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The article is devoted to a comprehensive study of the chemical composition and safety indicators of potato production waste. The main indicators that control the quality and safety of products include: the content of dry substances, ash, crude protein, starch, sugars, humidity, as well as toxic elements and microbiological indicators. Determination of physicochemical parameters was carried out in accordance with GOST 7698-78. "Sampling and methods of analysis." When processing potatoes, about 20% of the dry matter of the raw material is lost in the form of potato juice and 20% in the form of pulp. Complete recycling of secondary products helps to use potatoes more rationally and economically as an industrial raw material, and also helps to solve the problem of providing feed and significantly reduces the pollution of water bodies with wastewater from potato processing production. Based on the conducted studies, it was shown that the amount of dry substances in potato pulp and cell juice contains 14.6 and 1.5%, respectively. In addition, the chemical composition is also supplemented by vitamins such as C, PP, B9, carotene, pantothenic acid, minerals, monosaccharides and others. At the same time, the limits of change in potato moisture content in laboratory and production conditions are 86.65±4.6% and 97.4±0.85%, respectively. The content of toxic substances, as well as microbiological indicators in the pulp and cell sap do not exceed the current permissible levels. Safety indicators, including the moisture content of potato pulp and cell juice, prove that this type of product is perishable and cannot be stored for long. The results showed that the composition of potato production waste largely depends on the quality of the feedstock, thereby establishing the possibility of their use as feed for farm animals.

potato production waste

chemical composition

safety indicators

recycling

feed additive

1. Anisimov B.V. Potato growing in Russia: production, market, problems of seed production // Potatoes and vegetables. – 2000. – No. 1. – P. 2-3.

2. Anisimov B.V. Potatoes 2000-2005: results, forecasts, priorities // Potatoes and vegetables. – 2001. – No. 1. – P. 2-3.

3. Gapparov A. M. The problem of food supply for the population of Russia // Food Industry. – 2001. – No. 7. – pp. 13-14.

4. Goncharov V. D. Raw materials resources of the processing industry of the agro-industrial complex / V. D. Goncharov, T. N. Leonova // Storage and processing of agricultural raw materials. – 2003. – No. 4. – pp. 14-16.

5. Kokina T.P. Quality control and certification of seed potatoes / T.P. Kokina, B.V. Anisimov // Potatoes and vegetables. – 2001. – No. 2. – P. 6-7.

6. Kolchin N.N. Potato complex of Russia: state and development prospects // Potatoes and vegetables. – 2000. – No. 4. – P. 2-3.

7. Poznyakovsky V. M. Hygienic fundamentals of nutrition, quality and food safety: textbook. – 5th edition, corrected. and additional – Novosibirsk: Sib. Univ. publishing house, 2000. – 480 p.

8. Prosekov A. Yu. Market capacity Kemerovo region for semi-finished potato products / A.Yu. Prosekov, Ya.M. Karmanova // Food industry. – 2005. – No. 6. – P. 76.

9. Pshechenkov K. A. Suitability of varieties for processing depending on growing and storage conditions / K. A. Pshechenkov, O. N. Davydenkova // Potatoes and vegetables. – 2004. – No. 1. – pp. 22-25.

10. Stepanova V. S. Justification of the needs of the region’s population for food products // Food industry. – 2004. – No. 7. – pp. 42-43.

Introduction

One of the priority areas of the State Program for the Development of Agriculture and Regulation of Markets for Agricultural Products, Raw Materials and Food for 2013 - 2020 is the development of biotechnology and rational stimulation of growth in the production of main types of agricultural products and food production.

Food industry waste, in most cases, in moderate quantities, can be directly used in agriculture for feeding animals. They have high energetic and biological activity, are harmless, hypoallergenic, and are easily amenable to enzymatic and microbiological bioconversion and various types of processing. The limiting factor, in this case, is usually the high content of water in waste, which increases the cost of transportation, limits the amount of this waste in diets and does not contribute to long-term storage of the product.

