Red wine age estimation by the alteration of its color parameters: Fourier transform infrared spectroscopy as a tool to monitor wine maturation time

Abstract

Color, phenolic content, and chemical age values of red wines made from Cretan grape varieties (Kotsifali, Mandilari) were evaluated over nine months of maturation in different containers for two vintages. The wines differed greatly on their anthocyanin profiles. Mid-IR spectra were also recorded with the use of a Fourier Transform Infrared Spectrophotometer in ZnSe disk mode. Analysis of Variance was used to explore the parameters dependency on time. Determination models were developed for the chemical age indexes using Partial Least Squares (PLS) (TQ Analyst software) considering the spectral region 1830"1500 cm'1.The correlation coefficients for chemical age index i were 0.86 for Kotsifali (Root Mean Square Error of Calibration (RMSEC) = 0.067, RootMean Square Error of Prediction (RMSEP) = 0,115, and RootMean Square Error of Validation (RMSECV) = 0.164) and 0.90 forMandilari (RMSEC = 0.050, RMSEP = 0.040, and RMSECV = 0.089). For chemical age index ii the correlation coefficients were 0.86 and 0.97 for Kotsifali (RMSEC 0.044, RMSEP = 0.087, and RMSECV = 0.214) andMandilari (RMSEC = 0.024, RMSEP = 0.033, and RMSECV = 0.078), respectively.Theproposed method is simpler, less time consuming, andmore economical and does not require chemical reagents.