why does cilantro taste like soap to some people when stored?
The Short AnswerThe soapy taste in stored cilantro is caused by increased production of aldehydes, particularly (E)-2-decenal. This happens when enzymes in damaged or aging leaves break down fatty acids. People with a specific OR6A2 gene variant are genetically sensitive to these compounds, perceiving them as soapy or pungent.
The Deep Dive
Cilantro's distinct aroma comes from volatile compounds, mainly aldehydes like (E)-2-decenal and decanal. In fresh, undamaged leaves, these are present at low levels. However, storageāespecially at warm temperatures or after physical damage like bruisingātriggers enzymatic activity. Enzymes such as lipoxygenase and hydroperoxide lyase become active, breaking down membrane fatty acids into precursors that are rapidly converted into these aldehydes. For individuals with a common genetic variant in the olfactory receptor gene OR6A2, these aldehydes fit the receptor like a key, activating a neural signal interpreted as soap, pungent, or rotten. The storage process doesn't change the person's genetics; it amplifies the chemical signal their nose is wired to detect. Improper storage accelerates microbial growth, which can also metabolize leaf components into similar aldehydes, further intensifying the perception.
Why It Matters
Understanding this mechanism helps explain strong, subjective food preferences and can reduce food waste. Chefs and home cooks can minimize the soapy taste by using cilantro fresh, storing it properly (wrapped, chilled), and adding it at the end of cooking to limit enzyme activation. It's a classic example of nutrigenomics, showing how our genes shape our dietary experiences. This knowledge also aids in developing strategies, like breeding lower-aldehyde cilantro varieties or using culinary techniques (acidic marinades) to mask the compounds, making the herb more universally enjoyable.
Common Misconceptions
A common myth is that the soapy taste means the cilantro is spoiled or rotten. In reality, the increased aldehydes are a natural enzymatic response to damage or age, not necessarily microbial spoilage. Another misconception is that rinsing or cooking completely removes the taste. While heat can volatilize some aldehydes, the genetic sensitivity remains, and stored cilantro often has such elevated levels that cooking may not fully mask it for sensitive individuals. The core issue is genetic perception, not food safety.
Fun Facts
- The OR6A2 gene variant that makes cilantro taste soapy is also linked to heightened sensitivity to other pungent smells like cloves and certain soaps.
- Cilantro is called coriander in many parts of the world; the name 'cilantro' specifically refers to the leaves, while 'coriander' refers to the seeds, which have a completely different, nutty flavor profile.