摘要:

AbstractAdsorption of Electrolytes on Potato Starch. Heat Development, Swelling and Contraction.On addition of electrolyte solutions to moist potato starch an adsorption takes place, accompanied by the development of heat and by swelling. In alkali salts both phenomena proceed rapidly, usually within a few minutes, and reversible.In potassium salts the evolution of heat depends on the anion (in the sequence of the lyotropic series: rhodanid strongly adsorbed with high thermal effect, sulphate weakly adsorbed with hardly any effect). The amount of swelling on the contrary is hardly different in this case, and the amount of contraction is the same. In this respect there is a contrast with earlier research on the adsorption of water in air‐dry starch in which heat development and contraction proved to be proportional.Calcium hydroxyde is adsorbed in much higher quantities than those of the monovalent cations and this adsorption takes a much longer time (up to 50 minutes).The adsorption of hydroxyl ions from monovalent hydroxydes is augmented by the addition of neutral salts. The practical combination NaOH‐Na2SO4is stud

ISSN:0038-9056    

DOI:10.1002/star.19710230202

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractA practical, strictly chemical process has been developed for the periodic acid oxidation of starch to dialdehyde starch. In the procedure spent oxidant is converted by alkaline hypochlorite to insoluble sodium paraperiodate, which is recovered in high yield for recycling. The process is suitable for small‐scale production of dialdehyde starches of various carbonyl content

ISSN:0038-9056    

DOI:10.1002/star.19710230203

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe integral heats of dehydration of samples of wheat starch of varying moisture content have been determined by simultaneous differential thermal analysis (D. T. A.) and thermogravimetric analysis (T. G. A.). The heats are independent of moisture content up to about 1.5 water molecules per anhydroglucose unit. The value of the heat change is consistent with the rupture of two hydrogen bonds for the removal of each water molecule and it is suggested that each water molecule is hydrogen bonded between adjacent starch chains, or between two sites on the same coiled chain. A few results obtained with potato starch suggest a similar pattern of behaviour.

ISSN:0038-9056    

DOI:10.1002/star.19710230204

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractIn organic solvents, gelatin can induce the solubilization of glycogen and other polysaccharides. It was shown that the solubilization reaction was mediated through polysaccharide‐protein hydrogen bonds. Glycogen‐gelatin binding was influenced by the relative concentration of glycogen to the protein. The induced solubilization of glycogen was partially inhibited by temperatures above 0 °C. Water was shown to inhibit glycogen‐gelatin interactions in acidified methanol, ethanol, n‐propanol and tertiary butanol. In general, it was found that the most hydrophobic alcohols were the best solvents for the glycogen‐gelatin solubilization reaction. The solubility of the glycogen‐gelatin complex was determined and found to be 0.22 mg/ml. The presence of strong acids tended to inhibit complex formation while weak acids promoted the solubilization reaction. A method for the fractionation of gelatin into distinct molecular weight classes was developed by use of a methanol‐phenol solvent system. High molecular weight gelatins were better glycogen solubilizing agents than low molecular w

ISSN:0038-9056    

DOI:10.1002/star.19710230205

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe colorimetric iodine method of amylose estimation in rice has been simplified. The flour is dispersed in alkali by heating in water bath or by overnight soaking at room temperature. The extract is neutralized before colour development by direct addition of phenolphthalein and decolourizing with dilute acid.No simplified method of defatting (including extraction by methanol at room temperature) was found satisfactory. But apparent amylose content as determined in undefatted milled rice flour was close to 86% of the true value in 46 milled rice samples tested; hence determination without defatting and multiplication of the results with 1.16 was satisfactory for routine and approximate work. The apparent amylose value was, however, dependent on the degree of polish of the rice.Particle size of the flour within reasonable limits had no appreciable effect on the results. The extract was quite stable even when stored in the room temperature.

ISSN:0038-9056    

DOI:10.1002/star.19710230206

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe Influence of Various Factors on the Content of Starch‐free Substance in Potatoes.The influence of Substances containing nitrogen, phosphorus and potassium, which are present in potatoes because of various manuring conditions, on the total content of starch‐free matter in potatoes has been examined. It was found that those manuring conditions, which change the content of substances containing nitrogen, also influence the content of starch‐free substances. The effect of phosphorus is considerably less perceptible. The least influence on the content of starch‐free substances is exerted by potassium. The amount of starch‐free substance is steadily decreasing during the whole course of the vegetati

ISSN:0038-9056    

DOI:10.1002/star.19710230207

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractA hot‐press, protein‐dialdehyde starch glue was used experimentally to prepare plywood from yellow birch veneers. Gluing conditions were similar to those that were previously effective for bonding southern pine veneers to form interior‐type plywood test panels. Yellow birch plywood produced under the conditions so developed met the performance requirements for Type II hardwood plywood. The excellent tack that was obtained with cold‐pressed panels would allow prepressing in mill operations. Further‐more, yellow birch and southern pine veneers were sufficiently compatible with this moderately alkaline glue to permit mixing these species in the same plywood construction. Bleedthrough of glue was not observed in plywood panels having 1/26‐in. birch face veneers. Results indicate that the protein‐dialdehyde starch glue should be useful in the manufacture of birch Ty

ISSN:0038-9056    

DOI:10.1002/star.19710230208

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractRetrogradation has a positive influence on mouth appeal of rehydrated mashed potato products, and a negative effect on the consistency of dried pulses. The texture of rehydrated precooked rice can be improved by retrogradation.

ISSN:0038-9056    

DOI:10.1002/star.19710230209

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19710230210

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19710230211

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY