Entwicklungstendenzen in der Stärke- und Zuckerindustrie in Abhängigkeit vom Rohstoff. Teil 4. Kartoffel

Development Trends in Starch and Sugar Industries Depending on the Source Material. Part 4. Potato. In Western Europe (52°N. Latitude) the potential starch yield is estimated to be about 17 t ha⁻¹. For potato crops that can grow until October the average starch yield is estimated to be about 8 t ha⁻¹. The big gap between these two yields must be explained mainly by insufficient water supply to the potato crop. Also a more optimal quantity of foliage and possibly an improved type of haulm may help to bridge the gap. It is assumed that the starch yield will increase annually by about 100 kg ha⁻¹. The yield of coagulable protein is approximately 500 kg ha⁻¹. About the same quantity of N-compounds is processed with the cellwall material for fodder. It is shown that selection on starch yield is in general also a selection on protein yield. The energy output/input ratio for the production of 1 ha potatoes for the starch industry is about 2.5. It is likely that this ratio will increase.     

A New Hydrocyclone Process for the Production of Potato Starch with Lowest Fresh Water Consumption

A drastic reduction of fresh water consumption for extraction and refining of potato starch was reached in a new process. The undiluted potato rasp is pumped directly into a closed system of pumps and hydrocyclones in which the starch is separated from the fibres and washed out with fresh water. The fresh water consumption is reduced to about 200 l/t of potatoes. Quality and yield of starch are the same as in conventional processes.     

Unschädlichmachung der Abwässer durch bessere Ausnutzung des Rohstoffes bei der Kartoffelstärkeerzeugung

Neutralization of Waste Waters by Better Exploitation of Raw Material During Production of Potato Starch . Neutralization of fruit juice set free during the production of potato starch can be carried out efficiently in two steps. The first step is based upon the coagulation of protein at 85 °C in acidify medium. The first step of methane fermentation, which is the acid fermentation, is made use of for this process. At this step mainly heterogeneous lactic acid fermentation takes place. Coagulated protein may be efficiently processed into feed thus making the purification of waste water more profitable. The second step is the methane fermentation as such. Considering the concentration of fruit juice from the separators a maximum load of the fermentation tank of 1.5 kg/m³ of organic matter has to be taken in account. At a higher load the period of fermentation is shortened to an extent that makes anaerobic processes impossible. During fermentation 15.25 m³ of fermentation gas per m³ raw water with a methane content of 54% are produced. This amount of gas should be sufficient for heating of the waste water up to a temperature which is necessary for caogulation. The fermentation of fruit juice has to be succeeded by a one-hour period of sedimentation of the mud. Thus, purification is made more effective. With this system the concentration of the fruit juice decreases to an extent which makes it possible to purify it further together with the processing water in a biological activation filter plant.     

Developments in Potato Production for the Starch Industry

From the price relationship between potatoes and maize gross margins can be calculated for various prices and yields of these two crops. From this can be concluded that in general potato production for starch can compete with maize for starch production at maize prices about 35 guilders. In the nine EC countries tuber yield per ha increased from 1962 to 1973 annually by almost 3%. In the Netherlands the yield per ha of starch from potatoes used for the starch industry increased from 1960 to 1975 annually also about by 3%. The average yield is now about 7 t/ha. It is estimated that under ideal conditions in the Netherlands the potential yield of starch would be 16 t/ha. Therefore much can be done to improve yield. In the period 1965–1973 in the Netherlands the total cost of potato production for starch increased by about 4% per year. In the last few years this increase was however almost 14% per year. Before 1973 rise in cost of production could be compensated for a large extend by the annual increase in yield per ha. That is not the case with a rise in cost by 14%.     

Erfahrungen mit der Auswaschung von Kartoffelreibsel ohne Wasserzusatz

Experience in Potato Pulp Washing without Water Addition. In order to reduce the quantity of waste water from potato starch factories many have tried to keep the amount of water, required for washing out the starch from the pulp as low as possible. Our process is based on utilization of the water contained in the potatoes (approx. 80%, including soluble components) for starch extraction, in such a way that undiluted fruit water is separated and further treatment can be carried out in a comparatively economical way. Most of today's starch factories are tied up with production methods that make it impossible to utilize the water contained in the potatoes, as there is firstly no possibility of recirculating the fruit water and secondly there are foaming problems causing a negative effect on the efficiency. A continuous process guaranteeing a direct flow, excluding accumulation of foam, was installed and tested in both a Swedish and in a Dutch factory. The experience obtained showed that starch extraction with fruit water has no negative influence on the efficiency of the extraction (approx. 1 % free starch in the pulp DS/DS) and that up to 80% of the fruit water could be removed in a concentrated form. By extending the extraction process, and by using 300 l of process water from the refining section per ton of potatoes, separation of the fruit water can be increased up to 97%.     