At most potato processing plants, due to the lack of recycling shops for waste processing, only a small part of it is rationally used for feed purposes. At the same time, the amount of waste is constantly growing. It is known that when processing potatoes, by-products are formed that have an increased amount of moisture. In Russia alone, the following waste from potato production is generated per year: pulp - 60-70 thousand tons, waste from the production of dry mashed potatoes- up to 10 thousand tons, wastewater - 100-120 thousand tons.

In the Kemerovo region alone, up to 600 thousand tons of potatoes of various varieties are processed daily to obtain various types products, and during the processing process up to 30-50% of potato waste remains, from which starch can be obtained.

Despite the fact that the chemical composition and properties of potatoes and their production waste are covered in sufficient detail in the reference literature, they vary significantly in relative figures depending on various factors.

Based on the above, the purpose of this work is to study the chemical composition and safety indicators of potato production waste.

Objects of research appeared: waste from potato production (potato pulp, cell juice, starch).

When performing the work, we used standard, generally accepted and original research methods, including physicochemical: spectrophotometry, polarimetry, microscopy, refractometry. Determination of physicochemical parameters was carried out in accordance with GOST 7698-78. "Sampling and methods of analysis." The results obtained were compared with the standards and requirements for the quality of potato starch according to GOST R 53876-2010 “Potato starch. Technical conditions".

Research results

When using potato pulp and cell sap for food or feed purposes, knowledge of their chemical composition and other indicators that evaluate their technological properties is necessary. Therefore, to clarify the chemical composition of potato pulp and cell sap, research was carried out to assess their quality and safety.

Table 1 presents the limits of change in the physical and chemical properties of potato pulp and cell sap.

Table 1

Chemical composition potato pulp and juice

Indicators	Meaning
		Cell sap
Dry substances, %
Crude protein, %
Starch, %
Reducing sugars, %
Cellulose, %

Table 2 shows data on changes in the moisture content of potato pulp and cell sap obtained in laboratory and production conditions. During the research period, the limits of change in moisture content (average value) of potatoes in laboratory and production conditions were equal to 86.65±4.6% and 97.4±0.85%, respectively. The high humidity of the resulting by-products does not allow them to be stored for a long time.

table 2

Changes in the moisture content of potato pulp and cell juice

Humidity, %
		Cell sap
Laboratory conditions	Production conditions	Laboratory conditions	Production conditions

The pH value of the juice is 5.6-6.2. The high acidity of the cell sap is due to the presence of a significant amount of organic acids in the tubers. Among them are citric, malic, oxalic, pyruvic, tartaric, succinic and some other acids. Especially abundant in tubers citric acid(up to 0.4-0.6%).

Believing that the technological properties of biological objects are determined by the content of protein substances and amino acids contained in them, potato juice could therefore become one of the promising sources of natural plant protein. When studying cell sap in this direction, at least 12 free amino acids were found, among which there are vital amino acids: valine, leucine, methionine, lysine, arginine.

Fresh potato juice and pulp also contain vitamins such as C, PP, B9, carotene, and pantothenic acid. However, upon contact with iron parts of equipment, the content of some vitamins, especially vitamin C, in potato juice is significantly reduced compared to their content in tubers.

The ash elements of juice are widely represented. About 60% of the ash is potassium oxide. The ash of the juice contains almost all microelements. It was noticed that significant differences in the number minerals was not observed in the studied samples.

A study of cell sap carbohydrates showed that they are mainly represented by monosaccharides: glucose, mannose, fructose. The content of reducing sugars depends on the variety, degree of maturity of the tubers, growing and storage conditions. When the content of reducing sugars in tubers increases to 0.5%, the potato product acquires a brown color and a bitter taste, which are unacceptable for the final product.

During the research, the content of toxic elements, nitrates, pesticides and radionuclides in the studied samples was studied. The research results are presented in tables 3-4.

