Investigation of a Quantitative Method for the Analysis of Chiral Monoterpenes in White Wine by HS- SPME-MDGC-MS of Different Wine Matrices

A valid quantitative method for the analysis of chiral monoterpenes in white wine using head-space solid phase micro-extraction-MDGC-MS (HS-SPME-MDGC-MS) with stable isotope dilution analysis was established. Fifteen compounds: (S)-(−)-limonene, (R)-(+)-limonene, (+)-(2R,4S)-cis-rose oxide, (−)-(2S,4R)-cis-rose oxide, (−)-(2R,4R)-trans-rose oxide, (+)-(2S,4S)-cis-rose oxide, furanoid (+)-trans-linalool oxide, furanoid (−)-cis-linalool oxide, furanoid (−)-trans-linalool oxide, furanoid (+)-cis-linalool oxide, (−)-linalool, (+)-linalool, (−)-α-terpineol, (+)-α-terpineol and (R)-(+)-β-citronellol were quantified. Two calibration curves were plotted for different wine bases, with varying residual sugar content, and three calibration curves for each wine base were investigated during a single fiber’s lifetime. This was needed as both sugar content and fiber life impacted the quantification of the chiral terpenes. The chiral monoterpene content of six Pinot Gris wines and six Riesling wines was then analyzed using the verified method. ANOVA with Tukey multiple comparisons showed significant differences for each of the detected chiral compounds in all 12 wines. PCA score plots showed a clear separation between the Riesling and Pinot Gris wines. Riesling wines had greater number of chiral terpenes in comparison to Pinot Gris wines. Beyond total terpene content it is possible that the differences in chiral terpene content may be driving the aromatic differences in white wines.Keywords: Pinot Gris, MDGC-MS, monoterpenes, Riesling, chiralKeywords: Pinot Gris, MDGC-MS, monoterpenes, Riesling, chira

A BAC-based physical map of the Nile tilapia genome

BACKGROUND: Cichlid fishes, particularly tilapias, are an important source of animal protein in tropical countries around the world. To support selective breeding of these species we are constructing genetic and physical maps of the tilapia genome. Physical maps linking collections of BAC clones are a critical resource for both positional cloning and assembly of whole genome sequences. RESULTS: We constructed a genome-wide physical map of the tilapia genome by restriction fingerprinting 35,245 bacterial artificial chromosome (BAC) clones using high-resolution capillary polyacrylamide gel electrophoresis. The map consists of 3,621 contigs and is estimated to span 1.752 Gb in physical length. An independent analysis of the marker content of four contigs demonstrates the reliability of the assembly. CONCLUSION: This physical map is a powerful tool for accelerating genomic studies in cichlid fishes, including comparative mapping among fish species, long-range assembly of genomic shotgun sequences, and the positional cloning of genes underlying important phenotypic traits. The tilapia BAC fingerprint database is freely available at

Characterization of regional examples of New Zealand Pinot noir by means of sensory and chemical analysis

There are four main Pinot noir wine regions in New Zealand: Central Otago, Marlborough, Martinborough and Waipara. These regions specialize in this variety as the soil, climate and other conditions are well suited to this grape. Beside being grown in these regions the wines are also marketed as regional products. Place of origin labelling implies that wines from one region will have different aroma and flavour characteristics from wines from other regions. This project determined the characteristics that best differentiate the regional styles of New Zealand Pinot noir. Marlborough Pinot noir was characterized by greater raspberry, red cherry, red fruit and red berry aromas, longer finish length and more harmonious balance. Martinborough Pinot noir was characterized by greater black cherry, chocolate, oak and spice aromas and oak tannin. Waipara Pinot noir was characterized by greater barnyard, herbal and violet aromas and in-mouth fruit density/concentration. Central Otago Pinot noir was characterized by fuller body. As regional wines were found to be stylistically different, the ability of tasters to discriminate regional wines was tested using paired comparison and sorting analysis. Tasters were not successful at discriminating regional wine examples using these techniques. This may be due to conceptual models that are not representative of the regional wines. In order to determine the possible causes of these regional differences the chemical composition of the wines was also investigated. Three HS-SPME-GC-MS methods were developed specifically for Pinot noir wine to measure 34 different volatile organic compounds. One method measured compounds found at higher concentrations, namely esters and alcohols, the second method measured volatile fatty acids and the third measured trace compounds present at very low concentrations. With the two sets of information, sensory and chemical, it was possible to find relationships using canonical correlation analysis. Results indicated four aroma compounds of particular importance: ethyl octanoate, ethyl decanoate, 2-phenyl ethanol and benzaldehyde. Addition/omission tests were used to determine the influence of each compound on Pinot noir aroma. The compounds were added in combination and at varying concentrations to a wine matrix, which consisted of a commerical Pinot noir that contained low levels of the compounds of interest. In 8 of 10 triangle tests panellists were able to successfully identify samples with different concentrations of the components. Panellists also used descriptive analysis to determine the influence of these compounds. From the descriptive analysis results it was found the 2-phenyl ethanol influenced the perception of violet aroma, ethyl octanoate influenced red cherry aroma and the combination of ethyl octanoate and ethyl decanoate influenced black cherry aroma. The measurement of the effect of these aroma compounds is a first step to understanding some factors of regional style since red cherry, black cherry and violets were descriptors that characterize the regional styles of New Zealand Pinot noir

