An infochemical found on marine plastic debris elucidates a novel mechanism for plastic ingestion by marine wildlife.

Wine is an ancient beverage and has been prized throughout time for its unique and pleasing flavor. Wine flavor arises from a mixture of hundreds of chemical components interacting with our sense organs, producing a neural response that is processed in the brain and resulting in a psychophysical percept that we readily describe as “wine.” The chemical components of wine are derived from multiple sources; during fermentation grape flavor components are extracted into the wine and new compounds are formed by numerous chemical and biochemical processes. In this review we discuss the various classes of chemical compounds in grapes and wines and the chemical and biochemical processes that influence their formation and concentrations. The overall aim is to highlight the current state of knowledge in the area of grape and wine aroma chemistry.

Although hundreds of chemical compounds have been identified in grapes and wines, only a few compounds actually contribute to sensory perception of wine flavor. This critical review focuses on volatile compounds that contribute to wine aroma and provides an overview of recent developments in analytical techniques for volatiles analysis, including methods used to identify the compounds that make the greatest contributions to the overall aroma. Knowledge of volatile composition alone is not enough to completely understand the overall wine aroma, however, due to complex interactions of odorants with each other and with other nonvolatile matrix components. These interactions and their impact on aroma volatility are the focus of much current research and are also reviewed here. Finally, the sequencing of the grapevine and yeast genomes in the past ∼10 years provides the opportunity for exciting multidisciplinary studies aimed at understanding the influences of multiple genetic and environmental factors on grape and wine flavor biochemistry and metabolism (147 references).

Knowledge of wine flavor has paralleled developments in analytical chemistry. In the 19th century, analytical methods focused on the determination of major wine components such as ethanol, organic acids, and sugars. The development of chromatographic techniques in the early 1900s and particularly development of gas chromatography in the early 1950s ushered in a new era of discovery for analytical chemists. Currently, more than 1300 volatile compounds have been identified in alcoholic beverages and new compounds continue to be discovered. At the beginning of the 21st century, the focus is beginning to shift away from identification and quantification of new flavor compounds and toward developing dynamic analytical techniques that can model the complex relationships between volatile composition and sensory properties. In addition, rapid, readily automated techniques that can be used to optimize agricultural (viticultural) practices and processing or aging conditions are being evaluated and developed. Primar...