Table 3

Safety indicators of potato pulp and cell juice

Name	Permissible content level mg/kg, no more		Cell sap
Ochratoxin A sterigmatocystin T-2 toxin
Dioxin-like polychlorinated biphenyls ng WHO-TEF/kg, not more than:
Radioactive cesium, Bq/kg
Radioactive strontium, Bq/kg

Table 4

Microbiological parameters of potato pulp and cell juice

Name	Acceptable content level		Cell sap
HCG, CFU/g, no more
KMAFAnM, CFU/g, no more
Coliforms (coliforms), 0.01 g	not allowed	not detected	not detected
Presence of pathogenic microorganisms:
salmonella in 50.0 g	not allowed	not detected	not detected
pathogenic Escherichia in 50.0 g	not allowed	not detected	not detected
Yeast, CFU/g, no more			less than 1.0 10 1
Mold, CFU/g, no more		less than 1.0 10 1	less than 1.0 10 1

It was noted that the content of radionuclides in the pulp and cell sap does not exceed the current permissible levels. The presence of toxic substances and pathogenic microorganisms in the studied samples of raw materials and by-products of their processing was not detected. Mercury, arsenic, mycotoxins and pesticides were not detected in potato pulp and cell sap. The nitrate content in potato pulp and cell juice is on average 89.75 mg/kg.

It has been established that controlled potentially dangerous chemical substances are contained in the product in concentrations that do not exceed established standards, and comply with the requirements of SanPin 2.3.2.1078-01 “Hygienic requirements for safety and nutritional value food products" and technical regulations customs union“On the safety of feed and feed additives.”

Thus, an analysis of the literature and our own experimental data showed that the chemical composition and indicators characterizing the physicochemical and technological properties of potato pulp and cell sap are largely dependent on the quality of the feedstock. This predetermines further research on use in the food industry. The chemical composition of potato processing by-products indicates the possibility of their use as components of food products. At the same time, the main indicators of the technological properties of by-products indicate the need to use special methods for their processing or preparation.

With implementation innovative technologies processing, with changes in demand for manufactured products, food production waste can change its social utility and become the raw material for obtaining new high-quality feed.

Reviewers:

Kurbanova M.G., Doctor of Technical Sciences, Associate Professor, Head of the Department of “Technology of Storage and Processing of Agricultural Products” of the Kemerovo State Agricultural Institute, Kemerovo.

Popov A.M., Doctor of Technical Sciences, Professor, Head of the Department of Applied Mechanics at the Kemerovo Technological Institute of the Food Industry, Kemerovo.

Bibliographic link

Dyshlyuk L.S., Asyakina L.K., Karchin K.V., Zimina M.I. STUDY OF THE CHEMICAL COMPOSITION AND SAFETY INDICATORS OF POTATO WASTE // Contemporary issues science and education. – 2014. – No. 3.;
URL: http://science-education.ru/ru/article/view?id=13587 (access date: 02/01/2020). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences" Detailed characteristics of the production process:
The process of producing starch and dehydrated pulp occurs in four main areas that are in close interaction.

• raw material purification area (drawing 1/5)
• area for washing and refining starch (drawings 2/5 and 3/5).
• flour drying area (drawing 4/5)
• pulp dehydration area (drawing 5/5)

Technological diagrams of these sections are presented in the attached drawings.
Raw materials cleaning area:
The task of the site is to separate the contaminants associated with potatoes. Potatoes delivered to the enterprise by wagons or tractors, motor vehicles, etc., are unloaded by a water dispenser or heads with a strong stream of water into a concrete bunker, at the bottom of which there is a transport channel. Through this channel, the raw materials are supplied to the drum stone catcher, which catches stones and sand, and the raw materials are sent through a chute through a lattice valve further to the potato pump. This pump delivers the potatoes along with water to a transport chute, along the path of which there is a straw trap and an additional stone trap.
At the end of the chute there is a permanent rod dewaterer where the potatoes are separated from the transport water. Transporting water with fine contaminants is discharged to a sand settling tank and, after sand deposition, is used again for transporting potatoes.
Potatoes separated on a rod dehydrator fall onto a potato washer, in which a stream clean water removes the remaining contaminants.
Peeled potatoes from the potato washing machine are fed by a bucket elevator and a screw conveyor to a belt scale and then to the silo. From the silo, potatoes in a certain quantity are supplied to further processing using dispensers.

