A novel dextrin produced by the enzymatic reaction of 6-α-glucosyltransferase I: The effect of non-reducing ends of glucose with by α-1,6 bonds on the retrogradation inhibition of high molecular weight dextrin

2021 ◽  
Author(s):  
Akiko Yasuda ◽  
Manabu Miyata ◽  
Osamu Sano ◽  
Tatsufumi Sogo ◽  
Seiichiro Kishishita ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Corn Starch ◽  
Average Molecular Weight ◽  
Enzymatic Reaction ◽  
Amperometric Detection ◽  
Exchange Chromatography ◽  
Weight Average Molecular Weight ◽  
Waxy Corn Starch ◽  
Waxy Corn

Abstract We prepared a high-molecular-weight modified dextrin (MWS-1000) from a partial hydrolysate of waxy corn starch with a weight average molecular weight of 1 × 106 (WS-1000) using Paenibacillus alginolyticus PP710 α-glucosyltransferase. The gel permeation chromatography showed that the weight average molecular weight of MWS-1000 was almost the same as that of WS-1000. The side chain length of WS-1000 and MWS-1000 after isomaltodextranase digestion were also shown to be similar to each other by high performance anion exchange chromatography with pulsed amperometric detection. Since MWS-1000 confirmed the presence of α-1,6 bonds by enzyme digestibility, methylation, and 1H-NMR analyses, it was presumed that the structure of MWS-1000 was based on the introduction of α-1,6 glucosyl residues at the non-reducing ends of the partial hydrolysate of waxy corn starch. Furthermore, the MWS-1000 solution was not retrograded even during refrigerated storage or after repeated freeze-thaw cycles.

A novel dextrin produced by the enzymatic reaction of 6-α-glucosyltransferase Ⅱ: Practical advantages of the novel dextrin as a food modifier

2021 ◽  
Author(s):  
Rika Sumida ◽  
Seiichiro Kishishita ◽  
Akiko Yasuda ◽  
Manabu Miyata ◽  
Akiko Mizote ◽  
...  
Keyword(s):  
Corn Starch ◽  
Enzymatic Reaction ◽  
Viscoelastic Behavior ◽  
Wheat Starch ◽  
Terminal Point ◽  
Waxy Corn Starch ◽  
Gelatinized Starch ◽  
Tan Δ ◽  
Waxy Corn ◽  
Calorimetric Studies

ABSTRACT High-molecular-weight dextrin (WS-1000) was produced from waxy corn starch and enzymatically modified to link glucose by α-1,6 glycosidic bond at the terminal point of the glucose chain, forming MWS-1000. In this study, the physical properties of MWS-1000 were characterized, and the advantages of its use as a food modifier were described. From rheological and calorimetric studies, it was found that MWS-1000 does not undergo retrogradation, but it does not prevent the retrogradation of WS-1000, suggesting that they have no intermolecular interaction in solution. Investigation of the effect of MWS-1000 on the viscoelasticity of gelatinized wheat starch showed that in the linear viscoelastic region, storage modulus decreased and tan δ increased with increase in replaced MWS-1000 content. In addition, it was confirmed that gelatinized starch containing MWS-1000 showed viscoelastic behavior similar to that of commercially available custard cream.

Applications of waxy corn flour based on physicochemical and processing properties: comparison with waxy rice flour and waxy corn starch

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yuqiu Guo ◽  
Linlin Sun ◽  
Lirong Chen ◽  
Xingya Wang ◽  
Canguo Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Corn Starch ◽  
Rice Flour ◽  
Rice Starch ◽  
Corn Flour ◽  
Waxy Corn Starch ◽  
Waxy Rice Flour ◽  
Waxy Rice ◽  
Waxy Corn ◽  
Processing Properties

Abstract The proximate composition, molecular weight distribution and main processing properties of waxy corn flour (WCF) were investigated. Furthermore, waxy corn starch (WCS) and waxy rice flour (WRF) were also determined to discuss the applications of WCF. WCS contained more low-molecular-weight fraction (<5 × 105 g/mol) and had higher polydispesity than waxy rice starch (WRS). The water hydration capacity of WCF was the lowest, whereas it had the highest swelling power at 70 and 80 °C. WCF had the highest pasting temperature of 74.85 °C, whereas that of WRF was 68.40 °C and WCS was 73.25 °C. WRF exhibited the lowest melting enthalpy change with a value of 2.54 ± 0.11 (J/g). The retrogradation resistance of WCF was better than that of WRF and WCS. The degree of retrogradation (DR) of WCF was 9.58 ± 0.59% at 14 d, corresponding to WCS of 25.08 ± 0.44% and WRF of 15.68 ± 0.71%. WRF had the lowest glass transition temperature of −27.4 versus −26.2 °C for WCF and −26.0 °C for WCS. It was found that WCF could be used to directly prepare quick-frozen viscous foods. It could also be used as a stabilizer to improve the quality of staple foods.

