Functional, thermal and rheologicalbehavior of fenugreek (Trigonellafoenum– graecum L.) gums from different cultivars: a comparative study.

Abstract

Fenugreek gum (FG) was isolated from six different Indian fenugreek cultivars and studied for their functional, structural, thermal and rheological attributes. The highest yield (13.5%) was observed for cultivar RMT–365. All galactomannans depicted good water and oil holding capacities ranging from 2009 ± 5.5 to 2099.9 ± 2.5% and 523.5 ± 3.5 to 553.0 ± 2.0%, respectively. DSC thermograms of FG revealed the presence of one endothermic and one exothermic peak. For endothermic transition of gums from different cultivars, enthalpy change (Δ Ha) ranged from 234.2 to 351.8 J/g while for exothermic transition, Δ Ha values ranged from 72.0 to 102.1 J/g, much lower as compared with endothermic peak. The effect of variable shear rate on viscosity of 1% FG solutions showed their shear thinning behaviors for all the cultivars, whereby the viscosity decreased with increasing shear rate. Frequency sweep tests indicated typical viscoelastic fluid behavior for all the gum solutions. Increase in the magnitude of G′ and G″ of FG solutions was observed with an increase in frequency. A detailed understanding of different chemical, functional and thermal properties of FG could surely enlarge the radius of its application and eventually aid in its utilization in different food, pharma and cosmetic products.