The Potential Effect of β-Ionone and β-Damascenone on Sensory Perception of Pinot Noir Wine Aroma

Volatile compounds are responsible for driving the aroma of wine. Because of their low perception thresholds, norisoprenoids may play an important role in wine aroma. Studies have shown that β-damascenone may act as an aroma enhancing compound. However, the direct impact on wine aroma is unclear. Our study examined the direct impact of β-ionone and β-damascenone on the aroma sensory perception of Pinot noir wines. Triangle tests were used to determine if assessors could distinguish between wines with varying concentrations of β-ionone and β-damascenone in three different Pinot noir wine matrixes. Descriptive analysis was performed on these treatments, perceived as different in triangle tests. Results show that β-ionone acts as a significant contributor to aromas in Pinot noir wine, as individuals could differentiate both the low and high concentration wines from the control. How β-ionone impacted wine aroma depends on the wine matrix, as different aroma descriptors were affected based on the model wine used, resulting in floral, red berry or dark berry aromas. The effect of β-damascenone on Pinot noir aroma was less clear, as perception seems to be heavily influenced by wine matrix composition. This study contributes to our understanding of the complex chemical causation of fruity aromas in Pinot noir wine

Adapting Polarized Projective Mapping to Investigate Fruitiness Aroma Perception of White Wines from Oregon

Fruitiness is a highly desirable aroma quality in white wines. This study aimed to investigate the fruitiness aroma perception of white wines using a rapid sensory method and to compare the sensory maps obtained from wine experts and trained consumers. A polarized projective mapping (PPM) method was adapted by using fruit standards as fixed poles. Twenty-one white wines were selected for this study. Ten wine experts and twelve trained consumers participated in the adapted PPM followed by ultra-flash profiling (UFP). While experts and trained consumers used different poles to characterize the Pinot Gris and Viogniers, both panels used the stone fruit pole for the Chardonnays. UFP revealed that the Pinot Gris and Viognier samples presented fruity and floral aromas and most Chardonnay wines presented non-fruity aromas. The white wines investigated presented a wide range of fruity aromas. The use of aroma standards instead of products as poles seems to be a reliable alternative to investigate fruitiness in white wines. This study helped us to understand the predominant aromas of varietal white wines from Oregon and emphasized the importance of adapting sensory methods to investigate fruitiness perception

The Potential Effect of β-Ionone and β-Damascenone on Sensory Perception of Pinot Noir Wine Aroma

Volatile compounds are responsible for driving the aroma of wine. Because of their low perception thresholds, norisoprenoids may play an important role in wine aroma. Studies have shown that β-damascenone may act as an aroma enhancing compound. However, the direct impact on wine aroma is unclear. Our study examined the direct impact of β-ionone and β-damascenone on the aroma sensory perception of Pinot noir wines. Triangle tests were used to determine if assessors could distinguish between wines with varying concentrations of β-ionone and β-damascenone in three different Pinot noir wine matrixes. Descriptive analysis was performed on these treatments, perceived as different in triangle tests. Results show that β-ionone acts as a significant contributor to aromas in Pinot noir wine, as individuals could differentiate both the low and high concentration wines from the control. How β-ionone impacted wine aroma depends on the wine matrix, as different aroma descriptors were affected based on the model wine used, resulting in floral, red berry or dark berry aromas. The effect of β-damascenone on Pinot noir aroma was less clear, as perception seems to be heavily influenced by wine matrix composition. This study contributes to our understanding of the complex chemical causation of fruity aromas in Pinot noir wine

Analysis of Retronasal Flavor Alterations in Smoke-Affected Wines and the Efficacy of Various Inter-Stimulus Rinse Protocols in Clearing Smoke-Related Attributes

