摘要:

AbstractElectron Microscopic Studies of Amylose Fibrils and Star‐Shaped Molecules Derived from Glycogen in the Form of the Iodine Complex.The amylose‐iodine complex crystallizes in the form of fibrils with uniform diameters of 40 Å. From very diluted solutions single rodlike molecules of the same diameter are obtained. The fibrils are formed at degrees of polymerisation between 500 and 20000. With shorter chainlengths disordered structures appear. An essential condition for the formation of the fibrils is an iodine concentration sufficient for the complete filling of the amylose helices. For the amylose iodine fibrils a model is proposed with folded chains oriented parallel to the fibril axis. Foldlengths of 100 to 200 Å are assumed. The possibility to make amylose chains visible is applied on glycogens with enzymatically extended branches. The molecules appear in the electron microscope in the form of

ISSN:0038-9056    

DOI:10.1002/star.19710230402

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractAn improved apparatus for the semi‐micro, differential, potentiometric titration of starch and its components with iodine is described. The necessary experimental manipulations are given in detail. The factors affecting the measurement — the amount of dimethylsulphoxide present, the buffer concentration, the method of dissolving the starch, the defatting procedure used on the starch, and the temperature of measurement — are critically examined.The new technique results in values of iodine binding capacity for starches which are 5‐ 15% higher than previous measurements. The significance of this finding is di

ISSN:0038-9056    

DOI:10.1002/star.19710230403

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractAir‐oxidation of corn starch in the presence of ammonium meta vanadate at 35–40°C and pH 9 has been studied. The resulting oxidized starch contained more carbonyl but less carboxyl as compared to an industrial oxidized starch. However, the presence of undesirable amounts of the catalyst imparted extremely high viscosity to the oxidized starch.The ultraviolet irradiation was found to have a pronounced effect on the air oxidation of starch in the presence of ammonium meta vanadate. Increased carboxyl content was observed in the UV light catalyzed oxidized st

ISSN:0038-9056    

DOI:10.1002/star.19710230404

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractIn the previous part of this series (Stärke 21 [1969], 163) it has been shown that β‐E25 resins have affinity for aromatic compounds, e.g. benzoic acid and m‐chlorobenzoic acid. Now it appears that mainly the undissociated acids are involved. The isothermal inclusion of undissociated benzoic acid can be described by a Langmuir isotherm. The isothermal inclusion of undissociated metachlorobenzoic acid follows no Langmuir equation. However, this inclusion can be described by a Freundlich isotherm. The kinetics of sorption of both acids are very complicated. At least three kinetic mechanisms are probably inv

ISSN:0038-9056    

DOI:10.1002/star.19710230405

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractOn the Microscopy of Starch Granules of Germinated Potatoes.Microscopic examinations of normally germinated as well as germinated and dried potato tubers and of the germs as such showed that the generalized assertion of D. Grebel, according to which a “melting” should be characteristical for the fermentative degradation (germination) of starch, cannot be confirmed. Indeed, the described melting phenomena occurred with single starch granules, the majority of the fermentatively deformed starch granules, however, showed the typical changes (channel formation) as they are to be seen with starch granules of cereals.With partially dried potato tubers and their germs the starch granules showed changes like those occurring with curcuma starch. Factors that are responsible for this symptom are being discus

ISSN:0038-9056    

DOI:10.1002/star.19710230406

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractOn the Relationship between the Under‐Water Weight of Potatoes and their Analytical Composition. This contribution deals with the relations between the under‐water weight of potatoes and their analytical composition. After explaining the main problems and presenting an introductory literature survey the results of the investigations are discussed. Dealing with the determination of the under‐water weight and its possible error sources, the physical principles of the buoyancy, the calculation of the starch contents based on the specific gravity of the potatoes, the error sources derived from the determination of both the gravity and buoyancy, and the possible faults caused by the dipping liquid are taken into particular consideration. A further part of the contribution describing a modification of the present under‐water weight determination is occupied by the detailed discussion of carrying out the modified under‐water weight determination and the relations between the starch contents estimated by using the classic Ewers method, the present under‐water weight and the modified under‐water weight. Finally, the relations between the starch contents as obtained by the Ewers procedure and the portion of none‐starch substances as well as the relations between the under‐water weight and the starch contents are discus

ISSN:0038-9056    

DOI:10.1002/star.19710230407

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractBiochemical‐Technological Studies on Wet‐Processing of Maize. Part 6. Examination of the Proteolytic and the Lipolytic Enzyme System of Maize.1. Maize lipase shows the following optima: pH‐optimum about 8,0, temperature optimum about 40°C.2. The efficiency of the proteolytic enzymes covers a broad pH‐range (2,0–9,0). Efficiency reaches a distinct maximum between pH 3,5 and 4,5 and a weaker maximum at pH 8. Enzymes show high stability (45 °C). For proteolysis of the maize protein temperatures around 40 °C are the optimum.3. Maize proteases are inactivated by 2 · 10−3M potassium persulfate and 6 · 10−4M potassium bromate; 6,5 · 10−3M cysteine doubles activity.4. SO2‐contents up to 0,1% cause an increase of proteolytic degradation

ISSN:0038-9056    

DOI:10.1002/star.19710230408

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19710230409

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19710230410

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19710230411

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY