Molar mass and rheological characterisation of an exopolysaccharide from Pediococcus damnosus 2.6

• The molar mass and theological properties of an exopolysaccharide (EPS) from Pediococcus damnosus 2.6 were investigated. The molar mass was determined by asymmetrical flow field-flow fractionation coupled with multiangle light scattering and refractive index detection. The EPS was observed to be a flexible chain polymer with a molar mass value of 4 x 10(6) g mol(-1). Heating the sample at 80 degrees C for 10 min caused a shift to lower hydrodynamic radius. The theological behaviour of the EPS was compared to that of a commercial cereal beta-glucan (0.359 x 10(6) g mol(-1)). The maximum storage modulus, G'(max) for EPS solution was lower than that for the cereal beta-glucan at all concentrations, while the relaxation time, t(G'=G") was higher. The G'(max) was reduced on heating the EPS solution at 80 degrees C for 10 min, likely indicating some conformational changes. Three-dimensional models of the polymers revealed some differences in intramolecular hydrogen bonds. The EPS molecule had a ropy nature in solution and this could make it suitable for usage as a thickener in food systems. (c) 2006 Elsevier Ltd. All rights reserved.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Annan teknik -- Livsmedelsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Other Engineering and Technologies -- Food Engineering (hsv//eng)

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Näringslära (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Nutrition and Dietetics (hsv//eng)

Nyckelord

Pediococcus damnosus 2.6

exopolysaccharide

molar mass

root mean

square radius

loss modulus

polydispersity

storage modulus

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