Influence of amino acids, and their interaction with volatiles and polyphenols, on the sensory properties of red wine

Abstract

Background and Aims: The effect of amino acids, and their interactions with volatiles and other non-volatiles, on inmouth sensory properties of red wines is not known. This knowledge gap has been studied in a series of comprehensive sensory experiments. Methods and Results: A solvent-assisted flavour evaporation extract of Shiraz wine volatiles, a de-aromatised polyphenolic extract and amino acids were added to model wine and wine systems. Using full factorial designs, samples were evaluated by sensory quantitative descriptive analysis. Volatiles enhanced Viscous mouthfeel (F = 20.0, P < 0.001), Sweetness (F = 26.5, P < 0.001) and Body (F = 81.4, P < 0.001), while the phenolic extract directed Astringency (F = 170.5, P < 0.001) as well as Bitterness (F = 7.3, P < 0.001) and suppressed Sweetness (F = 16.5, P < 0.001). An amino acid by volatile interaction (F = 4.2, P < 0.05) was found, and further experiments showed that L-proline enhanced Viscosity (F = 5.0, P < 0.05), Sweetness (F = 14.4, P < 0.001), Red fruit flavour (F = 7.8, P < 0.001) and suppressed Astringency (F = 6.1, P < 0.05) and Bitterness (F = 7.0, P < 0.01), while L-glutamic acid imparted an Umami taste (F = 5.0, P < 0.05) at wine-like concentration. Conclusions: For the first time, these causal experiments showed that amino acids can influence the taste, mouthfeel and flavour of red wine. Significance of the Study: This work provides insight into a new class of wine compounds of sensory significance that can be targeted by producers to directly influence wine flavour.

The Role of Potent Thiols in “Empyreumatic” Flint/Struck-Match/Mineral Odours in Chardonnay Wine

“…Recently, Espinase Nandorfy et al [21] demonstrated the sensory infuence of the residual amino acid proline in dry red wine, which increased perceived sweetness, fruit favour, and viscous mouthfeel, while diminishing bitterness and astringency. Although the proline concentration is reported to be lower in white wines (0.025-1.4 g/L) compared to red wines (0.018-4.4 g/L) as reviewed by Gutiérrez-Gamboa et al [43], the range can span across the sensory detection threshold reported in water of approximately 2 g/L [44] and has been linked to wine "body" previously [45].…”

“…Using odour addition studies, the ethyl esters conferring "peach" aroma in Chardonnay have only recently been demonstrated [20], while the source of "sweetness" in sugar dry white wines is not well understood. In dry red wines, the residual amino acid proline has been shown to increase "sweetness," "viscosity," and fruit favours [21].…”

“…We hypothesised that PMT, as identifed by Tominaga et al [2] and Capone et al [4], would play the major role in directing these smoky/mineral-like aromas and would contribute positively to consumer acceptance. A secondary objective was to assess the relative importance of ester compounds and residual proline concentration identifed by Espinase Nandorfy et al [20] and Espinase Nandorfy et al [21], respectively, in conferring peach/stone fruit aroma, sweetness, and viscosity in Chardonnay.…”

Minerality in Wine: Textual Analysis of Chablis Premier Cru Tasting Notes

“…One hypothesis gaining more traction is that minerality comes from reductive wine-making and storage processes that produce or maintain sulphurous compounds, but not enough to spoil the wine with of favours [4,20,21]. For example, insufcient yeast assimilable nitrogen (YAN) in wine must can lead to the production of more permanent sulphur compounds (such as methionol) as opposed to the highly volatile forms (such as hydrogen sulphide, ethanethiol, and methanethiol) that have low boiling points and volatilise when a bottle of wine is aerated [20].…”

“…A major difculty is that agreement has not been reached on what minerality is in terms of its sensory profle [25] or, equally problematic, that the sensations referenced are too numerous. Minerality remains an ill-defned concept [5,21]. Nonetheless, most wine professionals and consumers maintain it is a real and distinct sensation, for example, Szymanski [13].…”