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A Lowly Digestible-Starch Diet after Weaning Enhances Exogenous Glucose Oxidation Rate in Female, but Not in Male, Mice
Fernández-Calleja, José M.S. ; Bouwman, Lianne M.S. ; Swarts, Hans J.M. ; Billecke, Nils ; Oosting, Annemarie ; Keijer, Jaap ; Schothorst, Evert M. van - \ 2019
Nutrients 11 (2019)9. - ISSN 2072-6643
13C-starch - amylase - amylopectin - amylose - C57BL mice - glucose oxidation - glycaemic index - indirect calorimetry
Starches of low digestibility are associated with improved glucose metabolism. We hypothesise that a lowly digestible-starch diet (LDD) versus a highly digestible-starch diet (HDD) improves the capacity to oxidise starch, and that this is sex-dependent. Mice were fed a LDD or a HDD for 3 weeks directly after weaning. Body weight (BW), body composition (BC), and digestible energy intake (dEI) were determined weekly. At the end of the intervention period, whole-body energy expenditure (EE), respiratory exchange ratio (RER), hydrogen production, and the oxidation of an oral 13C-labelled starch bolus were measured by extended indirect calorimetry. Pancreatic amylase activity and total 13C hepatic enrichment were determined in females immediately before and 4 h after administration of the starch bolus. For both sexes, BW, BC, and basal EE and RER were not affected by the type of starch, but dEI and hydrogen production were increased by the LDD. Only in females, total carbohydrate oxidation and starch-derived glucose oxidation in response to the starch bolus were higher in LDD versus HDD mice; this was not accompanied by differences in amylase activity or hepatic partitioning of the 13C label. These results show that starch digestibility impacts glucose metabolism differently in females versus males.
Direct and Long-Term Metabolic Consequences of Lowly vs. Highly-Digestible Starch in the Early Post-Weaning Diet of Mice
Fernández-Calleja, José M.S. ; Bouwman, Lianne M.S. ; Swarts, Hans J.M. ; Oosting, Annemarie ; Keijer, Jaap ; Schothorst, Evert M. van - \ 2018
Nutrients 10 (2018)11. - ISSN 2072-6643
adipose tissue - amylopectin - amylose - C57BL mice - carbohydrates - glycemic index - indirect calorimetry - metabolic flexibility - nutrition - sexual dimorphism
Starches of low and high digestibility have different metabolic effects. Here, we examined whether this gives differential metabolic programming when fed in the immediate post-weaning period. Chow-fed mice were time-mated, and their nests were standardized and cross-fostered at postnatal days 1⁻2. After postnatal week (PW) 3, individually housed female and male offspring were switched to a lowly-digestible (LDD) or highly-digestible starch diet (HDD) for three weeks. All of the mice received the same high-fat diet (HFD) for nine weeks thereafter. Energy and substrate metabolism and carbohydrate fermentation were studied at the end of the HDD/LDD and HFD periods by extended indirect calorimetry. Glucose tolerance (PW 11) and metabolic flexibility (PW14) were analyzed. Directly in response to the LDD versus the HDD, females showed smaller adipocytes with less crown-like structures in gonadal white adipose tissue, while males had a lower fat mass and higher whole body fat oxidation levels. Both LDD-fed females and males showed an enlarged intestinal tract. Although most of the phenotypical differences disappeared in adulthood in both sexes, females exposed to LDD versus HDD in the early post-weaning period showed improved metabolic flexibility in adulthood. Cumulatively, these results suggest that the type of starch introduced after weaning could, at least in females, program later-life health.
