Direct determination of the lipid content in starch–lipid composites by time-domain NMR

• Published in: Industrial crops and products Vol. 26; no. 1; pp. 77 - 84
• Main Author: Kenar, James A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2007
• Subjects: accuracy; chemical analysis; cooking; Excess steam jet cooking; heat treatment; lipid content; Low resolution NMR; milk fat; mixtures; nondestructive methods; nuclear magnetic resonance spectroscopy; product quality; Pulsed NMR; rapid methods; raw materials; soybean oil; Spin–spin relaxation; Starch; Starch–lipid composites; Time-domain nuclear magnetic resonance; time-domain nuclear magnetic resonance spectroscopy; Vegetable oil; water content; Excess steam jet cooking; Time-domain nuclear magnetic resonance; Low resolution NMR; Starch; Starch–lipid composites; Spin–spin relaxation; Vegetable oil; Pulsed NMR
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2007.01.008

Starch–lipid composites, prepared by excess steam jet cooking aqueous mixtures of starch and lipid, are used in a broad range of applications for which their performance can depend upon accurately knowing the amount of the lipid contributed by the composites. A rapid and non-destructive method based on time-domain nuclear magnetic resonance spectroscopy (TD-NMR) was evaluated to quantitate soybean oil (SBO) or butterfat (BF) content in a series of dried starch–lipid composites. Transverse hydrogen relaxation ( T 2) properties of the composites were examined using Carr, Purcell, Mieboom, Gill (CPMG) pulse experiments and multi-exponential decay fitting routines were utilized to evaluate the various components. Spin–echo TD-NMR experiments were used to quantitate the amount of lipid in the composites and agreed well with lipid extraction experiments ( R 2 = 0.998). Moisture levels in the composites were also simultaneously determined and compared reasonably well to moisture levels determined gravimetrically ( R 2 = 0.881). TD-NMR was shown to be a rapid method to determine lipid and moisture content in these starch–lipid composites without the need for labor intensive extraction and gravimetric methods currently employed.