Kitchen Mysteries_ Revealing the Science of Cooking Part 4

Roasting First Principle: Succulence A quick cooking process that is not meant to tenderize the meat, roasting is reserved for choice pieces that come from young, tender animals. It leaves the characteristic flavor of the meat intact, adding only a delicate touch on the surface. The juices, most of which remain in the flesh, flood the mouth with subtle flavors when one bites into the meat.

A roast retains its succulence only when it is seared. The oven must be preheated, the meat must be coated with oil, which conducts heat better than water, and ideally steam must be eliminated. Without allowing too many of the juices to be released, the heat produces new sapid and odorant compounds by destroying various molecules at the surface and thus blending the contents of various cell compartments, which react with one another. The lipids (fats), amino acids, and sugars bind together into large, dark-colored odorant and sapid molecules.

Traditional French cooking requires beef, for example, to be roasted in such a way that the center remains rare. The surface is covered with oil or b.u.t.ter so that, seared more rapidly, it forms the thin crust so prized by gourmands.

A long time ago, it was believed that searing produced an impermeable layer that would keep the juices from escaping. But it has been demonstrated that the juices escape regardless. If meat should be roasted in a hot oven, it is to limit the roasting time and thus the time during which the juices can escape. When the roast comes out of the oven, tender, odorant, and juicy, it must rest a few minutes so that the juices in the center migrate toward the dry periphery. Then it must be cut with a good knife that will not maul it, allowing the juices to be retained within.

Other countries, other customs: the English are renowned for their boiled meats but also for their well-done roasts. Across the English Channel, a roast remains respectable when the temperature at its center reaches 60 (140F) or even 80C (176F). In France, the temperature at the center of a roast sometimes does not even attain 30C (86F).

How Does a Roast Cook?

Let us recall the paragraphs devoted to cooking and review one by one the various kinds of heat transfers in order to see which one applies to roasts. We will consider three of them: radiation, convection (the hot air ensures the distribution of heat in the oven), and conduction (within the meat).

How does a roast cook? First of all, note that the thermic conductivity of meat diminishes considerably with temperature. Meat conducts heat very poorly (it is an insulating material) at low temperatures (at 0C [32F], for example), but it becomes a better conductor at higher temperatures. We can examine the consequences of these properties by a.n.a.lyzing how a Christmas turkey cooks.

THE CHRISTMAS TURKEY.

How to cook a turkey correctly? A turkey's sphericity holds some interest for physicists, who know how to calculate heat transfers within bodies with simple forms. In 1947 Horatio Scott Carslaw and John Conrad Jaeger studied the relations.h.i.+p between the radius of an ideal, spherical turkey and cooking time. They a.s.sumed that a turkey was a mixture of water, fats, and proteins in the ratio of 60/20/20, and they sought the optimal cooking temperature.

Why does the cooking temperature matter? When a turkey is roasted, its fibers contract until, at about 70C (158F), the individual muscle cells begin to deteriorate. During heating, the weakest bonds between the atoms of certain molecules are broken, so that the proteins are denatured. These long threads, folded back on themselves in specific configurations, unwind and move in all directions. Because the proteins can thus come into contact with one another, they bond and coagulate. The meat hardens, but not very much.

When the cooking is too prolonged, the water that remains bound to the proteins is released, and the meat becomes tough. Conversely, we have often seen that, the longer the cooking, the more the rigid network of collagen is broken down. In short, the cook who roasts a turkey must find a compromise in order to break down the collagen and at the same time avoid letting the proteins dry out and toughen after they have coagulated.

COOKING CALCULATIONS.

Since it is juicy, tender meat that we want, it is clear why there is no question of opening the oven while the meat is roasting. The water vapor that is released in a limited quant.i.ty could escape and then be replaced by the vaporization of a certain quant.i.ty of the juices. Opening the oven dries out the turkey. Neither, however, should one humidify the oven before putting the turkey in. In the presence of too much water, the surface water cannot evaporate, and the skin will not get crispy.

