Hirse und Bruchreis als Basismaterial für die Glucosegewinnung

Sorghum and Broken Rice as Basic Materials for Glucose Production. Two starch containing raw materials, Mexican sorghum flour and Pakistan broken rice, were processed to various saccharification products without previous starch isolation. The low viscosity fluids received by “direct” enzymatic saccharification of the starch material were worked up into high maltose or high glucose syrups, resp., the latter of which was undergone isomerization by means of glucoseisomerase. The used immobilized glucoseisomerase lost its activity very early and was not reactivated by treatment with pure glucose solution. From both raw materials saccharification products of lower purity were obtained, in comparison with purified starches. It is pointed out, however, that in the food sector as well as in the field of technical products exaggerated demands of purity are senseless, because in most cases starch saccharification products are contaminated again during further processing or are subjected to purification processes after conversion.     

EFFECT OF GAMMA RADIATION ON WHEAT STARCH AND ITS COMPONENTS

SUMMARY– Studies on the susceptibility of irradiated wheat starch, amylose and amylopectin to alpha- and beta-amylolysis reveal that they are more susceptible to enzyme actions, compared to their unirradiated controls; however, irradiated amylose seems to be comparatively more vulnerable. From irradiated starch, series of oligosaccharides of the maltose series are discernible, while glucose appears only above 200 Krad dose level. Quantitative analysis of the radiolytic breakdown products of starch reveal that at high dose levels (1 Mrad) maltose, maltotriose and maltotetrose are the main products. Results on the separation of radiolytic breakdown products suggest they resemble those produced by alpha-amylolysis of starch.     

Production and Application of a Maltogenic Amylase by a Strain of Thermomonospora viridis TF-35

An extracellular and thermostable maltogenic amylase-producing moderate thermophile (Thermomonospora viridis TF-35), which grew well at 28–60°C, with optima at 45°C and pH 7, was isolated from soil. Maximal enzyme production was attained after aerobical cultivation for 32 h at 42°C with a medium (pH 7.3) composed of 2% (w/v) soluble starch, 2% gelatin hydrolyzate, 0.1% K₂HPO₄ and 0.02% MgSO₄ · 7H₂O. The partially purified enzyme, which was most active at 60°C and pH 6.0 and stabilized with Ca²⁺, converted about 65, 80, 75, 75, 65 and 60% of maltotriose, maltotetraose, maltopentaose, amylose, amylopectin and glycogen into maltose as a major product under the conditions used, respectively. Glucose and small amounts of maltooligosaccharides were also formed concomitantly as by-products. The molar ratio of maltose to glucose from maltotriose were larger than 1 during all stages of the hydrolysis. About 70 and 76% of 25% (w/v) potato starch liquefites having a 3.5 DE value were converted into maltose by the enzyme in the absence and presence of pullulanase during the saccharification, respectively. About 90 and 94% of the starch liquefites were also converted into maltose with relatively low contents of maltooligosaccharides by the cooperative 2 step reaction with the enzyme after obtaining starch hydrolyzates containing about 85 and 90% maltose by the simultaneous actions of soybean ß-amylase and debranching enzymes.     

Changes of Carbohydrates and Molecular Structure of Dextrins During Enzymatic Hydrolysis of Starch with Maltogenase Participation

Investigations of the potato starch hydrolysis during bacterial α-amylase “BAN 240 L” liquefaction to 19.5 DE and then saccharification with exo-acting α-amylase “Maltogenase 1000 L” alone and together with pullulanase “Promozyme 200 L”, were carried out. Under adequate conditions at different enzyme dosages hydrolyzates of the maltose, content of 60 to about 80% in DS at significantly lower glucose and minimal maltotriose content were obtained. Investigations comprised both carbohydrate contents in hydrolyzates, changing with hydrolyse course and dextrin molecular structure in hydrolyzates. It was found that decreasing dextrin molecular weight and the number of branchings in dextrin molecules was accompanied by characteristic changes of the viscosity of hydrolyzate solutions.     

A more Efficient Starch Degradation by the Combination of Hydrolase and Transferase Activities of α‐Amylase and Cyclomaltodextrin Glucanotransferase

α‐Amylases catalyze the hydrolysis of internal α‐(1→4) linkages of glucose polymers as their main reaction; however, some α‐amylases catalyze transfer reactions in addition to hydrolysis. It has been observed that those α‐amylases capable of transferring glycoside residues are also those that generate low molecular weight products from their action on starch (i.e. saccharifying α‐amylases). In this paper the product profiles of a liquefying α‐amylase, a cyclomaltodextrin glucanotransferase and both enzymes acting together on starch and maltodextrins are compared. The increase in glucose and maltose concentration, when both enzymes act together, is due to the combined action of the transfer and hydrolytic activity of CGTase and the liquefying α‐amylase, respectively.     

