Kernresonanzuntersuchungen zum Einfluß der technischen Aufarbeitung auf die Wasserbindungsfähigkeit von Kartoffelstärke

Nuclear Resonance Investigations Regarding the Influence of the Preparation on the Water Binding Capacity of Potato Starch . In a preceding paper we stated that an increased content of more tightly bound water has been observed in a sample of industrial potato starch in comparison with a sample of starch which has been isolated under carefully controlled conditions. Now it can be shown that the conditions of drying and also the size of the starch granules have no influence on the above mentioned difference, in spite of the fact that the portion of more tightly bound water distinctly depends on the granule size. The differences in the behaviour of the bound water can be explained by the ion content of the water used during the isolation of the starch. The mechanism of this effect, however, is not yet clear.     

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.     

Untersuchungen an Kartoffelpulpe als Ballaststoffquelle. Zum Einfluß Von pektolytischen und cellulolytischen Enzymen

Investigations on potato pulp as a dietary fiber source. The influence of pectolytic and cellulolytic enzymes . The influence of treatment with pectolytic and cellulolytic enzyme preparations was investigated with reference to the separation of water and the composition of potato pulp. In contrast to pectinesterase, pectate lyase or cellulase it was found an intensive action on the pulp after incubation with Pectinex Ultra SP-L or pectinase/cellulase combinations. The content of pectin, starch and protein as well as the water binding capacity are varied in dependence of the used enzyme preparations. The occurring changes in the supermolecular structure of the potato pulp tissue are investigated by scanning electron microscopy. The grown biological structure is partly or extensive destroyed especially after combined action of pectinases and cellulases. The content of starch in the potato pulp preparations remains relatively high even after intensive treatment with cell wall degrading enzymes.     

Stufenweise Elutionsanalyse der Fraktionen von thermisch dispergierter Amylose-, Kartoffel- und Wachsmaisstärke

Stepwise Elution Analysis of Fractions of Thermically Dispersed High Amylose, Potato and Waxy Corn Starch. Changes in the starch constituents - the amylose and the amylopectin — from dispersions of high amylose, potato- and waxy corn starch were studied by stepwise elution analysis and determination of molecular weight. The dispersions were prepared by dispersing the pastes 1 and 3 h at 120 °C and the amyloses and amylopectins separated by means of n-butanol and methanol, resp. With the exeption of a partial separation in waxy corn starch no separation of pastes into amylose and amylopectin could be observed, probably due to the mild pasting conditions in the Brabender Viscograph. By stepwise elution analysis it could be stated that after prolonged thermic dispersing of the pastes of high amylose starch the amylose and amylopectin do no longer change, which is in good agreement with the values of molecular weight. By analogous treatment of the pastes of potato starch, however, a decomposition of amylose and amylopectin could be stated. In the dispersions of waxy corn starch the amylose molecules decompose to a degree whereafter thermic dispersing of 3 h practically no complex with n-butanol could be observed. Relatively great losses were stated at the isolation of the precipitated constituents. It was stated that the isolated amyloses of potato starch are suitable substrates for activity measurements of α-amylase in human serum and urine as well as in other biologic materials.     

Visual Observation of Hydrolyzed Potato Starch Granules by α‐Amylase with Confocal Laser Scanning Microscopy

Porous starch was produced by digestion of freeze‐dried potato starch with α‐amylase from Bacillus sp. The surface structure of the granules became perforated and in the interior of the granules a capsule‐like cavity was formed, i.e. the hydrolyzed starch can be used as an encapsulant. The structure change of the granules was observed with confocal laser scanning microscopy and scanning electron microscopy. The degree of starch hydrolysis could be correlated with the Avrami equation. The activation energy of starch hydrolysis by α‐amylase was 83 kJ/mol.     

