[Research on the quantitative determination of lime in wheat flour by near-infrared spectroscopy]

The safety of wheat flour is always focused by all quarters of society. Based on comparing the feature of NIR spectra of calcium oxide, calcium hydroxide and calcium carbonate in this research, the diffuse reflection NIR spectra of the wheat flour samples with different content of calcium oxide, calcium hydroxide and calcium carbonate mixed in were collected. The calibration models of lime and calcium carbonate were developed by partial least square algorithm, with the validation method of cross validation. The result indicated that the determination coefficients (R2) of lime and calcium carbonate are 99.80% and 96.98% respectively, the root mean square errors of calibration set are 0.19 and 0.34 respectively; the root mean square errors of cross validation set are 0.26 and 0.75 respectively; the root mean square errors of prediction set are 0.63 and 0.44 respectively; the ratio performance deviations (RPD) are 8.57 and 5.24 respectively, which indicated that the calibration models were precise enough to adapt to the on-site rapid determination of lime in wheat flour. The result of F-test indicated that a very remarkable correlation exists between the estimated and specified values of the calibration sets and the external validation sets. This research, to some extent, will provide some reference methods for the rapid determination of wheat flour for quality safety, which is important for the quality control of wheat flour.