FOOD SCIENCE: Ch. 3 Chemistry of Food Composition

SOLUBILITY OF CARBS a) *Put the following carbs in order of solubility in decreasing order: sucrose, fructose, glucose, maltose, lactose* * b) *What mouthfeel & texture does lactose have?* * c) What happens to solubility if temperature is increased? d) If there is an increase in solute concentration (like sucrose), what happens to boiling point?

a) (Most soluble) Fructose - sucrose - glucose - maltose - *lactose* * (Least Soluble) "First Seek God, My Love" b) *Gritty e.g. refrozen ice cream* * c) able to increase the amount of solute/sugar that can dissolve d) it increases! e.g. 0g of sucrose in water = 212 F boiling point, but if 80% sucrose - temp increases to 234 F

WATER FORMS a) *Water is present in food in what two forms?* b) What do these two forms determine about food?

a) *1. Free - Largest amount & easily separated from food; Able to dissolve salts, acids sugars & dilute substances ; Eg= water in fruits & vegetables* 2. *Bound - Incorporated into the *chemical structure* of food (e.g. bread) & not easily removed; not available to act as a medium for dissolving salts, acids, sugars; cannot escape as vapor; resistant to freezing & drying* b) The foods perishability. The more bound water in food the longer that food can stay fresh.

SWEETNERS a) *What are the two major sources of sugar?* * Is sugar the most widely used sweetner? b) Name 3 other kinds of sweetener

a) *1. Sugar cane* *2. Sugar Beets* * Sugar is the most widely used sweetener b) 1. Sugar 2. Sugar alcohols 3. Nonnutritive sweeteners

BOILING POINT a) *What is the Boiling Point of PURE WATER at Sea level?* * (most water is not pure & contains gases, organic material & mineral salts) b) How many calories does water require to overcome atmospheric pressure? c) After boiling point is reached, will additional heat increase temperature or cook food fast? d) *What cooking method is more gentle on food & lessens evaporation?* *

a) *212 degrees Fahrenheit or 100 degree Celsius at sea level* * b) 540 calories (0.54 kcal) (think: in mountains, boiling point is lower bc of less atmospheric pressure) c) NO d) *Slow Rolling Boil* *

WATER ACTIVITY a) *What is water activity?* * b) What does water availability determine? c) If there is increased bound water, how does that affect water activity, perishability, and shelf-life? d) Perishability of 2 foods with the same % of moisture may differ due to different ______ e) What are 3 methods to reduce water activity?

a) *A measure of water availability in foods (value <1.0)* * b) Perishability c)The more bound water = lower water activity = lower perishability = higher shelf-life d) aw (water activity). Example White cake (highly perishable) vs. White bread (see slide 10 for chart) e) Dehydration, freezing, adding sugar or salt

FUNCTIONS OF WATER IN FOOD a) What are the Two most important functions of water in food? b) What are two additional functions of water in food? c) What 3 chemical reactions require water?

a) *Acts as a Transfer Medium for Heat* & *Universal Solvent* b) Agent in chemical reactions (Reagent) & Factor in perishability and preservation of foods c) Ionization, hydrolysis, and acid-base reactions

STATE OF WATER a) *What is Latent Heat?* * b) *What is Heat Vaporization?* * c) *What is Heat Fusion?* * (think melting)

a) *Amount of energy released/absorbed during a CHANGE OF STATE without a change in temperature* * b) *Amount of heat required to convert liquid to gas, which 540 calories or 0.54 kcal to boil & vaporize* * c) *Heat/energy ABSORBED in the conversion of water as solid ice to liquid (melting) which is 80 cal/g water or 0.08 kcal* *

ELEVATION & BOILING POINT a) *As altitude increases, what happens to boiling point?* * b) What causes boiling point to decrease at higher altitudes? c) How many lbs do pressure cookers increase atmospheric pressure? d) Mountaineers can cook pasta in water at what temperature in Celsius? e) *Does the Hardness (increased Calcium and Magnesium) or Softness (increased Sodium) affect boiling point?* * f) How do water softeners work?