Having thus resolved the problem of the surface, the serious problem of tenderness within remains. We cannot disappoint our guests, who fear the proverbial dryness of the Christmas turkey.

Since tenderness results necessarily from the deterioration of the connective tissue, let us consider this tissue. It princ.i.p.ally contains three kinds of proteins: collagen, already discussed many times, reticulin, and elastin. Neither reticulin or elastin are notably altered by the heat of the oven, but the triple helixes of the collagen molecules can be broken up and form gelatin, which is soft when it is in water, as we all know.

Calculating the cooking time requires some skill, because the denaturation of the collagen and the coagulation of the muscle proteins (actin and myosin, mainly) take place at different temperatures and different speeds in the different parts of the turkey. It is necessary to know that the temperature of 70 (158F) is essential for transforming the collagen into gelatin and tenderizing the muscles. But the longer the turkey remains at a high temperature, the more water it loses and the more its proteins risk coagulating. The optimal cooking time, consequently, is the minimum time it takes to attain the temperature of 70C (158F) at the center of the turkey.

Thus defined, the problem is simplified because physicists are experts on heat transmission in different materials, even animal tissues. They make their calculations a.s.suming the temperature is h.o.m.ogeneous and the animal is cylindrical, h.o.m.ogeneous, and so on, and they end up with precise if complex results involving the radius of the animal, the coefficient of the thermic diffusion, the temperature of the turkey, and the temperature of the oven.

Fortunately, there is a simpler means for calculating the cooking time for turkeys. We can apply the Fick law, which stipulates that, for the center of the turkey to attain a given temperature, the time of heating (t) is proportional to the square of the radius of the turkey. Since the ma.s.s (M) of a sphere is proportional to the cube of its radius, we can determine the cooking time by applying the simple formula t t = ( = (M/Mo)2/3to.

My friend Peter Barham, a physicist and molecular gastronomer from Bristol, has calibrated this equation and calculated the following values: * at 180C (356F), a turkey weighing five kilograms (11 pounds) must cook two hours and twenty-five minutes, and a turkey weighing seven kilograms (15.43 pounds) must cook three hours;* at 160C (320F), a turkey weighing five kilograms (11 pounds) must cook three hours and thirty-five minutes, and a turkey weighing seven kilograms (15.43 pounds) must cook four hours and thirty minutes.33 One Can Become a Cook, but One Is Born a Roaster Brillat-Savarin's aphorism paraphrases an old Latin adage: poeta nascitur, orator fit poeta nascitur, orator fit (one can become an orator, but one is born a poet). I will end this chapter by attempting to prove Brillat-Savarin wrong; to that end, let me succinctly a.n.a.lyze the cla.s.sic rules of roasting, adherence to which will allow anyone to roast as to the manner born. (one can become an orator, but one is born a poet). I will end this chapter by attempting to prove Brillat-Savarin wrong; to that end, let me succinctly a.n.a.lyze the cla.s.sic rules of roasting, adherence to which will allow anyone to roast as to the manner born.

You want to obtain meat that is just right, that is to say, nicely browned, every bit of the flesh enhanced by the cooking, and oozing with juices when carved. To retain the juices, shorten the cooking time by placing the roast in a preheated oven, as hot as possible (too hot, and the meat will char).

As in the case of stew, season the roast only after completely cooking it, a few moments before taking it off the spit or out of the oven, because, once on the meat, the salt will draw the water from it, hamper browning, and dry out the inside (through the phenomenon of osmosis). Likewise, do not add pepper until the end of cooking. Pepper, when overheated, gives meat a strong, unpleasant taste.

Lard the meat with strips of pork fat or wrap it in a caul or strips of bacon; this enhances the browning by releasing fat, which will aid the transfer of heat and protect against overheating.

Finally, remember that the only true roasting takes place on a spit, because this is the only way to ensure that all parts have equal contact with the heat. Meat in a metal pan, for example, cooks more quickly at the points of contact than elsewhere.

THE STUFFING AND THE SAUCE.

