Methoxypyrazine Analysis and Influence of Viticultural and Enological Procedures on their Levels in Grapes, Musts, and Wines

Abstract

This review discusses the factors that affect the concentrations of methoxypyrazines (MPs) and the techniques used to analyze MPs in grapes, musts, and wines. MPs are commonly studied pyrazines in food science due to their contribution of aroma and flavor to numerous vegetables such as peas and asparagus. They are described as highly odorous compounds with a very low olfactory threshold. The grape varietals that exhibit green or herbaceous aromas that are characteristic of MPs are predominantly Vitis vinifera cv. Cabernet Sauvignon and Sauvignon Blanc, but include others. The most extensively studied MPs include 3-isobutyl-2-methoxypyrazine, 3-isopropyl-2-methoxypyrazine, and 3-sec-butyl-2-methoxypyrazine. It outlines the significance of methoxypyrazines in grapes, musts, and wines in terms of the concentrations that are capable of contributing their sensory characteristics to wines. This review discusses methods for analyzing MPs including gas chromatography-mass spectroscopy (one or two dimension) and high-performance liquid chromatography, the appropriate extraction techniques, and the efficacy of these methods. Additionally, this review explores factors that affect pyrazine content of grapes, must, and wines, such as the effects of different viticultural practices, effects of light exposure and grape maturation, climate, soil, the multi-colored Asian lady beetle and the effects of different vinification processes.

Chemical and Sensory Evaluation of Silicone and Polylactic Acid-Based Remedial Treatments for Elevated Methoxypyrazine Levels in Wine

“…The wine was spiked with 20 ng/L of IPMP, SBMP and IBMP. This concentration can be found in wines affected by ladybug taint as well as in wines produced from under ripe grapes, particularly for IBMP and IPMP [25]. It is also sufficient to cause a negative change in the aroma/flavor profile of the wines, yet potentially low enough for remedial treatments to remove MP-impacts to below sensory detection thresholds.…”

Impact of agronomic practices on grape aroma composition: a review

“…58 The odor perception threshold is very low, with values between 1 and 16 ng L −1 in wine and 1-2 ng L −1 in water. 60 C 6 alcohols and aldehydes Many C 6 compounds are derived from fatty acid molecules throughout oxidation by the lipoxygenase (LOX) pathway and are partly responsible for the 'green' aromas in grapes and wine. Besides alcohols and aldehydes, there are other C 6 compounds involved, which are ketones, acids, esters, and lactones.…”

“…Concentrations of MPs are very low in grape and wine (approximately 2–30 ng L −1 ) . The odor perception threshold is very low, with values between 1 and 16 ng L −1 in wine and 1–2 ng L −1 in water …”

The Transcriptional Responses and Metabolic Consequences of Acclimation to Elevated Light Exposure in Grapevine Berries

“…A significant number of studies have investigated the impacts of leaf removal on berry development and ripening. Depending on the cultivar, the objectives range from improving the acid balance (Hunter and Visser, 1990; Toda et al, 2013; Baiano et al, 2015); improving anthocyanin/color stability (Chorti et al, 2010; Sternad Lemut et al, 2011; Lee and Skinkis, 2013; Baiano et al, 2015; Song et al, 2015; Guan et al, 2016; Yu et al, 2016; Pastore et al, 2017); increasing specific secondary metabolites such as volatile aroma precursors (Staff et al, 1997; Tardaguila et al, 2010; Feng et al, 2015; Song et al, 2015; Suklje et al, 2016; Young et al, 2016) or lowering of metabolites that are perceived negatively in the grapes/wines (Sala et al, 2004; reviewed in Sidhu et al, 2015). One of the main outcomes of leaf removal in the bunch zones is the accumulation of protective phenolic compounds i.e., anthocyanins (Lee and Skinkis, 2013; Guan et al, 2016; Lee, 2017) and flavonols (Yu et al, 2016; Pastore et al, 2017), as well as changes to volatile aroma compounds i.e., the norisoprenoid, β-damascenone (Feng et al, 2015; Young et al, 2016) and monoterpenes (Song et al, 2015; Young et al, 2016).…”