a) *Boiling DECREASES 1 degree F for every 500 foot increase in altitude* * E.g Calculate boiling point 4,500 ft above sea level. 4,500/500 = 9. 212-9 = 203. b) Less air & atmospheric pressure pushing down. So, steam is faced with less resistance. c) to 15 lbs from 14.7 d) 90 C (10 degrees less than boiling point at sea level) e) *NO* * f) They exchange Ca & Mg (Hard water minerals) for Na

INFLUENCES ON BOILING POINT a) *What is a Vaccum pan?* * b) *In a vaccum pan,with lowered Atmospheric Pressure, what happens to boiling point?* c) Given an example of a Vaccum pan d) What does using a Vaccum pan involve? e) What products are made with Vaccum pans?

a) *Lower Atmospheric Pressure (used for rapid evaporation)* * b) *Boiling point lowered* c) Freeze drying d) freezing the product, lowering pressure, then removing the ice by sublimation (solid to gas) e) Evaporated milk for milk chocolate, tomato paste for ketchup. There are vaccum pans in beet sugar factories - used for crystallization of sucrose solutions

BASIC CHEM a) Atoms combine to make what? b) What do molecules and compounds combine to create?

a) *Molecules* (composed of one or more atom types) OR *Compounds* (substances whose molecules are composed of UNLIKE atoms) b) all substances on earth

POLYSACCHARIDES a) *In plants, glucose derived from _________________ is stored as starch* * b) Can the body break down starch into individual units? c) In food, what three things can be used to break down starches into smaller, sweeter segments called dextrins?

a) *Photosynthesis* * b) Yes c) heat, enzymes, acid

INFLUENCES ON BOILING POINT a) How does a Pressure Cooker work? *Does it lower or raise temperature above 100 C/212 F?* * b) With Pressure Cooking, is boiling point increased or decreased?

a) *Tight fitting lid, traps steam, pressure builds inside, raising T well above 100°C (212°F)* * b) INCREASED

OSMOSIS & OSMOTIC PRESSURE a) *What does Osmosis cause?* b) What is an example of Osmosis?

a) *causes water to be drawn to solutes* *, which has higher osmotic pressure. b) Salting

HFCS a) *HFCS is intensely sweet & has a yellow color. true or false?* * b) HFCS replaced what monosaccharide in soda? c) What does the AMA have to say about HFCS? d) Where as circulating glucose increases insulin release from the pancreas (Vilsboll et al., 2003), fructose: e) Typically, insulin released by dietary sucrose inhibits:

a) *false, it is colorless.* * because of it's sweetness & colorlessness = widespread use in a variety of foods. less can be used, resulting in cheap price. b) sucrose c) Insufficient evidence that HCFS is any more dangerous than other sweeteners d) does this less efficiently, because cells in the pancreas lack the fructose transporter e) eating and increases leptin release (Saad et al., 1998), which in turn further inhibits food intake

WATER a) Food has a water content between what percentages? b) Fruit & Vegetable Water Content c) Whole Milk Water Content d) Most meats water content

a) 0-95% b) 70-95% c) Over 80% (>80%) d) Just under 70% (<70%)

Appropriate water activity favorable to micoorganisms: a) Bacteria b) Yeasts c) Molds d) In 1953, William James Scott showed that microbial growth in food is governed not by water content, as most people thought, but by:

a) 0.85 - 1.00 b) 0.87 - 0.91 & 0.60 - 0.65 c) 0.80 - 0.87 & 0.60 -0.75 d) water activity

