Sara, Georgia, and Jee present green teas and mochi cakes

Another adventure in tea pairing by our intrepid trio, Sara, Georgia, and Jee!

These three tea bloggers have been enjoying tea-food pairings in exquisite venues all around New York City. Here are the links to the tea pairing I'll discuss this time, with its focus on pairing green teas with mochi cakes:

Georgia: http://www.notesontea.com/2017/08/tea-pairing-101-green-tea.html
Sara: http://www.tea-happiness.com/2017/08/tea-pairing-101-green-tea-and-mochi.html
Jee: https://www.ohhowcivilized.com/tea-pairing-101-green-tea/

The green teas were a Japanese Sencha, a Chinese Long Jing, and a Korean Woojeon. 

Left to right, Sencha, Long Jing, and Woojeon. Note the colors from pale green to green-brown with increasing roast.
Image from Jee's blog. 

The kill-green process (that is, the process for denaturing the oxidase enzymes with heat and thus stopping oxidation) for sencha is steaming. The resulting tea has almost exclusively "green" compounds, and a strong vegetal flavor that Georgia and Sara said tasted like asparagus, while Jee said it was like spinach. As a result the chemicals in sencha activate the cool/cold receptors almost exclusively.

By contrast, the Long Jing is quickly pan-fired and the Woojeon is pan-fired for a slightly longer time. The result is the development of compounds that we taste as roasty and nutty, all against a background of green vegetal-ness. Compounds in these teas activate the cool/cold receptors as well, but also activate the "hot" receptor TRPV1, which is why we get a roasty/nutty quality from them. Depending on the balance of these chemicals in the cup and mouth and on the pairings, one or the other flavor type will dominate.

The mochi cakes. Image from Georgia's blog.

The mochi cake selection included a strawberry with rose that had a fresh strawberry in its center. This cake may have been delicious on its own but was no good with any of the teas. This result is not surprising: the main flavor compound in strawberries, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (Furaneol®), activates the warm receptor TRPV3. Activation of this receptor clashes with activation of the cool/cold receptors, so they cancel each other out and the result is, as Sara put it, "intense sweetness" that overwhelmed any other flavor.

The next mochi cake selection was "Black warabi (bracken) mochi: adzuki bean paste / black warabi (bracken) skin / cinnamon kinako (roasted soybean powder)." It was a runner-up with the Woojeon, according to Jee. The results of this pairing, too, makes sense. The bracken has a somewhat vegetal taste, and cinnamon has compounds that activate both the cold (TRPA1) and the hot (TRPV1) receptors, so it should go well with a tea that has these qualities.

The third mochi cake selection was the winner with all the teas, fresh fig and pistachio mochi: fresh fig / pistachio paste / mochi skin [infused] with black mission fig balsamico. 

Judging from the purple skin color in the photo, as well as the description, the fig chosen for this mochi cake was a Mission fig, considered the most flavorful of the California fig varieties. While the chemical composition of fig fruits has not been exhaustively studied, there are certain compounds that appear to be common to all fig fruits. Among these are (E)-2-hexenal, the compound that grass makes and releases when it is cut. Tea leaves make this compound when they are plucked—it's one of the compounds that give green tea its "green-ness." 

Two other compounds that jumped to my attention in reading the list of fig volatiles were menthol and limonene, which as you can guess from their names are in mint and lemon. They are sensed as cool and refreshing because they activate the cool (TRPM8) and cold (TRPA1) receptors. 

And then the fig was described as "sweet." Well, figs and tea both have methyl salicylate. This is the compound that gives wintergreen its odor, and tastes very sweet. While there is more of this compound in black tea (it is produced during oxidation of the leaves) there is a little in green tea, especially in the more oxidized pan-fired ones. 

One curiosity: I have been fascinated by the characterization of some green teas, including the sencha here, as tasting like asparagus. As I noted in my book "Three Basic Teas & How to Enjoy Them," I have yet to have a green tea that reminds me of asparagus, but clearly I may be alone (or in small company). That said, there is one compound in fig fruit that is common with asparagus, namely (E)-2-nonen-1-ol. It's in cucumber and melons, too, and has a "green" waxy odor. However, figs appear not to have any of the sulfur compounds found in asparagus and in green tea. Yet I can imagine that the asparagus-ness of the figs might complement the asparagus-ness of the sencha.

Pistachios have a number of compounds that activate the cool/cold receptors, at least one of which of which is shared with figs, namely limonene. However pistachios share a different set of compounds with green tea, in particular phenyl acetaldehyde.**

This fascinating chemical combines its "green" aroma with a chocolate/cocoa earthy one. It's a product of a Maillard reaction that occurs with mild heat, so would be more abundant the more roasted the tea (and the roasted pistachio, too). As Sara noted about the Woojeon tea: 

"When I sniffed the dry leaves my nose was instantly met with fresh meadow grass and something a bit surprising-chocolate!"

That would be the phenyl acetaldehyde! Interestingly the flavor of this tea veered away from the usual green grassy quality of the sencha towards the more roasty side. Activation of TRPV1 by the roast products dampens perception of the flavor of grassy chemicals that activate the cool/cold receptors 

What I think the balsamic vinegar in this mochi cake did was to cut the sweetness of the fig and mochi. Acetic acid in balsamico activates the sour responsive cells in our taste buds, which in turn decrease signals from sweet responsive cells and thus our perception of sweetness. 

It was another fascinating excursion into tea and food pairing by our ever-so-observant guides Georgia, Sara, and Jee. And don't forget, as Georgia concludes:

"Experimentation is important in tea and food pairing!" 

All of you out there, keep experimenting and sharing your results, and let's see whether we can figure out why pairings do (or don't!) work.  


* Andreia P. Oliveira, Luís R. Silva, Paula Guedes de Pinho, Angel Gil-Izquierdo, Patrícia Valentão, Branca M. Silva, José A. Pereira, Paula B. Andrade, Volatile profiling of Ficus carica varieties by HS-SPME and GC–IT-MS, In Food Chemistry, Volume 123, Issue 2, 2010, Pages 548-557, ISSN 0308-8146, https://doi.org/10.1016/j.foodchem.2010.04.064.
(http://www.sciencedirect.com/science/article/pii/S0308814610005212) 

** Hojjati, M., Calín-Sánchez, Á., Razavi, S. H. and Carbonell-Barrachina, Á. A. (2013), Effect of roasting on colour and volatile composition of pistachios (Pistacia vera L.). Int J Food Sci Technol, 48: 437–443. doi:10.1111/j.1365-2621.2012.03206.x. I should note here that another group appears not to have found phenyl acetaldehyde in pistachios: Ling, B., Yang, X., Li, R. and Wang, S. (2016), Physicochemical properties, volatile compounds, and oxidative stability of cold pressed kernel oils from raw and roasted pistachio (Pistacia vera L. Var Kerman). Eur. J. Lipid Sci. Technol., 118: 1368–1379. doi:10.1002/ejlt.201500336. The differences may be due to both treatment methods and cultivars.