Vergleichende Kernresonanzuntersuchungen der Wasserbindungsverhältnisse von Stärke und rohen Kartoffelstücken während der Trocknung

Comparative NMR-Investigations of the Binding of Water in Starch and Raw Potatoes During the Drying Process. A reversible swelling which is caused partly by reorientational motion of water is observed by heat-moisture-treatment of native starch at 60°C. This means that water can either only loosen the outer amylopectine layer or that it gets through to the inner part of a starchgranule to become less loosely associated with amylose. Obviously this behaviour is important during hot-air-drying of potatoes. The drying-up of the outer layers of the material to be dried means a reduction of the self-diffusion-coefficient and a hindrance to the discharge of water. But apart from this another influence upon the drying-speed is observed which is in direct connection with the behaviour of starch already mentioned above. Soon at the beginning it is to be noticed that the mobility of the water within the cell increases and that it gets transported into the middle of the potato. At a temperature of 50°C to 60°C the swelling of starch starts and water therefore becomes immobilized. To some extend some water becomes enclosed in existing structures where it remains relatively flexible. These processes can be followed by nuclear-magnetic-resonance (NMR-Spectroscopy). On this basis statements about different water-molecules and their particular quantities can be made. The immobilisation of the water can be shown by the smaller water activity of the starch samples after the heat-moisture-treatment. Also it can be seen in the lowering of the drying speed.     

Einfluß von Sorte,Knollengröße,spezifischem Gewicht und Düngung auf die Viskositätseigenschaften von Kartoffelstärke

Influence of Sort, Tuber Size, Specific Weight and Fertilizing on Viscosity Properties of Potato Starch . From the example of three different potato cultivation tests the sort is shown to have a highly significant influence on ash and phosphorous acid content as well as viscosity properties of potato starch in case the environmental factors of year of cultivation and locality are not taken into consideration. Tuber size and specific weight, however, do not take effect. Moreover, it became apparent that starch quality cannot be influenced by way of fertilizing — be it organic or mineral. Hence the recommendation for cultivation of starch potatoes to adjust fertilizing to optimum yield with highest possible starch content is given.     

Kernresonanz-Untersuchungen zum Mechanismus der Wasserbeweglichkeit in verschiedenen Stärken

Nuclear Magnetic Resonance Investigations on the Mechanism of Water Mobility in Different Starches. From the temperature behaviour of the proton relaxation times of different starches can be concluded, that the water molecules at the starch structure carry out an anisotropic motion. Above room temperature exchange processes of the water protons with the OH-protons of the starch structure are observed. For potato starch the anisotropic motion results in a distinct splitting of the deuteron resonance, which can be used for studies of structural changes during the heat treatment of the starch at different moisture contents. Below 20% water content above 100°C changes in the spectrum can be observed indicating a hydrolytic attack of the starch structure. These damages partially heal at higher water contents. Irreversible changes at temperatures below 90°C can be obtained at water contents above 41%.     

Einfluß der Stärke auf die Textureigenschaften von Kartoffelknollen

Interaction of Starch and Textural Properties of Potato Tubers. By a two years glas-green-house test the influence of starch content on texture of raw and boiled potatoes was studied. Results show that only at certain conditions the starch content can affect a tendency of influencing the texture. Physical properties of starch play as well an important role referring to the texture of tubers. With reference to the influence of starch on texture of potato tubers other factors seem to play a role which still must be investigated.     

Drug release mechanisms of hot‐melt extruded starch‐based pellets

Hot‐melt extrusion with die‐face pelletisation is an excellent technique to continuously produce almost monodisperse spherical starch pellets. For a better understanding of drug release mechanisms from hot‐melt extruded starch‐based pellets the swelling behaviour in the release medium was examined by reflected‐light microscopy. From the microscopic images it can be concluded that the drug release mechanism of wx corn starch pellets is almost solely based on erosion. The release mechanism of corn starch, pea starch and potato starch pellets is primarily a swelling‐based process. Although the release mechanism of a swelling dosage form is theoretically complex, it was found that the fractional drug release from the hot‐melt extruded starch pellets can be described with the Noyes–Whitney equation. This facilitates the evaluation of the influence of the physicochemical properties of the matrix and the chemical properties of the active ingredient on the drug release rate. It was found that pellet size, porosity and velocity with which the penetrant diffuses into the pellet‐core the water solubility of the drug as well as the molecular structure and composition of the starches are the main factors influencing drug release from the swelling starch pellets.     

