100 Million Years of Food (4 page)

In its natural habitat, cave fruit bats pollinate the durian flower in its lofty perch high above the ground. The bulkiness of the fruit means that small animals cannot be used to disperse the seeds. Therefore, the extraordinary smell is used to lure large mammals, who eat the fruit and distribute the seeds. The fruit also yields tryptophan, a precursor for the pleasure trigger serotonin, which helps to explain the fruit's reputation as an aphrodisiac.
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It is well known that fruits have struck a deal with animals: Fruits yield sugars, oils, or amino acids, and in exchange animals disperse the seeds far from the parent tree in their feces, giving the future seedlings a chance to conquer new territory. What is less well known is that many fruit plants may engage in a tricky love triangle.
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The plants want their fruits to be consumed to transport their seeds, but bacteria, fungi, and insects also want to crash the party and feast on the succulent flesh. As a result, vulnerable fruits have to be protected with secondary compounds like phenols and tannins, which dampen the desirability of fruits to big eaters like ourselves by interfering with metabolism, digestion, and palatability but also restrain lecherous bacteria, fungi, insects, and other predators from spoiling the goods.
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One more consideration: Since plants want their seeds spread far away from the parent, plants may not be interested in fruit eaters who hang around the plant all day, monopolizing the fruits and discarding the seeds near the base of the plant. Like a mother who wants to wean her child or persuade her teenager to get a job and move out of the house, they must eventually practice some tough love. Plants can accomplish this by making their fruits enticing enough that eaters will gobble them down, but aversive enough that the eaters will eventually move on and leave the area. Thus the secondary compounds like phenols and tannins can be one more strategy for plants to ensure their progeny get broadcast far away from the parent. Or to put it another way, fruits were made to taste good, but not too good.

Humans take the eat-me-leave-me game yet one step further, by manipulating fruits so that their defensive compounds are neutralized. For example, olives are highly desired by animals for the high lipid content, but the fruits are also naturally bitter from their protective phenol compounds. People around the Mediterranean learned to tame these compounds through curing and fermentation. An extraordinarily hardy tree, olives were originally cultivated for oil that was valued as a means of lighting and as a skin lubricant, especially for ceremonial purposes (whence comes the term “Messiah,” or the anointed one). Nowadays, the olive fruit is stripped of its bitter phenols and processed into various grades of edible oils with a high content of monounsaturated fatty acids, particularly oleic acid. (Phenols have excited interest for their potential role as antioxidants, but so far their health benefits remain unproven.
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) The richness of olive oil complements foods like cereals, vegetables, fruits, and fish, by making dull but reputedly healthy fare more palatable. Hence the explosion in popularity of the Mediterranean diet: At last, Westerners can sit down to exquisite meals again without having to feel guilty and stressing out about calories and fat.
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As with the phenols, there's little evidence that olive oil itself is a healthy food. What makes olive oil valuable is that it helps to bind together an entire regional cuisine, making it possible for people to subsist on fare that is relatively low in animal products like meat and dairy yet still feel reasonably satisfied, especially when fresh, high-quality olive oil is available and when people are too poor to buy meat.
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As we'll discuss in a later chapter, humans are hardwired to crave meat because it increases our reproductive prospects; hence, when Greece began to increase her wealth after World War II, her citizens tended to give up the olive oil blessed by nutritionists in favor of the carnal pleasures of meat and animal fat.

