A Taste of Molecules

In Search of the Secrets of Flavor

Diane Fresquez

• Publisher: The Feminist Press at CUNY
• Year: 2013
• ISBN:
  9781558618404
• Topic: Política y relaciones internacionales
• Subtopic: Política agrícola pública

A delicious exploration of what creates the flavors we love—and why our taste buds respond to them—in a fascinating, "very pleasant and easy read" ( Flanders Today ). In this unique scientific study of food, drink, and how the human taste buds sense taste, food journalist Diane Fresquez brings readers along on a journey of gastronomic discovery. She begins by following a Belgian beekeeper who uses science to give the ancient drink of mead (or "honey wine") a modern taste-makeover. Fresquez then travels to Holland to learn how food memories are tested at a research center called the Restaurant of the Future. And elsewhere, she discovers how much skill it takes to make banana flavor in the lab, and experiments on a group of scientists during a surprise meal eaten in the dark. Stuffed with fascinating food facts, anecdotes from the author's own culinary life, and a selection of irresistible recipes (including a cocktail with dancing molecules), A Taste of Molecules is an exploration of the senses that will delight foodies andscience enthusiasts alike.

II. HIDING AND SEEKING FLAVOR

LICORICE ON THE INSIDE

But, as a general rule, we are bound to advise all mothers to abstain from such articles as pickles, fruits, cucumbers, and all acid and slowly digestible foods, unless they wish for restless nights and crying infants.

ISABELLA BEETON, MRS. BEETON’S HOUSEHOLD MANAGEMENT, 1861

Flavor is like oxygen: because we have endless supplies of it, we sometimes take it for granted. Without oxygen, we would die; without the ability to smell and taste, we might also end up in a bad state by losing our desire to eat, or by eating poisonous or spoiled food. But where does our lifelong companionable relationship with flavor begin? To find the answer, I flew to Copenhagen, then took a train to the small Danish town of Hillerød, in the North Zealand region. It was a breezy, damp morning, and I was met at the little station in town by two fair-haired Danish beauties: Helene Hausner, a thirty-one-year-old doctoral student at the University of Copenhagen in the Department of Food Science, who greeted me with a dazzling smile, and Selma, her four-month-old daughter who was bundled up in a pram. I had come to learn about Helene’s research into the complicated subject of how what a mother eats influences the flavor of her breast milk.

From the station it was a short walk to the center of town where we stopped outside a café facing a picturesque lake, in the center of which stood the Frederiksborg Castle, spread across three small islands. With slender spires, aqua-colored copper roofs and a Baroque garden, it was as fetching as any fairytale princess’s castle. Built by King Christian IV, with construction lasting from 1600 to 1620, it was severely damaged by fire in 1859 and was eventually rescued by beer. The founder of the Carlsberg Breweries, J.C. Jacobsen, financed the castle’s restoration on condition that it be turned into a museum, and in 1878 it became the Museum of National History.

Carlsberg Breweries was also the birthplace of one of the most familiar, universal science tools ever developed: the pH scale, the standard measurement of acidity, developed in 1909 by the head of Carlsberg Laboratory’s Chemical Department, Dr. Søren Sørensen.

Settled in the café, Helene and I each ordered a milky coffee and Selma alternated between breastfeeding and sitting in her mother’s lap, where, with the aid of soft toys, she became absorbed in honing her hand-eye coordination skills. Helene had spent four years studying sensory science and human nutrition, with a research focus on human eating behaviors. I had come to Denmark to visit her because of an article she had published in Physiology & Behavior in 2008, based on her study of how flavor molecules travel through the digestive systems of lactating mothers and into their breast milk. It was a flavor-to-milk journey that, up to that point, had not been studied much by scientists.

“I was surprised there’s so little knowledge about how flavor compounds act in the body,” she said.

In many cultures it is a common belief that some types of food eaten by breastfeeding mothers can affect their milk—that eating spicy food, for example, can give a baby an upset stomach. In Denmark, the two big forbidden foods for nursing mothers are chocolate and strawberries. Even doctors advise new mothers against eating them, as susceptible to old wives’ tales as anyone. But after her flavor in breast milk research, Helene felt confident that nursing mothers could disregard this deeply rooted Danish belief.

