1,720,976 research outputs found
Dimethyl Sulfide (DMS) in Amarone Wines: Influence of Aging, Withering, Grape Variety, and Geographical Origin
Full text linkOccurrence of dimethyl sulfide (DMS), a potent aroma compound accumulating during aging, was investigated in commercial and experimental Amarone wines. In commercial Amarone, DMS was observed in concentrations ranging from 2.9 to 64.3 mu g/L. Model aging studies on experimental wines indicated that DMS in Amarone is strongly associated with aging and that wines from different vineyards can vary significantly in their ability to accumulate DMS during aging. The capacity of certain vineyards to give wines with higher DMS-forming potential was consistent across three consecutive vintages, representing a true terroir factor to be expressed with aging. Wine content of primary amino acids (PAN), a commonly analyzed enological parameter of grape must, was shown to be positively correlated with DMS accumulation during aging. Grape withering also increased DMS-forming potential mostly due to increased PAN resulting from concentration due to water loss. Increased pH due to withering also contributed to a higher DMS content of withered wines, but to a lower extent. In certain vineyard sites, an influence of vintage conditions on DMS-forming potential was also observed
Variations in sensorially-relevant metabolites and indices in PDO wines of common ampelographic background: A case study on commercial Lambrusco wines
Full text linkPDOs are important regulatory tools with the aim to link specific food products to their geographical origin. Despite the widespread presence of PDOs in wine sector, there is limited understanding as to whether wines of the same PDO exhibit common chemical signatures which can be considered representative of the PDO. Improved understanding of these could help in the development of successful PDO policies. In this context, this study considers 40 wines of three different PDOs of Lambrusco (Salamino, Grasparossa and Sorbara), a sparkling red wine produced in Italy, with the aim to evaluate to which extent a chemical signature reflecting sensoriallyrelevant metabolites could be identified for each PDO, also considering technological variables such as production technique and vintage. In comparison to other Italian wines, Lambrusco PDOs exhibited common features such as high content of acetate esters, trans-3-hexen-1-ol and 1,8-cineole. Lambrusco appellations differed for volatile metabolites such as terpenes, VSCs, C6 alcohols, TDN. Sorbara was characterized by lower content of phenolic compounds. The study of the impact of aging and production techniques revealed a greater impact of the former on the volatile profile. Young Classico methods were more similar to Charmat wines from the same vintages, rather than to older classic methods
Influence of grape composition and origin, yeast strain and spontaneous fermentation on aroma profile of Corvina and Corvinone wines
Full text linkVolatile composition and sensory properties of Corvina and Corvinone red wines in relationship to grape origin, yeast strain and inoculated vs. spontaneous fermentation were investigated. Experimental wines were produced using freshly harvested grapes of the two varieties coming from two different areas. The results indicated that, by affecting grape composition, grape origin had a primary impact on wine aroma chemical and sensory properties. From a chemical point of view, this effect was associated not only with grape-derived compounds but also to some extent with fermentation-derived esters. Yeast strains influence was mostly associated with higher alcohols and certain esters, whereas the main characteristic of spontaneous fermentation was increased concentration of ethyl acetate. Sensory analysis confirmed the greater impact of grape origin compared to yeast strain, indicating clusters of odor similarities which were mostly associated with variations in the content of ethyl esters, C6 alcohols, and norisoprenoids in Corvina and of norisoprenoids, cyclic terpenes, acetate esters, and ethyl acetate in Corvinone, respectively
Approaches to the classification of wine aroma ageing potential. Applications to the case of terpenoids in Valpolicella red wines
Full text linkValpolicella is an Italian wine-producing region famous for premium red wines. Valpolicella wines often undergo a minimum ageing period between 1 and 4 years, according to the wine type. Therefore, identifying relevant types of aroma precursors and the related chemical mechanisms behind aroma development during ageing is of great importance for Valpolicella wines. This study assessed free and glycosidically-bound terpene compounds of Valpolicella wines as potential precursors of different ageing-related terpenes using a model ageing experimental approach. Results showed that terpene profiles changed substantially with ageing. The occurrence of cyclic terpenes (p-menthane-1,8-diol, 1,8-cineole and 1,4-cineole) was mostly associated with the content of free monoterpenols, linalool in particular, in young wines, whereas glycosylated monoterpenols appeared to play a minor role. Accumulation of cineoles was strongly modulated with pH; in fact, low pH values promoted higher cineole yields. </jats:p