Starch from Alberta potatoes: wet-isolation and some physicochemical properties

Starch content of six varieties of Alberta-grown potato tubers was more than 16% (wet basis). The tubers were wet fractionated in the laboratory and starch was recovered. The starch recovery ranged from 61 to 67%. The composition of the potato juice/fruit water (dry matter, protein, ash and mineral content) and starch isolations (moisture, starch, protein, lipid, ash, phosphorous and amylose content) was determined. The physicochemical characterization of the potato starch isolations were done in terms of granule size distribution, crystallinity (X-ray diffractometry), gelatinization (differential scanning calorimetry) properties, swelling factor and the changes in viscosity during heating and cooling of starch-water slurry (Brabender viscography). Substantial differences in the starch content of the tubers, fruit water composition and starch physicochemical properties were observed between potato varieties.     

Geringe Abwasserbelastung durch vollständige Nutzung der Kartoffeltrockensubstanz bei der Stärkegewinnung

Low Waste Water Load by Complete Exploitation of the Potato Dry Substance During Starch Production. As a result of mechanized harvesting processes for potatoes, special attention has to be paid in potato starch factories to the neutralization of flotation and washing waters. This means consequent recirculation as well as continuous pull-out of mud and suspended matter before decomposition of the organic material. The main source for pollution of starch waste waters is the biologically valuable fruit juice of the potato. An extensive separation and utilization of this substance leads to considerable relief of the waste water. A number of possibilities for utilization as a function of the processing capacity are discussed in detail. Apart from using it as feed either directly or after fermentation and acetone butanol fermentation, the use of fermented and de-proteinized fruit water concentrate is of importance in technological microbiology, in methane fermentation and feed granulation. Additional purification of the mixed and pre-purified waste waters in activation filter plants, biological ponds or by sprinkling become substantially more easy by two-step separation by means of suitable.     

Energiebedarf und Energiefluß in einer Kartoffelstärkefabrik

Energy Use and Energy Flow in a Potato Starch Plant . The aim of the study was to determine in a potato starch plant the energy flow and energy use to produce various products. The plant requires natural gas and electricity as energy carriers which are converted to steam heat (46.4%), heating gas (17.2%) and electricity (18.7%). The conversion losses amount to 17.3% in total. The end energy is used in large amount for the drying of starch (15.9%) and its modification (24.2%) as well as for the production of potato protein (18.2%) and the evaporation of the remaining potato juice (12.4%). The accumulated specific energy demand shows that the wet starch is the least energy intensive product (10 120 MJ/t d. s.). In comparison dried starch (12 120 MJ/t d. s.), starch derivates (17 840 or 20 900 MJ/t d. s.) and potato protein (41 900 MJ/t d. s.) have a significant higher energy intensity.     

不同品种甘薯制汁特性的比较

为了筛选出适宜制备甘薯汁的原料品种,选取了15个品种甘薯作为研究材料,对它们的基本制汁性能进行了研究,包括水分、淀粉、可溶性糖、还原糖、总酸、总蛋白质含量及酶解后的出汁率含量。结果表明,这15个品种甘薯的水分含量为52.5%~80.3%,淀粉含量为11.1%~18.1%,可溶性糖含量为1.76%~13.56%,还原糖含量为0.11%~1.24%,总酸含量为2.46~6.99 g/kg,蛋白质含量为0.88%~2.95%,出汁率为39.8%~77.9%。以出汁率及淀粉含量为主要评价指标,XN 1448-5出汁率最高,淀粉含量最低,水分含量较高,可溶性糖及蛋白质含量较高,因此认为XN 1448-5是这15个品种中制备甘薯汁的最佳品种。     

