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.     

马铃薯淀粉—VAc接枝共聚物制备条件优化及表征

该文报道主要研究马铃薯淀粉与醋酸乙烯酯接枝共聚反应影响因素,通过正交实验,确定最佳反应条件为:引发剂浓度18 mmol/L、反应温度60℃、反应时间3.5 h、单体配比2.5:1、淀粉浓度5％,得到99.85％接枝率.利用扫描电镜、X射线衍射、傅里叶红外光谱对马铃薯淀粉及其接枝共聚物进行表征,证实马铃薯淀粉—醋酸乙烯酯...     

Synthesis and Application of New Thickerners Part I: Preparation of Poly (Acrylic Acid)-Starch Graft Copolymer

Graft polymerization of maize starch with acrylic acid using potassium persulphate as free radical initiator was investigated under different conditions. Variables studied included initiator concentration, acrylic acid concentration, starch/water ratio and polymerization temperature. The carboxyl content of the grafted starch was determined and used for calculation of the grafted yield. It was found that the graft yield increases by increasing persulphate; no significant enhancement in grafting could be observed upon using higher persulphate concentrations. Grafting increases also by increasing acrylic acid concentration up to 150% (based on wt. of starch) and tends to decrease at higher concentrations. Starch/water ratio of 1:6 constitutes the optimal for maximum grafting. Raising the polymerization temperature from 25 to 43°C enhances the polymerization rate. The apparent activation energy of the copolymerization reaction amounts to 182.17 Joule/mole.     

微波场中土豆淀粉丙烯酸接枝浆料的制备及性能

在微波场中实现土豆淀粉与丙烯酸的接枝共聚，可制备土豆接枝淀粉。对接枝共聚物用红外光谱进行了表征，采用粗纱法研究了土豆淀粉，丙烯酸接枝浆料对棉与涤棉混纺纱的粘着性能。     

Struktur und Eigenschaften gepfropfter Kartoffelstärke. IV. Fließverhalten von Lösungen

Structure and Properties of Grafted Potatoe Starch. IV. Flow Properties of Solutions. Solutions of graft copolymers of starch-poly acrylic acid and starch polyacrylamid have lower viscosities than solutions of ungrafted starch. By grafting the coil density of the dissolved macromolecules is increased and the limiting viscosity number and the concentration dependence of viscosity decreases. The graft copolymers demand higher concentrations to give networksolutions than native starch does. Mixtures of starch and polyacrylic acid or polyacrylamid resp. show some diminution of viscosity in comparsion with starch. From this it is concluded, that the macromolecules of the synthetic polymer may penetrate into the coils of the polysaccharid molecules effecting contraction of the latter.     

Struktur und Eigenschaften gepfropfter Kartoffelsärke. II. Molekularer Aufbau der Propf-co-polymer-Phase

Structure and Properties of Grafted Potatoe Starch. II. Molecular Structure of the Graft-Co-polymer Phase The copolymer molecules of potatoe starch, which had been grafted with poly-(acrylic) acid and poly(methacrylic) acid resp. by the Scott-xanthation-process, consist of a backbone of amylopectin and of side chains of the synthetic polymer. There are always twice as many basic units of the side chain polymer in a molecule as there are anhydroglucose units. In solution the molecules are sphere-like in shape and they show a relatively high coil density. For an explanation it is proposed, that the amylopectin backbone serves as a matrix for the propagation of the grafting polymerisation reaction. The side chains are lined up along the backbone and they remain attached to it, fixed by weak bonds.     

马铃薯淀粉与醋酸乙烯酯接枝聚合影响因素的研究

以马铃薯淀粉为接枝骨架,过硫酸铵为引发剂,醋酸乙烯酯(VAc)为接枝单体进行接枝共聚。考察了不同引发剂浓度、反应温度、反应时间、单体配比、淀粉浓度对单体转化率、接枝率及接枝效率的影响,确定最佳工艺条件为:引发剂浓度18 mmol/L,反应温度60℃,反应时间3.5 h,单体配比2.5:1,淀粉浓度5%。并通过扫描电镜,X射线衍射,傅里叶红外光谱对淀粉接枝共聚物进行分析,结果表明:淀粉接枝共聚后,淀粉的微观形貌已经改变,结晶度降低且醋酸乙烯酯成功接枝在马铃薯淀粉上。     

Effects of starch alkenylsuccinylation on the grafting efficiency,paste viscosity,and film properties of alkenylsuccinylated starch‐g‐poly(acrylic acid)