In her study, Helene explored how caraway, licorice, banana and mint flavors were transferred from mothers’ digestive systems into their milk. Her subjects were eighteen lactating women who ranged from twenty-three to thirty-five years old. They were healthy nonsmokers who didn’t take medications or suffer from food allergies.

The data-gathering part of the study was completed over the course of three days during which milk samples were collected by the mothers two, four, six, and eight hours after they had swallowed four different flavor capsules after lunch. One capsule contained 100 mg of d-carvone (caraway flavor), one was l-menthol (mint flavor), one was 3-methylbutyl acetate (banana flavor), and one was transanethole (licorice flavor). The flavors were pure chemical compounds that had been prepared at the university’s pharmacy and encapsulated in gelatin capsules. (I thought of Xavier and the possibility that if agar didn’t work out to encapsulate drops of honey and mead, he could try gelatin.) Like Eves in the Garden of Eden, the mothers were allowed to eat anything they desired over the course of the three days, with the exception of caraway, mint, banana and licorice. One of the mothers, however, accidentally ate some cereal that contained dried banana, and she was soon eaten up with worry. But Helene (who thought all of the mothers in the study were terribly conscientious) simply didn’t use this mother’s milk on the day of the banana-in-cereal incident.

Although the study may sound straightforward, there was a lot going on at the molecular level. There were many factors involved, such as the way chemicals can either bond with or repel water, and the fat content of the mother’s milk. Much of this was a mystery, even to Helene. According to her article, “the absorption, storage and excretion of flavor compounds in the human body are complex processes that are poorly understood.” I personally found some of the flavor choices used in the experiment a bit bizarre—caraway and licorice, in my mind, are not flavors commonly liked by everyone—but they are widely enjoyed in Denmark. The flavors were chosen by Helene, not for their popularity, but because they represented different, basic molecular structures and are associated with a range of foods we eat—fruits, vegetables, candy and spices.

The results of her study showed that the licorice and the caraway flavors in the breast milk peaked approximately two hours after the capsules were eaten. Of these two, the licorice concentration was the highest—although it was actually only present in very low amounts. The mint flavor never peaked, but was present in fairly stable levels in the milk for up to eight hours. The big loser was the banana flavor, which couldn’t be detected in any of the milk samples. But although the banana didn’t show up in the milk, it did turn up some place else, and was the cause of the only side effect and complaint the mothers had about the study. They spent three days belching banana-flavored burps, all for the advancement of science.

According to Helene’s article, there are several reasons why the banana flavor molecules may not have shown up in the breast milk. “First, the compound is rather volatile and was more difficult to dose accurately in the subjects. Second, the ester may have been hydrolyzed [broken down] in the acidic stomach environment . . . A third possibility is that the compound peaks before the two hour sampling.”

Helene went back to the drawing board to determine whether the banana compound, indeed, peaked before two hours. And for this she asked an additional mother—a lactating friend of hers, not part of the original study—to ingest a capsule containing 100 mg of the banana flavor compound, and then collect milk samples one and two hours afterwards. In this case, Helene found small traces of the banana flavor in the milk samples. Her conclusion after this small, single-mother experiment was that fruit esters in general are transferred to mother’s milk almost immediately after eating, but in extremely low amounts.

“There’s hardly a chance a baby could detect the banana flavor,” Helene said.

Helene’s study confirmed the transfer of volatile flavors from a mother’s diet to her breast milk; the flavors were, however, “transferred selectively and in relatively low amounts.” To Helene, the big surprise was not that the flavors did, indeed, end up in the breast milk, or that the amounts differed depending on the flavor—but that there were so many differences in flavor quantity throughout the course of the three days in each individual woman’s milk. According to Helene, this suggests that each woman’s milk is “a continually varying flavor medium.”

In Helene’s study, she notes that another study showed that “infants whose mothers drank carrot juice during pregnancy or breastfeeding preferred carrot flavored cereals above water-based cereals.” Yet another study seemed to show that bottle-fed babies are not as easily weaned as breastfed—implying that the bottle-fed ones were not as open to new flavors as the breast-fed, but that after they got used to the flavors, they were fine. As a scientist and experienced mother, Helene came to the conclusion that the food flavors that appear in breast milk in relatively low amounts possibly aid weaning—“Flavors in breast milk are a clever way for nature to help facilitate the introduction of weaning foods,” she said—but are not the cause of any stomach upset in babies.

