Correlating Sensory Assessment of Smoke-Tainted Wines with Inter-Laboratory Study Consensus Values for Volatile Phenols.

Vineyard exposure to wildfire smoke can taint grapes and wine. To understand the impact of this taint, it is imperative that the analytical methods used are accurate and precise. This study compared the variance across nine commercial and research laboratories following quantitative analysis of the same set of smoke-tainted wines. In parallel, correlations between the interlaboratory consensus values for smoke-taint markers and sensory analyses of the same smoke-tainted wines were evaluated. For free guaiacol, the mean accuracy was 94 ± 11% in model wine, while the free cresols and 4-methylguaiacol showed a negative bias and/or decreased precision relative to guaiacol. Similar trends were observed in smoke-tainted wines, with the cresols and glycosidically bound markers demonstrating high variance. Collectively, the interlaboratory results show that data from a single laboratory can be used quantitatively to understand smoke-taint. Results from different laboratories, however, should not be directly compared due to the high variance between study participants. Correlations between consensus compositional data and sensory evaluations suggest the risk of perceivable smoke-taint can be predicted from free cresol concentrations, overcoming limitations associated with the occurrence of some volatile phenols, guaiacol in particular, as natural constituents of some grape cultivars and of the oak used for barrel maturation.

Development and Interlaboratory Evaluation of an LC-MS/MS Method for the Quantification of Lysozyme in Wine Across Independent Instrument Platforms.

BACKGROUND: Various processing aids and fining agents are used in winemaking to help improve sensory characteristics. Some of these materials may contain or be derived from allergenic foods, such as eggs. In order to ensure food safety and that products meet regulatory compliance, it is essential to have robust and effective analytical methods to verify the removal of allergenic proteins following their use. Current methods include ELISA and MS methods, which can target either whole foods or individual proteins, and provide either quantitative data or qualitative confirmation of proteins. MS methods offer the potential to test for multiple proteins within a single assay to improve cost and efficiency, whereas ELISA methods typically analyze for a single protein per assay. OBJECTIVE: This study focuses on the development of a LC-tandem MS (MS/MS) quantitative method for lysozyme in white wine and compares performance across two laboratories utilizing two different instrument platforms. METHODS: Lysozyme target peptides were selected by conducting bottom-up discovery proteomics. Candidate targets were evaluated using parallel reaction monitoring (PRM) or selected reaction monitoring (SRM) LC-MS/MS, depending on the instrument in each laboratory. Quantification of lysozyme was conducted using internal, stable isotope-labeled synthetic peptide standards. RESULTS: Three of eight candidate target peptides showed performance suitable for the final quantitative method. White wine spiked with 0.1 and 0.5 ppm lysozyme demonstrated quantitative recovery of 70-120%. While the PRM method delivered better repeatability, the SRM method gave higher quantitative recovery values. CONCLUSION: A targeted LC-MS/MS method for quantification of lysozyme in white wine has been developed and deployed on two different MS instrument platforms in two laboratories. HIGHLIGHTS: Both SRM and PRM targeted LC-MS/MS methodologies can be used for quantification of lysozyme in white wine. This study is among the first to evaluate an MS method for food allergen quantification in multiple laboratories.