Potential Grape-Derived Contributions to Volatile Ester Concentrations in Wine

Abstract

Grape composition affects wine flavour and aroma not only through varietal compounds, but also by influencing the production of volatile compounds by yeast. C9 and C12 compounds that potentially influence ethyl ester synthesis during fermentation were studied using a model grape juice medium. It was shown that the addition of free fatty acids, their methyl esters or acyl-carnitine and acyl-amino acid conjugates can increase ethyl ester production in fermentations. The stimulation of ethyl ester production above that of the control was apparent when lower concentrations of the C9 compounds were added to the model musts compared to the C12 compounds. Four amino acids, which are involved in CoA biosynthesis, were also added to model grape juice medium in the absence of pantothenate to test their ability to influence ethyl and acetate ester production. β-Alanine was the only one shown to increase the production of ethyl esters, free fatty acids and acetate esters. The addition of 1 mg·L −1 β-alanine was enough to stimulate production of these compounds and required for the stimulatory effect on ethyl and acetate ester production observed in this study.

Chemical and sensory profiling of Shiraz wines co-fermented with commercial non-Saccharomycesinocula

“…Wine colour and phenolic substances were determined with the modified Somers method (Mercurio et al 2007). The extraction and chromatographic conditions were identical to those reported in Boss et al (2015). The volatile composition of the wines was analysed by solid phase microextraction (SPME)-GC/MS.…”

Peduncle-girdling of Shiraz (Vitis viniferaL.) bunches and sugar concentration at the time of girdling affect wine volatile compounds

“…For harvest samples, the concentration of amino acids from 200 mg of powdered berry tissue was quantified as described by Boss et al (2015). Measurement of Pro in the Girdle 1 samples collected prior to harvest and in developmental berry samples was made according to the method of Rienth et al (2014) with the following modifications: 500 μL of diluted grape juice, formic acid and ninhydrin solutions was used for the reaction, and the absorbance at 520 nm was read in a 96-well, flat bottom, straight-sided microtiter plate (Greiner Bio One, Kremsmünster, Austria) using a FLUOstar Omega microtiter plate reader (BMG Labtech, Ortenberg, Germany).…”

Monitoring volatile compounds production throughout fermentation by Saccharomyces and non-Saccharomyces strains using headspace sorptive extraction

“…Presently, the most extensively used extraction technique for volatile compounds in wines is the solid phase microextraction (SPME) (Boss et al 2015;Renault et al 2015). The other extraction technique that has showed successful results in volatile profile analysis of wine is stir bar sorptive extraction (SBSE).…”

“…Wine is a complex solution containing abundant volatile compounds which contribute to wine aroma (Boss et al 2015). These aromatic components of wine are closely related to its sensory quality, which is determined by the consumer's acceptability (Vilanova 2006).…”

“…Secondary aromas, which are by far the greatest pool of volatile molecules, are produced through the winemaking process, the great majority produced by yeast as metabolism by-products (Robinson et al 2014). Tertiary aromas develop in finished wine through storage and maturation, and result from intermolecular chemical interactions and equilibrium effects as the wine matrix changes (Boss et al 2015). Therefore, volatile profile of wine depends on primary the quality and variety of grape employed, fermentation process (yeast, temperature…) and maturation (in bottle or wood barrel), if it takes place.…”