Correlation between NMR proton relaxation time and free fatty acids and total polar materials of degraded soybean oils
1996
Sun, X. | Moreira, R.G.
The objective of this study was to determine if a correlation exists between NMR proton relaxation times and the increase in free fatty acids and polar materials in soybean oil as it is degraded. Soybean oil was degraded by heating only and by frying corn tortilla dough for 10 min/h up to 50 h. Samples were collected every 10 h. Both analytical chemistry methods and nuclear magnetic resonance techniques were used to determine the extent of oil degradation. Results showed that free fatty acids (FFA) and total polar materials (TPM) increased as heating time increased. The longitudinal relaxation time (T1) and the transverse relaxation time (T2) decreased as oil degradation increased. There was a linear relationship between NMR measurements and analytical chemistry measurements. As the prices of NMR equipment decrease, NMR technique could be a promising tool for on-line oil quality control in deep fat frying processes.
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