Another major group of defensive plant compounds is tannins. Observant scientists have noticed that squirrels rotate their acorns so that the acorn “hats” point upward. Then the critters chomp through the caps and into the nuts. That's because tannin is concentrated in the bottom of the acorn, where it protects the seed embryo. (Irritants like urushiol and anacardic acid, related to poison ivy, similarly protect pistachio and cashew seeds, which explains why they have to be roasted before eating.) In high concentration, tannins render protein indigestible, inhibit a wide range of enzymes, sap energy, and stunt growth. Tannins are also sequestered in legumes, berries, and grapes, and they give red wine its characteristic dryness. (Incidentally, gray squirrels are better at digesting tannin than red squirrels and can therefore take advantage of oak tree forests. Red squirrels prefer hazelnuts, which contain less tannin than acorns, and will promptly kick the bucket if given nothing but acorns to munch on. The broader appetite of gray squirrels helps to explain why they are pushing out their red relations in England.) Birds like jays and grackles, as well as insects, similarly prefer to eat the top half of acorns. The rest of the acorn seems to have evolved to be a snack and lure for animals that do the necessary deed of widely dispersing the seed embryos.
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Oak trees can churn out roughly 500 to 1,000 pounds (225 to 450 kg) of acorns a year, albeit during a brief window of a few weeks. A Native American family living in California a few centuries ago, collecting over the span of two or three weeks, could set aside enough acorns to last two or three years. They could gather acorns from at least seven different species of oak trees, preferring oily acorns over sweet ones, and knew two methods to purge them of noxious tannins. The common technique was to de-hull the acorns, pound the acorn meat into mush and drop it into a pit, then douse the mush with water heated by hot stones until all the bitterness was leached. Alternatively, acorns could be buried in mud by streams or swamps for several months, after which they would become edible. To complement their protein-deficient acorn cuisine, Native Americans in California hunted salmon, deer, antelope, mountain sheep, and black bear and gathered earthworms, caterpillars (smoked and then boiled), grasshoppers (doused with salty water and roasted in earth pits), and bee and wasp larvae.
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The ancient Greeks made use of acorns; so did the Romans, as well as populations in medieval England, France, and Germany. Acorns were handy during the 1800s in Spain, Portugal, Arabia, Algeria, Italy, Greece, and Palestine and as of 1985 were still feeding people in South Korea, Morocco, and Iraq. Acorns are a cinch to gather, stay edible over extended storage, and provide a double whammy of fat and carbs, as well as vitamins A and C. These days, clever back-to-the-woods types stash their acorn meal in a cloth bag in the clean-water tank of a toilet, so that every flush expediently sucks away tannins. That marches the clever ones one step closer to ecological Valhalla, because not only do the oak trees lavish sustenance befitting a hero, but every call to nature effectively does double duty.
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So what's the catch? I had my first nibble of an acorn dish in South Korea, where acorn starch is boiled and set into a gelatinous block known as
dotorimuk
. From its lovely hues and quivering form, you guess that
dotorimuk
will taste like chocolate or almond Jell-O, but biting into an actual piece is like leaping into a kiddy pool at the height of a blazing summer: promising on the surface, with expectations soon dashed.
Dotorimuk
's tannin aftertaste is reminiscent of boiled newsprint with a few peanuts tossed in, but Korean cooks mask this uninspiring flavor with a brilliant topping of scallions, garlic, red chili, sesame seeds, and soy sauce. The dish may have been useful during hard times in Korea, but given its unimpressive taste and the arduous process of boiling acorn paste through multiple changes of water, it is easy to see why this reliable commoner's staple has been displaced by more sophisticated fare. Professor Jared Diamond at the University of California, Los Angeles, has also pointed out that oak trees are hard to domesticate because they grow slowly, disperse seeds widely via squirrels, and have several genes controlling their bitterness.
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Still, with all the talk today about the need for genetically modified (GM) foods and heavy fertilizer use to produce enough food for the world, it's sobering to think that our ancestors did rather well on ubiquitous fare like insects and acorns, which we literally tread on in our daily lives.

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Acorns may be a poor person's panacea in the northern hemisphere, but what about the tropics? Is there some tree there that could also fulfill the needs of the hungry in an environmentally friendly manner? Perhaps breadfruit could vie for the title of tropical manna. I first sampled this remarkable fruit while traveling in Papua New Guinea, the region where it originated. A little smaller than the size of an American football, it is green and scaly to the touch outside, while the baked interior is golden and imbued with a nutty, starchy flavor that indeed recalls a freshly baked loaf. Breadfruit is typically roasted in an earthen oven with hot stones but can also be boiled and then used like potatoes. With a carbohydrate content comparable to cereal crops, breadfruit has the potential to be a super-productive tropical food machine. A single tree is capable of yielding up to seven hundred fruits in a single year, each fruit weighing two to eight pounds.