While the turkey slowly roasts, let us examine how the stuffing we have put inside it cooks.

Remember that the stuffing, placed where the temperature is lower, will have a harder time cooking than the turkey. It is especially for this reason that stuffing is often forcemeat mixed with egg. Prepared in this way, the meat filling the turkey forms one coherent ma.s.s. The 70C (158F) attained at the center at the end of the cooking time is high enough to coagulate the egg and bind the various components in the stuffing.

Additionally, in order to avoid burning the outer layer of the meat, let us baste it for about three full minutes with the melted fat (not liquid, which would soften the outside crust). This forms a screen, stopping some kinds of radiation. Sometimes the roast can be protected by covering it with paper coated with oil, but basting is more effective. Naturally, we should not begin to baste before a crisp crust has formed on the surface.

The fat that drips over the meat falls back into the bottom of the roasting pan (or, if one is using spit, into a pan set below the roast to collect the drippings), bringing with it a bit of the browned juices of the meat.34 At the end of cooking, these delicious juices are recovered in what is called a glaze. Once the pan is removed from the oven, the meat is lifted out of it, a little boiling water is poured into the pan to dissolve these juices, the mineral salts from the meat, and the gelatin that emulsifies the fat. With a little whisking, a thickened sauce with a good consistency is quickly obtained.

If the sauce does not emulsify and remains in two phases, it can easily be h.o.m.ogenized with the help of gelatin.

Finally, remember that, depending on the kind of roast, the deglazing of the dripping pan can also be done with wine, milk, diluted cream, cognac, whatever you please.

Deep-Frying Why Is It Necessary to Fry in So Much Oil?

All cooks know that frying is cooking through contact with hot oil. They know that this operation creates a golden crust, but they distrust heated oil, which spatters, makes the kitchen greasy, and produces the taste and smell of burnt fat as it gradually darkens. And that is why some physicians condemn deep-frying on dietary grounds.

The makers of household appliances have already overcome the first two inconveniences of deep-frying by inventing deep-fryers equipped with a filter and in which the operation takes place in a closed vat. Is there a way to overcome the last inconvenience, of reconciling the pleasures of deep-frying with the concerns about health or even one's figure? How to fry well? What oil to use for deep-frying?

The principle of deep-frying is simple. The heated frying pan transmits its heat to the oil, which can rise in temperature well above the 100C (212F) maximum attainable with water. Brought to these very high temperatures, the cells on the surface of the foods to be fried, in drying, produce the characteristic crispness of good deep-fried food. Have you noticed that the surface of fried food seems dry? That is because the surface moisture, brought suddenly to a temperature higher than 100C (212F), has evaporated.

How to obtain good fried foods? By using oil as hot as possible, because if the crust is not formed very quickly, the oil penetrates the food. A dramatic release of vapor bubbles from the food's surface indicates that the frying process is going well.

Moreover, the initial temperature must be increased according to the size of the food. As it heats, the food cools the oil in which it is placed. A large piece of food cools the oil more than a small piece. Since the maximal temperature of the oil is limited, a good solution for cooking a large quant.i.ty of food is to use a large quant.i.ty of oil, in which a large quant.i.ty of heat will be stored.

It would be a serious mistake to use a small amount of oil for frying on the pretext of worrying that it will saturate the food. On the contrary, the food will fry in oil that is too cool to sear it and thus will become a horrible oil sponge.

It is equally important to realize that oil cannot withstand excessive heat. Just as overheated b.u.t.ter blackens and burns, too-hot oil deteriorates. A good deep-fry cook must remember that all oils do not have the same capacity for withstanding heat.

Try this experiment. Take oil and heat it quickly. It will eventually release a strong, sharp odor and a pungent smoke. A compound called acrolein is the source of this acridity that the cook must avoid. We can now turn to the farm-produce industry, which is working to produce special oils for deep-frying, that is to say, oils that have as high as possible a smoking point.

Why Must the Deep-Fry Oil Stay Clean?

Even the best oil can only produce good fried food if it is treated with care.