Although Helene originally met with some indifference when she applied for a grant for her study, it was eventually funded by the University of Copenhagen and her completed research created quite a buzz in the media. From a small article in New Scientist, a popular British science magazine, it was picked up by British newspapers, the BBC, and media as far as the Czech Republic and the United States. But although getting publicity was good, Helene was amazed by how many times her findings were manipulated and misquoted. One article in the British press reported that “nursing mothers have been shown to produce the human equivalent of a banana milkshake from their breasts.” Another UK article included a photo that showed a close-up of a woman’s large breasts, covered by a snug, low-cut outfit, but with no face to go with them. More appropriate for the Garden of Earthly Delights than as an illustration for a science article.

Helene never stopped talking to journalists, however, and was able to explain the study herself many times on Danish radio. When I met her, she had recently appeared on a Danish morning news program where she encouraged breast feeding mothers to eat as many different foods as possible.

Helene and I left the café to stroll through town toward the castle, where we were to have lunch. Along the way, she described her love of food as springing from sweet memories of the meals she had eaten at her grandmother’s farm in Jutland, the northern tip of Denmark. Jutland is also the location of Babette’s Feast, that gentle story (and film) of food and memory by Isak Dinesen. The pattern and caloric intake of a day of eating at Helene’s grandmother’s farm was based on a more active, outdoorsy life than many of us have now, and went something like this: Breakfast, mid-morning cake, lunch, mid-afternoon cake, dinner—finished off with cake. The love of food runs in Helene’s family; she has three cousins who are chefs and an aunt who works in the dairy industry. But from an early age, Helene was more interested in science.

“I wasn’t sitting around conducting experiments—but I was curious,” she said.

That curiosity, the desire for puzzle-solving, had also manifested itself in her love of orienteering, a popular Scandinavian sport that combines cross-country running with navigation. She was serious about it for many years, and was a member of the Danish national team from 1998-2006. Orienteering is both a mental and physical endurance sport. Runners navigate with a compass, as well as a map provided by the organizers—there is no marked route to follow. The map shows hills, ground surface, and features such as boulders or cliffs, as well as the control points where the runners check in.

“Sometimes you don’t want to take the trickiest route, even though it’s shorter, because you might make mistakes if you’re tired,” she explained. “In the forest—everything is unknown,” she said.

It seems perfectly natural that this love of finding her own way is linked to scientific inquiry. “People think scientists are in the lab all of the time,” she said, but for her an enjoyable part of her study was being able to meet a group of nursing mothers and spend time with them, even when she had to drive two hours each way, in one case, to collect the milk samples.

Helene and I arrived at the restaurant, the Leonora, located in the former stables of the castle and named after King Christian IV’s daughter. It was a serene place that combined old-world formality with crisp, modern simplicity. To begin our meal, we shared a plate of dainty herring from the tiny Danish island of Christiansø, with which we made our own little open-faced sandwiches of dark brown rye bread topped off with fish, minced onion, capers and crème fraîche. I guessed that the herring had been marinated with cloves which the waiter confirmed, but he couldn’t tell us more, saying that the recipe was a secret known only to a couple of families on the miniscule island.

“I guess the clove will go into my milk, but I’m not sure if Selma will be able to taste it,” said Helene.

We talked about Danish culture for a moment, and Helene tried to explain to me how important the concept of hygge (pronounced like who-ga, and translated loosely as “coziness”) is to Danes. She searched for a good example, and looked around at another table where a group of diners were eating and talking intimately. Their table, like ours, was lit by a large ivory-colored candle. It was breezy and damp outside, but they—and we—were snug, chatting softly and feeding contentedly. A perfect specimen of hygge, which in Denmark is often enhanced by firelight or candlelight.

“Having a cup of tea with friends on a cold day—that’s hygge,” said Helene, trying to make sure I had grasped the important concept. It was, I thought, like those cozy tea and cake moments Proust and his invalid aunt shared on Sunday morning...

Table of contents

• Front Cover
• Title page
• Copyright page
• Dedication
• Contents
• I. Taste Uncorked
• II. Hiding and Seeking Flavor
• III. The Taste Buds in Your Brain
• IV. Scents and Sensibility
• V. Recipes
• Acknowledgments
• About the Author
• About the Feminist Press
• Also Available From the Feminist Press