Expression of an amylosucrase gene in potato results in larger starch granules with novel properties
Huang, X. ; Nazarian, F. ; Vincken, J.P. ; Ji, Q. ; Visser, R.G.F. ; Trindade, L.M. - \ 2014
Planta 240 (2014)2. - ISSN 0032-0935 - p. 409 - 421.
antisense inhibition - branching enzyme - tuber - synthase - glycogen - amylopectin - reduction - amylose - sucrose - size
Main conclusion - Expression of amylosucrase in potato resulted in larger starch granules with rough surfaces and novel physico-chemical properties, including improved freeze–thaw stability, higher end viscosity, and better enzymatic digestibility. Starch is a very important carbohydrate in many food and non-food applications. In planta modification of starch by genetic engineering has significant economic and environmental benefits as it makes the chemical or physical post-harvest modification obsolete. An amylosucrase from Neisseria polysaccharea fused to a starch-binding domain (SBD) was introduced in two potato genetic backgrounds to synthesize starch granules with altered composition, and thereby to broaden starch applications. Expression of SBD–amylosucrase fusion protein in the amylose-containing potato resulted in starch granules with a rough surface, a twofold increase in median granule size, and altered physico-chemical properties including improved freeze–thaw stability, higher end viscosity, and better enzymatic digestibility. These effects are possibly a result of the physical interaction between amylosucrase and starch granules. The modified larger starches not only have great benefit to the potato starch industry by reducing losses during starch isolation, but also have an advantage in many food applications such as frozen food due to its extremely high freeze–thaw stability.
Comparison of waxy and normal potato starch remaining granules after chemical surface gelatinization: Pasting behavior and surface morphology
Huang, J. ; Chen Zenghong, ; Xu, Yalun ; Li, Hongliang ; Liu, Shuxing ; Yang, Daqing ; Schols, H.A. - \ 2014
Carbohydrate Polymers 102 (2014). - ISSN 0144-8617 - p. 1001 - 1007.
atomic-force microscopy - internal structure - physicochemical properties - noodle quality - yellow pea - amylose - maize - acetylation - sites - wheat
o understand the contribution of granule inner portion to the pasting property of starch, waxy potato starch and two normal potato starches and their acetylated starch samples were subjected to chemical surface gelatinization by 3.8 mol/L CaCl2 to obtain remaining granules. Native and acetylated, original and remaining granules of waxy potato starch had similar rapid visco analyzer (RVA) pasting profiles, while those of two normal potato starches behaved obviously different from each other. All remaining granules had lower peak viscosity than the corresponding original granules. Contribution of waxy potato starch granule's inner portion to the peak viscosity was significant more than those of normal potato starches. The shell structure appearing on the remaining granule surface for waxy potato starch was smoother and thinner than that for normal potato starches as observed by scanning electron microscopy, indicating a more regular structure of shell and a more ordered packing of shell for waxy potato starch granules. The blocklet size of waxy potato starch was smaller and more uniform than those of normal potato starches as shown by atomic force microscopy images of original and remaining granules. In general, our results provided the evidence for the spatial structure diversity between waxy and normal potato starch granules: outer layer and inner portion of waxy potato starch granule had similar structure, while outer layer had notably different structure from inner portion for normal potato starch granule.
The edible mushroom Laetiporus sulphureus as potential source of natural antioxidants
Klaus, A. ; Kozarski, M. ; Niksic, M. ; Jakovljevic, D. ; Todorovic, N. ; Stefanoska, I. ; Griensven, L.J.L.D. van - \ 2013
International Journal of Food Sciences and Nutrition 64 (2013)5. - ISSN 0963-7486 - p. 599 - 610.
ganoderma-lucidum - feruloyl oligosaccharides - chemical-characterization - polysaccharide extracts - agaricus-bisporus - diabetic-rats - fruit-bodies - components - complexes - amylose
Hot water extract (LN), partially purified polysaccharides (LP) and hot alkali extracted polysaccharides (LNa) obtained from fruiting bodies of the wild basidiomycete Laetiporus sulphureus were examined for their antioxidant activities. LNa was the most active antioxidant, as shown by the median effective concentrations (EC50 values) of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (0.5 +/- 0.2 mg/ml), reducing power (4.0 +/- 0.3 mg/ml) and ferrous ion-chelating ability (1.5 +/- 0.1 mg/ml). LNa contained the highest level of alpha-glucan (17.3 +/- 1.2 g/100 g dw), whereas LP contained mostly beta-glucans (66.8 +/- 1.3 g/100 g dw). The prevalent monosaccharide in all extracts was glucose. The EC50 values of all three antioxidant activity assays were well-correlated with the alpha-glucan content. Strong and significant correlation was found between total phenolic compounds and DPPH scavenging ability and also reducing power. The three investigated extracts (at concentrations of 0.1-10 mg/ml) were not toxic to HTR-8/SVneo trophoblast cell line.
