Rheological effect of gum addition to hot pepper–soybean pastes

Summary The effect of four different gums [carboxylmethylcellulose (CMC), guar gum, hydroxypropylmethylcellulose (HPMC) and tara gum] at 0.5% concentration on rheological properties of fermented hot pepper–soybean paste (HPSP) was evaluated in steady and dynamic shear. HPSP–gum mixture samples at 25 °C are highly shear thinning fluids with high yield stresses. All gums increased the consistency index ( K ) and apparent viscosity ( η a,100 ) of HPSP. Apparent viscosity of all samples obeyed the Arrhenius temperature relationship. Dynamic moduli ( G ′, G ′′ and η *) values of HPSP–gum mixtures were higher than those of HPSP with no added gum over most of the frequency range. Dynamic moduli, K and η a,100 values were increased in the presence of gums, and increased in the following order: control < CMC < guar gum < tara gum < HPMC. The Cox–Merz rule did not describe the relationship between dynamic ( η *) and steady shear viscosities ( η a ) for all samples.