uniform saturation of the liquid with hydrogen took place. Then, the liquid was supplied to a filter, for example, Cascad-APT 4 brand with a palladium catalyst, for example, APT-5 catalyst in the form of granules was used. The separation of excess hydrogen, which forms the gas phase from the liquid phase, takes place in the separation column 5. Unreacted excess hydrogen from the separation column 5 is returned to the hydrogen dosing system using a gas compressor or ejector 6.

The fluid flow rate was 40-45 m / h. The height of the catalyst layer in the filter was 100 cm. The oxygen concentration was measured on a Mark 302T instrument, hydrogen was measured on a Mavr 501 instrument, and the oxidation-reduction potential was measured on a RNT-027 instrument (The indicated measuring equipment is not shown in the figure).

In FIG. 2 shows the results of oxygen removal from demineralized water. In the initial water directed to the installation, the oxygen concentration was 6200 μg / dm ³ . At a flow rate of H ₂ equal to 0.4 dm ³ / min, the content of H ₂ in water is 16.7 ml / dm, and the oxygen content is less than 1 μg / dm ³ . Filtration rate 44 m / h (2000 l / h). There was a decrease in the oxygen content in water by no less than 6200 times. The redox potential of the water was in the range minus (685-700) mV.

In FIG. 3 presents the results of the removal of oxygen from beer. In the original beer sent to the installation, the oxygen concentration was 6600 μg / DM ³ . At a flow rate of H ₂ equal to 0.6 dm ³ / min, the content of H ₂ in beer is 18.2 ml / dm ³ , and the oxygen content is less than 1 μg / dm. Filtration rate 44 m / h (2000 l / h). There was a decrease in the oxygen content in beer no less than 6600 times. The redox potential of water was in the range minus (680-695) mV.

These studies and the subsequent operation of the plants in these modes showed that the proposed method for the removal of oxidizing agents for the purpose of preserving food products is reliable and promising, because provides a reduction of redox potential to negative values (up to -700 mV).

Claims (2)

1. The method of processing a liquid food product, characterized in that before the product is bottled or packaged in a storage container, inorganic and organic oxidizing agents are removed by saturation by bubbling with excess hydrogen more than 1.2 times with respect to oxidizing agents, a hydrogenated product passed through a filter with a palladium catalyst, and after filling or packaging, the product is brought into contact with a palladium catalyst placed in a storage tank. 2. The method according to claim 1, characterized in that the product is wine, or beer, or juice, or milk, or water.

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