Investigation on the pitting of potato starch granules during high frequency ultrasound treatment.
In this paper, the pitting of potato starch granules in aqueous suspensions (1%) by high-frequency high-power ultrasound (850kHz at a power of 0.2W, 2W or 3.7W; and also 500kHz and 1MHz at a power of 2W) is reported. The number of pits per starch granules was found to be independent of the amylose content of starches, and the surface properties of starch granules as modified through SDS and ethanol washing. At 850kHz, the maximum number of pits per starch granule, for both normal and waxy starches, did not exceed 11. However, a close inspection of fractionated starch granules based on their sizes showed that there is an optimum granule size for which a maximum pit number is obtained. For example, starch granules with diameter size range of ∼15 to ∼30μm had a maximum pit number (between 10 and 20 pits per granule) when sonicated (2W, 850kHz and 30min); while sonication of small (<10μm) and very large (>45μm) granules resulted in a smaller number of pits per granule (∼5). Further, the maximum number of pits per granules is also found to be proportional to the ultrasound frequency, with values of approximately 7, 10 and 11 at 0.50, 0.85, and 1MHz, respectively. FTIR measurements did not show any breakup of starch molecules.
School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
Wenzhe
W
Bai
IPCMS, UMR 7504, 23 rue du Loess, 67034 Strasbourg Cedex 02, France.
Pascal
P
Hébraud
School of Chemistry, University of Melbourne, VIC 3010, Australia.
Muthupandian
M
Ashokkumar
School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; The Riddet Institute, Palmerston North, New Zealand. Electronic address: y.hemar@auckland.ac.nz.
Yacine
Y
Hemar
D000688:Amylose / Q000032:analysis; D010316:Particle Size; D011198:Solanum tuberosum / Q000737:chemistry*; D013010:Sonication; D013213:Starch / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D014867:Water; D013213:Starch; D000688:Amylose
Cavitation; High-power high frequency ultrasound; Pitting; Starch granules