Expression of an engineered granule-bound Escherichia coli glycogen branching enzyme in potato results in severe morphological changes in starch granules
Huang, X. ; Nazarian Firouzabadi, F. ; Vincken, J.P. ; Ji, Q. ; Suurs, L.C.J.M. ; Visser, R.G.F. ; Trindade, L.M. - \ 2013
Plant Biotechnology Journal 11 (2013)4. - ISSN 1467-7644 - p. 470 - 479.
binding domain - gene-expression - beta-amylase - freeze-thaw - amylose - biosynthesis - amylopectin - arabidopsis - synthase - protein
The Escherichia coli glycogen branching enzyme (GLGB) was fused to either the C- or N-terminus of a starch-binding domain (SBD) and expressed in two potato genetic backgrounds: the amylose-free mutant (amf) and an amylose-containing line (Kardal). Regardless of background or construct used, a large amount of GLGB/SBD fusion protein was accumulated inside the starch granules, however, without an increase in branching. The presence of GLGB/SBD fusion proteins resulted in altered morphology of the starch granules in both genetic backgrounds. In the amf genetic background, the starch granules showed both amalgamated granules and porous starch granules, whereas in Kardal background, the starch granules showed an irregular rough surface. The altered starch granules in both amf and Kardal backgrounds were visible from the initial stage of potato tuber development. High-throughput transcriptomic analysis showed that expression of GLGB/SBD fusion protein in potato tubers did not affect the expression level of most genes directly involved in the starch biosynthesis except for the up-regulation of a beta-amylase gene in Kardal background. The beta-amylase protein could be responsible for the degradation of the extra branches potentially introduced by GLGB.
Pasting properties and (chemical) fine structure of acetylated yellow pea starch is affected by acetylation reagent type and granule size
Huang, J. ; Schols, H.A. ; Jin, Z. ; Sulmann, E. ; Voragen, A.G.J. - \ 2007
Carbohydrate Polymers 68 (2007)3. - ISSN 0144-8617 - p. 397 - 406.
sweet-potato starches - amylopectin populations - substitution patterns - acetic-anhydride - vinyl-acetate - amylose - cowpea - sites
Yellow pea starch was fractionated into small and large size granule fractions and then modified with acetic anhydride and vinyl acetate (acetylation after sieving) or first acetylated in the same way and then fractionated into small and large size fractions (acetylation before sieving). Acetylation with different procedures (acetylation before or after sieving) resulted in different degrees of substitution for small size granule fractions when acetic anhydride was used as reagent. Modification with vinyl acetate gave products with much higher peak viscosities than modification with acetic anhydride for the same granule size and same degree of substitution (DS). The location and distribution of acetyl groups was investigated by analyzing the ¿-amylase hydrolysates of isolated amylose and amylopectin with chromatography and mass spectrometry. Mass spectra showed that the substituent distribution mainly depended on the type of reagent and was not affected by the granule size. Both amylose and amylopectin were modified in an heterogeneous way and the reactions took place in different regions of the granule. It is postulated that acetylation occurs more homogeneously throughout the granule when vinyl acetate is used as reagent, while the reaction with acetic anhydride to a large extent takes place in the outer lamellae of granule. Keywords: Yellow pea starch; Amylose; Amylopectin; Acetic anhydride; Vinyl acetate
1-Allyloxy-2-hydroxy-propyl-starch : synthesis and characterization
Huijbrechts, A.M.L. ; Huang, J. ; Schols, H.A. ; Lagen, B. van; Visser, G.M. ; Boeriu, C.G. ; Sudhölter, E.J.R. - \ 2007
Journal of Polymer Science. Part A, Polymer Chemistry 45 (2007)13. - ISSN 0887-624X - p. 2734 - 2744.
