Why Does Asparagus Make Your Pee Smell? by Andy Brunning

0958a999d2e5819-261x361.jpg Author Andy Brunning
Isbn 9781612435510
File size 13MB
Year 2016
Pages 128
Language English
File format PDF
Category chemistry


Why Does Asparagus Make Your Pee Smell? Fascinating food trivia explained with science Andy Brunning Copyright © 2016 Andy Brunning. All rights reserved. Any unauthorized duplication in whole or in part or dissemination of this edition by any means (including but not limited to photocopying, electronic devices, digital versions and the Internet) will be prosecuted to the fullest extent of the law. Published in the US by ULYSSES PRESS P.O. Box 3440 Berkeley, CA 94703 www.ulyssespress.com First published as Why Does Asparagus Make Your Wee Smell? in Great Britain in 2015 by Orion, an imprint of the Orion Publishing Group Ltd., an Hachette UK Company ISBN: 978-1-61243-551-0 Library of Congress Control Number: 2015952141 10 9 8 7 6 5 4 3 2 1 Printed in Korea by WE SP through Four Colour Print Group US editor: Alice Riegert Design concept by Grade Design Cover design by what!design @ whatweb.com Cover photos from Shutterstock.com: asparagus © ksulee; beer © Serhiy Shullye; bacon © Joe Belanger; © GMEVIPHOTO; red onion © Amero; red hot pepper © Timmary; abstract background © Tusiy Interior photo credits: see page 143 Distributed by Publishers Group West IMPORTANT NOTE TO READERS: This book is independently authored and published and no sponsorship or endorsement of this book by, and no affiliation with, any trademarked brands or other products mentioned or pictured within is claimed or suggested. All trademarks that appear in ingredient lists, photographs and elsewhere in this book belong to their respective owners and are used here for informational purposes only. The authors and publishers encourage readers to patronize the quality brands mentioned and pictured in this book. To Anna, for her continued support and enthusiasm throughout the creation of this book. CONTENTS 7 Introduction 8 A Brief Introduction to Organic Chemistry 9 Functional Groups in Organic Chemistry Flavor 13 14 17 18 21 22 25 26 29 30 Why Do Some People Hate Brussels Sprouts? Why Do Artichokes Make Drinks Taste Sweeter? How Do Miracle Berries Make Sour Foods Taste Sweet? Why Does Orange Juice Taste Bitter After Brushing Your Teeth? Why Does Smoking Meat Change Its Flavor? What Causes the Sour Taste of Spoiled Milk? Why Does Cilantro Taste Soapy to Some People? What Do Dill and Spearmint Have in Common? What Causes the Bitterness of Coffee? What Causes the Bitterness and Taste of Beer? Color 51 52 55 56 58 61 Poison 65 66 69 70 73 74 76 Aroma 34 37 38 41 42 45 46 Why Does Garlic Give You Bad Breath? Why Does Asparagus Make Your Pee Smell? Why Does Durian Fruit Smell So Bad? Why Does Bacon Smell So Good? What Causes the Smell of Fish? What Causes Blue Cheese to Smell So Strong? Why Do Beans Make You Fart? Can Carrots Help You See in the Dark? Why Do Beets Turn Urine Red? Why Do Potatoes Turn Green? Why Do Avocados Go Brown So Quickly? Why Are Salmon and Prawns Pink? Why Does Tonic Water Glow under a Black Light? Why Are Raw Kidney Beans Poisonous? Why Are Some Mushrooms Poisonous? Do Apple Seeds Really Contain Cyanide? What Causes Shellfish Poisoning? Why Is Eating Pufferfish a Risky Move? Why Is Chocolate Poisonous to Dogs? Can Mixing Drinks make Your Hangover Worse? Sensation 81 82 85 86 88 Why Do Onions Make You Cry? What Makes Chilies Spicy? Why Does Mint Make Your Mouth Feel Cold? How Does Pop Rocks® Candy Work? What Causes the Pungency of Wasabi? Mind 93 95 96 99 100 Does Eating Turkey Make You Sleepy? Why Can Nutmeg Act as a Hallucinogen? Why Do the Stimulant Effects of Tea and Coffee Differ? Does Drinking Absinthe Cause Hallucinations? How Do Energy Drinks Work? Health 105 106 109 110 113 114 117 118 Why Can’t You Eat Grapefruit with Some Medications? Why Do Lemons Help Prevent Scurvy? Why Are Some People Allergic to Nuts? Can a Tick Bite Make You Allergic to Meat? Why Can Clove Oil Be Used as an Antiseptic? Does MSG Cause “Chinese Restaurant Syndrome”? Why Are Sweeteners Sometimes Used in Place of Sugar? What Are Sulfites And Why Are They in Alcoholic Drinks? Transformation 123 Do Bananas Help Other Fruit Ripen Quicker? 124 Why Does Adding Some Fruits to Jelly Stop It from Setting? 127 Why Does Whipping Cream Make It Thicker? 