Starch washing and refining area

The task of the site is to grind potatoes and separate starch from the rest of the potato components, i.e. pulp and dissolved substances.
The work of the site is as follows:

• A certain amount of potatoes is fed to the graters by a dosing conveyor. One of the graters is a reserve one.
• In a grater, using a rotating drum equipped with replaceable saw blades, potatoes are crushed to sizes smaller than the size of plant cells in order to extract starch and cell juice from them. After adding a small amount of antioxidant, the resulting porridge is pumped to the porridge centrifuges
• In a porridge centrifuge, under the influence of centrifugal force, partial separation of liquid from solids occurs.
• The liquid (cell sap) is removed by a pump to the starch sump. In turn, solids, i.e. starch and pulp, together with the remaining part of the cell sap (approx. 30%), go into a mixer in which they are mixed with water or molasses. After obtaining a homogeneous suspension, the pumps supply it through a distributor to the 1st stage porridge washers.
• The porridge after the 1st stage is fed by a screw conveyor into the porridge hopper and by a pump through a distributor to the 2nd stage washers. Then a screw conveyor into the bunker and a pump through the distributor to the pulp dehydrator (which is the third stage of washing).
• The condensed pulp is conveyed to a bunker for further use.
• At the same time, milk (starch washed with water) after each washing step flows into a reservoir with a foam destroyer.
• Washing machines and dehydrators are rotating cone sieves with horizontal axes, in which, under the interaction of a stream of water from shower heads and centrifugal force, the pulp is separated as a fraction above the sieve.
• Starch milk from the reservoir is pumped into a distribution tank that feeds the centrifuges. In centrifuges, under the influence of centrifugal force, liquid and starch are separated. The liquid is drained by gravity to the starch settling tank, and the starch in the form of condensed milk flows into a tank with a stirrer. A further portion of the antioxidant is supplied to this reservoir.

The described method of operation is the simplest, requiring minimum quantity equipment and providing best quality product, also with poor quality of raw materials used.

It is possible to make other connections in which the amount of water used can be significantly reduced. This depends on local conditions, mainly on the method of wastewater treatment.
The process then proceeds as follows:

• The pump, through a self-cleaning filter and a hydrocyclone that removes sand, delivers the milk to the first stage cleaning sieves, where the so-called small fibers are separated.
• Cleaning sieves operate on a principle similar to the scourers described above. Starch milk, freed from small fibers on the first stage cleaning sieves, is collected in a tank and pumped to the first stage multihydrocyclone installation.
• In multihydrocyclones, starch milk is separated under the influence of centrifugal force. The low concentration overflow flows into the reservoir and the effluent from the hydrocyclones is directed into the reservoir. Here, mixing occurs with the milk flowing from the overflow of the III stage multihydrocyclone installation and the pump delivers the milk through a self-cleaning filter to the II stage cleaning sieves. Small fibers from the 1st stage sieves are directed to the mixer, and from the 2nd stage to the tank. The sifted milk is sent to the tank. Then the pump takes the milk and supplies it to the second stage multihydrocyclone installation. The overflow from this stage is directed into the reservoir, and those leaving the installation into the reservoir. The milk is diluted in the tank clean water and molasses from a vacuum dehydrator to the appropriate thickness.
• Then the pump supplies the milk to the third stage multihydrocyclone installation. What comes out of this installation, in the form of thick, refined milk, is collected in a tank equipped with a stirrer.
• The milk is pumped further to vacuum dehydrators. In the dehydrator, under the influence of vacuum, starch is dehydrated to a content of 36 to 38% of dry matter. The dehydrated starch is conveyed to the drying section by conveyor.

