Free fatty acid formation and lipid oxidation on milled rice |
| |
Authors: | Henry S Lam Andrew Proctor Jean-François Meullenet |
| |
Affiliation: | (1) Department of Food Science, University of Arkansas, 2650 Young Ave., 72704 Fayetteville, AR |
| |
Abstract: | Milled rice was stored at 37°C and 70% humidity and sampled regularly for 50 d. Rice surface lipid was extracted with isopropanol
and analyzed for free fatty acids (FFA) and conjugated diene (CD) contents. Diffuse reflectance Fourier transform infrared
(DRIFTS) spectra of the rice samples were also obtained. FFA and CD levels increased together during rice storage and exhibited
three distinct phases. DRIFTS identified a decrease in intensity at 1746 cm−1 (ester, −C=O) and increases in intensity at 1731 cm−1 (aldehyde, −CO) and 1714 cm−1 (fatty acid, −C=O) during storage, which correlated well with the chemical analysis data. DRIFTS spectral data were analyzed
by a partial least squares regression method to identify spectral regions that correlate strongly with measured FFA and construct
prediction models. Overall, the mid-infrared region (4000–400 cm1) gave the best model (R=0.98, root mean square error of cross-validation=0.05) and also predcted the FFA content of milled rice well. The DRIFTS
technique has potential for use in studying qualitative chemical changes on the milled rice surface lipids and for predicting
FFA on milled rice. |
| |
Keywords: | Conjugated diene diffuse reflectance infrared spectroscopy free fatty acids milled rice partial least squares regression |
本文献已被 SpringerLink 等数据库收录! |
|