紫薯淀粉结构与理化性质研究

目的 了解紫薯淀粉的结构和理化性质。方法 利用碱提取法从紫薯中提取淀粉, 与普通玉米淀粉进行对比, 分别对淀粉结构(分子链结构、结晶结构等)和理化性质(透明度、凝沉性、冻融稳定性、热稳定性)进行研究。结果 紫薯淀粉直链含量(24.5%)比玉米淀粉(26.7%)低, 两者均为A型结晶结构, 但紫薯淀粉的结晶度和分子有序程度比玉米淀粉高; 紫薯淀粉糊的透明度高于玉米淀粉糊, 且随时间延长其透明度下降程度比玉米淀粉糊低; 紫薯淀粉糊不易发生凝沉现象, 但其析水率(21.4%)比玉米淀粉糊高, 即冻融稳定性弱于玉米淀粉糊; 此外, 紫薯淀粉部分结构的热稳定性大于玉米淀粉。结论 紫薯淀粉在分子链结构和结晶结构上与玉米淀粉有较小差异, 但在理化性质上与玉米淀粉差别较大, 可为其工业应用提供指导基础。     

Microwave‐accelerated Synthesis and Characterization of Potato Starch‐g‐poly(acrylamide)

Using a very low concentration of potassium persulfate as initiator, acrylamide could be efficiently grafted onto potato starch under microwave irradiation and for the grafting O₂ removal from the reaction vessel was not required. Under optimal conditions, grafting and efficiency observed were 160% and 89%, respectively. Grafted starch was characterized by using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA). It was observed that the microwave irradiation could significantly accelerate the synthesis of starch‐graft‐poly(acrylamide), because under identical conditions no grafting was observed in a conventional procedure. Viscosity, shear stability and water/saline solution retention of the microwave‐synthesized grafted starch were studied and compared with that of the parent starch.     

Étude,par diffraction des rayons X,de I'influence de la cryodessiccation sur la structure cristalline de I'amidon

Examination on the Influence of Freeze-Drying on Crystalline Starch Structure by Means of X-Ray Diffractometry. The influence of freeze-drying on the crystalline structure of various starches (potato, wheat, maize, waxy maize, manioca, arrow-root) and wheat amylose has been examined by means of X-ray diffractometric diagrams. Only the crystalline structure of potato starch is altered by the treatment. A change in structure becomes apparent only, if freeze-drying is done slowly and if the water content of starch is above 25%, related to d. s. However, a restoration of the original structure of starch is possible, by moistening under certain conditions as described in the text. An explanation for the observations is proposed by means of a new hypothesis on structure organization of starch granules as well as the part of water as a determining factor for organization.     

马铃薯抗性淀粉对韧性饼干品质及消化性能的控制

目的 研究马铃薯抗性淀粉对韧性饼干消化性能及品质的影响规律, 为评价和提高马铃薯抗性淀粉韧性饼干的品质奠定基础。方法 通过将马铃薯抗性淀粉作为膳食纤维成分, 按照不同比例替代面粉, 制作成韧性饼干, 对韧性饼干的延展性、色泽、感官、质构特性、表观结构等物理特性、营养成分及消化性能进行测定, 研究马铃薯抗性淀粉对韧性饼干品质及消化性能的影响。结果 随着马铃薯抗性淀粉的增加, 韧性饼干的延展性总体呈增长趋势,蛋白质和脂肪含量逐渐减少,水分和灰分含量差异不显著。在马铃薯抗性淀粉添加为20%时饼干色泽均匀,硬度、脆性和咀嚼性均较好, 感官评分最高, 为82.6分。SEM观察发现随着马铃薯抗性淀粉的添加饼干结构显示暴露在油脂外的淀粉颗粒逐渐增加。马铃薯抗性淀粉的加入降低系统中淀粉的水解速率, 进而调节饼干的体外消化率, 降低血糖指数, 添加30%马铃薯抗性淀粉时, 血糖指数为62.06, 已达到中等血糖指数。结论 适量的马铃薯抗性淀粉添加到韧性饼干中可以改善饼干品质, 随着马铃薯抗性淀粉含量的增加, 饼干血糖指数降低。为抗性淀粉饼干的开发提供理论基础。     

Ultrasound-treated starch: SEM and TEM imaging,and functional behaviour

Potato, wheat, corn and rice starch granules were suspended in water or ethanol and sonicated at frequency of 20 KHz and power 170 W for 30 min. The effect of ultrasonic treatment on starch structure was assessed on the basis of blue value (BV), A₆₈₀/A₅₄₅ ratio and λ_max determinations. The results showed that modification of starches in both solvents led to the reduction of all parameters connected with the starch–iodine complex. However, depolymerization of starch was higher when it was sonicated in water than in ethanol (e.g. BVs for potato starch: native and sonicated in water and ethanol were equal, respectively, 0.306, 0.275, and 0.279). Starch granules were also observed under scanning and transmission electron microscopes. The main effects of ultrasonic action were cracks and depressions on the surface of granules, which were especially well seen in the case of potato and wheat starches. Ultrasonic treatment, especially in water, influenced functional properties of starch causing an increase of fat and water absorption, least gelling concentration (except potato starch), solubility and swelling power, and a decrease of starch paste viscosity. Effect of ultrasounds on clarity of pastes was rather small, except potato starch for which its value increased from 70.3 to 82.5% after sonication in water.     

