Search

Cassava stems contain up to 40% starch (by dry mass) and are currently discarded as agricultural waste. The current study aims to understand the physicochemical traits of cassava stem and root starches for investigating trends in industrial cassava applications. In total, 11 traits of both cassava stem and root starches of 15 genotypes are investigated. All the examined traits of cassava root and stem starches vary by genotype. The amylose contents of root and stem starches are in the range of 19.0–33.0% and 18.44–34.51%, respectively. The resistant starch of root and stem starches are in the range of 1.72–17.72% and 4.42–13.37%, respectively. Only the starch content, solubility, and swelling power of root starches are significantly higher than those of stem starches. The root starch gel is more stable than the stem starch gel after the fourth and fifth freeze‐thaw cycles. Furthermore, principal component analysis calculated based on starch and amylose contents, degree of swelling, digestibility, and freeze‐thaw stability demonstrates that genotypes GW46, GW88, S1, E26, and GC49 gain higher scores than control varieties South China 12 and South China 205, which are the most favorable ones by farmers in China because of good root yields. [ABSTRACT FROM AUTHOR]

Herein we report on the preparation and structural characterization of six amphiphilic polymer conetworks (APCN) based on end-linked amphiphilic 'core-first' star block copolymers, comprising methyl methacrylate and 2-(dimethylamino)ethyl methacrylate as the monomer repeating units in the hydrophobic and hydrophilic blocks, respectively. The various APCNs differed either in the arm composition or in the arm molecular weight. APCN synthesis was accomplished via the one-pot, sequential group transfer polymerization (GTP) of cross-linker, hydrophobic monomer, hydrophilic monomer, and cross-linker again. The soluble precursors to the APCNs, i.e., the star homopolymers, the star block copolymers and the initial cross-linker cores, were characterized in terms of their composition, size and size dispersity. The degrees of swelling in tetrahydrofuran were found to increase with the molecular weight of the arms of the stars of the APCNs, whereas the degrees of swelling in water increased with the content in hydrophilic units in the arms of the constituting stars. Small-angle neutron scattering (SANS) indicated that most APCNs nanophase separated in D2O. The structure and size of the hydrophobic domains determined by fitting the SANS data to an appropriate model could be correlated with the molecular architecture of the APCNs. Finally, polarized light microscopy showed that all APCNs were birefringent both in water and in the dried state. [ABSTRACT FROM AUTHOR]

Various nanocomposite gels were prepared using cellulose nanowhiskers (CNWs) or chitin nanowhiskers (ChNWs) as reinforcing fillers and hydroxypropyl cellulose (HPC), carboxymethyl cellulose (CMC), or chitosan as network polymers. The use of CNWs with low surface charge induced significant CNWs aggregations, which were well explained by depletion effect. Young's modulus E and swelling ratio Q of CNWs/HPC · CMC gels were highest at zero electrolyte concentration and decreased above 0.01 M electrolyte, whereas stress at break σ of the gels showed its minimum at zero electrolytes and increased with an addition of electrolytes. In the case of ChNWs/chitosan gels, maximum of E and Q was located at 0.01 M electrolyte concentration, and σ did not indicate clear tendency with electrolyte concentration. Although all gels indicated an increase in E and a decrease in Q with an increase in whisker content, the most remarkable changes were observed under an absence of electrolytes, whereas the changes under the presence of electrolytes were somewhat negligible. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]