Saturday, August 27, 2016

Temperature and water and tea

No, this isn’t an article about brewing temperature and water (could write a bundle about that, and may do so at another time) — it’s about world temperatures this July, and precipitation patterns. Here’s the map of July 2016 temperatures from the National Oceanic and Atmospheric Administration (NOAA):

See all that salmon color? (Grey is for areas with no data). It’s been hot hot hot. When I was staying with my daughter in Massachusetts for the month of July, we had cabin fever in reverse.* It was just too hot to run around in the yard or anywhere outdoors. And dry, too—my son-in-law was kinda happy he didn’t have to do any mowing.

Now look at southern China. “Record Warmest” just where some of my favorite teas are grown. Quite warm in the tea growing areas of India as well, and Kenya was pretty hot, too.  

According to World Tea Expo speaker and friend Selena Ahmed,** the increased heat led to early budding of tea in Zhejiang. When the early budding is followed by a frost, which it was this past winter in the home of Longjing/Dragon Well tea, yields go down dramatically. ***

It’s not just the heat, though, it’s also the increased precipitation. To quote Selena: “For tea, when there’s too much rain, there’s a dilution effect of the secondary metabolites.” Those wonderful flavor compounds that make a superb oolong? They’re all secondary metabolites!

Look for the red box — I've circled the tea growing areas affected by increased precipitation this winter in the NOAA map below—yep, there’s a blue dot near where my beloved oolongs grow:

What to do? Selena offers some suggestions in the article, prominent among which is the creation of a diverse ecosystem, where plants can in essence protect each other, as the ancient tea trees in forests did.*** 

Another suggestion that has been made: switching from making green tea and oolong to making black teas, where the more thorough oxidation leads to a relative increase in secondary metabolite production…but then with oxidation you lose all the “green” flavor metabolites that make a Longjing or an oolong so exquisite. 

So all I can say right now is, reduce your carbon footprint however you can, and enjoy your tea for the treasure it is.

*For those of you who haven’t experienced it, cabin fever is the ennui you develop when you are cooped up at home and can’t leave due to snow piled up outside.

** Selena Ahmed is Assistant Professor of Sustainable Food Systems at Montana State University, Bozeman.

**** Here’s an article (it’s available to all)  by Selena and her colleagues about modeling climate change— the change will lead to lower yields, which will especially hurt the small farmer:  Boehm, R.; Cash, S.B.; Anderson, B.T.; Ahmed, S.; Griffin, T.S.; Robbat, A.; Stepp, J.R.; Han, W.; Hazel, M.; Orians, C.M. Association between Empirically Estimated Monsoon Dynamics and Other Weather Factors and Historical Tea Yields in China: Results from a Yield Response Model. Climate 2016, 4, 20.

Tuesday, August 23, 2016

Riffing on bitter receptors

Was looking through my 23ndme results, where I found that a certain change in my DNA could be associated with sneezing after eating dark chocolate. Turns out that this single change lies in the region of our DNA that is associated with two different bitter taste receptors, though not actually in the gene for either receptor.

Nevertheless, that observation led me to look into some of the recent data on the locations in the body where bitter receptors can be found, and lo and behold, we have bitter receptors in our nose…and sweet receptors, too!

According to Kook and colleagues, these receptors are not located on nerve endings or in fact apparently not on any specific type of cell, but on the skin-type cells lining the nose. When the receptors are activated by bitter compounds, the blood vessels around them constrict, so breathing was easier for their participants with allergic rhinitis. 

That said, if you do have allergic rhinitis, breathing in the vapors above your cup of tea probably won’t help you through direct activation of bitter receptors. The bitter flavonols such as epigallocatechin aren’t volatile at usual temperatures. They stay in the cup and aren’t part of the vapor.

BTW, I don’t sneeze when eating dark chocolate, even though I do carry the DNA change. Oh, and that little one sneezing is from —couldn't resist!

J. H. Kook, H. K. Kim, H. J. Kim, K. W. Kim, T. H. Kim, K. R. Kang, D. J. Oh and S. H. Lee. Increased expression of bitter taste receptors in human allergic nasal mucosa and their contribution to the shrinkage of human nasal mucosa. Clinical & Experimental Allergy, 2016 (46) 584–601.

Tuesday, August 16, 2016

Thinking about gums and purple tea...

