摘要:

AbstractDetermination of the Distribution of Molecular Weights in Native Starches by Gel Chromatography. The distribution of the molecular weights of polysaccharides in corn, potatoe and rice starch were investigated by fractionation of starch polysaccharides in a gel chromatographic system. The amylopectin component of the dispersed starch was excluded from the gel. Therefore the conclusion is likely that the molecular weight of amylopectin is higher than 20 × 106.The gel columns were calibrated by chromatography of dextran fractions of known molecular weight. By comparison of the elution volumes of dextran fractions of know molecular weight with the elution volumes of amylose fractions it was possible to determine their molecular weights. From curves of molecular distribution the amount of amylose as percentage of total amylose can be determined. The average molecular weight of potatoe amylose (M̄w50%) is about 400 000 whereas it amounts to 100 000–200 000 in the case of rice and corn starch. The amylose of a “High Amylose Starch” (about 75% amylose) has a molecular weight of

ISSN:0038-9056    

DOI:10.1002/star.19750271002

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

摘要:

AbstractSome cereal starches were investigated whether glucose phosphate residues were in the polysaccharides. Significant amounts (6–15 ppm, as P) of glucose 6‐phosphate were found in the acid hydrolysates of corn, waxy corn, rice and waxy rice starches. After the extensive action of bacterial α‐amylase on these starches phosphorylated oligosaccharide (α‐LPD) was recovered in reasonable yield by a DEAE‐Sephadex column chromatography. The α‐LPDs prepared from two sources of waxy rice starch contained 81.8 and 94,3% of P0at the 6th position of glucose residues and the rest of P0at the 2nd and/or 3rd positions of glucose residues. All these results show that these starches have glucose phosphate residues. In wheat starch, however, no evidence for the presence of glucose phosphate residues has

ISSN:0038-9056    

DOI:10.1002/star.19750271003

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

摘要:

AbstractSamples of 2‐O‐(2‐hydroxyethyl)‐D‐glucose, 3‐O‐(2‐hydroxyethyl)‐D‐glucose, and 6‐O‐(2‐hydroxyethyl)‐D‐glucose were made by allowing glucose derivatives containing suitable blocking groups to react with 2‐bromo‐ethanol, followed

ISSN:0038-9056    

DOI:10.1002/star.19750271004

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

摘要:

AbstractToxic Heavy Metals — Analytics and Importance to Starch Industries. In order to set limits concerning the maximal tolerable content of toxic heavy metals such as mercury, lead, cadmium and arsenic in food and feed‐stuff, the Federal Government ist preparing laws dealing with this matter. The present phase of this legislation is being explained.The analytical problems arising in connection with the determination of toxic heavy metals in food, particularly grain products are being outlined with emphasis on measurements by atom adsorptions photometry.Finally a survey of the present state of grain contamination by heavy metals is given, with special consideration to the grain most important for the starch indus

ISSN:0038-9056    

DOI:10.1002/star.19750271005

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

摘要:

AbstractThe extracellular α‐amylase from Streptomyces aureofaciens is adsorbed on modified starches, which are cross‐linked with epichlorhydrine or with phosphorus oxichloride. The affinity of the amylase towards the cross‐linked starch is influenced by the presence of soluble substrates, pH medium and accompanying pr

ISSN:0038-9056    

DOI:10.1002/star.19750271006

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

摘要:

AbstractProteins of rye flour extracts were fractionated between pH 3 and 10 applying the electrofocusing technique both in liquid column and gel slab. The extracts for the gel study were heated to 60, 70, 90 and 100°C to study the heat inactivation of the amylolytic activity. The protein content of the fractions was determined using the UV‐absorption at 280 nm. The amylolytic activity of the column factions was studied using agar‐plate diffusion test and the activity in the gel slabs was revealed by incubation at pH 4.7 in Lintner‐starch and limit dextrin solutions, respectively, followed by iodine staining.The heat treatment was found to cause displacement of the isoelectric points of the protein fractions as detected with Coomassie‐blue staining of the gel slabs. Amylolytic activity was frequently discovered after Lintner‐starch incubation without any counterpart after that in limit dextrin. Limit dextrin treatment again independently exhibited blur zones or colour strengthening. On an α‐1,6‐glucanase activity

ISSN:0038-9056    

DOI:10.1002/star.19750271007

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19750271008

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19750271009

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19750271010

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19750271001

出版商:WILEY‐VCH Verlag GmbH    

年代:1975

数据来源: WILEY