紫甘薯饮料制备工艺研究

以紫甘薯为原料探讨紫甘薯饮料制备的工艺条件。比较α- 淀粉酶液化和高温液化两种方式对淀粉液化的效果,并进一步添加糖化酶进行淀粉糖化,同时探讨各工序对花色苷的影响,以饮料的可溶性固形物增长率、吸光度及色差值为考察指标。结果表明：鲜薯用两倍水打浆,加入0.020g/100mL α- 淀粉酶于70℃条件下酶解40min,再添加0.04g/100mL 的糖化酶在pH5.0 条件下糖化40min,既可获得理想的淀粉水解效果,又可尽量减少花色苷的损失。较好的饮料配方为30% 甘薯原汁、8% 蔗糖、0.05% 柠檬酸,其余为软水。采用该工艺条件可制备色香味俱佳的紫甘薯饮料。     

Potato Starch Technology

Potato starch production encountered drastic changes during the last years, in particular in economics and substrate supply. Because of economically required reductions in subsidisation, production of potato starch will decrease. Changes in technology are characterised by savings in wash water and process water streams that are effected by increased efficiency introduced with new machinery and changed technological concepts. From an ecological point of view, an early and maximum fruit water separation (up to 95 %) based on dilution of gratings with process water and decanter separation allowed to reduce the fresh water supply to 0.4 to 0.5 m³/t of processed potatoes. For economical isolation of potato protein a correspondingly high protein recovery rate (up to 90 %) is essential. Concerning starch extraction, a minimum of 95 % is reached in modern potato starch plants, but optimum engineering (rasping, decanting, sieving) gives recovery rates of 97 to 98 %. In starch refinement, three-phase nozzle separators equipped with wash water supply and constructed for efficient displacement washing allow to achieve a fine fibre removal of 98 % within three separation stages and a final concentration of purified starch milk of 22 to 23°Bé. Potato protein isolates (protein content 83 to 85 %) are produced by isoelectric precipitation combined with heat coagulation while stringent solutions for treatment of de-proteinised fruit water are still lacking.     

Bedingungen für die Bildung von Trockensubstanz und Stärke bei zwei Arten von Stärkekartoffelsorten

Conditions for Formation of Dry Substance and Starch with Two Types of starch Potato Sorts. Two types of starch potato sorts (Kamýk, Boubin) were field tested. It was found that herb destruction is not favourable. It reduces tuber yield, content of dry substance and starch and increases the percentage of small tubers. Fertilization should depend upon type of the sort. With the stalk type, higher doses (120 kg N) may be used. Doses of P should depend upon P content in the soil starting from 50 kg P upward. With the leave type, 100–120 kg N, and 50 kg P are sufficient.     

New Developments in French Potato Starch Industry. Stone Removal Through Dense Medium Process,Environmental Protection

The French potato starch industry received a tremendous impetus since the beginning of the 19^th century. At that time it consisted of not less than 550 plants. At the beginning of the 20^th century it became greatly concentrated leading to a final number of five potato starch factories. The simultaneously increased production capacity has enabled the French potato starch industry to rise to the number two position among the potato starch producing nations of Western Europe. Closely connected with this concentration is a simultaneous modernization of the whole agriculture. All the five starch factories are located in the areas with vast cultivation plains where extensively mechanized agricultural operations are prevalent. However, as a result of this mechanization the deliveries of potatoes contain much larger amounts of earth and stones. For this reason a new process for the separation of stones is currently being tested, in order to reduce the up to now necessary amount of washing water by means of an enriched mud and to improve the effect of potato washing at the same time. The five French potato starch factories are equipped with total-continous and total-automatic machines, and they produce a high-quality potato starch. The concentration to large production units, however, has led in places to an increase of waste water amounts. According to official calculations the raining of potato fruit juice on large areas as well as use of aired ponds have led to a 90% superior purification. Protein recovery in connection with a decrease in waste water volumes will make it possible to even surpass the official standard of purification of 95%, approaching a purification effect of 100% in an already predictable period of time.     

Die Bedeutung der Schaumzerstörung bei der Kartoffelstärkegewinnung

The Significance of Foam Destruction for Potato Starch Production. During the production of potato starch destruction of the foam is inevitable at all stages of the process as it will interfere with the recirculation of the processing waters. This also affects the reduction of water consumption (related to the amount of raw material). The application of mechanical means or vapor for foam destruction is limited. Application of defoaming materials with simultaneous recirculation of floating and washing waters, two-step separation of the fruit juice and rendering innocuous of the starch waste waters by activation has proved to be the most advantageous process.     

Effect of Membrane Material on the Separation of Proteins and Polyphenol Oxidase in Ultrafiltration of Potato Fruit Juice

Ultrafiltration was applied to diluted potato fruit juice, a side-stream from potato starch production. The aim of the study was to selectively concentrate the potato proteins in the permeate, while isolating polyphenol oxidase (PPO) in the retentate. A profound difference was found in protein retention between two 300-kDa molecular weight cutoff (MWCO) ultrafiltration membranes, of either regenerated cellulose (RC) or polyethersulfone (PES). The use of the 300-kDa MWCO RC membrane resulted in a twofold higher retentate protein content as well as total retention of all PPO activity, as compared with the PES membrane. Comparison tests with 100- and 300-kDa MWCO PES membranes indicated that concentration polarization and gel layer formation, and not MWCO definitions, were governing factors for protein retention, since proteins with a MW of 10 kDa were retained in all the experiments. PPO activity in potato fruit juice was measured in permeate and retentate to assess its selective retention by the applied ultrafiltration processes. Of the specific PPO activity, 94–100 % was retained by either 300 MWCO RC or 100 MWCO PES, while only 49 % specific activity was retained by the 300 MWCO PES. By in situ blotting experiments, the molecular weight of active PPO was found to be present at three different molecular weights, at positions of 40, 47, and 100 kDa, respectively, with the major activity present at 47 kDa.     

Verwertung von Abfällen der kartoffelverarbeitenden Industrie

Utilization of Waste Products in the Potato Processing Industry. 1. Wastes from Norwegian potato starch plants have been analyzed. The composition found is summarized. 2. An alkohol plant has been constructed to utilize the wastes from a potato starch factory. Later on this alkohol plant has been modified to utilize the wastes of a potato flake plant and a potato chips line. To make profitable use of the wastes, they have to be collected and concentrated. A system for this purpose is indicated. The mash of the alkohol plant is prepared in a continuous tube system. The fermentation and distillation are carried out in a conventional equipment. 3. A pilot plant for the removal of water from potato fruit water by evaporation has been built and tried out. The concentrate from the evaporator was dried in a Rotadisc dryer with waste pulp as carrying material and used in mixed feeding-stuffs.     

Die Fraktionen des Kartoffeleiweißes

Fractions of the Potato Protein. Modern starch technology aims at utilization of potato protein from the fruit water for food stuffs, feeding materials or as a nitrogen source matrix in industrial fermentation. This is done to improve the economic situation of potato starch factories. Scientific knowledge of the matter, however, is still fragmentary. This is why the composition of fruit water protein as to the different fractions has been examined. It was found that protein fractions of the examined eight species of the world potato sortiment (early, medium early, medium late and late) did not show differences of quality. Quantitative differences, however, were found. For practical utilization of potato protein it is important to state the influence of heating during evaporation of the fruit water. The lowest influence on qualitative properties was found with temperatures up to 60°C.     

交联淀粉对甘薯浊汁饮料稳定性的影响

将不同浓度交联剂(6%,8%,10%,12%,14%)制备得到的交联马铃薯淀粉(Cross-linked potato starch,CLPS)应用于甘薯浊汁饮料中,测定浊汁饮料的浑浊度、流变特性、稳定性、Zeta电位和离心沉淀率。结果显示,随着交联程度的增加,浊汁饮料的浑浊度上升,但30d内浑浊度的变化程度降低,饮料体系的假塑性、黏度、黏弹性、凝胶强度与Zeta电位绝对值随着交联程度的增加而增加,在交联剂浓度为12%时取得最大值;交联淀粉能够抑制浊汁饮料底部出现沉淀,但对浊汁饮料顶部析水的控制有限,稳定性动力学指数与离心沉淀率随着交联程度的提高而下降,表明交联淀粉能够提高甘薯浊汁饮料体系的稳定性。综合结果表明,交联淀粉使甘薯浊汁饮料的稳定性有一定程度的提高,12%CLPS可作为稳定剂应用于淀粉质浊汁饮料中。