Physico-Chemical Characteristics of Media-Milled Corn Starch
2010
Chen, Chongren | Shen, Yu-Chin | Yeh, An-I
Nano/submicrometer scale corn starch particles have been prepared by using media milling. Molecular weight and pasting properties of milled starch were determined by HPSEC-MALLS-RI and an oscillatory rheometer, respectively. After 30-min of milling, the number-average diameter of the starch particle was reduced from 9.61 to 0.26 μm. Particle size was further reduced by extended milling. Microscopic observation confirmed the presence of particles smaller than 100 nm. As starch granules were being disintegrated, the mechanical energy imparted by media milling resulted in 43.7% of starch damage and 55% degree of gelatinization during the initial 30 min. In the meanwhile, the weight average molecular weight was reduced from 9.98 to 7.63 × 106 g/mol. The pasting properties were significantly altered by milling, which resulted in lower onset and peak temperature, and reduction in breakdown and set back. The importance of molecular weight on the physicochemical properties of milled starch was discussed.
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