Pancreatic Alpha Amylase Hydrolysis Products of Modified and Unmodified Tapioca Starches

Three gelatinized tapioca starches [unmodified (A), hydroxypropyl distarch phosphate (B) and hydroxypropyl starch (C)] were hydrolyzed by hog pancreatic α-amylase (EC 3.2.1.1 α-1,4-glucan 4-glucanohydrolase). Oligosaccharide constituents of the hydrolyzates were separated by thinlayer chromatography and quantified by spectrodensitometry. Glucose, maltose, maltotriose and maltotetraose were identified by cochromatography. Hydrolyzates from starches B and C had lesser amounts of the lower molecular weight oligosaccharides (G₁—G₄) than did those from starch A. The products of hydrolysis varied quantitatively with the degree of hydrolysis.     

Studies on Starch Granules Digestion by α-Amylase

Raw corn starch was partially digested with commercial α-amylase for a short period of 7–8 h at 25°C to obtain granular pitting. The patterns of granular digestion was observed by light and scanning electron microscopy (SEM). The main soluble products of starch digestion were glucose, maltose and higher oligosaccharides. In vitro digestion of starch was discontinued on the basis of nature of granular pitting and relative release of glucose in the reaction mixture. The pitted starch was obtained with high yields and found to be warm water soluble.     

A Flow Injection System for the Determination of Starch in Starch from Different Origins with Immobilized α-Amylase and Amyloglucosidase Reactors

A heat stable α-amylase (Termamyl) was immobilized on controlled pore glass (CPG) with a pore size of 1 489Å and amyloglucosidase (AMG) was immobilized on a ceramic silica support (Micropil A) with a pore size of 300Å. These enzyme supports were packed into two separate immobilized enzyme reactors (IMERs) which together with a third reactor containing co-immobilized glucose dehydrogenase/mutarotase were incorporated into a flow injection (FI) system for the determination of the total glucose content of starch related poly- and oligosaccharides. Samples of maltose, a maltooligosaccharide mixture, three soluble starches, three amylopectins, two amyloses, glycogen, and native starches from different origins were injected. The degree of hydrolysis was determined by comparing the produced amount of glucose in the FI system with the calculated amount of glucose in the samples and with samples to which had been added and let to react for six hours soluble α-amylase and AMG before injected into the FI system also containing the IMERs. Virtually complete conversion to glucose was obtained for maltose, maltooligosaccharides, two soluble starches and native potato starch. Maximum enzymatic degradation by the starch hydrolyzing enzyme reactors was obtained in most instances except for glycogen (96%), native wheat (88%), rice (93%), and corn starch (83%).     

Effect of different cultivation conditions on Lactobacillus manihotivorans OND32T, an amylolytic lactobacillus isolated from sour starch cassava fermentation

Study of the cassava sour starch fermentation has led to the isolation of a new homofermentative amylolytic lactic acid bacterium, Lactobacillus manihotivorans OND32T, whose nutritional requirements have been investigated in this work. The main effect of deleting one of the substrate components of the MRS-starch medium was to reduce the amylase production. When starch fermentation with nitrogen as a gas phase was compared to fermentation under aerobic conditions, both growth and amylase production were reduced whereas lactic acid formation was not affected. Addition of carbon dioxide (> or = 20% v/v) to the nitrogen gas phase restored growth and amylase production. The amylase production was high with starch, maltose or cellobiose contrary to glucose, fructose and sucrose. During mixed fermentation of glucose and maltose, a diauxic growth was observed. The maltose consumption and the amylase production started after the glucose depletion. The presence of maltose altered the carbon assimilation from glucose, whereas the energetic pathway was not affected. It is concluded that the elimination of soluble sugars by the wet extraction of starch during the processing of cassava, together with the expected in situ CO2 production, are conditions favouring the growth and the amylase synthesis. However, these are likely to be limited by the low nitrogen content in cassava.     