Wildfires produce smoke, which can then encounter wine grapes, causing the fruit to absorb smoke-related volatile organic compounds. These compounds impact the sensorial profiles of the resulting wines, introducing an uncharacteristic smokey flavor and ashy finish. Since these off-flavor attributes are observed to have longer-lasting perception, a proper inter-stimulus protocol is necessary to ensure an accurate sensory analysis. Previous work has indicated that a 1 g/L pectin rinse with 120 s of separation is effective for clearing the smoke flavor to mitigate potential carryover effects. The purpose of this work was to determine if there was a more efficient rinsing protocol to lessen the time taken between samples. By using wines with various levels of smoke exposure (high, moderate, and none), the efficacy of four different rinse systems were evaluated with a fixed-time-point evaluation system. These results indicate that a 4 g/L glucose solution is more efficient than pectin, requiring only 90 s of separation to clear smoke flavor perception. Additionally, this work identified appropriate references for the retronasal attributes associated with smoke taint in wine. These results can be used to guide a sensory analysis of wildfire-affected wines to ensure effective and accurate results

Analysis of Retronasal Flavor Alterations in Smoke-Affected Wines and the Efficacy of Various Inter-Stimulus Rinse Protocols in Clearing Smoke-Related Attributes

Wildfires produce smoke, which can then encounter wine grapes, causing the fruit to absorb smoke-related volatile organic compounds. These compounds impact the sensorial profiles of the resulting wines, introducing an uncharacteristic smokey flavor and ashy finish. Since these off-flavor attributes are observed to have longer-lasting perception, a proper inter-stimulus protocol is necessary to ensure an accurate sensory analysis. Previous work has indicated that a 1 g/L pectin rinse with 120 s of separation is effective for clearing the smoke flavor to mitigate potential carryover effects. The purpose of this work was to determine if there was a more efficient rinsing protocol to lessen the time taken between samples. By using wines with various levels of smoke exposure (high, moderate, and none), the efficacy of four different rinse systems were evaluated with a fixed-time-point evaluation system. These results indicate that a 4 g/L glucose solution is more efficient than pectin, requiring only 90 s of separation to clear smoke flavor perception. Additionally, this work identified appropriate references for the retronasal attributes associated with smoke taint in wine. These results can be used to guide a sensory analysis of wildfire-affected wines to ensure effective and accurate results

Exploring Retro-Nasal Aroma’s Influence on Mouthfeel Perception of Chardonnay Wines

There are many interactions that occur between taste and aroma that may impact perception. The main objective of this study was to ascertain whether the aroma fraction of wine should be considered when investigating relationships between chemical composition and sensory perception of mouthfeel. Chardonnay wines with different mouthfeels were produced by altering the fermentation temperature (15 °C and 21 °C) of the alcoholic and malolactic fermentations (MLF) as well as the timing of MLF and the presence of a non-Saccharomyces yeast during alcoholic fermentation. Napping® and Ultra-flash-profiling were conducted using a panel of white winemakers. Each procedure was conducted twice: once with retro-nasal aroma (+R) and once without retronasal aroma (−R). Napping® results showed that retronasal aroma impacted mouthfeel perception. Ultra-flash profiling of +R and −R displayed similar descriptive terms used. Several terms appear to be related to retronasal aroma as they were used in +R and not in −R. It is unclear if these terms are due to interactions or due to associated learning. These results suggest that for some mouthfeel terms the volatile fraction plays a role and, to establish relationships between chemical composition and mouthfeel perception, it is important to consider both the volatile and nonvolatile wine fractions

Revealing the sensory impact of different levels and combinations of esters and volatile thiols in Chardonnay wines

The assessment of different aroma families on tropical fruit aroma perception is still not well understood. This study aimed to investigate the effect of esters and volatile thiols on tropical fruit aroma perception in white wines. Four levels of thiols (none, low, medium and high) and three levels of esters (none, low, medium) were added to a dearomatized white wine base in a full factorial design. Check-All-That-Apply (CATA) was used to determine the aroma descriptors that most differentiated the wines followed by Sensory Descriptive Analysis (SDA) to evaluate the intensity of those significant aroma attributes. More than 78% of the total variance was described in the first two dimensions when using Canonical Variate Analysis. Tropical fruit aromas were associated with wines containing different levels of esters and ester-thiol combinations. Volatile thiols alone imparted an earthy aroma and were grouped with the control wine. The different ester-thiol combinations altered the tropical fruit aroma quality in the wines from citrus to passionfruit, pineapple and guava. Understanding the cause of tropical fruit aroma allows for targeted processing to achieve the desired wine sensory quality