Authentication of sweetness of mango juice using Fourier transform infrared-attenuated total reflection spectroscopy

Fourier transform infrared spectrometer equipped with attenuated total reflection and chemometrics were used to determine added sugar content (ASC), total soluble solids (TSS) and real juice content (RJC) in fresh and commercial mango juice. Sucrose solutions (0–27%), fresh mango juice adulterated with 0–27% sucrose, and two commercial brands were evaluated in wavenumber range of 4000–650 cm−1. Partial least squares (PLS) discrimination and principal component analysis (PCA) were used to classify the samples with or without ASC. PLS and multiple linear regression (MLR) were carried out with and without data treatments. The detection limit for ASC was 3% for samples with low natural TSS, 5% for samples with natural TSS more than 10% and 3.6% for commercial samples. ASC, TSS, and RJC were predicted in the wavenumber range of 1476–912 cm−1 using PLS (multiple correlation coefficient, R = 0.99) and three wavenumbers (1088, 1050, 991 cm−1) using MLR (R = 0.98).