Horizontal attenuated total reflection applied to simultaneous determination of ash and protein contents in commercial wheat flour

摘要

Partial least-squares(PLS)regression was used to generate various models for the determination of both the protein and the ash contents of wheat flours by using spectroscopic data in the mid-infrared region obtained with a horizontal attenuated total reflectance(HATR)accessory.One hundred samples of wheat flour were used as purchased in the market:55 for constructing the calibration model and 45 as external samples.The protein content varied between 8.85 and 13.23% and the ash content,between 0.330 and 1.287%,as determined by reference methods.Raw spectra and those corrected by multiplicative signal correction(MSC),first and second derivative spectra,were used as data for building the models.Different pre-treatments,such as mean centered and/or variance scaled(VS)methods,were tested and compared.Very good models were built as judged by the correlation coefficients(R~2),root mean square error of calibration(RMSEC),root mean square error of validation(RMSEV)and root mean square error of prediction(RMSEP)that were obtained.Best results were achieved with MSC treated spectra.