All-round mechanization of sugar beet harvesting, hauling from the field and unloading from the trucks at beet receiving stations of sugar-factories widely undertaken in many countries makes it possible to speed up to a great extent the field work and carry them out in optimally short time. This permits a more effective use of harvesting machinery and automotive facilities, as well as a reduction of beet production costs. At the same time it makes it possible to avoid withering and frost-biting of the beet in the field, these being rather harmful to its technological qualities.
However, fast mechanized beet root harvesting and transportation which, by the climatic conditions in most European countries should be carried out within 30-40 days, Inevitably leads to accumulation of beet stock which must be stored before processing.
So, practical beet storage in large-scale production is at present an imperative and vital problem for sugar industry in many countries.
The process of beet storage depends to a great extent on the conditions of beet cultivation : seed grades, agricultural technology, diseases and pests during the period of vegetation, harvesting time and facilities, etc. If follows then that the sugar industry should devote due attention to the problems of beet cultivation.
Proper beet storage, as recommended by modern science, makes it possible to retain healthy physical state of the roots for a more or less lasting time. As a result of this the beet processing will be facilitated from the technological point of view.
However, on account of continuous and essential life activity in the beet during its storage under natural conditions (without special preservation) physical and biochemical processes (breathing, metabolism, etc.) are inevitable. These processes cause considerable changes in its physical properties, chemical composition and technological qualities.
Hereby, the trend of principal changes taking place in the beet is the following : loss of weight (moisture and dry substances), deterioration of elasticity modulus and increase of beettissue resistance to cutting, partial decomposition of saccharose, increase of soluble forms of nitrogen, pectins and ash, additional accumulation of reducing substances, colloids and trisaccharides. The rate of these changes and transformations depends on the initial physical state of the beet before storage as well as on the storage time and conditions. At its minimum the rate of changes is in winter at the lowest ambient air temperatures. Higher rates of changes are in autumn and the highest in spring when the physical state of the beet is weakened.
In mechanized beet harvesting, apart from the inevitable increase of its storage volume, the beet roots are subjected to undesirable effects harmful to physical condition and initial technological qualities of the stock. These effects are : injuries inflicted on the roots, higher amount of stuck earth and other impurities, in many cases remaining sprouts, leaf stalks and leftovers.
All this complicates storage and is accompanied by increased intensity of root breathing, considerably greater sprouting and in some cases by more rapid development of microbiological processes. As a result of this the above changes and transformations taking place in the beet are even more intensified.
Such changes in the beet effect the composition and properties of juices and intermediate products during its processing. This results in reduction of : quality, pH, thermostability of juices and syrups : increased content in the products of : general and organic nonsugar components, reducing substances, colloids, soluble nitrogen, pectins, organic substances, calcium salts; higher colourity of all products ; deteriorated sedimenta! and filtrating properties in juice clarification; reduced effects in removal of nonsugar components, and reducing substances in particular, which enhances formation of melanoidins in the evaporator.
In the end there is a reduced rate of saccharose crystallization, retarded strike boiling and spinning, increased MB-factor and blackstrap yield, reduced plant coefficient (yield of crystallized sugar in per cent to the sugar introduced into the processing with the beet).
In case of highly developed microbiological processes during beet storage the above mentioned changes in the composition and properties of juices and products increase drastically to the worse. In that case not only plant indices are reduced but the entire processing conditions become upset.
Alterations of sugar works flow sheet recommended in the recent years aimed at processing putried beet help, usually, to do away with hindrances in the processing, primarily at the juice clarification and filter station.
However, these recommendations can be of little help where there is need of additional yield of sacked crystallized sugar.
Production experience of many years and special studies indicate that, with adequately organized harvesting and hauling the beet from the fields as well as with its proper storage at the plants, wide-scale microbiological processes can be prevented.
In that case the recommendations for beet processing after storage can be reduced, mainly, to selection and maintenance of optimal processing conditions for every given beet batch at the main plant stations : juice extraction, juice clarification, boiling and crystallizer stations.
The aforesaid signifies that further profound investigations in the improvements of both the beet storage and its subsequent processing are of major importance and necessity.
At present in the Soviet Union investigations in beet storage improvement are widely developed and are carried on in the following three directions :
Biochemical – investigations of the properties of breathing, sprouting and microbiological processes in beet roots mechanically harvested along with the studies of the nature of inherent immunity and the course of protective reactions in the root. Development on this basis of ways and means by which the stored beets can be treated with physiologically active substances (maleic hydrozlide, defoliants and desiccatives) by means of ionizing irradiation and antibiotics.
Engineering – investigations aimed at improving the storage technology as well as at mechanizing and automating the principal handling operations in large- scale beet piling and storage. This involves, first of all, the following problems : additional beet cleaning before storage, increase of the beet clamp sizes in height and base width, replacement of clamps by stationary open-type storehouses, application of mechanical ventilation with humidified air supply, reliable and mechanized facilities protecting the beet against atmospheric precipitation, wind, cold and other adverse outdoor effects ; remote automatic temperature measurements.
Management and Economy – investigations in selection and improvement of beet procurement and reception aimed at storage betterment.
This involves first of all the following : formulation of requirements on the beet as raw material, production capacity and optimal daily output of the plants, rationalization of the structure of plant raw material base, reduction of beet transportation by railways, payment for the beet depending on its quality at the time of reception.
It is highly desirable to join efforts in the future for better beet storage and processing by coordinating the investigations and exchanging the information.
Proceedings: CITS 1971
pdf download: CITS1971-599-615.pdf