Mango green tea and dirty socks

The other day, friend of Pairteas and tea connoisseur Marzi Pecen (www.pecen.net) asked me why her mango-flavored green tea had a smell of dirty socks, and why she couldn't taste the mango at all. Here's the (longish) answer — it has to do with the odorants in dried mango and how they interact with those in green tea.

First, what is the difference in odor profile between fresh and dried mango? 

Mango is highly perishable when fresh. By contrast dried mango is quite stable, and can readily be added to tea to create a flavorful blend. 

When I smell or taste dried mango by itself, I get a two step effect. The first effect is cool and slightly lemony, then a warm orange-like tropical fruit aspect quickly kicks in.

This two step effect can be explained from the data obtained by Bonneau and her colleagues, in which they compared fresh and dried versions of the most commonly cultivated mango, Mangifera indica L. cv. Kent.*

Fresh and dried mangoes differ dramatically in their aroma chemistry, though two compounds present in both fresh and dried mangoes — β-myrcene and 3-methylbutyl butanoate — together contribute strongly to the "mango" sensation.  Both of these compounds activate warm receptors.

The lemony sensation from dried mangoes comes from the presence of limonene and a small number of other terpenes with a citrusy flavor. Limonene in particular activates the cold receptor, which is why the first fleeting sensation is cool — cool receptors turn on quickly and turn off quickly, especially when turned off through activation of warm receptors, including sweet receptors. 

That's why the sensations quickly becomes warm: the "mango" compounds start activating the slow-responding warm receptors, and the flavor becomes intensely mango-y.

Next, what happens when you add dried mango to green tea?

Here's where we run into flavor problems! The process of drying mangoes leads to the production of hexanal and heptanal, and the disappearance of mesifuran. Hexanal and heptanal both activate the cool/cold receptors, while mesifuran is a major contributor to the sweetness and warm flavor of fresh mangoes. 

When dried mango is added to green tea (which itself activates cool/cold receptors) the balance of flavors shifts from warm to cool/cold. As a consequence, the major mango flavor compounds — β-myrcene and 3-methylbutyl butanoate — cannot be sensed => no mango flavor!

At the same time, the cool/cold activating aromas are exaggerated...and heptanal has a smell of dirty socks...

The following chart shows the relative odor activity values (OAVs) of these compounds in fresh and dried mango, according to the data from Bonneau et al.:

Odor activity values of selected compounds in fresh and dried mangoes. Data from Bonneau and her colleagues.*

As you can see, drying increases the OAVs of the two characteristic mango compounds, and completely eliminates mesifuran. The cool/cold-receptor-activating limonene increases slightly, while hexanal and heptanal make an appearance, so heptanal can offer its dirty odor.

Just thinking it would be very interesting to contrast mango-infused green tea with a mango-infused oolong. My guess is that the mango-ness would be enhanced and the dirty-sock effect diminished when you pair dried mango with a warm receptor activating oolong such as Tie Guan Yin. Give it a try?


* Bonneau, A., Boulanger, R., Lebrun, M., Maraval, I. and Gunata, Z. (2016), Aroma compounds in fresh and dried mango fruit (Mangifera indica L. cv. Kent): impact of drying on volatile composition. Int J Food Sci Technol, 51: 789–800. doi:10.1111/ijfs.13038