... the gums in your mouth, that is. Recently I sent Friend of Pairteas and Tea-cher Marzi Pecen a couple of tubes of toothpaste, because she was complaining of some gingivitis. 

Not ordinary toothpaste, but one developed by my friend and former student Jon Levine, that contains (among many other ingredients) cranberry powder.* A while back he realized that there was a growing body of literature suggesting that cranberry extracts could inhibit biofilm formation. Bacteria create biofilms to protect themselves against attack by your immune system, and as a way to spread around the enzymes they create in order to break down your guns and get the raw materials that they need to flourish.  Jon's toothpaste worked amazingly on my gingivitis and is working on Marzi's as well.

So my question was: what is in cranberries that inhibits biofilm formation? The literature says...catechins and proanthocyanins!**  Where do we find these chemicals? Purple leaf tea that is processed as a green tea—the purple for the proanthocyanins and the green for the catechins!

So I looked around some more, and found an article, reviewed in World Tea News, that suggested that a toothpaste containing green tea was superior to standard treatment for gingivitis.*** 

Now if we had a toothpaste with purple green tea...

* It's called Glo, and to get it you should contact Jon directly through his website, or via the perfume site It's expensive, but you only need to use a tiny bit per brushing—a tube lasts me 3 months or more.

** Yamanaka, A., Kouchi, T., Kasai, K., Kato, T., Ishihara, K. and Okuda, K. (2007), Inhibitory effect of cranberry polyphenol on biofilm formation and cysteine proteases of Porphyromonas gingivalis. Journal of Periodontal Research, 42: 589–592. doi:10.1111/j.1600-0765.2007.00982.x.
Note: there are many subsequent papers that confirm and extend these findings. The full extract appears to be best.

***; Int J Dent Hygiene 142016178183 DOI: 10.1111/idh.12131 Hrishi TSKundapur PPNaha AThomas BSKamath SBhat GSEffect of adjunctive use of green tea dentifrice in periodontitis patients – A Randomized Controlled Pilot Study.

Thursday, August 11, 2016

Memories of Rio

Been watching the Olympics, which brings me memories of visiting Rio de Janeiro as a child. At the time we lived a good part of the Southern winter in Montevideo, Uruguay, and the rest—the Northern winter—in NYC (yes, I had school all year round!), and we visited Rio now and then—always a treat!

Remembering Copacabana beach. Ipanema was almost in another planet at the time. Only the most adventurous lived there because the roads to get there were so poor. Enjoyed Copacabana from the shade of our hotel balcony - my red hair and pale skin were made for more Northern, less sunny climes. Didn’t enjoy the heat, either. But the food, oh the food!

Start with the most delicious chicken soup imaginable—canja de galinha! As someone who had previously only known Campbell’s in all its guises, to have a chicken soup in which you could actually find the parts of entire carcasses, complete with skin and bones, was a revelation! Just now I was looking for canja recipes on line—they are soooo sanitized compared to what I enjoyed way back when: they have only bone, no skin. Of course, as any cook knows, a good strong meat broth needs collagen from bones and skin, and the canja from those days had it in abundance.

Then feijoada—as someone who adores beans, and black beans in particular, this dish was heaven! Especially as it came with another of my most preferred foods, sausage.

But the true pièce de résistance was always the dessert: fried bananas with cinnamon…washed down with a bottle of guaraná—cream soda on steroids. Talk about happy mouth!

Rio was also the first place I saw deep poverty, but that is another conversation.

Picked this picture of Pão de Açúcar (Sugar Loaf) Mountain, along with Urca to the right of it, because it reminds me of the one opportunity we had to go up near there in all our times in electricity in most daytime hours in those days. And we could only go as far as Urca—no power for the rest of the ride. Have always dreamed of going to the top. Guanabara Bay (in front) was pretty clean in those days, though, and a boat trip to Niterói across the bay was exciting!

Wednesday, August 10, 2016

Asparagus aroma in tea

Just the other day I saw mention that a certain green tea tasted like asparagus. I love asparagus, but I have yet to taste a green tea that reminds me of the vegetable. That observation led me into looking at the nature of the volatiles in asparagus, and here’s what I found:*

The strongest odorants, and perhaps the most numerous, in asparagus are sulfur-containing and nitrogen-containing compounds—these can be detected by the human nose at the level of parts per billion. They will dominate any aroma mixture you can imagine. 

