Factors affecting the collection and fitting of nuclear magnetic cross-relaxation spectroscopy data with application to waxy corn starch.
J Agric Food Chem
; 48(10): 4469-76, 2000 Oct.
Article
en En
| MEDLINE
| ID: mdl-11052686
ABSTRACT
An examination of the methods for nuclear magnetic cross-relaxation spectroscopy (CRS) data collection and analysis was conducted using water and an aqueous waxy corn starch suspension to better perform and interpret the results obtained using CRS. The CRS data collection properties evaluated were the time to achieve steady state saturation, the direct saturation of liquid protons, generation of transverse magnetization, and dependence of the offset frequency and radio frequency (RF) field strength of longitudinal relaxation in the presence of RF saturation. Effects were evaluated for variations of input values of RF saturation field strength, apparent cross-relaxation rate, and solid longitudinal relaxation rate on the results for solid content and solid internal mobility from fitting NMR data to modified theoretical expressions. Discrepancies between fitted and stoichiometric values for the solid to liquid proton ratio were investigated. The fitting procedure used a Gaussian line shape for RF saturation of the solid-like spin system and a Lorentzian line shape for RF saturation of the liquid-spin system. Conditions under which acceptable results can be obtained with limited data sets are discussed.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Almidón
/
Zea mays
Idioma:
En
Revista:
J Agric Food Chem
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos