Researchers have unveiled the discovery of 21 chemical compounds responsible for the unique taste and aroma found in sourdough bread.
Through the innovative “sensomics” method, the significance of fermentation has been underscored, offering potential techniques to decrease salt content without compromising the delightful flavor.
In recent times, during a phase of lockdown monotony, a surge in perfecting the art of sourdough bread-making was observed across various places. This particular bread, a simple blend of flour and water left to ferment, gains its exceptional tang from a microbial powerhouse.
For well over a century, sourdough has been closely tied to San Francisco’s culinary identity. Notably, scientists have recently unveiled their findings, pinpointing and quantifying 21 crucial chemical elements responsible for the distinct taste and aroma of this bread. Their comparison of these elements across various bread types shed light on their uniqueness.
The unveiling of these discoveries occurred at the latest gathering of the American Chemical Society (ACS) during its Fall 2023 meeting—an event renowned for featuring approximately 12,000 presentations spanning an extensive array of scientific topics.
For centuries, sourdough breads have been part of human culinary history, tracing back to ancient Egypt well before their recent surge in popularity in 2020. Unlike conventional wheat or white breads, sourdough relies on a “starter” comprised of a thriving colony of bacteria and wild yeast, fostering fermentation to leaven the dough. These microbial communities, sourced from the local environment, imbue specific locales with a reputation for producing exceptional loaves. For instance, San Francisco’s distinctive foggy climate is credited with contributing to its renowned and delectable sourdoughs.
Despite their widespread presence, minimal effort has been directed toward understanding the precise chemical compounds responsible for their distinct taste and aroma. This knowledge holds significance for bakers seeking to regulate their bread’s quality, averting excessive sourness, while striving to deliver consistently enjoyable sourdough experiences to consumers. Hence, Thomas Hofmann’s team at the Technical University of Munich embarked on applying an updated technique, known as “sensomics,” to investigate the soft inner part of a loaf, termed the sourdough bread crumb. Hofmann, currently serving as the editor-in-chief of ACS’ Journal of Agricultural and Food Chemistry, led this endeavor.
“In sensomics, a handful of key compounds can entirely replicate the distinct taste of a food,”
Laura Eckrich
This approach involves chromatography, mass spectrometry, and akin methods. Previously, the team successfully applied this methodology to other foods, isolating flavor-active compounds, discerning their structures and concentrations, and elucidating their impact on taste. Leveraging this knowledge, they reconstructed the flavor profile of various foods from the ground up.
Hofmann’s team meticulously identified, categorized, and quantified the flavor compounds within sourdough bread crumb, pinpointing the most crucial elements.
These comprised 10 pivotal “tastants” and 11 essential “odorants,” amalgamated to form a sourdough “essence.”
Human sensory panels confirmed the resulting flavor profile. Notably, key taste compounds encompassed salt, directly incorporated into the dough, alongside acetic and lactic acids, generated during fermentation. Subsequently, employing a technique termed “unified flavor quantitation,” previously developed by Hofmann’s team, allowed simultaneous analysis of these unique taste and aroma compounds for the first time.
Further employing this method, the team conducted fresh investigations, quantifying compound concentrations in various bread types. They gathered yeast-based and sourdough breads from local bakeries and supermarkets, crafted using rye or wheat flours. While yeast-based breads contained some key sourdough compounds, such as lactic and acetic acids, these were notably lower in quantity.
These findings underscored the pivotal role of the fermentation process in imparting the distinctive flavor profile of sourdough.
Following their investigation into sourdough’s distinct flavor compounds, the researchers shifted their focus to exploring effective strategies for reducing salt levels in bread. Their approach involved unevenly dispersing saltier doughs within a dough mixture. Given that bread, particularly sourdough varieties, can significantly contribute to daily sodium intake, this method offers a promising solution to curbing salt content without compromising the bread’s unique taste.
Overall, the team believes their findings hold promise for the baking industry.
“Through the sensomics approach, we’ve unveiled the primary taste and aroma compounds in bread crumb for the first time. We hope that our insights will assist bakers in crafting exceptional sourdough breads.”
Laura Eckrich