128 Should You Keep Chocolate in the Fridge? 131 Why Are Beer Bottles Usually Made with Darkened Glass? 132 What Chemical Compounds Make Jams Set? 134 What Causes the Bitterness and Dry Sensation in Red Wine? 137 How Do Bubbles Enhance the Taste of Champagne? 138 References 143 Photo Credits 144 Acknowledgments Food plays a huge part in our everyday lives, but we hardly ever stop to think about the science behind it. We all know that chopping onions makes you cry, that eating garlic gives you bad breath and that mint makes your mouth feel cool, but most people don’t have a clue how to describe the chemical reasons behind these strange effects. The aim of this book is to look at the quirky and sometimes downright weird properties that food and drink can exhibit, and explain in simple terms the chemistry that leads to them. In our explanations, we’re going to be talking primarily about organic chemistry. This use of the word “organic” is different from the one that we usually associate with food in supermarkets; in chemistry, it refers to chemical compounds based on carbon. There are many millions of possible organic compounds, with a wide range of different properties. You, yourself, are made up of organic compounds, and so are the foods we eat. These compounds are responsible for the flavor and aroma of the foods and drinks we consume on a daily basis, and can also help explain some of the different effects that we see. INTRODUCTION INTRODUCTION The hope is that the material in this book will be accessible even to those who only have a basic understanding of chemistry. There is a brief introduction on the next page to some of the chemistry, to help with interpretation of the structures and descriptions later in the book. If you do have a background in chemistry, and want to read in further detail on some of the topics examined here, references to the studies consulted during the writing of this book are also given at the end. Whatever your interests or curiosities, I hope that the chemistry in this book will turn the everyday into the extraordinary for you. 7 INTRODUCTION A BRIEF INTRODUCTION TO ORGANIC CHEMISTRY 6 1 C 7 H Carbon Hydrogen N Nitrogen H H H C H H C H H H 8 16 Oxygen Sulfur O S 17 Cl Chlorine Organic chemistry is the study of carbon-based compounds. Organic compounds usually contain primarily carbon and hydrogen, but we’ll also see some containing the other elements shown here. The chemical bonds in organic compounds are formed by the atoms sharing a pair of electrons with each other. Carbon can form four bonds to other atoms; oxygen usually forms two bonds, while hydrogen can only form one bond. Bonds are shown as lines; two lines between atoms indicates a double bond, or two shared pairs of electrons. METHANE H H H H H C C OH H C C OH H H H H Displayed formula == OH OH Skeletal formula O O Carbon atoms Dashed bond (into page) HO HO 8 Wedged bond (out of page) Organic compounds can be drawn showing all their bonds and all their atoms, as on the left. However, for bigger molecules, this can end up looking pretty messy so we commonly use the skeletal formula to represent molecules. The skeletal formulas show each carbon atom as a bend in the chain of the molecule. Hydrogen atoms attached to carbons aren’t shown, to make the structure easier to interpret. Atoms other than carbon and hydrogen are shown. While chemical structures are shown in two dimensions on the page, obviously they are three dimensional in real life. In some cases, it is useful to indicate this in structures, so for this purpose we sometimes use dashed bonds, to show a bond going away from you and into the page, and wedged bonds, to show a bond coming toward you and off of the page. Functional groups are groups of atoms in organic compounds that are responsible for the characteristic reactions and properties of those compounds. In many compounds in this book, you will see several of these groups in one molecule. The functional groups present in a molecule are usually reflected in its name, as indicated here. introduction Functional Groups in Organic Chemistry You may also see “R” used in some molecules—this represents a further part of the molecule that may be variable. If you see “X” used, it indicates a halogen atom (the halogens are the elements fluorine, chlorine, bromine and iodine). Some typical functional groups are shown here. H