Physicochemical and Pharmaceutical Properties of Carboxymethyl Rice Starches Modified from Native Starches with Different Amylose Content

Abstract

Cereal Chem. 84(4):331-336Carboxymethyl rice starches (CMRS) were prepared from nine strains of native rice starches with amylose contents of 14.7-29.1%. The reaction was conducted at 50°C for 120 min using monochloroacetic acid as a reagent under alkaline conditions and 1-propanol as a solvent. After determining the degree of substitution (DS), the physicochemical properties including water solubility, pH, and viscosity of 1% (w/v) solution, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses of the granules, as well as some pharmaceutical properties of CMRS powders and pastes were investigated. The DS range was 0.25-0.40. All CMRS dissolved in unheated water and formed viscous gel. A good positive correlation was observed between amylose content and DS (r = 0.9278) but not viscosity. SEM and XRD concurrently revealed significant physical alteration of CMRS granules compared with those of native starches, which reflected the changes in the properties of CMRS. At 3% (w/w), CMRS can function as tablet binder in the wet granulation of both water-soluble and water-insoluble diluents. The tablets compressed from these granules showed good hardness with fewer capping problems compared with those prepared using the pregelatinized native rice starch as a binder. In addition, most CMRS pastes formed clear films with varying film characteristics, depending upon the amylose content of the native starches. This type of modified rice starch can potentially be employed as a tablet binder and film-former for pharmaceutical dosage formulations.

Physicochemical and Pharmaceutical Properties of Cross‐Linked Carboxymethyl Rice Starch Prepared by a Simultaneous Dual Reaction

“…SEM of the native KL1 starch showed polygonal granules of 2 and 10 μm consistent with other rice starch granules and in agree- ment with a previous report (Kittipongpatana et al 2007). SEM image of CMRS prepared in this study showed no change compared with that of the native starch.…”

“…At 1% w/v concentration, the viscosity of CMRS prepared in this study (M-KL1) was higher than that of CMRS prepared using 1-propanol as the reaction solvent (N-KL1) in the previous report, emphasizing the effect of reaction solvent on the physicochemical properties of CMS (Tijsen et al 2001;Kittipongpatana et al 2007). M-KL1-2.5 showed a viscosity comparable to that of CMRS when tested at 1% w/v concentration, but increases 2.1-fold when compared at 3% w/v concentration.…”

“…Rice flour and extraction of KL1 starch (AC 17.8%) were prepared as previously described (Kittipongpatana et al 2007). Rice flour and extraction of KL1 starch (AC 17.8%) were prepared as previously described (Kittipongpatana et al 2007).…”

Preparation and physicochemical properties of modified jackfruit starches

“…The procedure included repeated blendingfiltering step several times to maximize the yield and to eliminate soluble sugar (Mukprasirt & Sajjaanantakul, 2004). Jackfruit starch was then extracted from flour using a method modified from those described for isolation of jackfruit starch by Bobbio et al (1978) and for isolation of rice starch by Kittipongpatana, Chaitep, Kittipongpatana, Laenger, and Sriroth (2007). In brief, 600 mL of 0.05 mol/L NaOH was added into a 200-g portion of flour and stirred for 5 h at room temperature.…”

“…The degree of substitution and the reaction efficiency were determined as described previously (Kittipongpatana et al, 2007;Wang et al, 2010).…”