Changes of Carbohydrate Compositions During Enzymatic Hydrolysis of Starches of Various Origin

Hydrolysis of starch of various origin, liquefied with bacterial α-amylase to DE 13.5 and then saccharified only with glucoamylase and simultaneously with pullulanase to DE 97–98, was investigated. It was found that the hydrolysis of wheat starch was delayed in relation to the hydrolysis of potato and maize starch, particularly in the first period of saccharification. The delay decreased with time but at the end of the saccharification it was still 24 h. The carbohydrate composition of wheat starch hydrolyzates differed from the hydrolyzates of potato- and maize starch in a smaller content of glucose and lower oligosaccharides (G₁-G₄) and a greater content of higher oligosaccharides and dextrins (G₅-G_n). This, among other things, could have an influence on higher viscosity of solutions of wheat starch hydrolyzates in relation to respective hydrolyzates of potato and maize starch.     

Two-Dimensional Nuclear Magnetic Resonance Studies of Starch and Starch Products

The use of two-dimensional Nuclear Magnetic Resonance (NMR) spectroscopy as applied to studies of starch, starch products and glycogen is reported. The use of both homonuclear correlation (COSY, relay-COSY and HOHAHA) and heteronuclear correlation (HMQC, HETCOR) experiments is discussed. This approach makes it possible to obtain complete assignments of the proton NMR spectra of these polysaccharides. This is not possible from 1-D spectra due to excessive overlap of the non-anomeric proton signals. The resulting assignments are useful in obtaining structural information regarding starch and related products. Moreover, the greater inherent resolution of the two-dimensional spectra can reveal the presence of low molecular weight carbohydrates (glucose, maltose etc.) in dextrin samples, thus providing information about carbohydrate composition.     

Enzymatic Hydrolysis of Wheat Starch into Glucose

In the presented research, glucose hydrolyzates were obtained by acting on wheat starch, which was liquefied with the aid of bacterial α-amylase, with Spezyme GA 300W Y553, an enzymatic preparation composed of glucoamylase and lysophospholipase, as well as with Amyloglucosidase AMG 300L, a glucoamylase preparation. The following physical and chemical properties of the obtained hydrolyzates were tested the glucose equivalent, the filtration power, the colour factor and the transparency factor. In the process of saccharification of wheat starch into glucose, the optimum dose of Spezyme, the enzymatic complex, is a concentration equal to 0.3%/d.m., at which after 72 h of process duration, the maximum 98 DE reducibility was achieved. Using the Spezyme preparation, which, thanks to the fact that apart from glucoamylase, it contains lysophospholipase, results in an improvement of the filtration power of hydrolyzates obtained with the participation of this preparation.     

Untersuchungen über die Retroaradation der Stärke in konzentrierten Weizenstärkegelen. Einfluß von Stärkeabbauprodukten auf die Retrogradation der Stärke

Investigations on the Retrogradation in Concentrated Wheat Starch Gels. Part 2. Effect of Starch Degradation Products on the Starch Retrogradation . In the present work the influence of added starch degradation products on the rigidity and retrogradation of 50% wheat starch gels was investigated. The gels prepared with the addition of maltodextrin were extracted with 40% ethanol, the extracts were analysed for glucose oligomers. The effect of the added starch degradation products was dependent on the degree of degradation. Weakly degraded, acid modified starches take part in the retrogradation process as do white and yellow dextrins as well as maltodextrins with dextrose equivalents (DE) <30. Maltodextrins and glucose sirups with a DE ≧ 30 act as plasticizers: in concentrations of 5-30% (based on starch d. s.) they reduce gel strength without affecting the retrogradation velocity. The plasticizing effects are particularly evident with maltose and maltotriose as well as maltotetraose and pentaose. Even so the extractibility of oligomers with a degree of polymerisation (DP) ≥ 6 was reduced, the hexamer and octamer might still have a plasticizer effect. With glucose, concentrations ≥ 26% were needed to observe plasticizing. The relation of these findings to bread staling is discussed.     

High Performance Liquid Chromatographic Separation of Oligosaccharides Using Amine Modified Silica Columns

The separation of seven disaccharides (sucrose, turanose, maltulose, maltose, kojibiose, isomaltose, and gentiobiose) on Zorbax NH₂, an amine modified silica column, is described. Optimal conditions for resolution of saccharides present in natural honey, high fructose corn syrup, starch hydrolyzates of DE 17, DE 40, and DE62, and Jerusalem artichoke raw juice on Zorbax-NH₂ or micro Bondapak-NH₂ column are presented.     

Solubility of Maltose in Water in the Presence of Glucose and Maltotriose

Maltose is used in various forms in the food and pharmaceutical industries. Maltose syrups produced by enzymatic starch conversion usually contain impurity sugars, e.g. glucose, maltotriose, and higher saccharides, which affect the solubility of maltose. Using a simple refractometric technique, solubility data for the pure and impure maltose systems were determined. Glucose and maltotriose were found to decrease the equilibrium concentration of maltose but increase the total dissolved solids concentration.     