H R1 C C R2 H H ALKANE Naming: -ane e.g., ethane R1 R3 C C R4 ALKeNE Naming: -ene e.g., ethene O R1 C R2 O ALCOHOL Naming: -ol e.g., ethanol KETONE Naming: -one e.g., propanone R C X haloalkane Naming: haloe.g., chloroethane R C H ALDEHYDE Naming: -al e.g., ethanal O O R2 R R OH OH CARBOXYLIC ACID R C NH2 AMIDE Naming: -oic acid Naming: -amide e.g., ethanoic acid e.g., ethanamide R NH2 AMINE R ARENE Naming: -amine Naming: -ylbenzene e.g., ethanamine e.g., ethylbenzene 9 Flavor FlaVor O S N H NH NH2 N H S S N C R PHENYLTHIOCARBAMIDE PROPYLTHIOURACIL ISOTHIOCYANATEs (PTC) (PROP) Metabolism product of glucosinolates PTC TASTES BITTER TO 70% OF PEOPLE It’s thought that cruciferous vegetables can induce a similar eff ect, as their breakdown products, isothiocyanates, are chemically similar. EXAMPLES OF CRUCIFEROUS VEGETABLES OH HO HO SPROUTS BROCCOLI CABBAGE CAULIFLOWER Brussels sprouts generally have higher levels of glucosinolates compared to other cruciferous vegetables 12 O OH O N S R GLUCOSINOLATES O OH S O Found in all cruciferous vegetables (R group varies) There’s one vegetable at the Christmas dinner table that’s always bound to elicit strong and contrary opinions: brussels sprouts. Much like black licorice, they seem to conjure up a “love it or hate it” sentiment; however, if you fall into the latter camp there may be a chemical and genetic reason why you can’t stand the taste. Before discussing brussels sprouts specifically, we actually need to look at a chemical that isn’t even found in them, phenylthiocarbamide (PTC). This compound is an oddity in that it tastes bitter—but only to around 70 percent of people. To the other 30 percent it’s completely tasteless. This property of PTC was discovered by accident in 1931, when Arthur Fox, a chemist working for the chemical company DuPont, accidentally spilled some of the compound while he was working with it. His colleague working nearby complained of the bitter taste, but Fox couldn’t detect it. Fox went on to carry a series of taste tests with his friends and family, further confirming that it tasted bitter to some, but not all. These studies, along with further work, confirmed the ability to taste PTC as a dominant genetic trait, and one that can be inherited. Before the advent of readily available DNA testing, the ability to taste PTC was commonly used in paternity cases. Another compound, propylthiouracil (PROP), is similar in that it also tastes bitter to some and not others, and is now the more commonly used compound in taste research. FLAVOR WHY DO SOME PEOPLE HATE BRUSSELS SPROUTS? At this point, you’re probably wondering what this has to do with brussels sprouts. While PTC and PROP aren’t found in vegetables, they contain a thiocyanate group (nitrogen, carbon and sulfur bonded in series) which is thought to be related to its bitter taste. This same group is also present in compounds called glucosinolates that occur naturally in brussels sprouts, as well as broccoli, cabbage and kale (collectively known as cruciferous vegetables). There also seems to be a strong association between the ability to detect the bitter taste of PROP and a sensitivity to the bitterness of these vegetables. It’s not the case that sensitivity to PTC and PROP automatically implies a dislike of cruciferous vegetables; other environmental factors may also have an effect. However, if you’re a brussels sprout hater and you are berated for your perceived vegetable prejudice, you can now suggest a chemical reason for your dislike. 13 FLAVOR WHY DO ARTICHOKES MAKE DRINKS TASTE SWEETER? Artichokes have an unusual claim to fame—they’re the only known plants consumed on a large scale across the world that have taste-modifying properties. To some people it can cause drinks to taste sweeter straight after eating it, which apparently causes great difficulty when pairing dishes containing artichokes with wine. This effect comes down to particular chemical constituents contained within artichokes. This strange effect was first noted in research at an American Association for the Advancement of Science dinner. Artichokes were included in one of the courses, and after it was said that 60 percent of the 250 people attending reported that the water being served tasted sweeter. Decades later, a researcher investigated this effect by exposing subjects to artichoke extract, as well as individual