Effect of Degree Substitution on the Viscosity and Solubility of Carboxymethylated Amorphophallus muelleri Glucomannan
DOI:
https://doi.org/10.11113/mjfas.v22n1.4985Keywords:
Carboxymethylated Amorphophallus muelleri glucomannan, sodium hydroxide, monochloroacetic acid, solubility, viscosity, degree substitutionAbstract
Glucomannan, derived from Amorphophallus muelleri (AGM), is a highly viscous natural polysaccharide with reduced solubility, which has yet to be fully developed, hence constraining its application across numerous industries. Among the numerous modifications applied to AGM, carboxymethylation via the etherification process has garnered considerable interest owing to its straightforward methodology and its ability to reduce viscosity while enhancing the solubility of glucomannan. This study aims to examine the modification of Amorphophallus muelleri glucomannan by carboxymethylation (CMAGM) through the variation of sodium hydroxide (NaOH) and monochloroacetic acid (MCA) to ascertain the degree of substitution and its effects on viscosity and solubility. The degree of substitution was verified by titration methods, which corroborate the findings from Fourier Transform Infrared (FT-IR) and Nuclear Magnetic Resonance (NMR) analyses. The glucomannan yield achieved through acid hydrolysis with hydrochloric acid was 52.4%. The AGM was effectively altered and validated by the emergence of a new peak at 1587–1369 cm⁻¹ in the FT-IR spectra and δ = 3.3-4.1, δ = 8.057 ppm in the NMR spectra, indicative of the COOH functional group due to the modification process. The modification process indicated that the maximum degree of substitution achieved with a NaOH: MCA ratio of 4:2 % w/v was 0.577. It was found that a lower MCA corresponds to a higher degree of substitution. Overall, the carboxymethylation effectively reduced the viscosity and enhanced the solubility of glucomannan.
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Copyright (c) 2026 Risa Yunita, Roshanida A. Rahman, Nardiah Rizwana Jaafar, Mohammad Nashriq Jailani, Nur Aizura Mat Alewi, Rosli Md. Illias, Abdul Halim Mohd Yusof, Ni Nyoman Tri Puspaningsih, Mohd Faizal Ahmad Jaafar, Azura Aziz
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