Macromolecular and thermokinetic properties of a galactomannan from Sophora alopecuroides L. seeds: A study of molecular aggregation. (15th June 2021)

• Record Type: Journal Article
• Authors: Guo, Rui; Li, Xujiao; Ma, Xianda; Sun, Xianbao; Kou, Yuxing; Zhang, Jun'ai; Li, Deshun; Liu, Yanfang; Zhang, Hui; Wu, Yan
• Is Part Of: Carbohydrate polymers. Volume 262(2021)
• Publication Date: 2021-06-15
• Subjects: CSAP & NSAP crude and neutral Sophora alopecuroides L. polysaccharides -- CD circular dichroism -- PSD particle size distribution -- z-A.D. apparent z-average diameter -- M.D. apparent mean diameter -- FE-SEM & FE-TEM field-emission scanning and transmission electron microscopies -- AFM atomic force microscopy -- HPSEC high-performance size-exclusion chromatography -- MALLS multi-angle laser light scattering -- RI refractive index -- DP differential pressure -- dn/dc differential refractive index -- TG thermogravimetry -- DTG derivative thermogravimetry -- DSC differential scanning calorimetry -- Gal galactose -- Man mannose -- M/G mannose/galactose -- PDS polydisperse system -- LS light scattering -- A2 & A1/F1 Avrami-Erofeev second- and first-order equations -- D3 Jander three-dimensional diffusion mechanism -- Mn Mv, Mw & Mz, apparent number-, viscosity-, weight- and z-average molecular weights -- PDI apparent polydispersity index -- 〈Rhv〉z apparent z-average hydrodynamic radius -- 〈Rg〉z apparent z-average radius of gyration -- [η]w apparent weight-average intrinsic viscosity -- ρ apparent shape factor -- Rg apparent radius of gyration -- Rhv apparent hydrodynamic radius -- [η] apparent intrinsic viscosity -- M apparent molecular weight -- β, γ & α apparent conformational power-law exponents -- df apparent fractal dimension -- A2 apparent second virial coefficient -- ML apparent molecular weight per unit contour length -- Lp apparent persistence length -- C∞ apparent characteristic ratio -- Ea activation energy -- δ degree of conversion -- FWO Flynn-Wall-Ozawa -- KAS Kissinger-Akahira-Sunose -- ε heating rate -- Ae pre-exponential factor -- Tm derivative thermogravimetry peak temperature -- IPDT integral procedural decomposition temperature -- ITS comprehensive index of intrinsic thermal stability -- t0.05 lifetime at 5 % conversion of stage II -- Ti, Tp & Tf initial, peak and final temperatures of enthalpy change -- ΔH enthalpy change -- ΔS*, ΔH* & ΔG* computed entropy, enthalpy and Gibbs free energy of activation; Circular dichroism -- Particle size distribution -- Morphologic properties -- Conformational behavior -- Thermal analysis -- Molecular aggregate; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2021.117890
• Languages: English
• ISSNs: 0144-8617

Abstract

Graphical abstract: Abstract: The molecular aggregation of a galactomannan (NSAP-25) from Sophora alopecuroides L. seeds was investigated, where three polydisperse systems were confirmed during particle size analysis, indicating existence of different aggregates composed of random coil chains revealed by circular dichroism. Morphologically, NSAP-25 aggregate of various sizes (200–1200 nm) was possibly multi-stranded and formed by ellipsoid-like particles (20–60 nm) composed of compact coil chain, exhibiting extended amorphous structure with chain-like branches intertwined. Hence, NSAP-25 aggregation was inevitable, which exerted an unignorable effect on augmenting flexibility ( β ↓, γ ↓, α ↓ and L p / M L ↓) and compactness ( ρ ↓, d f ↑ and C ∞ ↓) of branched random coil chain based on macromolecular analysis, especially when concentration increased. Moreover, it could be relevant to thermokinetic behavior of random nucleation and subsequent growth (A 2 model and negative Δ S *) as well as good thermal stability (IPDT, ITS, t 0.05, T m and T p ), thus conferring potential applications for NSAP-25 in food and pharmaceutical industries.