constituents of the extract, and recording the perceived impact on the taste of water. It was found that, of the constituent compounds in artichokes, potassium salts of chlorogenic acids and cynarin were major 14 causes of the effect. Potassium ions are the dominant metal ions present in artichokes, hence why potassium salts of the compounds were used. Cynarin in particular was found to have a sweetening effect equivalent to adding two teaspoons of sugar to ¾ of a cup (170 milliliters) of water. That said, although these compounds were found to be the major sources, they still didn’t account for the full effect of artichoke, so other, lesser compounds may also be implicated. We still don’t know exactly how these compounds cause other substances to taste sweeter, but we do know it’s a result of them interacting with sweet-detecting taste buds on the tongue in such a way that non-sweet substances taste sweet. It also doesn’t affect everyone, as the survey taken at the dinner which initially highlighted the effect showed—it’s assumed that there must be some form of genetic basis to the effect. So, the next time you get a chance, why not try eating an artichoke and see if it works for you? OH HO O HO O OH HO HO FLAVOR APPROX. 60% Estimated percentage of the population who experience the sweetening effect of artichokes O CHLOROGENIC ACID artichoke CYNARIN OH Major compound that affects sweetness OH O HO HO HO O O OH OH O THE COMPOUNDS IN ARTICHOKES HAVE A SIMILAR SWEETENING EFFECT ON TASTE BUDS TO ADDING TWO TEASPOONS OF SUGAR TO ¾ cup OF WATER 15 FlaVor HOW MIRACULIN WORKS 191 NUMBER OF AMINO ACIDS THAT MAKE UP THE MIRACULIN PROTEIN Binds to sweet taste receptors 1725 First documentation by explorer Chevalier des Marchais while exploring West Africa. Modifies sweet receptors to be activated by acids The effect lasts 1–2 hours A BRIEF HISTORY OF MIRACULIN 1968 miracle berry 1974 MIRACULIN IN OTHER PLANTS Areas in which miracle fruit can be grown are limited due to its tropical origins. Scientists have attempted to produce miraculin in other plants, with mixed success rates. Robert Harvey’s hope to market miraculin as a sweetener is thwarted by the FDA, who deem it can’t be classified as “generally recognized as safe.” Miraculin successfully isolated from miracle fruit by Professor Kenzo Kurihara. 1989 Miraculin purified and sequenced by Professor Kurihara’s group. 2006 STRAWBERRY 16 TOMATO LETTUCE Researchers find that miraculin improves insulin sensitivity in diabetics. 2012 Miraculin piloted as a taste-masking agent for chemotherapy drugs. Miracle berries (Synsepalum dulcificum) grow on a shrub native to West Africa, and have curious taste-modifying abilities. After chewing the fruit, it can make sour food and drink taste sweet for up to an hour after. For example, eating miracle berries before drinking lemon juice removes the sourness completely. This effect is due to the presence of a particular protein which is only found in miracle berries, named miraculin. As a protein, miraculin has a very large molecular structure— too large to be shown here. To give an idea of its size, it’s made up of 191 amino acids, amino acids being the molecular building blocks of proteins. The molecule isn’t sweet by itself, and we actually still don’t fully understand how it produces its taste-altering effect. Your tongue is covered in receptors capable of detecting different tastes, and what we do know is that miraculin can bind to the taste receptors that detect sweetness very strongly. Then, when you eat or drink something sour, it can react with the miraculin. This reaction has a knock-on effect, causing the shape of the sweet taste receptors to distort. This distortion makes them much more sensitive, and the signals they relay to the brain overpower those of the sour tastes, causing you to experience a sweet taste even with sour foods. This lasts until the miraculin is eventually uncoupled from the receptors. FLAVOR HOW DO MIRACLE BERRIES MAKE SOUR FOODS TASTE SWEET? While this effect might seem like nothing more than a curiosity, food scientists have for many years been looking at ways in which miraculin could potentially be used as a sweetener. There are a number of problems to overcome—first, miraculin isn’t heat stable, and above 212° F (100°C) it loses its taste-altering properties, so it isn’t possible for it to be used in any foods that require cooking. Another problem is the duration of its effect, though scientists have succeeded in creating a version of the protein whose effect is much shorter lived, which could make its use much easier. The FDA (Food and Drug Administration) has ruled that miraculin is an additive, and cannot be given the status of “generally recognized as safe,” meaning it will likely require several years of testing before it can be included in food products. 