sweet-potato starches - acetyl substitution - amylopectin populations - amylose - cellulose - granules - acetate - pattern - waxy
New reactive unsaturated starch derivatives, 1-allyloxy-2-hydroxy-propyl-starches (AHP-starches), were synthesized by the reaction of waxy maize starch (WMS) and amylose-enriched maize starch (AEMS) with allyl glycidyl ether in a heterogeneous alkaline suspension containing NaOH and Na2SO4. The degree of substitution (DS) was determined by H-1 NMR spectroscopy, and a DS of 0.20 +/- 0.01 was found for both AHP-WMS and AHP-AEMS, respectively. The AHP derivatives of WMS and AEMS were further characterized with H-1 and C-13 NMR. It was shown that the AHP substitution was located on the C-6 hydroxyl group of the glucose residues in the starch. The substitution pattern of the AHP groups along the polymer chain was randomly clustered, as determined by enzymatic digestion using pullulanase, a-amylase, and amyloglucosidase, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of the digestion products. With X-ray diffraction and scanning electron microscopy, no changes in the granular morphology and crystallinity between the unmodified starches and AHP-starches were detected. (c) 2007 Wiley Periodicals, Inc.
Crystallinity changes in wheat starch during the bread-making process: starch crystallinity in the bread crust
Primo-Martin, C. ; Nieuwenhuijzen, N.H. van; Hamer, R.J. ; Vliet, T. van - \ 2007
Journal of Cereal Science 45 (2007)2. - ISSN 0733-5210 - p. 219 - 226.
heat-moisture treatment - mas nmr-spectroscopy - c-13 cp/mas nmr - phase-transitions - water-system - amylose - gelatinization - amylopectin - polymorphs - potato
The crystallinity of starch in crispy bread crust was quantified using several different techniques. Confocal scanning laser microscopy (CSLM) demonstrated the presence of granular starch in the crust and remnants of granules when moving towards the crumb. Differential scanning calorimetry (DSC) showed an endothermic transition at 70 degrees C associated with the melting of crystalline amylopectin. The relative starch crystallinity, as determined by X-ray and DSC, from different types of breads was found to lie between 36% and 41 % (X-ray) and between 32% and 43 % (DSC) for fresh bread crust. Storage of breads in a closed box (22 degrees C) for up to 20 days showed an increase in crust crystallinity due to amylopectin retrogradation both by X-ray and DSC. However, DSC thermograms of 1-day old bread crust showed no amylopectin retrogradation and after 2 days storage, antylopectin retrogradation in the crust was hardly detectable. C-13 CP MAS NMR was used to characterize the physical state of starch in flour and bread crumb and crust. The intensity of the peaks showed a dependence on the degree of starch gelatinization. Comparison of the results for two different types of bread showed that the baking process influenced the extent of starch crystallinity in the bread crust. Antylopectin retrogradation, which is the main process responsible for the staling of bread crumb, cannot be responsible for crispness deterioration of the crust as amylopectin retrogradation upon storage of breads could only be measured in the crust after 2 days storage. Under the same conditions loss of bread crust crispness proceeds over shorter times.
Expression of an engineered granule-bound Escherichia coli maltose acetyltransferase in wild-type and amf potato plants
Nazarian, F. ; Vincken, J.P. ; Qin, J. ; Suurs, L.C.J.M. ; Visser, R.G.F. - \ 2007
Plant Biotechnology Journal 5 (2007)1. - ISSN 1467-7644 - p. 134 - 145.
