New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

NHM 253 Exam 1 Study Guide

by: Regan Dougherty

NHM 253 Exam 1 Study Guide NHM 253

Regan Dougherty
GPA 4.0

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

This study guide is for exam 1 on 2/16/16. It contains information from lectures, the textbook, and lab lectures. Chapters: 1, 4, and 16
Food Science
Dr. Crowe
Study Guide
50 ?




Popular in Food Science

Popular in Nutrition and Food Sciences

This 15 page Study Guide was uploaded by Regan Dougherty on Thursday February 11, 2016. The Study Guide belongs to NHM 253 at University of Alabama - Tuscaloosa taught by Dr. Crowe in Fall. Since its upload, it has received 90 views. For similar materials see Food Science in Nutrition and Food Sciences at University of Alabama - Tuscaloosa.

Popular in Nutrition and Food Sciences


Reviews for NHM 253 Exam 1 Study Guide


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 02/11/16
Exam Date: 2/16/16 NHM 253 Exam 1 Study Guide This exam covers Chapters 1, 4, and 16 in addition to lab lectures. - Introduction to Food Science The chemical structure of an ingredient influences flavor, texture, color, shelf-life, • and how it interacts with other ingredients. • Vitamins and Minerals - Vitamins - organic (can be destroyed by heat, light, oxygen) Fat-soluble - A, E, D, K • • Water-soluble - B, C - Minerals - inorganic (not destroyed in the cooking process) • ex. iron, sodium, potassium, calcium - Altering the Vitamin and Mineral Content of foods • Enrichment - process of adding nutrients that were lost during processing - Ex. When wheat is processed into flour, it loses 5 key micronutrients: riboflavin, thiamin, niacin, iron, and folic acid. The FDA mandates that all wheat is enriched upon processing (all 5 minerals are added). Fortification - adding nutrients to food products that were never present in the • raw ingredients - ex. fortified cereals, vitamin D added to milk, calcium added to orange juice • Phytochemicals - plant compounds which are shown to have beneficial health properties beyond basic nutrition • Food Additives - approved substances added to food so that it becomes a component of the food product and it affects the characteristics of the product - Most common food additives: sugar, salt, and their derivatives - 4 Reasons for Additive Use • protect the nutrients in food • extend the shelf-life of food 1 Exam Date: 2/16/16 • improve the sensory appeal/enhance flavor • maximize ingredient performance (how ingredients work together) - Chapter 4: Food Composition • Water - Functions in food: • medium for heat transfer • universal solvent • agent in chemical reactions - When water breaks down, it breaks down into oxygen and hydrogen. The hydrogen levels affect the pH of food. • factor in perishability and preservation - The more water a food contains, the greater that food’s perishability. - 2 Forms of Water in Food: • Free water - water that is visible and can be extracted easily • Bound water - water that is within macronutrients and cannot be extracted easily - Both free and bound water contribute to microbial growth and reactions. - Water in Mixtures • Solution - solute molecules completely dissolve in a solvent • Dispersion - substances called colloids are too large to dissolve in a solvent. There are 2 classifications: - Suspension - mixture in which particles that are too large to be dissolved by the solvent remain suspended in the solvent - Emulsion - two liquids that will not mix • ex. lecithin (found in eggs and soy) - Water activity (a w - amount of free water in foods • Pure water has an a 1w00. 2 Exam Date: 2/16/16 • You can lower water activity by adding substances (ex. salt, sugar). - Any added solute will bind to water molecules and make them unavailable for microbial growth/reactions. - Boiling point: 212 F or 100 C - Freezing point: 32 F or 1 C • Carbohydrates (4 calories/gram) - Functions in food: • color • moisture absorption • texture flavor • • fermentation - Contain carbon, hydrogen, and oxygen. - Plants are the primary source of carbohydrates but diary is also high in carbohydrates. - Found in 3 forms: • Sugars • Starches • Fibers - Monosaccharide - simplest sugars; cannot be broken down • Glucose - most common monosaccharide in foods • Fructose - fruit sugar; sweetest monosaccharide - Glucose and fructose are isomers but they taste different. • Galactose - found in milk - Disaccharide - 2 monosaccharides • Sucrose - table sugar; glucose + fructose 3 Exam Date: 2/16/16 • Lactose - milk sugar; glucose + galactose • Maltose - glucose + glucose - uses: fermentation of alcohol, gives cereals their “nutty” flavor - Oligosaccharide - 3-10 monosaccharides • Not very common in food, but found in legumes - Polysaccharide - many monosaccharides linked together; very large molecule Most are not water soluble. • • 2 Main Categories: - Digestible • Starch - stored energy in plants • Glycogen - stored energy in muscles - Indigestible • Plant gums (ex. guargum, locust bean, carrageenan, xanthan) • Fiber (ex. cellulose, hemicellulose, lignin, inulin (these 4 are not water soluble), pectin (water soluble)) - Digestibility is determined by how glucose units link together. • Locating the anomeric carbon: - Locate the oxygen inside the ring - Find the carbon that’s directly attached to one hydroxyl group (this is the anomeric carbon). • Alpha linkages - hydroxyl group attached to anomeric carbon is pointing down; digestible • Beta linkages - hydroxyl group attached to anomeric carbon is pointing up; indigestible - The Influence of Chemical Structure • The larger the molecule, the less it will penetrate the case buds (the less you will be able to taste it). 4 Exam Date: 2/16/16 • Structure determines whether or not ingredients will mix. - The High Fructose Corn Syrup Controversy • It is called high fructose because it contains more fructose then normal corn syrup (which is made of only glucose). • In terms of metabolism, it is no different than table sugar (provides 4 calories/ gram). • It’s controversial because: it is in so many foods we consume (to lengthen shelf-life). With every exposure, we are less and less likely to notice the sweetness. We then start craving even sweeter things (things with even more sugar). • Lipids - Contain carbon, hydrogen, and oxygen. - Lipids are insoluble in water. - 2 Groups of Lipids: • Fats - source: animals - generally saturated - solid at room temperature • Oils - source: plants - usually unsaturated - liquid at room temperature - Triglycerides are the most common form of edible lipids. • Formation of a triglyceride: - glycerol backbone (3 carbon compound with 3 hydroxyl groups) + 3 fatty acids connected to the backbone • The fatty acids can differ. 5 Exam Date: 2/16/16 - 3 water molecules are released when the fatty acids bond to the glycerol backbone (dehydration synthesis). - Saturation • Saturated - all carbons ar bonded to 2 carbons and 2 hydrogens - meat, poultry, milk/butter/cheese, egg yolk, lard, chocolate, coconut/coconut oil, palm oil, vegetable shortening • Unsaturated - one or more double bonds are present between carbons due to an absence of hydrogen(s) - Monounsaturated - only one double bond • avocado, peanuts/peanut butter, olives/olive oil • Polyunsaturated - more than one double bonds - vegetable oils (corn, safflower, soybean, sunflower, canola, etc.), margarine, mayonnaise, certain nuts (almonds, pecans, walnuts) • Hydrogenation - the addition of hydrogen atoms to an unsaturated fatty acid, causing the double bonds to become single bonds • Lipids with a greater number of double bonds are more easily oxidized (have a shorter shelf life). • Lipids with a greater number of double bonds adhere less easily to artery walls. • Saturated fatty acids have a higher melting point. // The longer the fatty acid chain, the higher the melting point. • Free radical - contains an unpaired electron in its outermost shell (it is unstable) - Lipids are the most easily oxidized molecule in food and in the body. - If a lipid becomes a free radical, it loses a lot of its nutritive value. • It smells bad. • It seeks to “steal” an electron from another lipid (forming another free radical). - Phospholipid - glycerol backbone + 2 fatty acids + phosphate group 6 Exam Date: 2/16/16 • Ampiphilic - both hydrophilic and hydrophobic properties • Phospholipids are found in liquid foods that contain fats because they act as emulsifiers. • Phospholipids are found in cell membranes. - Functions of Lipids in Food • heat transfer • aid in tenderization of foods • texture and mouthfeel • flavor and satiety • phospholipids act as emulsifiers Food Proteins • - composed of amino acids joined by peptide bonds - contain carbon, hydrogen, oxygen, and nitrogen. - 4 Levels of Structure • Primary - liner arrangement of amino acids in a protein chain • Secondary - folding or coilings within a protein structure that are stabilized by hydrogen bonding • Tertiary - final 3D structure of protein that involves numerous nonequivalent interactions between amino acids Quaternary - how multiple peptide chains are aggregated together by hydrogen • bonds, disulfide linkages, and salt bridges into a final specific protein shape (usually involves a hydrophobic core) - Protein Denaturation - the disruption of bonds that make up tertiary and secondary structure of proteins; important for taste • Chemical denaturation - Food-grade acids break down proteins. • ex. lemon juice, orange juice, vinegar, coffee, Sprite/Coke (carbonic acid) - Enzymes break down proteins. 7 Exam Date: 2/16/16 • Physical denaturation - exposure of proteins to heat - ex. cooking food • Mechanical denaturation - stress applied to protein - ex. pounding meat, cutting meat, tenderization - Functions of Proteins in Food • hydration - ability of protein molecules to attract and bind water - Amino acids must be polar for water binding to occur (only some are polar). - Allows proteins to thicken foods, form gels, etc. • emulsification due to amphiphilic nature - If a protein has polar and nonpolar amino acids, it can serve as an emulsifier. • buffering - protein molecules aid in resisting extreme pH shifts in food products • browning - two basic types of browning reactions - enzymatic browning - polyphenol oxidase (PPO) catalyzes the oxidation of phenols into brown-colored melanins Causes loss of nutritive value (phenols have antioxidant activity) • - non-enzymatic • ex. Maillard reaction - color development in the browning of meat, roasted coffee, chocolate, some baked goods, fried foods. - slightly sweet with a robustness of other flavors - Caramelization is a 3rd type of browning. • enzymes - catalysts that speed up the rate of a biochemical reaction without getting destroyed in the process - Chapter 16: Food Preservation • The more water and/or protein a food has, the more perishable it is (and the shorter its shelf life). • 3 Major Typer of Changes in Food: 8 Exam Date: 2/16/16 - Biological - the growth of microorganisms in or on food - Chemical - brought about by the presence of enzymes - Physical - detectable by the senses (ex. loss of color, separation of ingredients) • Spoilage vs. Contamination - Spoilage - detectable changes occurring in food that affect the quality of food (appearance, taste, texture, odor) - Contamination - commonly undetected growth of microorganisms in food which affects the safety of food • Most bacteria have a reproductive rate of 20 minutes (doubling by binary fission every 20 minutes). - Temperature danger zone - temperature conditions best for bacterial growth • 41 F - 135 F - FAT TOM (conditions for microbial growth) • food • acidity (bacteria flourish between a pH of 4.6 and 7) • time • temperature (temperature danger zone) • oxygen - anaerobic - do not need oxygen to grow moisture • • Food and moisture are a must for growth, everything else simply enhances the rate of growth. - Low temperature storage is the best line of defense against microbial growth. • Foodborne Infection - illnesses occurring from ingestion and growth of causative bacteria in the intestinal tract - The bacteria growing inside you makes you sick. - Symptom onset: 12 hours to 2 days (depending of number of cells ingested) 9 Exam Date: 2/16/16 • Foodborne Intoxication - illnesses involving ingestion of toxins produced as by- products of microbial growth - The toxin produced by the bacteria growing on the food you ate makes you sick. - Symptom onset: within hours of ingestion • Foodborne Intoxification (toxin-mediated infection) - illnesses occurring when causative bacteria are ingested, grow, and produce toxins within the small intestine - The toxin produced by the bacteria growing inside of you makes you sick. - Symptom onset: 2-9 days • Chemical Hazards Associated with Food is found in Title 21. • 8 Most Common Food Allergens: - eggs - milk - soy - peanuts - tree nuts - fish - shellfish - wheat - All allergens are proteins. • The FDA requires labeling of foods that contain or have been processed in a facility with one of these allergens. - Preservation Methods • Drying - decreasing water content in food makes it difficult for microorganisms to grow - Water activity required for preservation is usually below 0.6. • Refrigeration - slows the rate of ripening by slowing enzyme reactions involved in ripening 10 Exam Date: 2/16/16 • Freezing - moisture is bound within ice so it is unavailable to microorganisms - also slows rate of chemical and physical change, but these do still occur • Pickling - addition of acids to lower pH (below 4.6) and limit microbial growth - Most microorganisms grow best at a neutral pH (7). They usually cannot survive in a pH lower than 4.6. - Many fruits are naturally acidic enough to discourage bacterial growth on their own. • Fermentation - limited to no available oxygen - The growth of “friendly” bacteria inhibits the growth of pathogenic bacteria. • Canning - food is sealed in cans or jars and heated to high temperatures - Heat does not destroy bacterial spores. • Irradiation - ionizing radiation destroys chemical bonds within enzyme systems and DNA in microorganisms that influence food deterioration and food safety - AKA cold sterilization - Irradiation is considered a food additive by the FDA. - exposure of gamma rays - Commonly irradiated products: spices, meats/poultry, nuts, sprouts, eggs - Radura - symbol indicating that a food has been irradiated • Only applies to “first generation” foods (that we purchase directly); does not apply if an ingredient has been irradiated. • Edible Coating - Ex. bell peppers, winter squash, cucumbers - barrier to oxygen, gases, and moisture loss - vehicle for added flavors, antioxidants, antimicrobials - types: lipid, CHO, protein-based, and wax (most common) • Other Preservation Methods: - Curing - adding salt to bind to water in foods (making the water unavailable) 11 Exam Date: 2/16/16 - Pasteurization - the food or beverage is heated to a high temperature; usually not all organisms are destroyed, so the product still needs to be refrigerated • Often used with dairy products and juices. - Packaging as Preservation • Common packaging materials: glass, paper/paperboard, metals, plastics • Modified Atmospheric Packaging (MAP) - slows the exchange of gases between the food and its environment and the external environment • Intelligent Packaging - technology built into a package that lets a food processor, distributor, seller, or consumer know something about the internal or external environment of the package • Active Packaging - packaging that releases scavenging chemicals in response to spoilage reactions or the presence of chemicals or compounds, such as excess water, oxygen, or ethylene - COVER LAB LECTURE NOTES - Lab Lecture 1: Sensory Science • Sight - Color - ripeness, length of time food was heated - Presentation - a variety of colors is more appealing • Odor - Smell is second only to taste. - Heat makes food easier to smell. Taste - the deciding factor in food selection • - Taste buds - bud-like structures; found on the underside, side, and tip of the tongue, palate, and pharynx - 5 Basic Tastes: sweet • • salty • sour (acidic) 12 Exam Date: 2/16/16 • bitter • savory/umami - Flavor - combination of taste, odor, and mouthfeel • Mouthfeel - sensation detected by the lining of the mouths it interacts with food • Texture - combination of sight, touch, and mouthfeel - Tenderness - how easily food gives way to the pressure of the teeth - Chemethesis - feel foods chemical properties • ex. heat (hot peppers), cooling (cucumbers) • Hearing - Sound relays messages about ripeness, doneness, and texture. - Lab Lecture 1: Knife Skills • The goal of cutting food is to produce uniform shapes and sizes. This is important so that food cooks evenly. - Lab Lecture 2: Measuring Accuracy • Weight - mass - used for both liquid and dry ingredients - most accurate form of measurement • Volume - space occupied - mostly used for liquid ingredients (can be used for dry ingredients when amount is too small to be weighed) • Techniques to Ensure Accuracy - Sifting: When flour is stored, finer particles settle and larger particles remain at the top. Sift to redistribute particles evenly. - Whisking: Ingredients with particle sizes larger than the sifter screen must be whisked prior to measuring. • ex. nonfat dry milk, whole wheat flour • Measuring cups should be made of metal (plastic expands). 13 Exam Date: 2/16/16 - Lab Lecture 2: Recipe Conversions • To adjust your recipe to a new “yield,” determine the conversion factor (divide new yield by old yield) and multiple each ingredient by the conversion factor. - Lab Lecture 3: Heating Foods • Moist heat - use water or steam as the heat transfer medium • Dry heat - use air or fat as the heat transfer medium - Don’t be fooled: the heat is a liquid but there is no water in fat. - Dry heat is hotter than moist heat. • Roasting - heating food in dry, heated air in closed environment - applies to meats and poultry Baking - heating food in dry, heated air in closed environment • - applies to fish, fruit, vegetables, starches, breads, and pastries • Sautéing - small amount of fat covers the pan - Heat is transferred to food via conduction. • Pan-frying - uses enough fat to come 1/3 to 1/2 way up the sides of the pan - The fat should be at a lower temperature than sautéing. • Deep-frying - food is submerged in oil - Smoke point - temperature at which fat breaks down to glycerol and free fatty acids • Oils with low smoke point should not be used as a frying medium. • Combination methods use both dry and moist heat. • Heat Transfer to Foods - Conduction - direct contact • good conductors: copper, tempered glass/pyrex, cast iron, aluminum • poor conductors: stainless steel, carbon steel, silicon bakeware • Also causes heat transfer within foods as food molecules absorb energy and move around, colliding with other molecules. 14 Exam Date: 2/16/16 - Convection - transfer of heat through a fluid (water, steam, fat, or air) such that heat is circulated - Radiation - transfer of heat energy as waves of heat or light striking food surfaces • Infrared - energy waves from heat lamps or the heating element of an oven • Microwave - cooking food from the inside out (energy waves are aimed at water molecules within food // these molecules move // the heat from their movement cooks food) • Carryover Cooking - cooking that occurs within a food as it continues to increase in temperature after removing from heat source 15


Buy Material

Are you sure you want to buy this material for

50 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Anthony Lee UC Santa Barbara

"I bought an awesome study guide, which helped me get an A in my Math 34B class this quarter!"

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.