Commercial cornstarch was alkenylsuccinylated with alkenylsuccinic anhydride to different degrees of substitution (DS) and then the products were graft‐copolymerized with acrylic acid for investigating the effects of starch alkenylsuccinylation on the graft copolymerization with vinyl monomer, as well as on paste viscosity and film properties of alkenylsuccinylated starch‐g‐poly(acrylic acid) (ASS‐g‐PAA). The number of carbon atom of alkenyl in alkenylsuccinates considered was 8 and 12, corresponding to octenylsuccinylation and dodecenylsuccinylation of starch, respectively. The graft copolymerization was accessed by grafting efficiency, grafting ratio, and conversion of monomer to polymer, and the film properties of ASS‐g‐PAA considered included tensile strength, breaking elongation, and work‐to‐break. Experimental results demonstrated that the alkenylsuccinylation showed marked effects on the copolymerization, paste viscosity, and film properties. It resulted in increased grafting efficiency, stable paste viscosity, and strong starch film. Carbon‐chain length of the alkenyl and DS value of the alkenylsuccinates also exhibited evident effects on the copolymerization and film properties. Octenylsuccinylation of starch before the copolymerization was superior to dodecenylsuccinylation in improving the efficiency and film properties. Low levels of octenylsuccinylation could be utilized to increase the efficiency of the copolymerization and improve the properties of starch film.     

Grafting of 2‐(Dimethylamino)ethyl Methacrylate onto Potato Starch Using Potassium Permanganate/Sulfuric Acid Initiation System

Graft copolymerization of 2‐(dimethylamino)ethyl methacrylate onto potato starch was carried out in an aqueous medium using a potassium permanganate/sulfuric acid initiation system. The grafting percentage and grafting efficiency were determined as functions of the concentrations of potassium permanganate, sulfuric acid and the monomer, and also polymerization temperature and time. The IR spectrum of the graft copolymer showed the peaks characteristic of the grafted chains. The grafting percentage and grafting efficiency increased and then decreased with increasing the concentrations of potassium permanganate, sulfuric acid, and the monomer, as well as polymerization temperature. The grafting reaction was characterized by an initial fast rate followed a lower rate which leveled off after a certain time. The overall activation energy for the grafting was estimated to be 66.9 kJ/mol.     

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.     

Graft Polymerization of Vinyl Acetate onto Potato Starch Dissolved in an Alkaline Solution

Graft polymerization of vinyl acetate (VAc) onto gelatinized and dissolved granular potato starch has been carried out using an initiation system of ceric ammonium nitrate (CAN)/nitric acid (HNO₃) at 50°C. The granular starch was dissolved in an aqueous alkaline solution (0.25 M NaOH) for 24 h before graft reaction. The effects of reaction variables, such as the concentrations of acid, monomer, and initiator, on the grafting parameters of prepared starch/VAc copolymers have been investigated in both grafting methods for comparison. Although the scanning electron microscopy (SEM) images showed a rather similar homogeneous structure for dissolved and gelatinized starch, a higher grafting level, especially at lower monomer concentrations, was obtained for the copolymers prepared using the dissolved starch. A larger number of reactive sites uniformly created on the starch molecules led to greater accessibility of the monomer and improved considerably the grafting efficiency in the grafting conditions using the dissolved starch. The effects of the grafting methods on the microstructure, morphology, and thermal stability of the resulting copolymers have been studied by Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy, and thermogravimetric analysis (TGA), respectively. The TGA results showed that the grafting of VAc onto dissolved starch led to the formation of more thermally stable graft copolymers.     

经丙烯酸共聚物改性的淀粉糊的流变性能的研究

采用溶液聚合法合成了三元丙烯酸酯共聚物（MA／BA／AA）。红外光谱和X－射线衍射分析了共聚物的组成,并探讨了该共聚物与淀粉反应的过程。结果表明,该共聚物在淀粉颗粒上进行自由基接枝共聚反应,反应主要发生在淀粉颗粒的无定形区,改性后的淀粉能够保持原淀粉颗粒的完整结构。     

