Isolation and rheological characterization of Mucuna flagellipes seed gum

Abstract

The gum from M. flagellipes seed endosperm has been isolated and characterised using capillary viscometry and steady shear and small deformation oscillatory rheometry. The endosperm was found to constitute 67.15% of the whole seed and yielded 32.6% of gum.The Huggins and Kraemer plots obtained by capillary viscometry gave an intrinsic viscosity of 7.9 dL/g and viscosity average molecular mass was calculated to be 2.1 x 10 6 using the Mark Houwink relationship. The zero shear viscosity was plotted against the coil overlap parameter, C [η], and the slopes of the lines in the dilute and semi-dilute regions were found to be ~ 1.0 and 4.6 respectively. The curves were fitted to the Tuinier and Martin equations and showed only qualitative agreement. The shear flow viscosity profiles indicated that M. flagellipes gum did not exhibit significant shear thinning at polymer concentrations less than 0.5%, however, at higher concentrations, pronounced shear thinning was observed with the relaxation time (τ) increasing with increase in polymer concentration. The dynamic viscosity profiles showed that at all polymer concentrations examined, a Newtonian plateau was obtained at low frequencies indicating that the loss modulus was the dominant response. Plots of log η versus log and log η* versus log ω were not superimposible and hence did not obey the Cox-Merz rule.

Physicochemical characterisation of the exopolysaccharides of Streptococcus thermophilus ST‐143

“…b), indicating some phenomenological similarities (see also Mende et al ., ). The master curves of the three polysaccharides fit well to the Martin equation (Ren et al ., ) with k m being a parameter that expresses the balance between polymer–polymer and polymer–solvent interactions (Nwokocha & Williams, ). A k m of 0.30 was calculated.…”

“…In the presence of capsular EPS, the shear thinning behaviour of the free EPS polymers was more pronounced, because the entangled polymer chains require more time to separate from each other compared with solutions with only free EPS. Furthermore, the critical shear rate ( at 0.95 η 0 ) (Tuinier et al ., ) where the viscosity starts to decrease shifted to lower values at higher polysaccharide concentration, which is a characteristic of nongelling polysaccharides (Tuinier et al ., ; Goh et al ., ; Nwokocha & Williams, ). Proportionality was ∝ c −3.0 ( R 2 = 0.93) for EPS f and ∝ c −2.2 ( R 2 = 0.99) for EPS total , which is close to that reported for EPS from L. bulgaricus ( ∝ c −2,75 ) (Goh et al ., ) and from L. lactis ssp.…”

Rheological properties of a polysaccharide isolated from Adansonia digitata leaves

“…The performance of these plants in local cookery indicates they have potential for exploitation; however, there is a lack of information on the properties of the hydrocolloids. Recently, some of them are receiving attention: Afzelia africana (Ren, Picout, Ellis, & Ross-Murphy, 2003;Ren, Picout, Ellis, Ross-Murphy, & Grant Reid, 2005), Irvingia gabonensis (Ndjouenkeu et al, 1996;Uzomah & Ahiligwo, 1999), Brachystegia eurycoma (Nwokocha & Williams, In press;Uzomah, & Ahiligwo, 1999), Corchorus olitorius (Yamazaki, Kurita, & Matsumura, 2009), Detarium microcarpum (Wang et al, 1996), Mucuna flagellipes (Nwokocha & Williams, 2009) and Hibiscus esculentum (Ndjouenkeu et al, 1996).…”

Steady shear flow behavior of gum extracted from Ocimum basilicum L. seed: Effect of concentration and temperature

“…There are a few reports about rheological properties of new sources of seed gums such as yellow mustard seed (Cui et al, 1993), flaxseed (Cui et al, 1994), white mustard seed (Balke and Diosady, 2000), fenugreek seed (Brummer et al, 2003), Prosopis flexuosa DC seed (Ibanez and Ferrero, 2003), Ipomoea turpethum seed (Singh et al, 2003), Lallemania royleana seed (Razavi and Karazhiyan, 2009) and Mucuna flagellipes seed (Nwokocha and Williams, 2009). However, there is no published report related to rheological properties of BSG.…”