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Energy Balance of Low Hydrated Starches Transition Under Shear
Author(s) -
Barron C.,
Valle G. Della,
Colonna P.,
Vergnes B.
Publication year - 2002
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2002.tb10301.x
Subject(s) - shearing (physics) , rheometer , starch , materials science , dissipation , energy balance , composite material , granule (geology) , shear rate , thermodynamics , chemistry , rheology , physics , organic chemistry
Moistened (25% to 30% total basis) starches were processed on a pre‐shearing rheometer under controlled conditions of temperature, residence time, and shear rate. The specific mechanical energy (30 to 1000 J.g ‐1 ) was measured and starch transformations assessed. The conversion of compacted native starch into a suspension of granule fragments in a melt was modeled by a simplified energy balance of the shearing zone. A theoretical fragmentation mechanism was proposed with a critical fracture energy of 125 J.m ‐2 . The computed mechanical energy and time necessary for achieving this transition varied in agreement with experimental results, for different operating conditions and starch botanical origins. Interparticle friction influenced granule fragmentation, whereas crystal melting was associated with viscous dissipation.