Rheological characterization of tahin/pekmez (sesame paste/concentrated grape juice) blends


Arslan E., Yener M. E. , Esin A.

JOURNAL OF FOOD ENGINEERING, vol.69, no.2, pp.167-172, 2005 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 69 Issue: 2
  • Publication Date: 2005
  • Doi Number: 10.1016/j.foodeng.2004.08.010
  • Journal Name: JOURNAL OF FOOD ENGINEERING
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.167-172
  • Keywords: rheology, tahin (sesame paste), pekmez (concentrated grape juice), blend, EMULSIONS, VISCOSITY
  • Middle East Technical University Affiliated: Yes

Abstract

Rheological properties of tahin/pekmez blends were determined at different tahin concentrations (20-32%) and temperatures (35-65 degrees C) by using a concentric cylinder rotational viscometer. Tahin/pekmez blends were found to exhibit non-Newtonian, shear thinning behavior at all temperatures and tahin concentrations. Apparent viscosity versus shear rate data was successfully fitted to the power-law model. The flow behavior index, n varied in the range of 0.7-0.85. The consistency coefficient, K, was in the range of 282-2547 mPa s(n). Both parameters were significantly affected by temperature. The effect of temperature on n did not follow a descriptive trend while the relation between temperature and K was described by an Arrhenius-type equation. Activation energies appeared in the range of 13376-28592J/mol with increasing concentration. The effect of concentration was significant for only K and it was described by exponential and power functions. A mathematical expression to relate apparent viscosity to temperature, tahin concentration and shear rate was proposed. (c) 2004 Elsevier Ltd. All rights reserved.