BACKGROUND This work aims at developing a method, based on near-infrared (NIR) spectroscopy, to quantify 2-phenylethanol (2-PE) and l-phenylalanine (l-Phe) concentrations during its microbial production by Yarrowia lipolytica. For this purpose, 197 samples obtained from different batch cultures were analyzed using Fourier transform (FT)-NIR transmission spectroscopy in the range of 200-14 000 cm(-1). RESULTS A principal components analysis was performed for cluster identification and outlier removal. A partial least squares regression was next applied to develop the calibration models, by an iterative method. The predictive ability of the models was confirmed by an external validation procedure with an independent sample set. The obtained results could be considered promising, with coefficients of determination (R-2) of 0.92 for l-Phe and 0.95 for 2-PE, and residual prediction deviation above 3, for the ensemble data. CONCLUSION The described methodology, using NIR spectroscopy and chemometrics, can be seen as a promising fast tool to determine both studied flavor compounds during biotechnological processes as an alternative to chromatographic methods. (c) 2018 Society of Chemical Industry