EVALUATION OF REACTION CONDITIONS FOR CARBOXYMETHYLATION OF MUNG BEAN STARCH USING MONOCHLOROACETIC ACID

  • Le Thi Hong Thuy
  • Le Nguyen Phuong Thanh
  • Nguyen Quynh Nhu
  • Nguyen Thi Thao
  • Ho Thi Thu Thao
  • Nguyen Thi Luong
  • Nguyen Van Khoi
  • Nguyen Thanh Tung
Từ khóa: Carboxymethylation, carboxymethyl starch, monochloroacetic acid, mung bean, modified starch.

Tóm tắt

Carboxymethyl mung bean starch (CMS) was synthesized under different reaction conditions. The influence of sodium hydroxide concentration, monochloroacetic acid (MCA) concentration, type of organic solvent, reaction time, and temperature were evaluated for degree of substitution (DS). Optimal DS of 0.59 was obtained at 50 °C, 120 minutes in isopropanol-starch ratio of 7.5 mL/g. The ratio of sodium hydroxide and monochloroacetate acid moles to anhydroglucose unit (AGU) moles for the optimal DS were 2.4 and 1.5. Scanning electron microscope (SEM) of CMS particles showed the starch grain structure remains the same but the surface appeared many alveolar holes and no longer smooth as MS. Fourier transform infrared spectra (FTIR) of CMS and MS confirmed that carboxymethylation takes place on native starch molecules when the absorption band appears at a wavenumber of 1710 cm-1 corresponding to the vibrations of featured functional C=O group in CMS structure.
Keywords: Carboxymethylation, carboxymethyl starch, monochloroacetic acid, mung bean, modified starch.

điểm /   đánh giá
Phát hành ngày
2020-11-26
In ra
Tập. 20 Số. 03 (2020)
Chuyên mục
Bài viết