retrogradation properties - starch granules - structural gene - amylose - biosynthesis - substitution - reduction - sequence - synthase - cloning
Starch is used in many industrial applications, but often requires chemical derivatization to enhance its properties before use. In particular, the stability of starch polymers in solution is improved by acetylation. A drawback of this treatment is the use of pollutant chemicals. A biological alternative to chemical derivatization was investigated by the expression of an amyloplast-targeted Escherichia coli maltose acetyltransferase (MAT) gene in tubers of wild-type (Kardal) and mutant amylose-free (amf) potato plants. MAT was expressed as such, or fused to the N- or C-terminus of a non-catalytic starch-binding domain (SBD) to target the starch granule. Starch granules derived from transgenic plants were found to contain acetyl groups, although their content was low, opening up an avenue to move away from the post-harvest chemical derivatization of starch. MAT inside starch granules was found to be active post-harvest when supplied with acetyl-coenzyme A and glucose or maltose, but it did not acetylate starch polymers in vitro. Starch granules from transformants in which MAT alone was expressed also showed MAT activity, indicating that MAT is accumulated in starch granules, and has affinity for starch by itself. Furthermore, starch granule morphology was altered, and fusion proteins containing MAT and SBD seemed to have a higher affinity for starch granules than two appended SBDs. These results are discussed against the background of the quaternary structure of MAT.
Efficiency of transcriptional gene silencing of GBSS1 in potato depends on the promoter region that is used in an inverted repeat
Heilersig, H.J.B. ; Loonen, A.E.H.M. ; Janssen, E.M. ; Wolters, A.M.A. ; Visser, R.G.F. - \ 2006
Molecular Genetics and Genomics 275 (2006)5. - ISSN 1617-4615 - p. 437 - 449.
bound starch synthase - solanum-tuberosum-l - directed dna methylation - rna - granule - amylose - expression - arabidopsis - cloning - plants
Transcriptional gene silencing (TGS) of the endogenous GBSSI promoter in potato was induced by inverted repeat constructs containing different regions of the GBSSI promoter. Clear differences in silencing efficiency were observed. The 35SGBP-IR construct, containing sequences from ¿766 to ¿168 bp relative to the transcription initiation site (TIS), induced weak silencing effects in 57¿60% of the transformants. Weak silencing effects were also induced by the ASP-IR construct harbouring allele-specific sequences covering the region from ¿531 to ¿330 bp relative to the TIS, but only in a low percentage (4¿5.5%) of the transformants. These percentages are too low to distinguish effects between the two potato cultivars. Therefore, this approach cannot be used to induce allele-specific TGS. Strong silencing effects were obtained in 49% of the transformants harbouring the full promoter inverted repeat construct. This construct contained sequences from ¿766 to +194 bp relative to the TIS. In the strongly silenced transformants no GBSSI mRNA could be detected by Northern blot analysis. This was accompanied by the accumulation of GBSSI promoter-specific small interfering RNAs. Methylation studies revealed that, in the weakly silenced 35SGBP-IR transformants, the HpaII site at ¿213 bp relative to the TIS was methylated. Apparently, methylation of this sequence does not result in strong silencing effects. In the full promoter transformants, both CG methylation and CNN methylation were detected. We show that, to obtain strong TGS, it is important to include sequences in the vicinity of the TIS.
Production of dextran in transgenic potato plants
Kok-Jacon, G.A. ; Vincken, J.P. ; Suurs, L.C.J.M. ; Wang, Denong ; Liu, S. ; Visser, R.G.F. - \ 2005
Transgenic Research 14 (2005)4. - ISSN 0962-8819 - p. 385 - 395.
bound starch synthase - solanum-tuberosum-l - sucrose - expression - gene - sequence - cdna - amylose - granule - tobacco
The production of dextran in potato tubers and its effect on starch biosynthesis were investigated. The mature dextransucrase (DsrS) gene from Leuconostoc mesenteroides was fused to the chloroplastic ferredoxin signal peptide (FD) enabling amyloplast entry, which was driven by the highly tuber-expressed patatin promoter. After transformation of two potato genotypes (cv. Kardal and the amylose-free (amf) mutant), dextrans were detected by enzyme-linked immunosorbent assay (ELISA) in tuber juices of Kardal and amf transformants. The dextran concentration appeared two times higher in the Kardal (about 1.7 mg/g FW) than in the amf transformants. No dextran was detected by ELISA inside the starch granule. Interestingly, starch granule morphology was affected, which might be explained by the accumulation of dextran in tuber juices. In spite of that, no significant changes of the physicochemical properties of the starches were detected. Furthermore, we have observed no clear changes in chain length distributions, despite the known high acceptor efficiency of DSRS
A mechanistic model of the relation between molecular structure of amylopectin and macromolecular degradation during heating-shearing processes
Einde, R.M. van den; Linden, E. van der; Goot, A.J. van der; Boom, R.M. - \ 2004
Polymer Degradation and Stability 85 (2004)1. - ISSN 0141-3910 - p. 589 - 594.
