Fluorescence sensing technology for the rapid detection of haze-forming proteins in white wine

Abstract

The methods currently available for determining haze proteins in wine are time-consuming, expensive, and often not sufficiently accurate. The latter may lead to bentonite over-fining of a wine, which might strip wine phenolics and aroma compounds, or wine under-fining, which increases the risk of protein instability. In this work, an efficient and rapid fluorescence-based technology to detect haze-forming proteins in white wines was developed. A fluorescent compound was synthesised to selectively bind haze-forming proteins. Studies involving HPLC demonstrated a linear dependence over a range of relevant haze protein concentrations and a low detection limit of 2 mg/L. Forty-eight control and bentonite fined wines were analysed to validate the analytical performance of the fluorescent dye in the detection of haze-forming proteins. The method can be deployed rapidly, without sample preparation, presenting an opportunity to use in routine testing and overcome limitations of the "heat test" currently used in the wine industry.

Keywords: Chitinases; Fluorescent dye; Haze-forming proteins; Protein detection; Protein haze; Thaumatin-like proteins.