We know that reused oils smoke as soon as the temperature rises even the slightest bit. They have lost their frying properties because they have gradually become full of little particles, of meat, for example, which cook at 70C (158F) and blacken above that temperature, releasing acrid compounds. Moreover, the oil itself generates compounds that further increase its degradation. The solution is imperative: if an oil must be reused, it must be filtered in order to remain clear.

This same phenomenon of protein carbonization prevents the use of b.u.t.ter, without some preparation, for deep-frying. At the temperature of 45C (113F), b.u.t.ter melts; at 100C (212F), it sputters (because the water it releases evaporates); then, at 120C (248F), it decomposes unless someone has taken the precaution of clarifying it.

Even though it is simple, clarifying b.u.t.ter is an operation lost among the household arts. What does it consist of? Eliminating the proteins (especially casein) that the b.u.t.ter contains, in order to obtain a fatty substance as pure as possible that can withstand a good heating without turning black. Decomposing at a low temperature, the proteins in b.u.t.ter darken and impart a burnt flavor at the same time that they prompt the decomposition of the b.u.t.ter's lipids.

And, say what you like, deep-frying done with the aid of a good clarified b.u.t.ter is a true gastronomic pleasure. (This same clarified b.u.t.ter will be very useful in many other preparations, such as grilling.) How to set about clarifying b.u.t.ter? It is a matter of placing the b.u.t.ter in a saucepan and heating it a long time and very gently. After about thirty minutes, the caseins precipitate. The supernatant (the clarified b.u.t.ter), which can be recovered by simply pouring it into a container where it can be stored, retains the sapid and aromatic qualities of the original b.u.t.ter.

Why Must the Food for Frying Be Dry?

We have seen that there must be an abundant quant.i.ty of frying oil, because the thermal inertia of a heated body is proportional to its ma.s.s. Cold pieces of food introduced into heated oil cool the oil less if there is a large amount of it.

Let us also not forget that the pieces of food should be cut small, if possible, so the inside has time to cook before the surface molecules begin to burn.

And, finally, let us remember that foods placed in hot oil must be dry. First of all, it would be a useless loss of heat if the oil first had to evaporate the water on the surface of the food before carrying out the actual frying. Second, one can avoid spattering fat if the foods for frying are dry. When water is suddenly immersed into oil at a temperature much higher than its vaporization temperature, it is transformed very quickly into vapor and, by expanding so violently, spatters fat everywhere.

What to Fry?

I will not launch into a tiresome list, but I do want to note that the flaky, crispy consistency, the golden color, and the characteristic flavor of fried foods are due in part to the coagulation of proteins and the caramelization of glucides (sugar and starch) over the course of the frying. That is why potatoes were predestined to be deep-fried: they consist, on the surface, of sugars and starch that are favorably transformed.

Nevertheless, the preparation of fried potatoes can go wrong when too many or too large pieces are placed in the oil. The fat (which smokes at about 190C [374F]) is cooled to 130C (266F) and remains at that temperature, so the potatoes do not cook.

For perfect french fries, place the potatoes in a large quant.i.ty of hot oil. After about five minutes, turn up the heat to increase the oil temperature, so that a crisp crust forms. Then, as soon as you remove them from the oil, blot the french fries with paper toweling. This method takes into account the pressure (yes, the pressure!) inside french fries. When measured, the pressure can be observed to increase gradually as the water in the potato evaporates as they cook. Thus a french fry has a crisp outside, some puree, and a lot of vapor inside (cutting one open will reveal this). When the french fries are taken out of the oil, the pressure decreases because of the recondensation of the vapor into water, which sucks in the oil on the potato's surface. Immediately blotting the french fries reduces the amount of oil they absorb.

For foods that do not contain glucides on the surface, bread crumbs are a good solution, since they come from flour, which is essentially composed of glucides. However, since bread crumbs will not stick to meat, for example, you must coat such foods in beaten egg before applying the bread crumbs. The egg binds the bread crumbs to the meat, and it also provides proteins that react chemically with the sugars through Maillard reactions (again!).

