Abstract:

Fatty acid composition and LF-NMR relaxation characteristics of peanut oil adulterated with lard at different
ratios were studied and the corresponding correlations were also analyzed. The results showed that as the adulteration ratio
of lard increased, the content of saturated fatty acid increased significantly while the adulteration parameter (AP) value
decreased, and the single component relaxation time T2W decreased linearly. When the adulteration ratio was above 30%, T21
decreased significantly and then remained stable. However, there was no obvious change in T22. S21 and S22 linearly increased
(R2 = 0.936) and decreased (R2 = 0.972), respectively. Adulterated oil samples were all located from the top-right corner to
the lower-left corner in the principal component analysis (PCA) map and PCA could clearly discriminate oil samples with
an adulterated ratio above 20%. Besides, good correlation was found between the F value (PCA overall score) and AP value
(R2 = 0.969). Therefore LF-NMR characteristics can be used to predict the changes in fatty acid composition and thus rapidly
detect the quality of peanut oil.

Key words: lard, peanut oil, adulteration, fatty acid composition, relaxation characteristics