light-scattering - thermomechanical treatment - lamellar droplets - starch - amylose - size
A molecular scale model describing the molecular breakdown of low moisture amylopectin melts by shear forces was derived and compared to engineering scale experiments. The model is based on the assumption that the maximum shear stress on the polymer equals the effective surface stress on that polymer, which is related to the strength of the glycosidic bonds. The molecules are approximated as spheres, with a radius that exhibits fractal scaling with molecular weight. The molecular weight reduction as a function of applied shear stress as deduced from the model agrees satisfactorily with the results from experimentally obtained engineering scale data. The results show a successful example of a coupling between engineering scale experiments and micro-scale models and contribute to the understanding of fundamental changes in the properties of starch during industrial scale heating-shearing processes. (C) 2004 Elsevier Ltd. All rights reserved.
Starch granule size strongly determines starch noodle processing and nnodle quality.
Chen Zenghong, ; Schols, H.A. ; Voragen, A.G.J. - \ 2003
Journal of Food Science 68 (2003)5. - ISSN 0022-1147 - p. 1584 - 1589.
physicochemical properties - barley - wheat - amylose - baking - grain - waxy
Chemical compositions, physical properties, and suitability for starch noodle making of different granule size fractions from potato and sweet potato starches were studied. The ash content, amylose content, phosphorus content, gel firmness, and freeze-thaw stability of small-size granule fractions (<20 mum) were significantly different from those of the large-size granule fractions. The processibility and the qualities evaluated by objective and subjective methods of both dried and cooked starch noodles made from small-size granule fractions were significantly better than those made from their initial starch preparations and much better than those made from the large-size granule fractions.
The influence of various small plasticisers and malto-oligosaccharides on the retrogradation of (partly) gelatinised starch
Smits, A.L.M. ; Kruiskamp, P.H. ; Soest, J.J.G. van; Vliegenthart, J.F.G. - \ 2003
Carbohydrate Polymers 51 (2003)4. - ISSN 0144-8617 - p. 417 - 424.
glass-transition - chain-length - amylopectin retrogradation - crystalline-structure - gelatinization - amylose - release - gels - saccharides - stabilities
Ageing of gelatinised and partly gelatinised potato starch and wheat starch were investigated in the presence of plasticisers with increasing size and number of OH groups (ethylene glycol, glycerol, threitol, xylitol, glucose, and for potato starch also maltose). The influences of these plasticisers and of granular remnants (ghosts) on recrystallisation were determined by using X-ray diffraction. Recrystallisation of potato starch samples in the presence of plasticisers resulted in crystallinity indices of 0.5. The largest reduction in potato starch recrystallisation is found for threitol (4 OH) and xylitol (5 OH). In the plasticiser range examined, the crystallisation inducing effect of granular potato starch remnants is reduced better when the plasticiser contains more OH groups. Wheat starch recrystallises to a lesser extent than potato starch, resulting in crystallinity indices of 0.4. The results for wheat starch do not show clear trends for the influences of plasticiser size and of ghosts. The difference in behaviour of the two starches is probably caused by wheat starch having shorter amylopectin chains. Resulting from these shorter amylopectin chains, the remaining structure in wheat starch ghosts may resemble A-type crystallinity, making it more difficult to form B-type crystals. Alternatively, the trends as found for potato starch may occur, but are less manifest for wheat starch, due to the lower total extent of recrystallisation. Solid state CP/MAS NMR spectra of the wheat starch samples containing ethylene glycol were obtained, in order to compare completely and partly gelatinised systems. The spectra were identical, confirming that the ghost structures do not influence wheat starch recrystallisation. Apparently, wheat starch ghosts do not act as nuclei for crystallisation. Similarly, the influence of various malto-oligosaccharides in combination with granular remnants (ghosts) was investigated on wheat starch ageing. Gelatinised and partly gelatinised wheat starch were plasticised with maltose, maltotriose, maltotetraose, maltopentaose or maltohexaose. This resulted in crystallinity indices of 0.2, with the largest reduction in recrystallisation for maltotriose and maltotetraose. No trend was found for the influence of ghosts. The presence of ghosts did not influence the 13C solid state HP/DEC NMR spectra. Less recrystallisation took place than with the previously mentioned smaller plasticisers that resulted in crystallinity indices of 0.4. The finding that maltose was able to reduce retrogradation better than glucose could be of practical importance.