You can improve the process and prevent the crust that forms from coming detached by first dusting the meat with flour, then dipping it in egg, and finally applying the bread crumbs. The coagulated layer of bread crumbs will stick to the meat because of the starch that is formed. This method is even more effective if you first pierce the food with a fork. The egg and flour penetrate these holes and further anchor the fried coating to the food.

Sautes and Grills Braising with Very High Heat Strictly speaking, to saute is to cook meat, fish, or vegetables in a fatty substance over high heat, uncovered, and without adding any liquid. In practice, however, for large pieces of food especially, this first phase of cooking must be followed by more gentle cooking, in an open pan, so that the odorant molecules in the vapor can add the finis.h.i.+ng touches to the initial saute. A true saute differs from braising in that, with an uncovered pan, no vapor limits the cooking temperature. As with deep-frying, cooking takes place at a temperature higher than the 100C (212F) of boiling water.

For sautes, the fatty substance is of primary importance. To obtain good sauteed meat, vegetables, or fish, clarified b.u.t.ter is essential because, in addition to its flavor, it can withstand a temperature higher than can natural b.u.t.ter without burning. Can higher temperatures also be attained by mixing oil and unclarified b.u.t.ter? Our experiments did not confirm this old wives' tale.

For grilling as well, the cooking takes place at high temperatures, although without oil. The meat rests in direct contact with the grill. To improve the contact and transfer of heat, the meat can be brushed with a little oil or clarified b.u.t.ter.

Many culinary works claim that the superficial caramelization of the meat's proteins, in forming a crust, forms an impenetrable layer that traps the nutritive juices. (We have seen that there is no caramelization involved and there is no impenetrable layer; I will come back to this in the next section.) Additionally, books advise not to salt or p.r.i.c.k the meat so as to avoid the loss of juices. Do you recall that these same instruction were given with regard to roasts?

Good Sense Gone Wrong Adding salt is certainly to be avoided in some cases, because the phenomenon of osmosis causes the juices to escape the meat when muscular fibers are cut and open, and p.r.i.c.king the meat is harmful because it creates channels from which the juices can leak out. But the impermeable crust is a myth for which the German chemist Justus von Liebig (1803-1873) is responsible.35 In the nineteenth century, Liebig understood that heat coagulates the proteins on the meat's surface. He extrapolated, however, when he a.s.sumed that the coagulated crust trapped the juices. The idea that cooking with a hot flame can cauterize meat and limit the loss of juices, though never proven, traveled rapidly to England, then to the United States, and finally back to France, where it has reigned in error until very recently. In the nineteenth century, Liebig understood that heat coagulates the proteins on the meat's surface. He extrapolated, however, when he a.s.sumed that the coagulated crust trapped the juices. The idea that cooking with a hot flame can cauterize meat and limit the loss of juices, though never proven, traveled rapidly to England, then to the United States, and finally back to France, where it has reigned in error until very recently.

Many observations carried out by Harold McGee in Palo Alto, California, demonstrate the falseness of Liebig's hypothesis.36 First of all, a grilled steak sizzles while it cooks. That is a sign that liquid-the juices-is escaping the meat and vaporizing. The sizzle is the sound of the vapor spurting out. First of all, a grilled steak sizzles while it cooks. That is a sign that liquid-the juices-is escaping the meat and vaporizing. The sizzle is the sound of the vapor spurting out.

Second, even if the steak is removed from the pan, the plate that receives it is soon filled with juices. These juices escape the meat as soon as it is finished cooking. Thus the supposedly impermeable layer is hardly that.

Third, if the pan is deglazed with wine, for example, it is to dissolve the juices that have escaped the steak during the cooking process and caramelized deliciously.

Fourth, that vapor that is released throughout the cooking: what is it, if not the juices vaporizing?

All in all, it seems obvious that juices leave meat as it cooks, even if the surface is seared at the very beginning of the cooking process. By contracting the connective tissue that surrounds the muscle fibers, the cooking process prompts the expulsion of the meat's juices.

