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The objectives of this were to investigate the chemical composition and physicochemical properties of taro during growth period and effect of mucilage on the physicochemical properties of taro starch. Several techniques were applied in this research. Differential scanning calorimetry(DSC) and rapid visico-analyser(RVA) were used to analyze thermal and pasting properties of taro flour and starch. Scanning electron micrometer(SEM) and laser mastersizer were incorporated to the analysis of microstructure and starch granule diameter. Moreover, gel permeation chromatography(GPC) and high pH anion exchange chromatography (HPAEC) measured the molecule weight distribution and monosaccharide composition of taro mucilage. The results showed the size of starch granule, mucilage content, gelatinization temperature range and enthalpy of taro starch were increase of growth period of taro from 5th to 9th months. The drought treatment at 6th month resulted in rapid increase of taro mucilage and the decrease of taro starch content. The lowest peak viscosity, breakdown, and setback of pasting properties of taro starch were found at 6th month of growth period. However, the higher onset(To) and peak temperature(Tp) were observed in drought treatment period (6th month) than in other growth periods. The monosaccharide compositions of taro mucilage included arabinose and galactose with the ratio of 1:4. The molecule weight distribution of mucilage contained two major zones which included 800,000 Daltons and 100,000 Daltons. Mucilage added into taro flour system did not significantly influence thermal properties, swelling power and gel consistency of taro flour. However, the onset and peak viscosity of taro starch were increased, but swelling power, gel consistency, peak viscosity and breakdown viscosity of pasting properties were decreased, when mucilage was added into taro starch system.
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