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Steady and dynamic shear rheological behavior of semi dilute Alyssum homolocarpum seed gum solutions: influence of concentration, temperature and heating–cooling rate
Author(s) -
Alaeddini Behzad,
Koocheki Arash,
Mohammadzadeh Milani Jafar,
Razavi Seyed Mohammad Ali,
Ghanbarzadeh Babak
Publication year - 2018
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.8765
Subject(s) - rheology , viscoelasticity , dynamic mechanical analysis , shear thinning , viscosity , shear rate , thermodynamics , chemistry , dynamic modulus , atmospheric temperature range , materials science , apparent viscosity , analytical chemistry (journal) , chromatography , composite material , polymer , physics
BACKGROUND Alyssum homolocarpum seed gum (AHSG) solution exhibits high viscosity at low shear rates and has anionic features. However there is no information regarding the flow and dynamic properties of this gum in semi‐dilute solutions. The present study aimed to investigate the dynamic and steady shear behavior of AHSG in the semi‐dilute region. RESULTS The viscosity profile demonestrated a shear thinning behavior at all temperatures and concentrations. An increase in the AHSG concentration was acompanied by an increase in the pseudoplasticity degree, whereas, by increasing the temperature, the pseudoplasticity of AHSG decreased. At low gum concentration, solutions had more viscosity dependence on temperature. The mechanical spectra obtained from the frequency sweep experiment demonstrated viscoelastic properties for gum solutions. AHSG solutions showed typical weak gel‐like behavior, revealing G ' greater than G ' within the experimental range of frequency (Hz), with slight frequency dependency. The influence of temperature on viscoelastic properties of AHSG solutions was studied during both heating (5–85 °C) and cooling (85–5 °C) processes. The complex viscosity of AHSG was greater compared to the apparent viscosity, indicating the disruption of AHSG network structure under continuous shear rates and deviation from the Cox–Merz rule. During the initial heating, the storage modulus showed a decreasing trend and, with a further increase in temperature, the magnitude of storage modulus increased. The influence of temperature on the storage modulus was considerable when a higher heating rate was applied. CONCLUSION AHSG can be applied as a thickening and stabilizing agents in food products that require good stability against temperature. © 2017 Society of Chemical Industry