So how to retain the most juices possible in grilled or sauteed meat? One solution consists of not overcooking it, naturally. The less the connective tissue is contracted, the less juice is expelled. A second solution consists of cooking with high heat. In this way, the meat cooks rapidly, and the juices do not have time to escape the meat in very significant amounts. Third, salting and p.r.i.c.king the meat should be avoided, for the reasons previously shown. Finally, the grilled meat should be eaten without delay, as soon as it is cooked. In this way, the juices will not have time to leak out onto the plate.

As an aside, if a sauce is served with the grilled meat, it must be thickened a bit more than may seem necessary, because it may be diluted by the juices that will inevitably leave the meat and run out onto the plate.

Even More Tender Between Tough and Putrid Very fresh meat is tender, but fresh meat is tough; gradually it becomes tender again, and then it rots. How to conserve it in that precarious state in which it does not require excessive chewing but neither does it release an unbearable odor, revealing an unhealthy degree of putrefaction? Our ancestors invented many processes for long-term conservation: smoking, salting, drying. But today's cooks can get meat anytime at all from the neighborhood butcher, who sells cuts that are aged for exactly the right amount of time. They no longer have to solve the problems of long-term conservation. Beginning with products aged under supervision, their chief goal is to obtain meat that will be tender after cooking.

Our consideration of stews showed us the importance of lengthy cooking in a liquid, in order to break down the collagen fibers that toughen meat. Other processes produce the same result. Hanging, marinating, and "proteasizing" are appealing for reasons it would be a shame to overlook.

By the Neck or by the Beak?

Let us read Brillat-Savarin: Above all other feathered game should come the pheasant, but once again few mortal men know how to present it at its best.A pheasant eaten within a week after its death is more worthless than a partridge or pullet, because its real merit consists in its heightening flavor.37 How can we attain the summits reached by the master? Ask all around. You will hear that hanging game is an abominable operation, that our forefathers ate putrid meat, that, after being suspended by its neck, the pheasant was consumed when it fell, its head detaching from its body because of rotting. Is that the last word on the subject? Would we be here today if our ancestors willingly poisoned themselves on rotten pheasant? And who among us has seen, with his own eyes, the hanging of a pheasant by its head?

Bibliographic research has shown me that hanging pheasant does not follow any absolute rule but that good sense is essential. First of all, yesterday's great cooks did not recommend hanging pheasant by the neck, or even by the beak, but by the tail feathers. Being generally a heavy bird, a pheasant falls well before it rots.

A second precept is that the animal must be hung with its feathers still on, which protects it from insects and other small pests who would threaten our feast. Finally, the length of the hanging depends on the temperature and the weather. Just as we see fish turn when they are not cleaned and there is a storm, a pheasant can only hang for two or three days when the air is humid but can remain in a cool draft for six days when the weather allows. Supposedly, during this operation, a special juice that is present in the shaft of the feathers is reabsorbed into the flesh. This claim deserves an experimental study.

Brillat-Savarin, whose colleagues, it is said, took offense at the odor of hung meat that accompanied him (supposedly he put pheasants in his pockets to age them), wrote that "the pheasant is an enigma whose secret meaning is known only to the initiate."38 How to become an initiate? How to cook a pheasant with the attentive care necessary to take it to the point where it surpa.s.ses a good chicken? How to become an initiate? How to cook a pheasant with the attentive care necessary to take it to the point where it surpa.s.ses a good chicken?

According to Grimod de la Reyniere, "the pheasant is done on a skewer, wrapped in paper, well b.u.t.tered. The paper is then removed to give it good color; then it is served in a verjuice sauce, with pepper and salt." Today, instead of the verjuice, made from unripe grapes, a slice of lemon, salt, and pepper can be subst.i.tuted.

How Many Days for Marinades?

If hanging is good for pheasant and its feathered cousins, marinade is more suitable for large, furry beasts, like wild boar (which is often tough), mutton, and beef.

