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Native jackfruit seed starch (JFS) contains 30% w/w type II resistant starch (RS2) and can potentially be developed as a new commercial source of RS for food and pharmaceutical application. Heat-moisture treatment (HMT) was explored as a mean to increase RS content of native JFS. The effect of the conditions was tested at varied moisture contents (MC), temperatures, and times. Moisture levels of 20–25%, together with temperatures 80–110°C, generally resulted in increases of RS amount. The highest amount of RS (52.2%) was achieved under treatment conditions of 25% MC and 80°C, for 16 h (JF-25-80-16). FT-IR peak ratio at 1047/1022 cm−1 suggested increases in ordered structure in several HMT-JFS samples with increased RS. SEM showed no significant change in the granule appearance, except at high moisture/temperature treatment. XRD revealed no significant change in peaks intensities, suggesting the crystallinity within the granule was mostly retained. DSC showed increases in T g and, in most cases, ΔT, as the MC was increased in the samples. Slight but significant decreases in ΔH were observed in samples with low RS, indicating that a combination of high moisture and temperature might cause partial gelatinization. HMT-JFS with higher RS exhibited less swelling, while the solubility remained mostly unchanged.

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Cereal Chem. 87(3):214-220Cross-linked carboxymethyl rice starches (CL-CMRS) were prepared from reactions between a native Klong Luang 1 (KL1) rice starch and varied concentrations (2.5-15% w/w) of sodium trimetaphosphate (STMP) in simultaneous carboxymethylation and cross-linking reactions set up using methanol as a solvent. Physicochemical as well as pharmaceutical properties of CL-CMRS were evaluated in relation to the amount of STMP used and the degree of cross-linking (DCx). At a low DCx, the viscosity of CMRS solution was enhanced through the formation of cross-linked polymeric network and chain entanglement. At higher concentrations in the preparation reaction, STMP caused proportional de-creases in the water solubility and ≤70-fold of the solution viscosity, but promoted swelling and water uptake of the modified starches. Rheological behavior of the nonsoluble but swellable CL-CMRS was similar to that of commercial superdisintegrants sodium starch glycolate (SSG), and cross-carmellose sodium (CCS). The swelling and water uptake of CL-CMRS were 5-7 and 6-25 times higher, respectively, than that of the native starch. Disintegration test of tablets containing 1 and 3% w/w of native and modified rice starches showed that M-KL1-5 and M-KL1-10 could be developed as tablet disintegrants.

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.

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