A rapid identification method of rice protein in rice starch based on synchronous fluorescence spectroscopy

Rice protein is a protein with high nutritional value and its essential amino acids are complete. Rice protein content is related to the Nutritional value of rice powder mixture. Three-dimensional synchronous fluorescence spectroscopy combined with Parallel factor analysis (PARAFAC) and Partial least squares (PLS) was applied for Protein content in rice starch. Synchronous Fluorescence Spectroscopy were obtained at 250-400 nm (excitation) and 260-750 nm (wave-length deviation). Firstly, data of Rice starch were collected using synchronous fluorescence spectroscopy equipment and the protein content of samples were got by Dumas Nitrogen analyzer ; secondly, three improved PLS methods, including interval partial least squares (iPLS), backward interval partial least squares (biPLS) and synergy interval partial least squares (siPLS),were used to find the most informative range. Lastly, models with better predictive turbidity of fragrance vinegar using PLS was established in the whole wavelength range .The results showed that the models by siPLS method, which separated the whole spectra into 10 intervals, and combine four intervals of [1 3 4 5]had the best predictive ability, the RMSECV and RMSEP were 0.1482 and 0.1696, and the calibration and prediction correlation coefficient were 0.8513 and 0.8236. Using three-dimensional synchronous fluorescence spectroscopy for rapid detection of Protein content in rice starch was feasible.