Papers by Keyword: KGM

Abstract: A pH-sensitive semi-interpenetrating polymer network (semi-IPN) hydrogel based on Konjac glucomannan(KGM) and methylacrylic acid(MAA) was prepared by free radical polymerization at different concentrations of initiator potassium persulfate (KPS) in presence of crosslinker N,N-methylene-bis-acrylamide (MBA). The chemical structure and rheological properties of hydrogels were characterized by FT-IR and rheometry, respectively. In addition, the swelling behavior of the hydrogels were studied in buffer solution at different pHs.

Abstract: The influences of processing parameters on the tensile strength (TS) of KGM/CaCO₃ composite films (KCaCF) were investigated through orthogonal experiment method. Calcium carbonate and KCaCF were characterized, respectively, by XRD, laser diffraction particle size analyzer, zeta potential analyzer and SEM. The results showed that micron-sized calcite CaCO₃ crystals with-16.4 mv of Zeta potential were synthesized. Calcium carbonate dispersion was blended with KGM to fabricate KCaCF. The mass of CaCO₃, KGM and swelling time affected TS of composite films differently, but didnt reach the significant level (p>0.05). The optimal preparation process for KCaCF is that 5.0% (wt) of KGM powder is added into the dispersion with 2.0% (wt) of CaCO₃, swelling for 1.0 hour at 50 °C and pH 8.0 and then poured onto plate and dried at 50 °C for 15 h.

Abstract: Amorphophallus bulbifer (A. bulbifer) is a promising species in Amorphophallus sp., with great potentiality of developing, low risk for cultivation and considerable commercial benefits, mainly locates in tropical and subtropical regions or near the equator. Konjac glucomannan (KGM) is the main component of Amorphophallus tuber which is a water-soluble dietary fiber. In this work, some physiochemical properties of KGM in three Amorphophallus species flour [one was A.bulbifer, the other two were current main species namely Amorphophallus rivieri (A. rivieri) and Amorphophallus albus (A. albus)] were studied and compared with each other. The KGM content in A. rivieri, A. albus and A. bulbifer flour were 85.03%, 76.28% and 88.07% (w/w), respectively. The apparent viscosity, viscosity average molecular weight, whiteness, gel-forming properties and chemical structure of KGM in the three flours were investigated by using viscometer, colorimeter, texture analyzer and Fourier transform infrared (FT-IR) spectroscopy. The results indicated that the viscosity and M_w of A. bulbifer was the largest, gel strength was almost same (p>0.05) and the molecular structure were of no differences of three KGM. It may be proposed that transplanting A. bulbifer from its native land in the tropical and subtropical regions to temperate zone in the southwest part of China would be feasible, and it would cause the revolution of Amorphophallus sp. and more considerable benefits.

Abstract: In this paper, the effect of environment factors on KGM molecular dimension was discussed, such as ultrasonic, enzyme, concentration and temperature. The KGM polarity, molecular weight (Mw) and conformation were analyzed by digital polarimeter and LLS. The result indicated that the polarity change influenced by temperature and ultrasonic accorded with linear function equation. Mw of KGM gradually decreased with ultrasonic time and concentration of enzyme increase. The concentration of KGM was lower, the effect was more obviously. The changes of KGM Mw also brought regular change of molecular conformation. All offers the reference to reliabletheoretical foundations on controlling KGM molecular dimension and industrial application in exploiting KGM potential function and activity.

Abstract: Konjac Glucomannan (KGM) was modified by maleic anhydride (MA). The influences of processing parameters on the mechanical properties of KGM films were investigated through orthogonal experiments. The results showed that the effects of pH, temperature and time of KGM swelling on tensile strength and folding endurance of modified KGM membranes were insignificant (FF0.01). Folding endurance and tensile strength of KGM membranes could be improved by proper addition of MA. The optimum conditions of KGM modification were that the mixture of KGM and MA was swelling at pH 4.0 and 60°C for 2 h, and then cast on a flat and dried at 50°C to give modified KGM membranes.

Abstract: A novel thermoplastic konjac glucomannan(TKGM) was synthesized with KGM and methyl acrylate(MA) initiated by ammonium persulfate. The percentage grafting (PG) and the grafting efficiency (GE) was affected by concentration of initiator and monomer, temperature, and time. The results indicated that the percentage grafting (PG) and the grafting efficiency (GE) can attach 70% and 90% at optimal conditions, respectively. The structure and properties of TKGM were characterized by FTIR and DSC. FTIR results demonstrated that graft copolymerization was occurred between MA and KGM. The results of DSC indicated that a new glass transition temperature (Tg) of TKGM at 16.4°C was appeared compared with KGM with no glass transition temperature. It suggested that product of TKGM can be made through thermoplastic process.