Inter-regional characterisation of New Zealand pinot noir wines: Correlation between wine colour, monomeric and polymeric phenolics, tannin composition, antioxidant capacity, and sensory attributes.

A total of 116 New Zealand Pinot Noir wines from Central Otago (CO), Marlborough (MLB), and Martinborough (MTB) were analysed for colour, monomeric and total phenolics, antioxidant capacity, and tannins using colourimetric and HPLC methods. Correlations among chemical compositions and analytical techniques were examined. Additionally, a sensory study assessed wine colour and five mouthfeel attributes.

Insights into the relative contribution of four precursors to 3-sulfanylhexan-1-ol and 3-sulfanylhexylacetate biogenesis during fermentation.

The desirable wine aroma compounds 3-sulfanylhexan-1-ol (3SH) and 3-sulfanylhexyl acetate (3SHA) are released during fermentation from non-volatile precursors present in the grapes. This work explores the relative contribution of four precursors (E-2-hexenal, 3-S-glutathionylhexan-1-ol, 3-S-glutathionylhexanal, and 3-S-cysteinylhexan-1-ol) to 3SH and 3SHA. Through the use of isotopically labelled analogues of these precursors in defined fermentation media, new insights into the role of each precursor have been identified.

A green liquid chromatography-tandem mass spectrometry method for the simultaneous analysis of volatile thiols and their precursors in oenological samples.

Improvements to the quantification of three white wine impact odorants 3-sulfanylhexan-1-ol, 3-sulfanylhexyl acetate, and 4-sulfanyl-4-methylpentan-2-one, and the non-volatile precursors from which they are released during fermentation, is of great interest to the wine science community. Recent reports of a "Quick, Easy, Cheap, Effective, Rugged and Safe" (QuEChERS) based method for the concurrent analysis of these thiols and their precursors via liquid chromatography tandem mass spectrometry (LC-MS/MS) has enabled the development of far simpler methods, as well as aligning these analyses with principles of green analytical chemistry. This current work reports the development and validation of a QuEChERS based LC-MS/MS method utilising a safer derivatising agent, 4,4'-dithiodipyridine, while greatly minimising the reagents involved and waste produced.

Synthesis of a novel isotopically labelled standard for quantification of γ-nonalactone in New Zealand Pinot noir via SIDA-SPE-GC-MS.

γ-Nonalactone is a linear aliphatic lactone ubiquitous in wine, associated with coconut, sweet, and stone fruit aroma descriptors. Little research has been conducted looking at the importance of this compound to New Zealand (NZ) wine aroma. HC-γ-Nonalactone, a novel isotopologue of γ-nonalactone, was synthesised in this work for use in a stable isotope dilution assay (SIDA) for quantification of γ-nonalactone in NZ Pinot noir wines for the first time.