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Steady and Dynamic Shear Rheological Properties of Starch and Decolorized Hsian‐tsao Leaf Gum Composite Systems
Author(s) -
Lai LihShiuh,
Liao ChihLun
Publication year - 2002
Publication title -
cereal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.558
H-Index - 100
eISSN - 1943-3638
pISSN - 0009-0352
DOI - 10.1094/cchem.2002.79.1.58
Subject(s) - starch , rheology , chemistry , dynamic mechanical analysis , dynamic modulus , viscosity , composite number , apparent viscosity , food science , composite material , materials science , organic chemistry , polymer
Rapid Visco Analyser (RVA) and dynamic rheological measurements were performed on a mixture of decolorized hsian‐tsao leaf gum (dHG) and starch as a function of starch‐to‐gum ratio (S/G 0:6, 1:5, 2:4, 3:3, 4:2, 5:1, and 6:0), starch type (wheat, corn, and tapioca), and total solid content (2, 3, and 4%). Under S/G of 5:1, 4:2 and 3:3, dHG interacted with starch synergistically, which resulted in a marked increase in viscosity during cooling. The storage modulus of the resulting mixed gel was higher than the loss modulus, and both moduli were almost frequency‐independent throughout the frequency range tested, indicating that the composite gels could be classified rheologically as elastic gels. Mixed systems with tapioca starch showed higher pseudo‐gel viscosity in the RVA test, but lower storage modulus in the dynamic test than those with wheat or corn starch. Such results implied that tapioca starch contributed a more viscous property but wheat and corn starch contributed a more elastic property to the mixed systems.