17 FLAVOR WHY DOES ORANGE JUICE TASTE BITTER AFTER BRUSHING YOUR TEETH? Most people have probably made the mistake of drinking orange juice immediately after brushing their teeth. The effect generated isn’t a pleasant one—the resulting taste is bitter, with none of the original sweetness of orange juice. Research suggests that this effect can last up to 30 minutes after the use of toothpaste, and it can also be subtly noticed with other foods. The root of the effect can be found in one of the chemical constituents of toothpaste. Sodium lauryl sulfate is a compound commonly used in personal care products, including toothpaste, shampoo and shower gel. It acts as what chemists call a “surfactant.” Essentially, the molecule has one end which will dissolve in water and one end which is insoluble in water, but soluble in grease and oils. This helps it dissolve and remove dirt when you wash your hair. It also stimulates foaming; in toothpaste, it lowers the surface tension of saliva, allowing a foam to form. Sodium laureth sulfate is a chemical commonly used instead of sodium lauryl sulfate, but it performs exactly the same role. Some rumors have falsely claimed that these chemicals are cancer 18 causing, but there is scientific evidence that they are completely safe at the concentrations we usually encounter. The presence of sodium lauryl sulfate (or its alternative) in toothpaste is thought to be the cause of its effect on the taste of orange juice. The commonly accepted explanation for this effect is that sodium lauryl sulfate suppresses the receptors in your mouth that help you detect sweetness. At the same time, it’s also thought they can alter membranes formed by compounds called phospholipids, which usually inhibit your bitter taste receptors to an extent. As a consequence, when you drink orange juice immediately after toothpaste, the sweet taste is dulled and the bitter taste is emphasized, producing the somewhat unpleasant effect. If, for whatever reason, you want to avoid this unfortunate effect of toothpaste (instead of never brushing your teeth again), there are alternatives to sodium lauryl sulfate toothpastes. These often use glycyrrhizin, a compound isolated from licorice root, in order to produce their foaming effect. The surfactant molecules in toothpaste aff ect our sense of taste. FLAVOR BITTERNESS Alters phospholipid membrane structures, which usually inhibit bitterness. SWEETNESS Surfactants inhibit sweet taste receptors, reducing sweetness. orange O O SODIUM LAURYL SULFATE O S O- Na+ aka SLS, foaming agent in many toothpastes O O O S O O- Na+ SODIUM LAURETH SULFATE sometimes used in place of SLS DURATION LASTS FOR UP TO 30 MINUTES 19

Author Andy Brunning Isbn 9781612435510 File size 13MB Year 2016 Pages 128 Language English File format PDF Category Chemistry Book Description: FacebookTwitterGoogle+TumblrDiggMySpaceShare FOOD QUESTIONS ANSWERED WITH COLORFUL GRAPHICS AND FUN, EASY-TO-UNDERSTAND SCIENTIFIC EXPLANATIONS Have you ever wondered… • Why bacon smells so good? • Why onions make you cry? • If eating turkey makes you sleepy? • If mixing drinks makes a hangover worse? • How energy drinks work? • Why chocolate is poisonous to dogs? • Why coffee makes you more wired than tea? • Why cilantro tastes soapy to some? The answers to these baffling questions and more are revealed in this friendly, informative collection of trivia. Not a scientist? No problem. This book’s colorful graphics and easy-to-understand explanations make these food facts fun for everyone.     Download (13MB) Bitter: A Taste of the World’s Most Dangerous Flavor, with Recipes Handbook Of Mineral Elements In Food Your Brain on Food: How Chemicals Control Your Thoughts and Feelings How Life Works : The Inside Word From a Biochemist Chemistry and Technology of Soft Drinks and Fruit Juices, 3rd Edition Load more posts

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