The fall meeting of the American Chemical Society (ACS), held virtually and in person August 13–17, 2023, features more than 10,000 presentations on a wide range of science topics. Read on to discover some of the exciting research presented at the meeting—and check back as we continue coverage throughout the week!

loaves of sourdough bread on a counter

The COVID-19 lockdown spurred a baking frenzy around the world, as millions of people were confined to their homes and in need of new and creative ways to both pass the time and feed themselves. Many used this time to develop and perfect their recipes for sourdough bread—a basic mixture of flour and water brought to life by the magic of fermentation.

Sourdough is unique in that instead of using traditional yeast as a leavening agent, it relies on a "starter," a live colony of naturally occurring bacteria and wild yeast that helps the dough to rise through the fermentation process. While many are familiar with sourdough and how to make it, there has been little research into the exact chemistry behind its tangy, one-of-a-kind smell and taste—until now.

Professor Thomas Hofmann, Ph.D., and his team at the Technical University of Munich, Germany, used a new version of a technique called "sensomics" to identify the different chemical compounds in sourdough. Prof. Hofmann currently serves as Editor-in-Chief of ACS Publications' agricultural and food chemistry journal portfolio: Journal of Agricultural and Food Chemistry, ACS Agricultural Science & Technology, and ACS Food Science & Technology.

Sensomics applies chromatography, mass spectrometry and related methods to isolate the flavor-active compounds in food, determine their structures, and identify how they contribute to taste. “With sensomics, you can take just a few key compounds and completely recreate the characteristic taste of a food,” says Laura Eckrich, a graduate student in Prof. Hofmann’s lab.

The researchers were able to isolate 21 key flavor compounds in sourdough bread crumb and determine which ones were the most important in giving the bread its distinct flavor. Key taste compounds included salt, which is added directly to the dough, and lactic and acetic acids, which are produced during the fermentation process. Then, they compared their concentrations to those in traditional yeast-based breads. While key compounds such as lactic and acetic acids were present in the yeast-based breads, they occurred in much smaller concentrations, confirming the crucial role of fermentation in contributing to sourdough's special taste.

The researchers are hopeful that their findings will prove beneficial for the baking industry to better maintain quality control and create consistent, delicious sourdough loaves. “This was the first time the key taste and aroma compounds of bread crumb were elucidated using the sensomics approach, and we hope what we learned will help bakers create the best sourdough breads they can,” says Eckrich, who presented these findings at the ACS Fall 2023 meeting.

Watch Laura Eckrich discuss this work in greater detail:

What makes those pandemic-era sourdoughs so deliciously, uniquely, sour? | ACS Meeting Newsroom

Explore more sensomics research by Prof. Hofmann and colleagues:

Discovery and Identification of Tastants and Taste-Modulating N-Acyl Amino Acid Derivatives in Traditional Korean Fermented Dish Kimchi Using a Sensomics Approach
Peter Christa, Andreas Dunkel, Alin Krauss, Timo D. Stark, Corinna Dawid, and Thomas Hofmann*

Sensoproteomic Discovery of Taste-Modulating Peptides and Taste Re-engineering of Soy Sauce
Manon Jünger, Verena Karolin Mittermeier-Kleßinger, Anastasia Farrenkopf, Andreas Dunkel, Timo Stark, Sonja Fröhlich, Veronika Somoza, Corinna Dawid, and Thomas Hofmann*

Dry-Hopping to Modify the Aroma of Alcohol-Free Beer on a Molecular Level—Loss and Transfer of Odor-Active Compounds
Sabrina Brendel, Thomas Hofmann, and Michael Granvogl*

Numerous Compounds Orchestrate Coffee’s Bitterness
Tatjana Lang, Roman Lang, Antonella Di Pizio, Verena Karolin Mittermeier, Verena Schlagbauer, Thomas Hofmann, and Maik Behrens*

Sensomics Analysis of Taste Compounds in Balsamic Vinegar and Discovery of 5-Acetoxymethyl-2-furaldehyde as a Novel Sweet Taste Modulator
Hedda Hillmann, Juliane Mattes, Anne Brockhoff, Andreas Dunkel, Wolfgang Meyerhof, and Thomas Hofmann*

Comprehensive Sensomics Analysis of Hop-Derived Bitter Compounds during Storage of Beer
Daniel Intelmann, Gesa Haseleu, Andreas Dunkel, Annika Lagemann, Andreas Stephan, and Thomas Hofmann*

Sensomics Mapping and Identification of the Key Bitter Metabolites in Gouda Cheese
Simone Toelstede and Thomas Hofmann*

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