Metathesis Polymerization of Phenylacetylene by Tungsten Aryloxo Complexes

1995 ◽  
Vol 60 (3) ◽  
pp. 489-497 ◽  
Author(s):  
Hynek Balcar ◽  
Jan Sedláček ◽  
Marta Pacovská ◽  
Vratislav Blechta
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Induction Period ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Polymer Yield ◽  
Positive Effect ◽  
Ligand Addition

Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOCl3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)2C6H3, 2,6-Cl2C6H3, 2,4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (20 °C, monomer to catalyst molar ratio = 1 000) was studied. The activity of WCl5(OAr) as unicomponent catalysts increases with increasing electron withdrawing character of the -OAr ligand. Addition of two equivalents of organotin cocatalysts (Me4Sn, Bu4Sn, Ph4Sn, Bu3SnH) to WCl5(O-C6H2Cl3-2,4 ,6) has only slight positive effect (slightly higher polymer yield and/or molecular weight of poly(phenylacetylene)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2, 6) catalyst, it enhances the activity considerably by eliminating the induction period. Poly(phenylacetylene)s prepared with the catalysts studied have weight-average molecular weight ranging from 100 000 to 200 000. They are trans-prevailing and have relatively low molar fraction of monomer units comprised in cyclohexadiene sequences (about 6%).

Characterization of Normal and Waxy Corn Starch for Bioethanol Production

2013 ◽  
Vol 61 (2) ◽  
pp. 379-386 ◽  
Author(s):  
Hanyu Yangcheng ◽  
Hongxin Jiang ◽  
Michael Blanco ◽  
Jay-lin Jane
Keyword(s):  
Corn Starch ◽  
Bioethanol Production ◽  
Waxy Corn Starch ◽  
Waxy Corn

scholarly journals Characterisation of Sequential Solvent Fractionation and Base-catalysed Depolymerisation of Treated Alkali Lignin

BioResources ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. 4137-4151 ◽  
Author(s):  
Aikfei Ang ◽  
Zaidon Ashaari ◽  
Edi Suhaimi Bakar ◽  
Nor Azowa Ibrahim
Keyword(s):  
Molecular Weight ◽  
Chemical Structure ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Solubility Parameters ◽  
Low Molecular Weight ◽  
Sequential Fractionation ◽  
Weight Average Molecular Weight ◽  
Solvent Fractionation ◽  
Alkali Lignin

An alkali lignin (OL) with a weight-average molecular weight (Mw) of 11646 g/mol was used to prepare low-molecular weight lignin for resin synthesis. The low-molecular weight lignin feedstock was obtained via base-catalysed depolymerisation (BCD) treatments at different combined severity factors. Sequential fractionation of the OL and BCD-treated lignins using organic solvents with different Hildebrand solubility parameters were used to alter the homogeneity of the OL. The yield and properties of OL itself and OL and BCD-treated OL dissolved in propan-1-ol (F1), ethanol (F2), and methanol (F3) were determined. Regardless of the treatment applied, a small amount of OL was dissolved in F1 and F2. The BCD treatment did not increase the yield of F1 but did increase the yields of F2 and F3. Gel permeation chromatography (GPC) showed that the repolymerization reaction occurred in F3 for all BCD-treated OL, so these lignins were not suitable for use as feedstocks for resin production. The GPC, 13Carbon-nuclear magnetic resonance, and Fourier transform infrared spectroscopy analyses confirmed that the F3 in OL exhibited the optimum yield, molecular weight distribution, and chemical structure suitable for use as feedstocks for resin synthesis.

scholarly journals Influence of Dextransucrase of Weissella Cibaria Nitcsk4 on Low Molecular Weight Dextran Yield: a Statistical Approach using Mixed Level Taguchi Design and Artificial Neural Network

2019 ◽  
Vol 9 (2S2) ◽  
pp. 657-664
Keyword(s):  
Neural Network ◽  
Molecular Weight ◽  
Mean Squared Error ◽  
Sucrose Concentration ◽  
Average Molecular Weight ◽  
Taguchi Design ◽  
Percentage Error ◽  
Low Molecular Weight ◽  
Weight Average Molecular Weight ◽  
Weissella Cibaria

In the present study, the influence of dextransucrase of Weissella cibaria NITCSK4 (DSWc4), sucrose concentration, and reaction temperature on the yield of low molecular weight dextran (LMWD-DexWc4) was investigated using mixed level Taguchi design and back propagation neural network (BPNN). BPNN model with three neurons in a hidden layer generated a low mean squared error (MSE). The determination coefficients (R2 -value) for ANN and Taguchi models were 0.991 and 0.998, respectively. Considering absolute average deviation (AAD) and MSE, Taguchi model is more adequate. Among three factors, the percentage yield of low molecular weight of dextran is invariably dependent on the sucrose concentration. The study suggested that a low sucrose concentration (3% w/v), DSWc4 (0.25 IU/ml) and slightly high temperature (35°C) ultimately favored the production of LMWD-DexWc4 (91.639%). LMW-DexWc4 produced by DSWc4 at optimized conditions was analyzed. The weight average molecular weight of LMW-DexWc4 was calculated using M-H expression, found to be 85775 (≈90 kDa). The relative percentage error between the number and weight average molecular weight was found to be less (4.42%). The polydispersity (PD) index of the LMW-DexWc4 was found to be 0.9576 and the value is close to 1. The PD value depicted that the molecular weight distribution of dextran was narrowly dispersed.

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