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Influence of tragacanth gum exudates from specie of Astragalus gossypinus on rheological and physical properties of whey protein isolate stabilised emulsions
Author(s) -
Samavati Vahid,
EmamDjomeh Zahra,
Mohammadifar Mohammad Amin,
Omid Mahmoud,
Mehdinia Ali
Publication year - 2011
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2011.02661.x
Subject(s) - tragacanth , creaming , rheology , whey protein isolate , chemistry , whey protein , viscoelasticity , chemical engineering , shear thinning , materials science , chromatography , food science , emulsion , composite material , organic chemistry , engineering
Summary The aim of this work was to investigate the effects of Iranian tragacanth gum ( Astragalus gossypinus ) (0.5, 1 wt.%), Whey protein isolate (WPI) (2, 4 wt.%) and acid oleic‐phase volume fraction (5, 10% v/v) on droplet size distribution, creaming index and rheological properties of emulsions with various compositions. Rheological investigations showed that both loss and storage modules increased with gum and oil contents. However, the viscoelastic behaviour was mainly governed by the gum concentration. Delta degree (storage and loss modules ratio) increased with frequency indicated that liquid like viscose behaviour dominates over solid like elastic behaviour. The shear‐thinning behaviour of all dispersions was successfully modelled with power law and Ellis models and Ellis model was founded as the better model to describe the flow behaviour of dispersions. Droplet size distribution was measured by light scattering; microscopic observations revealed a flocculated system. Increase in gum, WPI and oil contents resulted in decrease in creaming index of emulsions with dominant effect of gum concentration.