Flour drying area:
The job of the area is to dry the starch and then cool, homogenize, sift and bag the finished product.
The starch is dried in a pneumatic dryer using a stream of air heated by diaphragms with water vapor. The dryer consists of an air inlet, an air heater filter, a drying duct, cyclones with a collector and fans - discharge and suction.
The incoming air temperature is adjusted automatically. The drying process is controlled by measuring instruments for temperature, pressure and steam flow. Dried potato flour is fed by pneumatic transport and a screw conveyor into a homogenization hopper with a beam mixer.
To impart uniformity to the properties of the finished product, a hopper is designed in which the flour is constantly mixed during use. transport system, consisting of a beam mixer, a bucket elevator and screw conveyors.
The homogeneous product is conveyed to the burat by conveyors with adjustable productivity. After sifting, the finished product is collected in a storage bin and then packaged using conveyors and a beam mixer equipped with a mixer filler.
The entire system is maintained at negative pressure created by an aspiration unit, which prevents dust in the room.

Pulp dewatering area

The pulp obtained after the last washing step contains approx. 8% dry matter and may be the final waste that can be used.
Wanting to increase the dry matter content in the pulp, we send it using conveyor B.18 to hopper D.1, from where we use pump D.2 to centrifuge D.3, where water is separated and the pulp is thickened to approx. 18% dry matter.
The condensed pulp is conveyed by screw conveyor D.4 into the pulp reservoir D.5 or into a concrete bunker.
Electrical equipment:
The delivery includes:

• distribution devices
• control panels
• control cabinet
• cables in the amount necessary for maintaining and monitoring the technological process.

Potatoes are not only a valuable food crop and feed product used in livestock farming, but also one of the most common types of raw materials for a number of branches of the food industry, in particular the alcohol and starch paste industries. Nitrogen-free extractives are represented in potatoes by starch, sugars and some amount of ientosan. Depending on the storage conditions of potatoes, the sugar content in them varies noticeably and in some cases can exceed 5%. Potato nitrogenous substances consist mainly of soluble proteins and amino acids, which account for up to 80% total number protein substances. According to the conditions of starch production technology, soluble substances are usually lost with wash waters. The production waste at potato starch factories is pulp, which after partial dehydration (humidity 86-87%) is used as livestock feed.

The starch content in the pulp depends on the degree of potato grinding. According to M.E. Burman, in large, well-equipped plants, the coefficient of starch extraction from potatoes is 80-83%, and in low-capacity plants it is 75%. Its increase is associated with a significant increase in the energy capacity of the enterprise, and, consequently, capital costs. Currently, at some leading enterprises of the starch and syrup industry it reaches 86% and higher. Pulp used as feed is a low-value and perishable product. 1 kg of pulp contains 0.13 feed units, while fresh potatoes- 0.23. Feeding fresh pulp to livestock should be limited. When processing potatoes in specialized starch factories, 80-100% of the pulp by weight of the potato is obtained, and a significant part of it often remains unsold.

Use of potato solubles

Many years of experience in the starch industry have shown that the problem of using potato solubles is one of the most difficult. It is still not permitted either at domestic starch factories or at foreign enterprises. Even in pre-revolutionary Russia, with the aim of more effective use Potato pulp began to be processed at distilleries located near starch factories. However, according to G. Fota, such processing turned out to be unprofitable due to the low alcohol content in the mash. Some distilleries in Czechoslovakia used combined processing of potatoes into starch and alcohol, in which they used not only potato pulp, but also part of the concentrated washing water.

This technique not only increased the utilization rate of starch, but also made it possible to partially use the soluble substances of potatoes. Below is a diagram of the balance of potato dry matter during the combined production of starch and alcohol at a pilot plant in Norway. In the USSR, M.E. Burman and E.I. Yurchenko proposed combining starch and alcohol production on a fundamentally new basis. It is recommended to extract only 50-60% of starch from potatoes, which makes it possible to transfer the pulp richer in starch for processing into alcohol, and also to simplify the process of starch isolation by eliminating the operations of repeated washing of the pulp and secondary grinding.

With this method of potato processing, production efficiency is ensured by the following factors: almost complete use of the starch contained in potatoes for the production of main products (starch and alcohol); receiving stillage instead of low-value pulp -. very valuable nutritious feed for livestock; the use of most of the soluble substances of potatoes in the alcohol workshop or for microbiological production organized at distilleries; reduction of transport and general plant costs; savings on capital investments in the construction of a starch shop according to a simplified scheme at an existing plant.

