Red Wine Age Estimation by the Alteration of Its Color Parameters: Fourier Transform Infrared Spectroscopy as a Tool to Monitor Wine Maturation Time.

M Basalekou,Y Kotseridis,E Kontaxakis,C Pappas,S Kallithraka,P A Tarantilis

doi:10.1155/2017/5767613

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 parameter's 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 (r) for chemical age index i were 0.86 for Kotsifali (Root Mean Square Error of Calibration (RMSEC) = 0.067, Root Mean Square Error of Prediction (RMSEP) = 0,115, and Root Mean Square Error of Validation (RMSECV) = 0.164) and 0.90 for Mandilari (RMSEC = 0.050, RMSEP = 0.040, and RMSECV = 0.089). For chemical age index ii the correlation coefficients (r) were 0.86 and 0.97 for Kotsifali (RMSEC 0.044, RMSEP = 0.087, and RMSECV = 0.214) and Mandilari (RMSEC = 0.024, RMSEP = 0.033, and RMSECV = 0.078), respectively. The proposed method is simpler, less time consuming, and more economical and does not require chemical reagents.

Highlights

Wine age is a parameter of great importance as it is linked with wine quality
Different types of containers were used and samples were taken from each container every three months over the period of nine months for two consecutive vintages (2012 and 2013) (12 months of contact only for the 2013 vintage), resulting in 12 red wine samples for each vintage’s trimester (Table 1)
The results showed that total anthocyanins, hue, pigments resistant to SO2, and chemical ages i and ii were influenced by time; variety and vintage had a stronger effect in all cases except for chemical age i (Table 3) where time had the most definitive effect

Summary

Introduction

Wine age is a parameter of great importance as it is linked with wine quality. there is no direct way to measure it. Young wines’ color depends on the concentration of free anthocyanins, which on the wine’s pH are on their colored form (positively charged flavylium). As monomers, they are highly susceptible to changes in the medium’s environment, such as pH and SO2 changes [1]. The purple hue of young red wines is replaced by brickish red to tawny red hues. Those changes in color can be observed with the naked eye, and using a spectrophotometer by measuring color parameters such as intensity and hue [2].

Methods

Results

Conclusion