ARS | Publication request: DIRECT DETERMINATION OF THE LIPID CONTENT IN STARCH-LIPID COMPOSITES BY TIME-DOMAIN NMR

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 28, 2007
Publication Date: June 1, 2007
Citation: Kenar, J.A. 2007. Direct determination of the lipid content in starch-lipid composites by time-domain NMR. Industrial Crops and Products. 26(1):77-84.

Interpretive Summary: Starch-lipid composites known as FanteskTM are prepared by excess steam jet-cooking aqueous mixtures of agriculturally renewable materials such as starch, with vegetable oil or animal fats. These composites find use in various applications for which their performance can depend upon accurate quantitation of lipid contained within these composites. In this work, a rapid non-destructive analytical technique (low resolution nuclear magnetic resonance, NMR) was used to quantitate the lipid and moisture content in these dried starch-lipid composites. Using this analytical method, the lipid and moisture content of the composites were readily determined. The basic knowledge gained from this research has clear importance for potential applications utilizing these composites. The development of new analytical techniques to characterize materials derived from renewable resources, not only benefits farmers in the United States, but also reduces our dependence on petroleum-based resources.

Technical Abstract: Starch-lipid composites, prepared by excess steam jet-cooking aqueous mixtures of starch and lipid, are used in various applications for which their performance can depend upon accurate quantitation of lipid contained within these composites. A rapid and non-destructive method based on time-domain nuclear magnetic resonance spectroscopy (TD-NMR) was evaluated to quantitate the lipid (soybean oil or butterfat) content in a series of dried starch-lipid composites. Tranverse hydrogen relaxation (T2) of the composites were identified using Carr-Purcell, Mieboom-Gill (CPMG) pulse experiments and showed three distinct components to be present. Lipid determination in the composites by spin-echo TD-NMR agreed well with lipid extraction determinations (R2 = 0.998). Moisture in the composites was also simultaneously determined using spin-echo TD-NMR and compared reasonably well to moisture levels determined gravimetrically (R2 = 0.881). Results showed TD-NMR is useful to determine lipid and water content in these starch-lipid composites thereby avoiding current tedious extraction and gravimetric methods.