On the unpredictability of odor

Area of Science:

• * Olfactory science and computational chemistry.
• * Understanding the molecular basis of scent perception.

Background:

• * The connection between a molecule's structure and its perceived odor has been studied for over 100 years.
• * Despite extensive research, accurately predicting odor characteristics like scent profile, detection threshold, and intensity remains difficult.

Purpose of the Study:

• * To evaluate the current state of predicting molecular odor based on structure-odor relationships.
• * To explain the limitations in predicting novel fragrant molecules.

Main Methods:

• * Review of existing structure-odor relationship models and their predictive capabilities.
• * Analysis of recent advancements in understanding the mechanism of olfaction.

Main Results:

• * Current structure-odor models provide only probabilistic predictions for odor character, threshold, and intensity.
• * Serendipity and surprise remain significant factors in discovering new fragrant molecules.
• * Recent insights into olfaction mechanisms explain the persistent challenges in odor prediction.

Conclusions:

• * Predicting the odor of novel molecules is currently a statistical exercise with inherent limitations.
• * Significant improvements in odor prediction accuracy are unlikely in the near future due to the complexity of the olfactory system.