Study the effect of temperature and hydrocolloid concentration on rheological characteristics of fig juice concentrates using response surface methodology  Forozandeh, N. 1, Maftoon Azad, N. 2 ïª, Farahnaki, A. 3, Hosseini, S. A. 4

Study the effect of temperature and hydrocolloid concentration on rheological characteristics of fig juice concentrates using response surface methodology Forozandeh, N. 1, Maftoon Azad, N. 2 ïª, Farahnaki, A. 3, Hosseini, S. A. 4

Abstract

Rheological behavior of fig juice concentrates was studied with the objective of defining suitable models for use in evaporation and other processing procedures. The flow properties were determined for juice concentrate with solid content of 70° Brix containing different concentrations of pectin from 0.2 to 0.8% over the temperature range of 5 to 65°C using response surface methodology. A rotational viscometer was used to characterize the flow behavior of concentrates. Samples were subjected to a programmed shear rate increasing from 0-100 s^-1 in 10 min. The flow of all combinations was adequately described by Herschel Bulkely model and the consistency coefficient (m), the flow behavior index (n), yield stress (τ₀) and apparent viscosity (η) were obtained. m and τ₀ increased with pectin concentration and decreased with temperature, while pectin concentration and temperature had opposite effects on n and (η). All parameters were sensitive to changes in temperature and pectin concentration.

Keywords

Key Words: Rheology

fig juice concentrate

Herschel Bulkely

Pectin concentration