Water relations of simple sugar solutions and skim milk powder as studied by nuclear magnetic resonance spectroscopy

The water mobility in simple sugar-water systems as a function of sugar concentration was monitored by $\sp1$H, $\sp2$H and $\sp1$H decoupled $\sp{17}$O NMR transverse relaxation rates (R$\sb2$). For all three nuclei, R$\sb2$ increased with increasing sugar concentration with different magnitude and different trends of increases. Comparison of $\sp1$H, $\sp2$H and $\sp{17}$O NMR R$\sb2$ relaxation rates, on a normalized basis ($\Delta$R$\sb2$/R$\sb{\rm 2F}$), suggested that only the $\sp{17}$O monitors directly the water in the sugar-water systems. The contribution of proton exchange broadening effect to the $\sp{17}$O NMR R$\sb2$ measurement in both water and sugar-water systems as a function of pH could be eliminated by applying the proton decoupling on the $\sp{17}$O NMR. The trend of the relaxation rates versus sugar concentration were the same for R$\sb1$ and R$\sb2$ measured by single-pulse and multipulse methods. Water mobility measured by $\sp1$H decoupled $\sp{17}$O NMR R$\sb2$ relaxation rate was used as a method of monitoring lactose crystallization in supersaturated solutions over time. $\sp2$H NMR R$\sb2$ relaxation rate was used to monitor the water mobility during the amorphous to crystalline state transition of lactose in skim milk powder. Changes in water mobility were found to be directly related to the observed moisture changes and the transition of lactose from the amorphous to crystalline state.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Human and Community Development

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Lai, Hsi Mei

Contributors dc:contributor

• Klein, Barbara P.

• Agriculture, Food Science and Technology
• Chemistry, Agricultural

Statement dc:rights

• Copyright 1990 Lai, Hsi Mei

Language dc:language

eng

Identifier

AAI9026239
(UMI)AAI9026239

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/19666