The impact of concentration, temperature and pH on dynamic rheology of psyllium gels

• Published in: Journal of food engineering Vol. 100; no. 2; pp. 294 - 301
• Main Authors: Farahnaky, A., Askari, H., Majzoobi, M., Mesbahi, Gh
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-09-2010; [New York, NY]: Elsevier Science Pub. Co; Elsevier
• Subjects: Biological and medical sciences; chemical concentration; dietary fiber; dynamic rheology; dynamic testing; Dynamic tests; Dynamics; food analysis; food composition; Food engineering; Food industries; FT-IR; functional properties; Fundamental and applied biological sciences. Psychology; Gels; General aspects; Melting; Microscopy; microstructure; Psyllium; psyllium gum; Rheological properties; Rheology; SEM; Spectra; temperature; Viscoelastic; Weak gel; FT-IR; Psyllium; SEM; Weak gel; Viscoelastic; Rheological properties; Infrared spectrometry; Scanning electron microscopy; Temperature; Fourier transformation; pH; Concentration
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2010.04.012

Structural aspects of the psyllium gum prepared from the seed husk of the plant of
Plantago ovata Forsk was characterized by dynamic rheology and microscopy. Dynamic rheological properties of psyllium gel in the linear viscoelastic region, as a function of concentration (2, 2.5 and 3% w/w), temperature (5–95
°C) and pH (2.5–10) were investigated. Mechanical spectra of the psyllium gels were obtained by frequency sweep measurement classified into that of weak gels because
G′ was larger than
G″ throughout the tested frequency range and the separation of the two moduli (tan
δ) was greater than 0.1. The phase angle increased with temperature and a peak associated with gel melting appeared at about 40
°C. All gels at different pH presented a typical weak gel spectrum. Scanning electron microscopy showed porous structures with different pore-size distribution for psyllium gels under different conditions in terms of concentration, pH and temperature.