title: Effect of salt on the glass transition of condensed tapioca starch systems.
abstract: This work examines the effect of including hydrated NaCl and CaCl2(up to 6% w/w) on the physicochemical properties of condensed tapioca starch. Samples were prepared by hot pressing at 120°C to produce condensed systems that covered a range of moisture contents from 7.34% w/w (23% relative humidity) to 19.52% w/w (75% relative humidity). Tensile storage modulus and heat flow measurements were taken using DMA and MDSC, which were accompanied by FTIR, WAXD and ESEM. Increasing the salt level enhances the mechanical strength of starch in the glassy state and shifts the glass transition temperature to a higher value. Antiplasticising effects of NaCl and CaCl2on the non-phosphorylated tapioca starch are indistinguishable from each other. Observations are complemented by intensification of absorbance peaks in FTIR spectra and a systematic change in shape and intensity of diffraction patterns with increasing addition of salt consistent with interactions between added ions and macromolecule.
authors.affiliation: School of Science, RMIT University, Bundoora Campus, Bundoora, Melbourne, VIC 3083, Australia.
authors.forename: Lillian
authors.initials: L
authors.lastname: Chuang
authors.affiliation: School of Science, RMIT University, Bundoora Campus, Bundoora, Melbourne, VIC 3083, Australia.
authors.forename: Naksit
authors.initials: N
authors.lastname: Panyoyai
authors.affiliation: School of Science, RMIT University, Bundoora Campus, Bundoora, Melbourne, VIC 3083, Australia.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Shanks
authors.affiliation: School of Science, RMIT University, Bundoora Campus, Bundoora, Melbourne, VIC 3083, Australia. Electronic address: stefan.kasapis@rmit.edu.au.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kasapis
mesh_terms: D002122:Calcium Chloride / Q000032:analysis / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D002365:Manihot / Q000737:chemistry*; D017673:Sodium Chloride, Dietary / Q000032:analysis*; D013213:Starch / Q000737:chemistry; D044366:Transition Temperature
chemical_list: D017673:Sodium Chloride, Dietary; D013213:Starch; D002122:Calcium Chloride
keywords: Calcium chloride; Glass transition; High-solid systems; Sodium chloride; Tapioca starch