Rapid and real-time analysis of compositional parameters in commercial white grape juice
Nevil Shah, Wies Cynkar, Paul Smith and Daniel Cozzolino*. J. Agric. Food Chem., 2010, 58 (6), pp 3279–3283
A simple and fast midinfrared (MIR) spectroscopy method was developed for simultaneously determining total soluble solids (TSS, °Brix), pH, total phenolics, ammonia, free amino nitrogen (FAN), and yeast assimilable nitrogen (YAN) contents in grape juice samples using attenuated total reflectance (ATR).
Results from this study demonstrated the capability of ATR-MIR coupled with partial least-squares regression to measure TSS and pH and to monitor FAN, ammonia, and YAN in a wide range of grape juice samples.
The standard error in cross-validation and the residual predictive deviation obtained were 0.20 °Brix and 9 for TSS, 0.07 and 3.3 for pH, 14.8 mg/L and 2 for ammonia, 28.3 mg/L and 2 for FAN, and 36.9 mg/L and 2 for YAN, respectively.
Both the time of analysis and the volume of sample required were considerably reduced as compared to the transmission MIR measurements currently used by the wine industry.
(We recommend that you consult the full text of this article).
Published on 04/07/2011