Abstract:

Using a mixture (2:1, by mass) of Na2HPO4 and NaH2PO4 as the esterifying agent, konjac glucomannan (KGM)
was esterified with phosphate. Based on degree of substitution (DS), the optimum conditions for microwave-assisted
modification of konjac glucomannan were determined as follows: temperature, 60 ℃; microwave radiation time, 7 min; pH,
4.0; phosphate dosage, 30%, and microwave power, 800 W. Glucomannan phosphate monoester with a degree of substitution
of 0.055 4 was acquired. Infrared spectroscopic studies showed that phosphate groups were introduced onto the main chain
of the KGM molecules, confirming the formation of KGMP. Scanning electron microscopic (SEM) examination displayed
that the particle size of KGMP was bigger and its structure was more compact.

Key words: konjac glucomannan, phosphoric acid esterification, microwave-assisted modification