Study of cryostructuration of polymer systems. XVI. Freeze–thaw-induced effects in the low concentration systems amylopectin–water

✍ Scribed by Vladimir I. Lozinsky; Lilija G. Damshkaln; Rupert Brown; Ian T. Norton

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 121 KB
• Volume: 75
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(20000401)75:14<1740::aid-app8>3.0.co;2-1

✦ Synopsis

Studies of the freeze-thaw behavior of low-concentrated (0.01-0.25 g/dL) water solutions and dilute pastes (0.5-1.0 g/dL) of maize starch amylopectin showed that cryogenic treatment of these systems resulted in the formation of precipitated matter, whose yield and thermal characteristics (melting temperature and enthalpy) depended on the initial polymer concentration and conditions of freezing, frozen storage, and thawing. Research of the kinetic features of these cryoprecipitation events revealed at least two stages for this process: (i) a rapid stage, when the precipitation of virtually all of the dissolved polysaccharide occurred while the system was freezing, and (ii) a slower stage, the rate of which was mainly dependent on the thawing regimes or duration of the sample storage frozen at subzero temperatures. Cryoprecipitation phenomena were observed to be most extensive at temperatures 1-2°below the melting point of the frozen system.