Fractionation of maltodextrins by ethanol

Defloor, I; Vandenreyken, V; Grobet, Piet J.; Delcour, Jan A.

doi:10.1016/s0021-9673(97)01268-5

Cited by 34 publications

(17 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The soluble material contained linear dextrins and soluble glycogen. The addition of ethanol precipitated glycogen as well as long linear dextrins with a degree of polymerization of greater than 7 to 8 glucosyl units (14). The precipitate was solubilized in water, and size exclusion chromatography (SEC) and multiple laser light scattering (MALLS)/refractive index analysis were performed with this material.…”

Section: Resultsmentioning

confidence: 99%

Role of Maltose Enzymes in Glycogen Synthesis by Escherichia coli

et al. 2011

View full text Add to dashboard Cite

Mutants with deletion mutations in the glg and mal gene clusters of Escherichia coli MC4100 were used to gain insight into glycogen and maltodextrin metabolism. Glycogen content, molecular mass, and branch chain distribution were analyzed in the wild type and in ⌬malP (encoding maltodextrin phosphorylase), ⌬malQ (encoding amylomaltase), ⌬glgA (encoding glycogen synthase), and ⌬glgA ⌬malP derivatives. The wild type showed increasing amounts of glycogen when grown on glucose, maltose, or maltodextrin. When strains were grown on maltose, the glycogen content was 20 times higher in the ⌬malP strain (0.97 mg/mg protein) than in the wild type (0.05 mg/mg protein). When strains were grown on glucose, the ⌬malP strain and the wild type had similar glycogen contents (0.04 mg/mg and 0.03 mg/mg protein, respectively). The ⌬malQ mutant did not grow on maltose but showed wild-type amounts of glycogen when grown on glucose, demonstrating the exclusive function of GlgA for glycogen synthesis in the absence of maltose metabolism. No glycogen was found in the ⌬glgA and ⌬glgA ⌬malP strains grown on glucose, but substantial amounts (0.18 and 1.0 mg/mg protein, respectively) were found when they were grown on maltodextrin. This demonstrates that the action of MalQ on maltose or maltodextrin can lead to the formation of glycogen and that MalP controls (inhibits) this pathway. In vitro, MalQ in the presence of GlgB (a branching enzyme) was able to form glycogen from maltose or linear maltodextrins. We propose a model of maltodextrin utilization for the formation of glycogen in the absence of glycogen synthase.The synthesis of glycogen in bacteria occurs when they are grown with limited nutrients but an abundance of a carbon source (33,34). Escherichia coli accumulates glycogen at levels of more than half of its cell mass under optimal conditions. The glycogen gene cluster in E. coli consists of two operons oriented in tandem, glgBX and glgCAP, encoding enzymes that synthesize and degrade glycogen (12). The encoded enzymes are a branching enzyme (glgB), a debranching enzyme (glgX), an ADP-glucose pyrophosphorylase (glgC), a glycogen synthase (glgA), and a glycogen phosphorylase (glgP). The polymerization of the ␣-1,4-linked glucosyl chain is mediated via the transfer of glucose from ADP-glucose by GlgA, the glycogen synthase, onto the nonreducing ends of linear dextrins that are subsequently branched (formation of ␣-1,6-glycosyl linkage) by GlgB, the branching enzyme. The expression of the glg gene cluster is complicated. It involves the global carbon storage regulator CsrA (2, 53), the cyclic AMP (cAMP)/catabolite gene activator protein (CAP) system (39), and the stringent response (38). In addition, the two-component regulatory system PhoP-PhoQ (29) connects the system to Mg 2ϩ levels, and even the phosphotransferase system appears to affect the glycogen phosphorylase involved in the degradation of glycogen (42,43). glgS, an additional gene involved in glycogen synthesis, is not part of the glg gene cluster. It is not essential for ...

show abstract

Section: Resultsmentioning

confidence: 99%

Role of Maltose Enzymes in Glycogen Synthesis by Escherichia coli

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The carbohydrates used were D-glucose, maltose (Sigma, St. Louis, MO); maltotriose (Fluka, Chemie AG, Buchs, Switzerland); Paselli MD6 (a commercial potato starch maltodextrin with an average DP of 17, Avebe, Antwerpen, Belgium, hereafter referred to as PSMD17); Star-Dri 5 (a commercial waxy maize starch maltodextrin with an average DP of 20, Amylum, Aalst, Belgium, hereafter referred to as WMSMD20); αand γ-cyclodextrins (Wacker Chemie GmbH, Glostrup, Denmark, hereafter referred to as CD); and the hereafter-described maltotetraose preparation. More data on PSMD17 and WMSMD20 are given by Defloor et al (1998).…”

Section: Carbohydratesmentioning

confidence: 99%

Effects of Low Molecular Weight Carbohydrates on Farinograph Characteristics and Staling Endotherms of Wheat Flour‐Water Doughs

1999

View full text Add to dashboard Cite

Cereal Chem. 76(2):227-230Glucose, maltose, maltotriose, maltotetraose, αand γ-cyclodextrins, and maltodextrins from potato starch (average degree of polymerization [DP] of 17) and maize starch (average DP of 20) were added to wheat flour-water doughs at levels of 1.0 and 3.0% (based on dry flour weight). Additions of 3.0% (w/w) αand γ-cyclodextrins increased the 500 farinograph unit (FU) consistency by 174 and 193 FU, respectively, while the same levels of potato and maize starch dextrins increased the consistency by 32 and 21 FU, respectively. Expressed in an alternative way, the water absorption corresponding to 500 FU consistency was increased by 4.2 and 4.6% after addition of 3.0% (w/w) αand γ-cyclodextrins, respectively. Differential scanning calorimetry was used to evaluate the direct effects of addition of low molecular weight carbohydrates on amylopectin recrystallization in baked flour-water doughs. A significant reduction in amylopectin recrystallization was found after the addition of 3.0% (w/w) γ-cyclodextrin after seven days of storage of the baked wheat flour-water dough.

show abstract

“…Contrary to this, the radical was found to be precipitated by addition of ethanol, as the radical signal was detected in the ethanol precipitations and not in the supernatants. Ethanol precipitation is suitable for precipitating proteins as well as carbohydrates and melanoidins (Bekedam, Schols, van Boekel, & Smit, 2006;Defloor, Vandenreyken, Grobet, & Delcour, 1998;Wu, Russell, & Powrie, 1987). In general, addition of ethanol causes HMW carbohydrate compounds to precipitate because of lost solubility, and with higher concentrations of ethanol also LMW carbohydrate compounds can be precipitated (Defloor et al, 1998).…”

Section: Precipitation Of the Stable Radicalmentioning

confidence: 99%