正交试验法优化马铃薯氧化淀粉制备工艺

使用正交试验法优化马铃薯氧化淀粉制备工艺,以马铃薯淀粉为原料,FeSO4为催化剂,H2O2为氧化剂干法制备氧化淀粉,并以羧基含量为评价指标,分别考察反应时间、反应温度、氧化剂用量、催化剂用量、体系含水量等因素对马铃薯淀粉氧化反应影响。得到最优工艺条件为:反应时间3.5h、反应温度60℃、FeSO4在淀粉中质量分数0.025%、H2O2与淀粉摩尔比0.285、反应体系含水量24.000%,在此条件下制得马铃薯氧化淀粉羧基含量为0.530%。     

Versuche zur Quellung des Kartoffelstärkekorns

Depending on the nature of the swelling agents the potato starch granules swell differently. The way of reaction depends on the hydrolizing, solvatizing, and hydrogen-linksplitting capacity of the solvent. The differences are explained by a new more detailed structure model of the starch grain. This model consists of a combination of different concepts, taking into account a core-shell structure, density layers, and cristalline micells.     

Stärkecitrate – Produktion und anwendungs-technische Eigenschaften

Starch Citrates – Production and Technical Application Properties. A dry reaction method for the esterification of root and cereal starches with organic poly-carbonic acids is described. With citric acid as reagent the native starch is mixed thoroughly with a concentrated solution in which the citric acid is available in a form of salt corresponding to the chosen pH value. With respect to the dry weight of starch the acid is used in concentrations of 5 to 40%. The pH value of the reaction mixture normally varies between 4.0 to 6.5. The mixture is first dried at a temperature below the gelatinization temperature of the starch and then heated for 1 to 5 h at temperatures between 110 and 140°C. After the heat treatment the free acid is washed out with water and the starch derivate is dried subsequently. Since the non-reacting citric acid can be recovered from the washing fluid and used again there is no waste water problem at all. Under appropriate reaction conditions products with high freeze-thawstability and/or acid- and shearstability can be obtained. The in vitro digestibility of the starch citrates decreases with increasing degree of esterification, in fact more with potato starch derivatives then with corn starch derivatives. All values for the digestibility, however, are better than those found with the same method in 8 commercial products of starch derivatives.     

Dynamische Entwicklung der Stärkeforschung und Stärkeindustrie in Japan

Dynamic Development of Starch Research and Starch Industry in Japan Refering to two lectures and visiting tours throughout Japan in 1962 and 1978 the dynamic development is indicated which has taken place in the Japanese starch research and Japanese starch industries within the past 16 years. In this connection the annual production figures as well as the most important field of applications for white potato, sweet potato, corn, and wheat starches are reported. Correspondent data are also made for starch saccharification products, whereat particular consideration is directed to the industrial production and marketing of high fructose syrup. As far as the starch research is concerned, the tremendous investments are emphasized which recently have been increased to a considerable extent. In this connection it is concluded that the remarkable progress which has taken place in both the Japanese starch research and Japanese starch industries obviously are based on two main factors. One of these two factors seems to be the almost unlimited financial possibilities of both government and industries, whereas the other one is connected with the extremely expressed working discipline of the Japanese employees. The great progress gained by the Japanese starch research as well as by the Japanese starch industries particularly within the past decade are not only very impressing, but at the same time also rather depressing with regard to the limited possibilities in the Federal Republic of Germany.     

Stärkegewinnung aus konserviertem Kartoffelreibsel

Starch Production from Preserved Potato Gratings. During industrial starch production potato gratings are produced which can be preserved by the addition of a 1.2% sodium hydrogensulfite solution. Preserved this way the durability of the gratings is defected neither by extreme differences in temperature nor by storage of 6 months and even longer. After storage the gratings can be returned into the industrial process to obtain the starch by washing out. The quality of this starch differs from the quality of potato starch washed out from non-preserved gratings: The pH-value is somewhat lower and the hot paste viscosity is slightly reduced. Contrary to this the typical curve of potato starch in the Brabender-Viscograph remains the same.     

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.     

Morphology of Some Legume and Tuber Starches Grafted with Polyacrylonitrile

Morphological aspects of three legumine and three tuber starches and their graft copolymers with polyacrylnitrile (PAN) prepared from granular and gelatinised states have been reported. Scanning electron microscopy revealed that grafting characteristics of legumine and tuber starches are quite different. In potato starch the hydrolysed S-g-PAN product showed that the grafting has occurred in the interior. In case of sweet potato starch a little grafting occurred on the surface of depression while normal grafting might have taken place in the interior through the depression. Little grafting seems to have occurred inside the tapioca starch granules. The grafting on legumine starches has mainly occurred on the surface of granules.     

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.