Authentication of β-casein milk phenotypes using FTIR spectroscopy

The ability to accurately and cost-effectively distinguish between different genetic protein variants in milk is of pivotal significance to the dairy industry as the natural proteoforms of caseins affect the composition and functionality of dairy products. Recently, beta-casein proteoforms have received increased consumer attention in regards to A1 and A2 milk families. Fourier transform infrared (FTIR) spectroscopy coupled with multivariate analysis was used to discriminate milk samples from 114 Holstein-Friesian cows possessing different beta-casein genetic variants. Principal component and partial least squares discriminant analyses were used to characterise and distinguish A1 and A2 beta-casein genetic families based on spectral data. Milk containing A2 beta-casein had higher proportions of random coil and beta-sheet conformations than milk containing A1 beta-casein and the lowest amount of alpha-helical and beta-turn structures, due to additional proline. This may provide a feature to distinguish between these phenotypes using FTIR spectroscopy in association with chemometric analyses. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The ability to distinguish between different genetic protein variants in milk is important to the dairy industry. FTIR spectroscopy coupled with multivariate analysis can be used to identify the differences between A1 and A2 milk.