Though this glowing praise may make you eager to sink your teeth into a fruit that evokes the comforting flavors of baked bread or potatoes, cultivating breadfruit has its hurdles.
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Breadfruit comes from a tall tree that can grow up to sixty-six feet in height, so much of the crop is damaged by falling and spoils within a few hours. (Breadfruit that is fermented in pits can still be eaten a year later, but decomposing breadfruit is an acquired taste.) The breadfruit tree does best in tropical regions with abundant rainfall and temperatures between 70°F and 90°F, so that rules out most Western countries, including the United States, where attempts to grow breadfruit in Florida have sputtered. The kind of breadfruit that is commonly eaten doesn't have seeds, so it must be propagated through root transplants, a substantial barrier to distribution. Early seafarers carefully nurtured their breadfruit cuttings on extraordinary voyages as they settled islands around the South Pacific.

Breadfruit trees take their sweet time in putting out fruit—around five years or so for the first crop—which may make them less profitable to grow commercially than, say, bananas, which bear their first bunches within one or two years.
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Like a moody suburban teenager, breadfruit grows to lofty heights but takes a long time to mature, is picky about the weather and easily injured, and won't yield a penny on your investment for years to come. Fortunately, Hawaii residents Pierre Omidyar, founder of eBay, and his wife, Pam, have picked up the breadfruit craze and are bankrolling efforts to popularize the locally grown fruit in restaurants and with young people, which may help to cut Hawaii's extreme dependence on imported foods. The wood of breadfruit trees was once used to build houses and canoes (with breadfruit gum as caulking). The bark doubled as bedding and clothing, and the leaves served as trays for cooking and serving. The gum and bark were also used in traditional medicines, to relieve skin ailments, diarrhea, stomachaches, ear infections, and headaches.
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The flower heads traditionally served as mosquito repellents when burned.
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Thus, like acorns, breadfruit is a crop that has great nutritional, economic, and eco-friendly (as well as medicinal) potential, but it will require us to look both backward, to remember how people once used and ate this prodigious fruit, and forward, to devise technological workarounds to the problems of rearing, storing, and transporting breadfruit.

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India is a paradise for lovers of fruits, flavors, and spice. I fly into the southwestern Indian state of Kerala, where my friend Bajish meets me at his parents' house on the outskirts of the city of Thrissur. He eyes me as I struggle to scoop up his mother's cooking with my inept right hand. Over the course of a week, she prepares breadfruit, chicken and fish curries, carrot and chickpea chilies, and tomato dahl, all steeped in rich coconut cream and tongue-flaying dosages of chili, accompanied by fried fish, eggplant, white rice, crumbly rolls of coconut and rice flour, crispy lentil flatbread, fragrant chapatti, creamy cassava, sour yogurt, and buttermilk. Bajish's expression is part amusement, part disgust. “You have to pick up the food like this,” he says. To demonstrate, he puts his fingers together, like a spade, then raises them to his mouth with his elbow tilted outward. “Otherwise the food will fall down.”

I try again, but somehow I just can't knit my fingers together and maneuver the grains of rice and bits of food into my mouth with Bajish's gracefulness. I have to keep my elbow lowered or the food spills, but then my fingers don't meet my mouth at the proper angle. It's a subtle art, but I have to master it, and soon, because the flavors of his mother's Keralan cooking have been astonishing.

Nostalgic Indian tunes blare from a little radio in his parents' bedroom. Bajish's mother swirls across the spotless white tiles, praying for her son's success. He's been looking for an academic job in oceanography for several months, ever since he graduated from studying in Japan, where I first met him. This next stage in Bajish's career is crucial, not only because it will provide him with status, income, and independence but because, according to his parents, it's high time for him, at the cusp of thirty, to get serious about marriage, and no good prospect could be contemplated without his having a decent career in place. So as my friend settles at the coffee table with his laptop, ready to send out more cover letters and résumés to universities around the world, his mother plies him with fried banana chips, papaya slices, and cups of ginger cardamom tea and wonders aloud about his marriage prospects. She is particularly intrigued by a girl in Thrissur who is educated and has a good office job.