Multiple Ethanolic‐Precipitation: An Approach to the Separation of Dextrin Fractions with Narrow Molecular Weight Distributions from Acid‐Hydrolyzed Waxy Corn Starch

2020 ◽  
Vol 72 (11-12) ◽  
pp. 2000038
Author(s):  
Xuechen Zhuang ◽  
Shufen Zhang ◽  
Heping Li
Keyword(s):  
Molecular Weight ◽  
Corn Starch ◽  
Molecular Weight Distributions ◽  
Waxy Corn Starch ◽  
Weight Distributions ◽  
Waxy Corn

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.

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.

The Use of Novel F-RAFT Agents in High Temperature and High Pressure Ethene Polymerization: Can Control be Achieved?

2007 ◽  
Vol 60 (10) ◽  
pp. 788 ◽  
Author(s):  
Markus Busch ◽  
Marion Roth ◽  
Martina H. Stenzel ◽  
Thomas P. Davis ◽  
Christopher Barner-Kowollik
Keyword(s):  
Molecular Weight ◽  
High Pressure ◽  
High Temperature ◽  
Degree Of Polymerization ◽  
Molecular Weight Distributions ◽  
High Pressure High Temperature ◽  
Reversible Addition ◽  
Weight Distributions ◽  
Raft Agent ◽  
Initial Results

Simulations are employed to establish the feasibility of achieving controlled/living ethene polymerizations. Such simulations indicate that reversible addition–fragmentation chain transfer (RAFT) agents carrying a fluorine Z group may be suitable to establish control in high-pressure high-temperature ethene polymerizations. Based on these simulations, specific fluorine (F-RAFT) agents have been designed and tested. The initial results are promising and indicate that it may indeed be possible to achieve molecular weight distributions with a polydispersity being significantly lower than that observed in the conventional free radical process. In our initial trials presented here (using the F-RAFT agent isopropylfluorodithioformate), a correlation between the degree of polymerization and conversion can indeed be observed. Both the lowered polydispersity and the linear correlation between molecular weight and conversion indicate that control may in principle be possible.

Environmentally Benign Adhesive Synthesized by Dispersion Copolymerization of Styrene and Butyl Acrylate

2006 ◽  
Vol 11-12 ◽  
pp. 757-760
Author(s):  
Jun Ying Zhang ◽  
Peng Dou
Keyword(s):  
Molecular Weight ◽  
Butyl Acrylate ◽  
Monomer Concentration ◽  
Environmentally Benign ◽  
Functional Monomer ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Stabilizer Concentration ◽  
Ethanol Medium ◽  
Weight Distributions

Environmentally benign adhesive was synthesized by dispersion copolymerization of styrene(St) and butyl acrylate (BA) in an ethanol medium with benzoyl peroxide (BPO) as the initiator and poly(vinylpyrrolidone) as the stabilizer in the presence of acrylic acid(AA) as the functional monomer. The effect of the concentration of stabilizer, initiator and functional monomer on the conversions, molecular weights and molecular weight distributions was investigated. The results show that the conversions almost keep invariable with the increasing of stabilizer concentration, but the molecular weights increase and molecular weight distributions decrease. Conversions increase with the increasing of initiator concentration, but the molecular weights and molecular weight distributions decrease. However with the increasing of functional monomer concentration, conversions and molecular weight distributions increase but the molecular weights decrease.

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