Cinnamon Chemistry: From Spice Trade to Cinamaldehyde

Explore the chemistry and history of cinnamon, tracing how cinamaldehyde gives the spice its distinctive flavor and festive fragrance. The episode weaves myth and maritime trade with modern science, explaining how true cinnamon from Sri Lanka and its bark processing became a global commodity, and how cinamaldehyde stands out among other constituents like eugenol. It also highlights surprising uses from insect repellents to protecting steel, discusses possible health implications, and notes a computational study related to SARS-CoV-2. A seasonal tale connects ancient trade routes to contemporary laboratories, all guided by host Ben Valsler.

Introduction

Ben Valsler guides listeners through a seasonal exploration of a familiar spice, tracing how cinnamon's iconic aroma and flavour arise from cinamaldehyde, a phenyl propanoid responsible for much of its character. The episode sets the stage by contrasting myth and history with chemistry, showing how cinnamon's story spans ancient Egypt, Greek poetry, and the age of exploration, all the way to modern labs and industrial extraction.

"The compound that gives cinnamon its desirable properties is a phenyl propanoid called cinamaldehyde." - Ben Valsler

Spice History and Myth

The episode recounts stories used to guard the spice's origins, such as the cinnamon bird and hidden lands, and explains how those myths persisted as traders sought to protect valuable knowledge. It moves to the real geographies, identifying the true source as the inner bark of a small evergreen tree native to Sri Lanka, and detailing how colonial powers disrupted the trade in pursuit of monopoly and profits, culminating in the British monopoly on true cinnamon by the 19th century.

"Stories like these help to maintain the mystery and prevent would-be competitors from seeking out the true source." - Ben Valsler

Cinnamon Chemistry: Cinamaldehyde and Related Constituents

The main aroma and flavour of cinnamon comes from cinamaldehyde, which can account for up to 90% of essential oil extracted from bark. The host contrasts cinamaldehyde with other components like eugenol from cloves, and explains how these compounds may have evolved in plants to deter herbivores and pathogens. The segment also covers how cinnamon is produced and processed traditionally, including bark removal, inner bark loosening with a brass rod, and drying to form quills. Cinamaldehyde is the principal component in true cinnamon, with variations among varieties and processing methods reflected in flavour profiles.

"cinamaldehyde accounts for up to 90% of the oil extracted from cinnamon bark" - Ben Valsler

Applications, Health and Industry

The transcript highlights cinamaldehyde's insecticidal properties, its potential to influence metabolic health and adipose tissue, and the possibility of interactions with tau protein tangles relevant to neurodegenerative disease research. It also notes antimicrobial effects, including the ability to kill certain bacteria outright, inhibit others, and prevent biofilm formation, illustrating a spectrum of potential benefits and the current limits of evidence for specific health claims. An additional application described is the polymerization of cinamaldehyde to form a protective film on steel surfaces, offering corrosion resistance in challenging environments.

Cinaldehyde polymerizes to form a protective film on steel surfaces and protects them from corrosive liquids." - Ben Valsler

COVID-19 Spike Protein and the Spice Frontier

In 2020, the program notes a computational study indicating that plant-oil constituents, including cinamaldehyde, may have structures capable of binding to the SARS-CoV-2 spike protein, offering a computational glimpse into potential antiviral mechanisms, though further work is required to establish real-world efficacy.

"A paper published just a few weeks ago uses computational studies to show that components of plant oils, including cinamaldehyde, contain structures that should be able to bind to and inhibit the spike protein that SARS-CoV-2 uses to merge with the host cell membrane." - Ben Valsler

From Spice to Seasonal Tradition

The episode closes by connecting the chemical properties of cinamaldehyde to the seasonality of winter feasts, explaining how antimicrobial spices helped preserve meat before refrigeration and how technological advances moved cinnamon from a precious, guarded resource to a widely enjoyed spice at Christmas tables around the world.

"Through time and technological advances, this once essential spice has transformed into a tasty tradition." - Ben Valsler