Rapid strategies for the determination of sensory and chemical differences between a wealth of similar wines

Role of gas chromatography and olfactometry to understand the wine aroma: Achievements denoted by multidimensional analysis

“…1DGC is predominantly used for the evaluation of odorous compounds in wines (73% of the studies reported in Table 1). Nevertheless, due to the complex volatile profile of wine, the separation capacity of the 1DGC was found to be insufficient and the MDGC has emerged as an important tool to improve the chromatographic separation of important compounds for the wine aroma [22–25,27].…”

“…Scheme of proposals for combining olfactometry with 1DGC, GC‐GC and GCxGC. (A) GC‐GC‐O‐FID/MS system showing the coupling of chromatograph 1 (GC1) to the flame ionization detector (FID) and to the olfactometer and chromatograph 2 (GC2) to the mass spectrometry (MS) and olfactometric detectors [22,24,25,56,65,82,84,86]; (B) GCxGC/MDGC‐O‐FID/MS with first chromatographic dimension ( 1 D) coupled to a long ( 2 D L , 30 m) and a short column ( 2 D S , 0.9 m) in the second dimension [10]; (C) polydimethylsiloxane (PDMS) trap collects specific fractions of the 1DGC to be evaluated by an off‐line olfactometer and GCxGC/MS [44]; (D) GC‐O/GCxGC‐FID system in parallel to GC×GC/MS [11]; (E) Affinity chromatography and GC with sulfur chemiluminescence detector (GC−SCD), and GCxGC/MS to evaluate sulfur‐containing compounds [5]; (F) GC‐O/MS in parallel to GCxGC/MS to quantify odor‐active compounds [70]; (G) GC‐O‐FID/MS in parallel to GCxGC/MS to identify and quantify odor‐active compounds and to elucidate the entire volatile profile of wine [23,26,27]…”

“…GC‐GC is a successful strategy for target‐analysis, whenever a few fractions contain all the compounds of interest. An approach based on the GC‐GC‐O‐FID/MS system as represented in Figure 4A has been used in the analysis of wine [22,24,25,56,65,82,84,86]. In this system, two independent gas chromatographs are interconnected by means of a heated transfer line and a driven switching valve, which enables selective transfer of heart cuts eluting from the first column (polar) to a second chromatograph containing a nonpolar column.…”

“…Compounds whose presence in wines was first reported are also important achievements in this field due to the use of GC‐GC‐O‐FID/MS, including the role of wine aging [56] in the formation of fruity ethyl esters (cyclohexanoate, 2‐hydroxy‐3‐methylbutyrate, and 2‐hydroxy‐4‐methylpentanoate), identification of markers of grape variety [24,86] and terroir [82]. Evaluating wines made with different grape varieties, 3‐methyl‐2‐butene‐1‐thiol was pointed out as an odorant (odor described as marijuana, rubber, and beer) related to the Pietro Picudo grapes [86].…”

“…An analytical approach encompassing multiple dimensions, such as multidimensional GC (MDGC), including heart‐cutting GC (GC‐GC) or comprehensive two‐dimensional GC (GCxGC), may help separating coeluting compounds and detect some trace compounds important to wine aroma [22,23]. GC techniques combined with olfactometry have been used to identify odor‐active compounds that are essential to differentiate wines according to the terroir [24], to understand the role of fungal infection of grapes for wine quality [25], to find best canopy management practices [26] and to define the ideal balance between maturation degree and maceration time of grapes to obtain the best quality [27], among others.…”