Pflanzenbauliche Möglichkeiten zur Beeinflussung einiger Qualitätsmerkmale von Kartoffelstärke

Effect of Agricultural Possibilities on Some Quality Criteria of Potato Starch Investigations were made to find out wether the quality of potato starch con be influenced by different ways of cultivation. The results show that starch granule volume as well as viscosity are highly affected by year and location of cultivation. Furthermore, potato variety is of high importance. This influence, however, can be covered with year and location of cultivation. No effect of organic or mineral fertilizers could be stated. Hence, there is no possibility to produce a wanted starch quality in the plants.     

Sulphated and carboxymethylated polysaccharides from Lycium barbarum L. leaves suppress the gelatinisation,retrogradation and digestibility of potato starch

Processing starch with polysaccharides promotes broader applications, and it is important to consider all possible structural interactions among the molecular ingredients. In this study, polysaccharides isolated from Lycium barbarum L. were chemically modified by sulphation (SLP) and carboxymethylation (CLP), and the effects on the gelatinisation, retrogradation, and digestibility properties of the potato starch were investigated. After chemical modification, the slope of the curve between the molar mass and molecular radius of polysaccharides decreased, revealing that the relatively rigid rod-like structure of native polysaccharide (0.78) changed to SLP's random linear chain (0.53) and CLP's spherical conformation (0.23), and the water solubility increased from 63.6% to 70.4% (SLP) and 84.1% (CLP) in distilled water at 25 °C. Moreover, testing polysaccharides as an additive indicated that both derivatives significantly decreased the peak viscosity, breakdown, and setback viscosity during potato starch pasting. Furthermore, the possible interactions could be further examined by structure analyses, suggesting the polysaccharide and SLP hydrogen bonds interacted with the surfaces of starch granules, while CLP penetrated the interiors of pasted starch granules, destroyed the helixes and backbone structure of starch, and formed type V crystallinity with amylose. The results of in vitro digestion analysis revealed that polysaccharides could decrease the amount of resistant starch and increase the amount of slowly digestible starch, which might be related to the inhibition of starch gelatinisation. These results facilitate the application of chemical derivatives in starch-based functional foods and understand the interaction mechanism between potato starch and polysaccharides.     

Properties of Potato Starch in Relation to Varieties and Environmental Factors

An extensive assortment of potato varieties in connection with different growing conditions was analyzed concerning several starch quality criteria. Significant variations were evident for starch content, phosphorus content of starch, and granule size distribution. On the contrary, amylose content varied only little. Environment had influence on starch content and viscosity behaviour. Fertilization effects could not be observed. This underlines the significant variety effect. The results clearly point out that an improved accentuation of potato starch quality is possible. In connection with a selected variety spectrum and altered separation strategies new markets for potato starch utilizers can be opened within short time.     

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%.     

Effects of sodium dodecyl sulphate and sonication treatment on physicochemical properties of starch

Effects of sodium dodecyl sulphate (SDS) and sonication treatment on physicochemical properties of starch were studied on four types of starch, namely, corn, potato, mung bean, and sago. The SDS and sonication treatments caused a significant reduction of protein content for all the starches. The SDS treatment did not cause apparent damage on granular structure but sonication appeared to induce changes such as rough surface and fine fissures on starch granules. The combination of SDS and sonication increased amylose content for all starches. This could be attributed to the removal of surface protein by SDS and structural weakening by sonication which facilitated amylose leaching from swollen starch granule. The X-ray pattern for all starches remained unchanged after SDS treatment, suggesting no complexation of amylose–SDS had occurred. Combined SDS-sonication treatment increased swelling and solubility of corn, mung bean, and potato starch. The treated starches showed significant increase in peak viscosity with reduction in pasting temperature, except for potato starch. Results of the present study indicate the possibilities of exploring SDS and sonication treatments for starch modifications.