Friday, December 30, 2005

When good antioxidants go bad

During a rare naptime retreat, I tried to figure out why exactly antioxidants in large amounts tend to become pro-oxidants. It involves the antioxidant reducing iron (or other transitional metals) from Fe3+ to Fe2+ and the metal being freed up to react with the antioxidant (normally metals are bound to proteins so they are soluble enough to be carried through the bod). As far as I can figure.

For example, Vitamin C helps with the absorption of iron because it can reduce it to the heme state, Fe2+. Iron needs to be heme iron to be absorbed. Too much Vitamin C would mean you
might absorb too much iron -- it might then not have enough transporters and float around free. If that were the case, the iron could react with Vitamin C or other antioxidants, and er, be oxidized. You could rust, I suppose.

Well. It would be easy to be more intelligent than I and have something to offer here (please do). This is just what I'm sort of gleaning from the literature. It caused me to take a nap....and now you'll probably go face down from the excitement too. When you awaken refreshed, you can think of me with gratitude.

Saturday, December 10, 2005

Primary antioxidants in black, green and rooibos teas.

I've been peeking to see where the few people who dropped in have found this blog. One was a person looking for "mechanisms of camellia sinensis other than tannin." So it occurred to me that for some of you (okay, one of you) it might be helpful to list the most active antioxidants in green and black teas from Camellia sinensis and Aspalathus linearis (rooibos) teas. Because I'm a lazy sod I won't name all of them -- besides, if you're looking for every last one you should be consulting academic papers. But in black and green teas from Camellia sinensis, catechin is your man -- the breadwinner of that polyphenolic family. In Rooibos, Aspalathus linearis, the big man on campus is aspalathin, which is unique to rooibos and one other plant on Earth, which is why it's being studied. Quercetin is another biggie, and both teas have it. There. Now the next time you look me up on Google, "geekity geek" ought to land you right

Thursday, December 01, 2005

Getting cheesy.

The other day, during our speed-dating version of marital chat (roughly 10 minutes a day -- how could we ever tire of each other at this rate?), the subject somehow turned to cheese. Cheddar cheese. Then Swiss. Then tofu. They don't call it Asian cheese for nothing.

So. Of course you know that cheese was originally developed as a way of preserving milk. It likely happened by accident, since folks used to carry around milk in animal hides, and er, animal stomachs. The enzymes in animal's bellies can curdle milk -- leaving the liquid part, whey, and cheese. Miss Muffet sat on her tuffet eating...cottage cheese. Manufacturer's still use rennin -- an enzyme from calves' stomachs -- to make some cheese. Luckily, they have also started using other enzymes with less awful origins. Additionally, of course, there are some cheeses (bleu being the most obvious) with bacteria added to give flavor and texture. The protein in cow's milk is called casein.

Cheddar cheese is characterized by...cheddaring. First whole milk is inoculated with bacteria (Streptococcus lacti, if you must know), fermented for up to an hour and annato added if it's going to be orange (it's normally off white). Then it's heated to around 100 degrees and enzymes are added. If you've seen an egg cook til it forms an egg white, you've watched a protein denature and coagulate. The proteins unwind (denature), then reform in a different shape (coagulate). The enzymes for cheese work at a certain temperature, and the combination curdles (denatures, then coagulates) the protein into cheese. When the protein coagulates, it squeezes out water like a sponge -- the whey.
Cheddaring keeps the cheese from forming little holes which could get moist and lead to rot. The curds are cut and stacked to eliminate this problem. Then the cheese is "ripened" or aged for between 2 months to a year or so to develop flavor.
Cheddar is from England, but it's the most consumed cheese in the U.S.

The people of Emmental Valley, Switzerland feared not the holey cheese. (In Europe, Swiss is called Emmentaler cheese). Basically the same rules as above apply; the curds are heated, inoculated and stirred to get rid of the whey, but no cheddaring and 4 kinds of bacteria, including one Propionibacterium shermanii for flavor and those really cool holes. The cheese isn't ripened as long -- just 4-9 months. During the first month, at room temperature, the holes are formed from bacteria farting carbon dioxide. That's a pleasant thought, no? Don't care. It still tastes good.

Now -- tofu. It's heated soy milk, to which a calcium or magnesium salt is added to coagulate it, it's pressed to get rid of the whey and hacked into blocks. It's called bean curd sometimes because that's what it is.

And this is why cheese and tofu are so damned high in protein -- because they are made of coagulated proteins (and a fair amount of fat too). That must be why it came up. Who can remember.

As an aside, whey has found quite a market in all those power bars and meal replacement bars. In concentrated form it is high in protein. And if you're lactose intolerant, it will make you into a giant gasbag, because most of the lactose in cheesemaking is left in the whey.