There’s a silky-textured ingredient commonly used in Asian cuisine that unfortunately is overlooked. It never wins the culinary Oscar for Best or even Supporting Actor and is usually simply found in the credits after the movie (or dish) is finished. Full of protein and healthier polyunsaturated fats but with enough bulk to “beef” up dishes and the ability to enhance role players that shine in their supporting roles, this point guard of the culinary world deserves its due…What is it? Tofu!
The science of tofu
Most of us know the basics of the science of tofu. Basically curdled soy milk right? That would be accurate if you also feel that the Sistine Chapel simply has a painting on its roof or the Pyramids of Giza in Egypt are simply a pointy stack of bricks.
All tofu starts life as soybeans. There are tofu that are produced from fresh soybeans but most of what’s available to the average consumer comes from the dried variety. The dried soybeans are usually soaked for a half to a full day then ground and the resulting soymilk is then boiled, strained and coagulated to produce your basic tofu. Depending on the coagulant used and the pressing technique employed, the final product can be as silky as soft silken tofu, or on the other end, be an extra firm tofu block. Most of the labor involved occurs in the production of soy milk, as the softened soybeans need to be ground to extract their liquid or soy milk. Therefore, if you find yourself involved in tofu production, volunteer for the latter half or better yet, choose that final phase of production — quality control.
For most Japanese-style tofu, the coagulant of choice (or nigari) is either magnesium or calcium chloride — concentrating desalinated seawater originally produced it. Chinese-style tofu usually employs calcium sulfate while silken tofu often is produced from acid coagulants like glucono-delta lactone. I know that this is beginning to sound like a chemistry class but for all intents and purposes, cooking really is chemistry. We just use culinary terms to describe basic chemical reactions.
Browning or toasting in cooking equals the Maillard reaction or a heat induced reaction between an amino acid and a reducing sugar in chemistry. Whipped cream in culinary speak, a lipid and air colloid in chemical speak. Tofu for the culinary inclined, a magnesium or calcium precipitated soy protein solid for the chemically inclined… and dinner for the Gochiso Gourmet.
Since tofu is produced from beans, it’s no wonder that it is a good source of vegetarian protein providing roughly 10 grams of protein per 4 ounce serving. This protein also includes a hefty dose (up to 44 percent of the daily requirement) of the essential amino acid tryptophan. Tofu also is a good source of magnesium, calcium, manganese, iron, copper, selenium and phosphorus.
Tofu even contains the isoflavones genistein and daidzein and though the jury is still out on whether these compounds can help alleviate the symptoms of menopause or reduce breast cancer risk, preliminary small trials show a possible benefit and at the very least, no risk of harm.
There are also small trials that
show that a diet supplemented with soy protein can reduce LDL cholesterol or “bad cholesterol” as much as a 20 mg dose of the statin medication lovastatin when added to a diet also high in fiber.
Variations on a common theme
I know that the simplest form of tofu — the fresh block of tofu — seems the same to everyone but nothing could be farther from the truth. For starters, actual freshly made tofu is leagues apart from the variety found in supermarkets. Freshly made tofu has a creamier consistency and a sweeter flavor and is worthy of being the centerpiece of the meal. Of course that flavor comes with a price. Since tofu doesn’t have a very long shelf life, you’d have to wake up early every morning to soak and grind beans, extract milk then coagulate the proteins. In that sense, I think the supermarket variety is fine. Of course that still leaves the decision of soft, medium, firm or extra firm, fried or deep fried, flavored or pre-cooked. Whew! And that doesn’t even include fermented red and yellow tofu for jai or yuba and okara that are by-products in tofu production… but that’s another column.
Because I normally use tofu in stir-fry or nabe dishes, I usually purchase the firm or extra firm variety. The soft variety is great when using tofu for dessert recipes, especially the silken soft types, which are basically soft tofu custards. I rarely use the medium variety… unless I have a grill basket. Heated over charcoal then covered with fine bonito flakes (which writhe and twist from the heat), finely sliced green onion and a touch of reduced sato-shoyu sauce. Maybe with tsukemono and a light bodied ginjo sake…
Freezing then thawing tofu produces a totally different textured product somewhere between aburage and cooked chicken. Since tofu is mostly water, freezing and thawing removes most of the moisture content giving it a “meatier” texture. Added to curries, it adds additional protein without extra fat (I once tried this approach in vegetarian chili… it didn’t work since the white strands stood out against the dark red chili sauce) or added to nabes to replace aburage.
Northern California Soy and Tofu Festival
For a day filled with soy and tofu, plan on attending the Northern California Soy and Tofu Festival in San Francisco Japantown’s Peace Plaza on Saturday, June 11 from 11 a.m. to 4 p.m. The day’s festivities include a Tofu Dessert Competition with a $100 grand prize! In celebration of all that is soy, I’ve included my own updated take on a classic Japanese dish, oyako donburi. Referring to the chicken and egg in the dish (oya = parent, ko = child), I’ve updated the dish to a soy-based creation featuring edamame and tofu (soybean = parent, tofu = child) over a flavored brown rice.
The Gochiso Gourmet’s new oyako donburi
20 to 24 ounce firm tofu, mashed
2 tbsp dried or fresh sliced green onion
1 large carrot, peeled then thinly sliced
1 small onion sliced with the grain to 1/4 inch slices
2 bamboo shoots, thinly sliced with the grain
1/3 c dried shiitake rehydrated overnight
1 thumb-sized piece of peeled fresh ginger
1 c water from rehydrated shiitake
3 tbsp shoyu
2 tbsp sugar
1 tbsp sake or shochu
4 to 6 egg whites beaten
Cooked brown rice with 1/4 cup of nametake chazuke (bottled enoki mushrooms cooked in flavored shoyu)
3/4 cup of frozen shelled edamame.
Combine mashed tofu and green onions and let sit. Combine shiitake water, shoyu, sugar and sake/shochu.
Over medium heat, saute carrot, onion and bamboo shoots with non-stick spray for several minutes. Add rehydrated shiitake and ginger. Add shoyu mixture and bring to a simmer. Add tofu and simmer for several minutes then add beaten egg whites and cook until the egg white have congealed. Serve over the edamame brown rice.
Freezing then thawing the tofu gives it a firmer texture like cooked chicken. Adding the tofu as is gives it a creamier texture (but makes the dish a little more watery). Your choice on the consistency.
The Gochiso Gourmet is a column on food, wine and healthy eating. Ryan Tatsumoto is a graduate of both the University of Hawai‘i and UC San Francisco. He is a clinical pharmacist during the day and a budding chef/recipe developer/wine taster at night. He writes from Kane‘ohe, HI and can be reached at firstname.lastname@example.org.