Of these 20 or so compounds in asparagus, the most abundant and dominant is dimethyl sulfide. This compound can be present in tea, where (to me at least) it contributes a “marine/seashore/oceanic” quality. You can find it most abundantly in green and oolong teas, so it would not be surprising that when you encounter it in a green tea, it might give the impression of asparagus. It is notable, however, that the remaining sulfur compounds detected in asparagus, with the exception of dimethyl sulfoxide, are not usually found in tea. The nitrogenous compounds common in asparagus—pyrazines—are also rare in teas. 

What is found in both tea and asparagus are a few volatiles with a decidedly less asparagus-like aroma, for example hexanal, which gives a “green” aroma and has a lingering after-taste; and two of my favorites, benzene ethanol and phenyl acetaldehyde, both of which have the fresh, sweet rose-like aroma that I love in oolongs, and especially white tea. Next time I have asparagus, will have to look for them.

Asparagus cooking, by Seeman, from
In the olfactory bulb, before we ever are conscious of an aroma, we assemble the signals from volatile chemicals into an “odor object.” As Ulrich and colleagues note: 
a lot of weaker smell impressions were recognizable in the odor spectrum which are potentially able to contribute by interactions to the whole aroma impression.” other words to the assembly of a recognizable “odor object.” 

Further, people surely differ in the odor objects they create from a given panoply of possibilities—remember that we don’t all smell the same things in a mixture, and we may not use the same array of volatiles to construct a recognizable odor object. 

So what I myself may experience as simply “seashore” may be just one part of someone else’s “asparagus” aroma.** 

* Ulrich, D., Hoberg, E., Bittner, T. et al. Contribution of volatile compounds to the flavor of cooked asparagus. Eur Food Res Technol (2001) 213: 200. doi:10.1007/s002170100349.

** Incidentally, I’m talking about the smell of cooked asparagus in the plate, not the smell that some people create and some people can smell in urine. These are metabolites of asparagusic acid. These metabolites do include dimethyl sulfide and also the garlic-like dimethyl disulfide, which can also be found in tea. People may smell these compounds in tea and associate them with asparagus because they are present in post-asparagus urine.

Tuesday, August 9, 2016

Tea, coffee, wine (and more), and kidney stones

Saw an article about sugary drinks, tea drinking and kidney stones in World Tea News,* so I thought I might go back to the original paper on which it was based. 

An amazing photo from Wikipedia by GrammarFascist:
"The yellow object in the center of the image is a kidney stone composed of calcium oxalate. The sharp edges which cause pain and bleeding as such stones pass through the ureter are visible. The green stone at right is a sail-cut chrome tourmaline gemstone, and the kidney stone and gemstone are resting on a synthetic whetstone."
The article by Ferraro and colleagues** presents yet another analysis of the long-term data from the Nurses’ Health Studies I and II, and the Health Professionals Follow-Up Study. The focus of their analysis was the relationship of consumption of beverages of all kinds to the development of kidney stones. The usual recommendation to people with kidney stones is to drink plenty of fluids. The question is then: which fluids?

Turns out that plain water drunk more than once a day is protective, a good choice, but there are (possibly) better ones. So what are they?

Not tea, really — if you drink more than one cup a day, it may have a small effect (at least if you are a nurse or a physician).  In their discussion in the paper, the authors extol the virtues of tea, but the data only bear out an effect with more than one cup a day, and a slight effect at that. 

But coffee, yes, both caffeinated and decaffeinated, though caffeinated is better; and wine, both red and white, and beer.

Juices (apple, grapefruit, tomato juice, orange juice) and milk (whole and skim) are fairly neutral.

The baddies: sugared sodas and punch—they increase the risk!  Nothing said about sweet tea, but a good guess is that it may be like the sodas.

One of the questions not asked: relationship of fluid type to type of kidney stones—oxalate stones are the most common, but uric acid stones, associated with gout, can be made worse, not better, with alcohol. And of course the populations studied were limited demographically.

My bottom line: enjoy your tea, but don’t expect it to protect you from kidney stones…or cause kidney stones, either.


** Ferraro PM1, Taylor EN, Gambaro G, Curhan GC. Soda and other beverages and the risk of kidney stones. Clin J Am Soc Nephrol. 2013 Aug;8(8):1389-95. doi: 10.2215/CJN.11661112. Epub 2013 May 15.