Determination of whey adulteration in milk powder by using laser induced breakdown spectroscopy

• Whey powder adulteration in milk powder was determined quantitatively by using LIBS.
• Mineral contents of milk and whey powders were measured by LIBS.
• Identification between milk and whey powders was performed with chemometrics.
• LIBS is a rapid and in situ method for determination of whey powder adulteration in milk powder.

A rapid and in situ method has been developed to detect and quantify adulterated milk powder through adding whey powder by using laser induced breakdown spectroscopy (LIBS). The methodology is based on elemental composition differences between milk and whey products. Milk powder, sweet and acid whey powders were produced as standard samples, and milk powder was adulterated with whey powders. Based on LIBS spectra of standard samples and commercial products, species was identified using principle component analysis (PCA) method, and discrimination rate of milk and whey powders was found as 80.5%. Calibration curves were obtained with partial least squares regression (PLS). Correlation coefficient (R2) and limit of detection (LOD) values were 0.981 and 1.55% for adulteration with sweet whey powder, and 0.985 and 0.55% for adulteration with acid whey powder, respectively. The results were found to be consistent with the data from inductively coupled plasma – mass spectrometer (ICP-MS) method.