The process is simple. The meat rests in a mixture of wine, oil, vinegar, spices, various condiments, and a few vegetables (this mixture can be cooked beforehand). With time, the meat becomes tender and flavorful. Subsequent cooking completes the dish, be it grilling, roasting, cooking it in the marinade itself, in short, whatever you prefer.

What are the princ.i.p.al elements for a marinade? Vinegar, flavors, time.

Vinegar is an acid that attacks the connective tissue and breaks it down. That is one reason it was thought that the meat gets tender, but not the main reason. From our laboratory experiments, we concluded that meat becomes tender in a marinade because, while it is protected from putrefaction, the muscular fibers age and protein aggregates are slowly dissociated, just as when butchers age meat in their special refrigerators. Previously, we had thought that tenderization occurred where the flesh had been in contact with the marinade. But our more recent experiments have shown that a marinating solution penetrates meat to a much more limited extent than our model systems had suggested, in which this diffusion occurred at the rate of about ten millimeters per day.

Other experiments, more culinary in nature, lead to impressive results. A marinated roast pork can be taken for a leg of very young wild boar; marinated mutton can pa.s.s for venison.

Whether you wish to fool your guests or not, serve marinated meats with red currant jelly: it's delicious!

Pineapple Power Having explored various methods of tenderizing meat, my esteemed friend Nicholas Kurti, whom I have already mentioned, during a March 14, 1969, meeting of the Royal Inst.i.tution to which the BBC had been invited, demonstrated that an injection of fresh pineapple juice into a pork roast resulted in absolute tenderization.

Another English fad? Not entirely, because first, although Nicholas Kurti was a professor of physics at Oxford and a member of the very old and venerable Royal Society of London, he was Hungarian by origin. A longtime record holder for the lowest temperature ever reached (a millionth of a degree below absolute zero, that is, about 273 degrees below the temperature at which water freezes), Nicholas Kurti was a pa.s.sionate cook. With his public experiment, he wanted to demonstrate the power of the enzymes in pineapple juice and confirm experimentally a method extolled by the Aztecs.

Enzymes are molecules that promote various reactions in live bodies. They are found in all living cells and notably in fresh pineapple, papaya, and fig juice, among other plant products. The specific enzymes found in pineapple, papaya, and fig (bromelain, papain, and ficin, respectively) have one peculiarity: they are proteolytic, that is, they break down proteins. Now, meat, as we have seen on several occasions, is composed of many proteins; collagen, especially, responsible for meat's toughness, is a protein.

Nicholas Kurti demonstrated how to put the useful properties of these enzymes to work in preparing meat. He squeezed a fresh pineapple, placed the juice in a hypodermic syringe, and injected the pineapple juice into a pork roast (in just one-half in order to compare the results of the enzyme action). He let the roast rest for a few minutes, so that the enzymes would have time to react. Then he put the roast in the oven and let it cook for less time than necessary to cook the untreated half thoroughly.

Taking the roast out of the oven, he cut it into slices. The half that had not received the pineapple juice was still the pink color characteristic of undercooked pork, even though the meat was covered with a crisp crust. By contrast, the meat on the other side was almost reduced to puree. Naturally, the meat had a distinct pineapple taste, but isn't there a recipe for pork with pineapple?

Medicine and Cooking "From your foods, you will make your medicine," said Hippocrates. While we wait for modern medical nutritionists to define for us the perfect foods to ensure our health and longevity, let us borrow one of their instruments: the syringe.

This tool, used by Nicolas Kurti for his pineapple juice injection, can also improve the marinating process.39 While the meat marinates, draw off the marinade at regular intervals and use the syringe to inject it into the meat. The results are superb because the marinade works from the inside out, and the preparation time can thus be shortened. While the meat marinates, draw off the marinade at regular intervals and use the syringe to inject it into the meat. The results are superb because the marinade works from the inside out, and the preparation time can thus be shortened.

In addition, a number of cookbooks mention that marinated meat must not be roasted, for fear of drying it out. That is correct, according to my experience, but by injecting the marinade into the center of the meat, you can avoid that danger.