Exploratory data fusion of untargeted multimodal LC-HRMS with annotation by LCMS-TOF-ion mobility: White wine case study.

Applied sciences have increased focus on omics studies which merge data science with analytical tools. These studies often result in large amounts of data produced and the objective is to generate meaningful interpretations from them. This can sometimes mean combining and integrating different datasets through data fusion techniques.

Chemometric and sensometric techniques in enological data analysis.

Enological evaluations capture the chemical and sensory space of wine using different techniques; many sensory methods as well as a variety of analytical chemistry techniques contribute to the amount of information generated. Data fusion, especially integrating data sets, is important when working with complex systems. The success reported when trying to integrate different modalities is generally low and has been attributed to the lack of statistically considerate strategies focusing on the data handling process.

Untangling the impact of red wine maceration times on wine ageing. A multidisciplinary approach focusing on extended maceration in Shiraz wines.

Phenolic composition of young red wines has been shown to play an important role in their ageing potential. Therefore, the modulation of phenolic extraction during maceration may influence the subsequent phenolic evolution of these wines. The present work aimed to evaluate the impact of three different maceration times on the phenolic levels and evolution observed over time, using spectrophotometric and chromatography methods, and the effect on the aroma, taste, and mouthfeel sensory properties using Projective Mapping.

Relationship between anthocyanins, proanthocyanidins, and cell wall polysaccharides in grapes and red wines. A current state-of-art review.

Numerous research studies have evaluated factors influencing the nature and levels of phenolics and polysaccharides in food matrices. However, in grape and wines most of these works have approach these classes of compounds individually. In recent years, the number of publications interconnecting classes have increased dramatically.

Exploring the Typicality, Sensory Space, and Chemical Composition of Swedish Solaris Wines.

The Swedish wine industry has exponentially grown in the last decade. However, Swedish wines remain largely unknown internationally. In this study, the typicality and sensory space of a set of twelve wines, including five Swedish Solaris wines, was evaluated blind by Swedish wine experts.

Wine Quality Drivers: A Case Study on South African Chenin Blanc and Pinotage Wines.

The aim of the study was to propose a methodology for the elucidation of sensory and chemical wine quality drivers. The winners of the 2018 Top 10 Chenin Blanc and Top 10 Pinotage challenges and additional lower scoring wines for each cultivar were evaluated. The two sets underwent sensory profiling by Check-All-That-Apply (CATA) and a 20-point quality rating by industry experts in non-competition conditions and chemical fingerprinting by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS).

Comparison of an Offline SPE-GC-MS and Online HS-SPME-GC-MS Method for the Analysis of Volatile Terpenoids in Wine.

The aroma profile is an important marker for wine quality. Various classes of compounds are responsible for the aroma of wine, and one such class is terpenoids. In the context of this work, a validated gas chromatography-mass spectrometry (GC-MS) method for the quantitation of terpenoids in red and white wine using headspace solid-phase microextraction (HS-SPME) and solid-phase extraction (SPE) was established.

Investigation of olfactory interactions of low levels of five off-flavour causing compounds in a red wine matrix.

The qualitative sensory perception of individual and of complex mixtures of five compounds, guaiacol ('burnt note'), o-cresol ('phenolic/tar'), 4-ethylphenol (4-EP, 'leather/barnyard'), 2-iso-butyl-3-methoxypyrazine (IBMP, 'green pepper/herbaceous'), and 2,4,6-trichloroanisole (TCA, 'cork taint/ mouldy') were tested in a partially de-aromatised red wine matrix using descriptive analysis by a trained panel of eleven judges. Compounds were characterised at peri- and sub-threshold concentrations using a partial D-optimal statistical design and response surface methodology. Results indicated that complex mixtures in red wine elicit an olfactory response that could not be predicted from the attributes or descriptors of single compounds.

A multivariate approach to evaluating the chemical and sensorial evolution of South African Sauvignon Blanc and Chenin Blanc wines under different bottle storage conditions.

Volatile compound composition contributes to the aroma profile of wine and is susceptible to change due to oxidation which may occur during storage and transportation, especially at high temperatures. Changes in sensory attributes may also occur, altering the sensory profile of wine. Classical univariate analysis only looks at the deviations for one factor at a time and may overlook the overall effect of treatments.

Viability of IR spectroscopy for the accurate measurement of yeast assimilable nitrogen content of grape juice.

Up to date, there have been only a few reports on the measurement of YAN and/or its components using IR spectroscopy, suffering from various limitations (number of samples, validation strategies, etc.). In this work, three IR spectral instruments measuring in different modes and ranges of the IR spectrum (FT-IR, FT-NIR, and ATR-MIR), were compared and evaluated for their accuracy to measure both total YAN as well as the components, FAN and ammonia separately, using over 900 grape juice samples from 28 cultivars over three seasons.

Matrix effects influencing the perception of 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA) in different Chenin Blanc wines by Projective Mapping (PM) with Ultra Flash profiling (UFP) intensity ratings.

Interaction studies are used in sensory evaluation to elucidate the complex influences (additive, masking, synergistic) that various compounds have on the perception of wine aroma. To these, the interactions between the matrix and the compounds of interest add another layer of complexity. Unlike previous interaction studies, the current work used a rapid method, Projective Mapping (PM) coupled with intensity of attributes, to evaluate the interaction effects two thiols (3-mercaptohexan-1-ol, 3MH, and 3-mercaptohexyl acetate, 3MHA) have in various matrices.

