title: Dynamic and shear stress rheological properties of guar galactomannans and its hydrolyzed derivatives.
abstract: Guar galactomannan from seed of Cyamopsis tetragonolobus was hydrolyzed using acid (HCl), base [Ba(OH)2] and enzyme (mannanase) method to obtain depolymerized substances with possible functional applications as soluble dietary fiber. Rheological behavior of crude, purified, and depolymerized guar gum solutions was studied at 25 °C, using shear stress and dynamic oscillatory measurements, performed with controlled stress rheometer Bohlin CVO (Malvern Instruments) fitted with cone-and-plate geometry. The various guar gums solutions with different viscosities exhibited shear-thinning behavior at high shear rate and Newtonian behavior at low shear rate. At low shear rate, sigma crude guar gum (SCGG), crude guar gum (CGG), acid hydrolyzed guar gum (AHGG) and enzyme hydrolyzed guar gum (EHGG) exhibited viscosities of 18.59, 1.346, 0.149 and 0.022 Pas, respectively. Oscillatory experiments (G", G') of gums solutions showed typical behavior of weak viscoelastic gel. All investigated guar gums were further used for glucose bio-accessibility using a novel in vitro small intestinal model (SIM). All gums solutions resulted in 20% reduction in simulated glucose absorption, indicating a non-significant functionality difference between various guar gums. So, it can be concluded that hydrolyzed guar gums without disturbing their rheological and physiological behavior would be useful for incorporation in various food products as soluble dietary fiber.
authors.affiliation: Food Microbiology and Biotechnology Section, NIFSAT, University of Agriculture, Faisalabad (UAF), 38040, Pakistan. Electronic address: majidhussain447@yahoo.com.
authors.forename: Majid
authors.initials: M
authors.lastname: Hussain
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Serafim
authors.initials: S
authors.lastname: Bakalis
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Ourania
authors.initials: O
authors.lastname: Gouseti
authors.affiliation: Food Microbiology and Biotechnology Section, NIFSAT, University of Agriculture, Faisalabad (UAF), 38040, Pakistan.
authors.forename: Tahir
authors.initials: T
authors.lastname: Zahoor
authors.affiliation: Department of Food Science, Nutrition & Home Economics, GC-University, Faisalabad 38000, Pakistan.
authors.forename: Faqir Muhammad
authors.initials: FM
authors.lastname: Anjum
authors.affiliation: Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad (UAF), 38040, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Shahid
mesh_terms: D031293:Cyamopsis / Q000737:chemistry*; D004043:Dietary Fiber; D005685:Galactans / Q000737:chemistry*; D005690:Galactose / Q000031:analogs & derivatives; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism; D008351:Mannans / Q000737:chemistry*; D053149:Plant Gums / Q000737:chemistry*; D012212:Rheology; D012639:Seeds / Q000737:chemistry; D012996:Solutions; D014783:Viscosity
chemical_list: D004043:Dietary Fiber; D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D012996:Solutions; C012990:galactomannan; C007894:guar gum; D005947:Glucose; D005690:Galactose
keywords: Guar galactomannans; Hydrolysis; Rheology; SIM; Viscoelastic properties