EurekaMag.com logo
+ Translate

The chemical structure of amylose and amylopectin fractions of starch from tobacco leaves during development and diurnally-nocturnally


, : The chemical structure of amylose and amylopectin fractions of starch from tobacco leaves during development and diurnally-nocturnally. Carbohydrate Research 282(2): 247-262

Starches, isolated from rapidly expanding tobacco leaves four times during the day and night and once from fully expanded leaves, were fractionated with concanavalin A. From an examination of the amounts and properties of amylose, the diurnal decrease in iodine absorption of the starches on illumination appeared to be due to an increase in its branched character, and possibly the presence of unbranched polymer of low dp, combined with a decrease in the proportion of amylose fraction. The increase in apparent amylose content with age was due to an increase in the proportion of amylose. The amylose fractions at different times had only small differences in average mol size in solution and relative mol wt (M-r near 4 times 10-5) which were lower than those of storage organs. The average mol size in solution and relative mol wt of the amylopectins decreased during illumination, increased in darkness, and were lower (M-r 2-2.7 times 10-6) at all times than those from storage organs. Debranching followed by size-exclusion chromatography (on Fractogel TSK 50(S)) gave similar proportions of long, medium, and short chains for all amylopectin samples, and these proportions differed from those for debranched amylopectin from n-maize seed starch. On debranching and chromatography of the amylopectin beta-limit dextrins (which gives an estimate of the proportions of core chains) differences persisted. Structural characteristics of amylopectin from tobacco leaf starch were similar to those of normal genotypes from storage organs. The proportion of glucosyl units in core chains, the external-to-core chain ratio, and indices of compactness were calculated for a number of (1-4)(1-6) alpha-glucans. A plot of the index of compactness for glycogens and amylopectins showed that the decrease in compactness and the increase in total average chain length that occurs from glycogen to normal and then to amylose extender amylopectins involves a proportionate increase in average internal, external, and core chain lengths and not a selective increase in one type of chain.

Order PDF Full Text

Close
Close

Click here to order any other PDF Full Text


Accession: 002980248

PMID: 8901089

DOI: 10.1016/0008-6215(95)00381-9

Download PDF Full Text: The chemical structure of amylose and amylopectin fractions of starch from tobacco leaves during development and diurnally-nocturnally


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Related references

Krishnaswamy, K.G.; Sreenivasan, A., 1948: Separation and determination of the amylose and amylopectin fractions of starch. A comparative study on pea starch was made of procedures for the fractionation of starch based on the differential solubilities of amylose and amylopectin in hot water and in butanol- or thymol-saturated water. Extraction with hot water at 60 Cyie...

Katz, J.; Hassid, W.Z.; Doudoroff, M., 1948: Arsenolysis and phosphorolysis of the amylose and amylopectin fractions of starch. Nature 161(4081): 96-96

Mua, J.P.; Jackson, D.S., 1998: Retrogradation and gel textural attributes of corn starch amylose and amylopectin fractions. An understanding of relationships between starch molecular structure and function could increase the opportunity to develop additional uses for starch. Using a combined aqueous (aq.) leaching and alcohol precipitation technique, six amylose fracti...

Mua, J.P.; Jackson, D.S., 1997: Relationships between functional attributes and molecular structures of amylose and amylopectin fractions from corn starch. Understanding starch structure-function relationships is vital to the continued development for new uses for starch. Fractionated corn amylose and amylopectin, with known molecular weights, chain lengths, and branching and crystalline ratios, were...

Damaschun, G.; Gernat, C.; Stute, R., 1997: Structure of amylopectin and amylose in starch granules. Starch 49(9): 371, Sept

Menzel, C.; Andersson, M.; Andersson, R.; Vázquez-Gutiérrez, Jé.L.; Daniel, G.; Langton, M.; Gällstedt, M.; Koch, K., 2016: Improved material properties of solution-cast starch films: Effect of varying amylopectin structure and amylose content of starch from genetically modified potatoes. High-amylose potato starches were produced through genetic modification resulting in changed granule morphology and composition, with higher amylose content and increased chain length of amylopectin. The increased amylose content and structural ch...

Klucinec, J.; Thompson, D., 2002: Amylopectin nature and amylose-to-amylopectin ratio as influences on the behavior of gels of dispersed starch. The importance of the nature of the amylopectin and the amylose-to-amylopectin ratio in the gelation of high-amylose maize starch was examined by preparing gels of model systems using amylose (AM) from a high-amylose maize starch mixed with an amy...

Zhu, F.; Bertoft, E.; Seetharaman, K., 2014: Characterization of internal structure of maize starch without amylose and amylopectin separation. Normal maize starch was used to characterize the internal structure of starch without separating amylose and amylopectin, and the result was compared with amylose-free waxy maize starch. The clusters in the whole starch were produced by partial hy...

Shi, Y.C.eng; Capitani, T.; Trzasko, P.; Jeffcoat, R., 1998: Molecular structure of a low-amylopectin starch and other high-amylose maize starches. The molecular structure of two commercially available high-amylose maize starches, HYLON V starch and HYLON VII starch, and of a newly developed low-amylopectin starch (LAPS) was examined. These high-amylose starches give three apparent fractions...

Mua, J.P.; Jackson, D.S., 1997: Fine structure of corn amylose and amylopectin fractions with various molecular weights. Characterization of starch molecular structure is vital to comprehending starch structure-function relationships. Four corn starches were fractionated by aqueous leaching into six amylose and five amylopectin fractions. Molecular weight (MW), bran...