Contribution of terpenes, methanethiol, and fermentative esters to sparkling wine aroma in relation to production technology, vintage, and aging: a case study on Durello wines
No full textBACKGROUNDThe present study aimed to assess the chemical and sensory variability existing across sparkling white wines of a single appellation in relation to production technique and aging, identifying the existence of specific aroma chemical and sensory (odor) signatures. For this purpose, we selected Durello, an emerging sparkling white wine from the Veneto region produced using either Charmat or Classico methods. RESULTSComparison of Durello varietal volatiles profile with other Italian sparkling and still wines highlighted specific features of Durello, such as high content of 1,4-cineole and non-megastigmane norisoprenoids. The production technique (Charmat or Champenoise) impacted both the volatile chemical profile, influencing the content of esters, fatty acids, cyclic terpenoids, C-6 alcohols, beta-damascenone and methanethiol. With regard to wine age and vintage, an influence on esters, p-menthane-1,8-diol, cineoles and methyl salicylate was observed. CONCLUSIONSensory evaluation by means of a sorting task approach indicated the existence of two main types of odor profile, one clearly associated with Classico method. The main drivers of such aroma diversity were esters, 1,4-cineole and methanethiol. (c) 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
Fate of Grape-Derived Terpenoids in Model Systems Containing Active Yeast Cells
No full textTerpenes are important contributors to wine aroma. Free and glycosidically bound terpenes are primarily formed in grapes. During fermentation, they undergo important transformation catalyzed by yeast, so that the terpene profile of grape is substantially different from that of the corresponding wine. The present paper assessed the ability of a Saccharomyces cerevisiae strain to transform 17 different terpenes. Biotransformation was performed by placing target compounds in incubation with resting cells. Volatile compounds produced were extracted by solid-phase extraction and analyzed by gas chromatography-mass spectrometry. Geranyl acetate, neryl acetate, citronellyl acetate, and menthyl acetate were formed from the corresponding terpene alcohols. β-Citronellol was the main product of geraniol transformation; geranial, an intermediate of this pathway, has also been detected. Limonene was hydroxylated by yeast to form carveol, trans-2,8-menthadien-1-ol, and cis-2,8-menthadien-1-ol. Moreover, yeast cells were found to be able to adsorb a significant portion of the terpenes present in the reaction batches, with the extent of this phenomenon being linked to terpene hydrophobicity
MOLECULAR MARKERS OF BIOACTIVITY IN PORK MEAT PRODUCTS: CHARACTERIZATION OF GASTRO-INTESTINAL DIGESTED SAMPLES
No full textContribution of non-Saccharomyces yeasts to wine volatile and sensory diversity: A study on Lachancea thermotolerans, Metschnikowia spp. and Starmerella bacillaris strains isolated in Italy
No full textSaccharomyces cerevisiae starter cultures are largely used in winemaking to repress the wild microorganisms and achieve more predictable and desired outcomes. Notwithstanding, alternative microbial resources received increasing attention for their potential to produce wines with more distinctive and typical features. Our previous survey revealed a great inter- and intra-species diversity in an extensive collection of non-Saccharomyces wine yeasts from multiple regions of Italy. This study aimed to explore the detected biodiversity evaluating the quality of wines obtained by sequential inoculation of specific selected strains of the collection (Lachancea thermotolerans or Metschnikowia spp. or Starmerella bacillaris), and S. cerevisiae EC 1118. Fermentations of natural grape must at laboratory scale were followed by microbiological, chemical and sensorial analysis of the wines. The results indicated that each yeast species and strain exerted a distinctive impact on the wine, giving final products clearly separated with Principal Component Analysis. In particular, L. thermotolerans contributed producing relevant amounts of lactic acid and had the highest potential to reduce ethanol content; the presence of S. bacillaris increased the level of glycerol, and, remarkably, reduced acetaldehyde and total SO2; Metschnikowia spp. promoted the formation of higher alcohols and esters, and reduced volatile phenols. The sensory analysis based on the orthonasal aroma confirmed the separation between the wines obtained with the sequential fermentations and the control with single inoculation of EC 1118, although the three non-Saccharomyces species used could not be clearly distinguishable by the panelists. This study indicates that the use of selected native non-Saccharomyces strains in conjunction with S. cerevisiae positively modulates some relevant chemical parameters, and improves the aromatic intensity of wine, therefore justifying investments in non-conventional yeasts as co-starter cultures
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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