Amylose biosynthesis in potato : interaction between substrate availability and GBSSI activity, regulated at the allelic level = [Amylose biosynthese in aardappel : interactie tussen beschikbaar substraat en KGZ activiteit, gereguleerd op allel niveau]
Wal, M. van de - \ 2000
Agricultural University. Promotor(en): R.G.F. Visser; E. Jacobsen. - S.l. : S.n. - ISBN 9789058082244 - 109
aardappelen - solanum tuberosum - zetmeel - amylose - biosynthese - multipele allelen - glycogeen (zetmeel) synthase - potatoes - solanum tuberosum - starch - amylose - biosynthesis - multiple alleles - glycogen (starch) synthase
Besides the role of starch as the primary source of calories in both human and animal diet, it is used as raw material for industrial application such as the paper industry, textile industry, chemical industry, and pharmaceutical industry. Starch isolated for industrial applications, is mainly derived from corn. However in Europe a significant proportion of starch is isolated from potato tubers. Starch consists of two glucose polymers, amylose, which is essentially linear and amylopectin, which is highly branched. Industrially important properties, which are responsible for the functional quality of starch, are highly affected by the ratio of amylose to amylopectin. Therefore, different strategies have been applied to obtain starch with altered amylose content. Mutations leading to the selective loss of amylose have been described in many species, including potato. From the synthesis of amylose-free starch in mutants lacking granule-bound starch synthase I (GBSSI) it is clear that GBSSI is responsible for amylose biosynthesis.
The goal of this thesis research was to unravel the amylose biosynthesis in potato and to determine the role and regulation of GBSSI in this process. Therefore amylose biosynthesis was studied in vitro and in vivo . GBSSI, like other starch synthases, catalyses the transfer of a glucose residue from ADP-Glc (donor substrate) to the growingα-1,4 linked glucan (acceptor substrate). This reaction can be studied in vitro by the incubation of purified starch granules, containing the active GBSSI, with radiolabelled ADP-Glc. In this thesis we show a new mechanism for amylose biosynthesis, using amylopectin as acceptor substrate. Transfer of chains from amylopectin to amylose was evidenced from pulse-chase experiments performed with starch isolated from Chlamydomonas and higher plants.
To alter the amylose content within the plant, different strategies can be applied. Subtle changes in amylose content, can be obtained by classical breeding. These relatively small changes may significantly improve quality as was shown by the effect of GBSSI on amylose content and noodle quality in wheat. The genetics behind amylose content in potato is described in this thesis. Amylose-free potato starch can be obtained by suppression of GBSSI using antisense technology. The effect of allelic composition on antisense inhibition was shown after analysing a large number of transgenics per variety.The allelic composition of a variety can therefore be used as a selection criterion in breeding programs with the aim to obtain cultivars with altered starch composition.
Bepaling van het gehalte aan enzymatisch aantastbaar zetmeel in zetmeelrijke diervoedergrondstoffen
Essers, M.L. ; Muuse, B.G. - \ 1981
Wageningen : RIKILT (Verslag / RIKILT 81.06) - 5
diervoedering - pancreatine - amylose - verteerbaarheid - animal feeding - pancreatin - digestibility
Vergelijkend onderzoek naar de inwerking van amyloglucosidase (AGS) en pancreatine op ontsloten en natieve zetmeelrijke diervoedergrondstoffen.