The method of combining the production of starch and alcohol based on a distillery has found wide application in industry. By 1963, more than 60 potato starch shops were put into operation at distilleries. Technological schemes for the production of starch are based on the above-mentioned principle, however, in the hardware design they are somewhat different from each other. Below is a diagram proposed by M.E. Burman and E.I. Yurchenko for the Berezinsky plant. It provides for the use in alcohol production of not only potato pulp, but also soluble potato substances. The latter are released in the form of cell sap on a shaking sieve when the potato porridge is slightly diluted with water.

To separate the starch, the cell juice is sent to a sedimentation centrifuge, after which it is sent to a collection of products transferred to the alcohol workshop. The pulp is washed on a two-tier extractor or shaking sieve and sent to a pulp press, then enters the collection. Mud starch from traps is also supplied to the distillery for processing. Starch milk is purified from soluble substances in a sedimentary centrifuge, and from fine pulp - in refining sieves.

Its final cleaning takes place on the gutters. The separation of potato soluble substances is provided before the starch is washed out from the porridge, in order to obtain potato cell sap in a slightly diluted form and not to reduce the concentration of dry substances in the mixture of products entering the distillery. However, as factory experiments have shown, a shaking sieve is an unsuitable apparatus for isolating concentrated cell sap. According to the author's research, on a sieve with an area of ​​2.5 m2 with twill mesh No. 43, with a potato productivity of 1.0 thousand per 1 m2 of sieve and a vibration frequency of 1000-1200 per minute, cell juice from undiluted porridge is released in small quantities. In table Table 1 shows data characterizing the release of cell sap when potato porridge is diluted with water.

When processing potatoes, it produces a large number of waste. In potato starch production, the main wastes are potato pulp and cell juice.

The high moisture content in potato pulp (over 90%) makes it difficult to transport, which makes it difficult to sell. In favorable years, potato pulp is not completely used as fresh livestock feed and is stored in pits, which leads to large losses nutrients(up to 30 – 35% dry matter). On farms located next to starch and molasses enterprises, fresh and ensiled pulp is fed to large cattle, pigs, poultry.

Potato pulp is sold as livestock feed in its raw form (fluid, with a moisture content of 86 – 87%). In order to facilitate transportation and disposal, it is advisable to dehydrate it. To reduce losses and increase transportability, the pulp is dried. In this case, all substances are completely preserved. 100 kg of dried pulp contains 95 feed units. It is used as a component of mixed feed. Potato cell juice contains up to 6% dry matter. However, it is hardly used. Cell sap makes up about 50% of the mass of processed potatoes.

Currently, a scheme for recycling waste from potato-starch production to produce carbohydrate-protein hydrolyzate and protein feed is being introduced into production. It allows you to use potato dry matter by 97% and reduce the consumption of fresh water for technological needs. Enrichment of the pulp with cell juice increases nutritional value feed Protein feed (coagulated cell sap protein) is absorbed by animals by 80%.

Full sale of raw potato pulp and juice is possible only in small factories that process up to 200 tons of potatoes per day. At larger factories, it is advisable to build recycling workshops to produce concentrated and dry feed.

When processing potatoes in the alcohol industry, the bulk of the stillage containing 3.2 – 4.1% dry matter, fed to animals. Stillage is a valuable, but watery and poorly transportable feed. Transporting it to farms by road is ineffective, as the cost of this feed increases significantly. Therefore, feedlots should be located near distilleries.

The most rational way to utilize potato stillage is to process it into feed yeast and use it in livestock farming in dry form as part of compound feed, as well as in the form of a liquid feed product. Many distilleries experience difficulties in selling stillage in the spring and summer, when the need for it due to the availability of green fodder sharply decreases.

Much attention is paid to the issue of producing liquid feed yeast, since their addition to feed rations enriches them with highly digestible protein.