23Na NMR relaxation rate studies in hydrocolloid-NaCl solutions as influenced by NaCl concentration and pH

Shelly J. Schmidt, Nalini Ayya, Lena Shirley

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Abstract

23Na NMR longitudinal (R1) and transverse (R2) relaxation rates were measured for 0.5 g/L aqueous solutions of sodium carboxymethyl-cellulose (CMC) and methylcellulose (MC) as a function of added NaCl (0 to 800 mg/100 mL) and pH (2 to 13). In the case of CMC. R1 and R2 decreased rapidly as the concentration of added NaCl increased. Whereas in the case of MC, after a small initial decrease, R1 and R2 were relatively constant with increasing added NaCl. This difference in relaxation rates was attributed to the difference in the chemical nature of the two hydrocolloids. R1 and R2 increased as pH increased from 2 to 7 for CMC at 0 and 50 mg added NaCl/100 mL. This increase in R1 and R2 is attributed to the deprotonization of the carboxyl group at approximately pH 4.5.

Original languageEnglish (US)
Pages (from-to)540-543
Number of pages4
JournalLWT - Food Science and Technology
Volume25
Issue number6
StatePublished - Dec 1 1992

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ASJC Scopus subject areas

  • Food Science

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