 the absorbance data for every tested wavelength) are thus processed by a statistical algorithm, such as Principal Component Analysis (PCA) or Partial Least Squares regression (PLS), to estimate the oil acidity.The feasibility to measure olive oil free acidity and peroxide value by NIR spectroscopy in the wavenumber range 4,541 to 11,726 cm−1 was reported.Many commercial spectrophotometers exist  that can be used for analysis of different quality parameters in olive oil.