Investigating the relationship between grape cell wall polysaccharide composition and the extractability of phenolic compounds into Shiraz wines. Part I: Vintage and ripeness effects.

Phenolic compounds play an important role in colour stability and sensory properties of red wine. This study evaluated berry skin cell wall composition and how this influences grape and wine phenolics at different ripeness levels (21°Brix, 23°Brix, and 25°Brix) over two consecutive vintages. The vintage effect was highly significant, especially in the pectin fraction of the grape cell walls and affected the concentrations of certain phenolics extracted.

Investigating the relationship between cell wall polysaccharide composition and the extractability of grape phenolic compounds into Shiraz wines. Part II: Extractability during fermentation into wines made from grapes of different ripeness levels.

This study evaluated the relationship between cell wall breakdown, from Shiraz grapes harvested at three different ripeness levels and the colour and phenolics extracted during alcoholic fermentation into wines. Phenolic differences between the ripeness treatments were minimal after ¼ of the fermentation was completed. However, colour and phenolic content were significantly higher in finished wines made from 25°Brix grapes compared to those from 21°Brix and 23°Brix.

Chitinases and thaumatin-like proteins in Sauvignon Blanc and Chardonnay musts during alcoholic fermentation.

Protein precipitation, also referred to as protein instability, may lead to haziness in bottled wines and result in significant commercial losses. To avoid problems of this nature, fining finished wines with clay (bentonite) is the most commonly applied methodology. However, bentonite fining reduces yield and may affect wine quality.

A statistical exploration of data to identify the role of cultivar and origin in the concentration and composition of yeast assimilable nitrogen.

The study was undertaken to gain insight into the nitrogen status of grape juices currently used to make commercial wines in South Africa. This was done as yeast assimilable nitrogen (YAN) is most often suspected as the cause for problematic fermentations and has major implications for the organoleptic qualities of the final product. Using exploratory statistical methods, this study explored the possibility of identifying the role of cultivar and grape-growing district in the determination of the concentration and composition of YAN.

Testing the Sensitivity of Potential Panelists for Wine Taint Compounds Using a Simplified Sensory Strategy.

The odor detection threshold (ODT) of a compound is the lowest concentration at which individuals can reliably perceive a difference between a sample and its corresponding control, with 50% performance above chance. Wine is a complex matrix, and ODTs used in studies on wine can be based on inappropriate matrices and informal sensory methodologies. Formal studies confirming ODTs in wine are relatively scarce in the literature, and are complex and expensive to carry out.

Measuring Thiols in Single Cultivar South African Red Wines Using 4,4-Dithiodipyridine (DTDP) Derivatization and Ultraperformance Convergence Chromatography-Tandem Mass Spectrometry.

Wine varietal thiols are important contributors to wine aroma. The chemical nature of thiols makes them difficult to measure due to low concentrations, high sensitivity to oxidation, and low ionization. Methods for the measurement of thiols usually consist of multiple steps of sample preparation followed by instrumental measurement.

Indications of the prominent role of elemental sulfur in the formation of the varietal thiol 3-mercaptohexanol in Sauvignon blanc wine.

Elemental sulfur is a fungicide traditionally used to control Powdery Mildew in the production of grapes. The presence of sulfur residues in grape juice has been associated with increased production of hydrogen sulfide during fermentation, which could take part in the formation of the varietal thiol 3-mercaptohexanol. This work examines whether elemental sulfur additions to Sauvignon blanc juice can increase the levels of sought-after varietal thiols.

Spectrophotometric Analysis of Phenolic Compounds in Grapes and Wines.

Phenolic compounds are of crucial importance for red wine color and mouthfeel attributes. A large number of enzymatic and chemical reactions involving phenolic compounds take place during winemaking and aging. Despite the large number of published analytical methods for phenolic analyses, the values obtained may vary considerably.

Inactive dry yeast application on grapes modify Sauvignon Blanc wine aroma.

This study investigated the potential to improve wine aroma by applying two inactive dry yeast products (IDYs) at the onset of ripening on Sauvignon Blanc grapes. Both products led to increased reduced glutathione concentrations in the grape juice and corresponding wines, as well as differences in individual higher alcohol acetates (HAAs) and ethyl esters of straight chain fatty acids (EEFAs) at the end of fermentation. After two months of storage, a significantly slower decrease of EEFAs and to a lesser extent of HAAs was found for wines made from grapes with IDY applications.

Clonal differences and impact of defoliation on Sauvignon blanc (Vitis vinifera L.) wines: a chemical and sensory investigation.

Background: The aim of this study, performed on Sauvignon blanc clones SB11 and SB316, grafted on the same rootstock 101-14 Mgt (Vitis riparia × V. ruperstris) and grown at two adjacent vineyards, was two-fold: (1) to study wine chemical and sensory composition of both clones within an unaltered canopy; and (2) to determine the effect of defoliation (e.g.

Determination of sotolon content in South African white wines by two novel HPLC-UV and UPLC-MS methods.

Sotolon has been reported to play an important role in the atypical ageing and aroma character of many wines. A number of analytical techniques for sotolon analysis in wine have been reported, but these often require extensive sample preparation. In this work we report a HPLC-UV method and a novel UPLC-MS method to determine sotolon concentrations in white wines with little sample preparation applied for the first time for the evaluation of sotolon levels in South African wines.