A Novel Debranching Enzyme for Application in the Glucose Syrup Industry

Some of the properties of a novel, microbial, amylopectin debranching enzyme are described. The enzyme belongs to the class of debranching enzymes known as pullulanases (EC 3.2.1.41) and is characterized by being stable at higher temperatures and lower pH's than previously described enzymes of this type. The novel debranching enzyme can be used together with Aspergillus niger glucoamylase to improve the efficiency of starch conversion to glucose or together with cereal ß-amylases to increase the maltose level in high maltose syrups. Examples of these applications are given. It is expected that the enzyme will gain widespread acceptance in the glucose syrup industry.     

Enzymic Determination of Starch in Samples with High Sugar Content

Starch may be determined by hydrolysis with α-amylase and amyloglucosidase followed by specific measurement of glucose using glucose oxidase. However biological samples to be analysed for starch often also contain glucose, maltose and higher oligosaccharides derived from the hydrolysis of starch. These sugars may be difficult to remove quantitatively by solvent extraction. We have found that reduction with sodium borohydride followed by evaporation with 2,2 dimethoxypropane removed interference from glucose, maltose and the two reducing terminal residues from higher oligosaccharides. The specific glucose test was not sensitive to glucitol produced by reduction of free glucose. Maltitol was not hydrolysed significantly by the amyloglucosidase, removing interference from maltose and the two reducing terminal residues from higher polymers. The method has potential for monitoring the hydrolysis of starch especially in the mobilisation of starch reserves in plant tissues such as in the endosperm of germinating cereal grains. A reduction ratio based upon the method is proposed for use in characterising starch hydrolysates.     

Über die chemische Bindung der Stärkeproteine an ihre Kohlenhydrate

On the Chemical Bonding of Starch Proteins on their Carbohydrates After acetylation of potato, maize and rice starch there is a residue with a complex of carbohydrate and protein. Hydrolysis with 2-N HCl produces glucose and maltose; a hydrolysis with 6-N HCl produces the named amino acids. Also in strong sulfuric acid there is a residue with glucose, maltose and amino acids after hydrolysis. In the residues of the three starches are the same eight amino acids and in rice starch arginine, leucine and histidine besides them. Proline and hydroxiproline are not present. The starch granules are described as tissues.     

Isolation and Characterization of Starch-Iodine Positive Material Formed During Saccharification of Corn Starch

The increasing sophistication of customers has put pressure on corn wet-millers to improve product quality. One quality requirement is that glucose and corn syrups be free of material stained blue or green by iodine, i.e. free starch. Observations from a number of corn wet milling plants indicate that liquified corn starch may test negative for free starch but yield a positive iodine test after saccharification. Such dextrose hydrolyzates are difficult to process into product and often fail to meet customer specifications. The problem has been traced to small (0.2 to 1.0 μm) particles which are present in the starch supply. The particles exhibit an iodine spectrum similar to that of gelatinized corn starch. Enzymatic degradation of the particles was compared to that of gelatinized and non-gelatinized starch, and lipid-amylose complexes; the behavior of the particles most closely resembled nongelatinized starch. Extended liquefaction reduces, but does not eliminate the problem. Cellulase, hemicellulase, amylase, and proteasewere tested as adjuncts to normal glucoamylase products; none of these were effective in assisting hydrolsis of the particles under saccharification conditions. The particles can be completely eliminated by microporous filtration of liquefact or dextrose hydrolyzate.     

Optimierung der Gewinnung von Maltosesirupen durch verschiedene Enzymkombinationen

Optimization of the Production of Maltose Syrups by Different Enzyme Combinations. Maltose syrups are of importance for the production of many sweets and baking goods, resp. These starch hydrolysates show reduced browning capacity, retarded crystallization phenomena, and are less sweet, less viscous and less hygroscopic in comparison with syrups of higher glucose content. Enzymatic preparation of such products with regard to the influence of substrate and enzyme concentration, reaction time and added calcium on maltose formation by fungal-α-amylase or barley-β-amylase was investigated. For increasing the maltose content pullulanase as a debranching enzyme was applied. Commercial maltodextrin was used as substrate. The maltogenic enzymes showed different substrate tolerances. High amounts of enzyme did not lead to the expected high amounts of maltose. On the other hand, low enzyme concentrations could not be compensated by extended reaction times. Different substrate tolerances also appeared when mixtures of maltogenic and debranching enzymes came into use.