SWEETNESS COMPARED TO SUCROSE a) There are different degrees of sweetness relative to sucrose. One value of sweetness is sucrose given? b) Sweeteners that are less sweet than Sucrose c) Sweeteners that are more sweet than Sucrose

a) 1 b) Lactose, Maltose, Sorbitol, Galactose, *Glucose*, Mannitol, Xylose, Invert Sugar, Xylitol (Basic Di-, Mono-, and sugar alcohols) c) Invert Sugar SYRUP, *Fructose*, Cyclamate, Glycyrrihizin, Acesulfame-K, Aspartame, Stevioside, Saccharin, Sucralose, Thaumatin, Alitame, Talin, Monelin, Neotame (Artificial sweeteners)

CARBOHYDRATES a) Carbs broken down into: b) There are two classes of Monosaccharides: c) Give examples of Hexoses d) Give examples of Pentoses e) Name the 3 Disaccharides f) What are the two classes of Polysaccharides? g) What are the Digestible Polysaccharides? h) What are the Indigestible Polysaccharides?

a) 1. Polysaccharides 2. Disaccharides 3. Monosaccharides b) Hexoses w/ 6 Carbons & Pentoses w/ 5 Carbons c) Glucose, Fructose, Galactose d) Ribose (RNA & DNA) & Arabinose (vegetables) e) Sucrose (fructose + glucose), Lactose (galactose + glucose), Maltose (glucose + glucose) f) Digestible & Undigestible g) Plant Starches - Amylose & Amylopectin Animal Starch - Glycogen h) Fibers - Cellulose, Hemicellulose, Pectin, Gums, Inulin, etc.

HONEY a) What percentage of water is honey b) What percentage of carbs is honey c) What additional compounds does honey contain d) What are the percentages of fructose, glucose, and sucrose in honey?

a) 18% water b) 82.5% carb c) small amts of minerals, vitamins, enzymes, etc. d) 40% fructose 35% glucose 2% sucrose, etc.

WATER CHEMICAL STRUCTURE a) What atoms is water made up of? b) Are the atoms of water evenly balanced? c) What is a Dipole? d) What kind of bond hold two water molecules together? e) All molecules have ___________ bonds, but only some have __________ bonds.

a) 2 hydrogen atoms bonded to 1 oxygen atom - H2O b) NO (angle of 105) resulting in a water molecule with a negative pole and a positive pole aka DIPOLE - which gives water its unique properties c) Molecule that is electrically asymmetrical - one portion slightly negative & another slightly positive . Dipolar molecules have poles with partial charges that oppose each other. d) HYDROGEN BOND e) Covalent; Hydrogen

OLIGOSACCHARIDES a) How many monosaccharides are oligosaccharides composed of? b) What are the 2 most common oligosaccharides? c) What are oliogaccharides used for? d) Examples of foods naturally high in raffinose e) Examples of foods high in Stachyose f) Are humans able to digest oligosaccharides?

a) 3-10 monos b) 1. Raffinose - 3 monosaccharides (galactose, glucose, fructose) 2. Stachyose - 4 monosaccharides (2 galactose, glucose, fructose) = *non cariogenic aka cavity producing* * c) *Bulking agents in low-calorie foods* * d) beans, asparagus, cotton seeds, sugar beet molasses, cabbage, broccoli, Brussel's sprouts, sweet potatoes and whole grains e) beans & peas f) Humans do not have enzymes to digest them, so they pass unchanged to the colon where the normal intestinal bacteria ferment them to gases (methane, carbon dioxide, hydrogen), which can cause abdominal bloating

FREEZING POINT a) What is waters freezing point at normal atmospheric pressure? b) When does *Heat of Solidification* * occur? c) What physically happens to water when it becomes frozen? d) *Does adding salt or sugar to water raise or lower freezing point?* * *What happens when too much is added?* e) Lower temperature decreases water's ________ energy, which slows movement of water molecules until they finally set into a compact configuration.

a) 32 degrees Fahrenheit or 0 degrees Celsius b) when *at least 80 calories (0.08 kcal) are lost/released per gram of water* * c) Water expands & becomes less dense d) *ADDING SALT OR SUGAR LOWERS FREEZING POINT. But, too much slows freezing point* * (So lowers it below 32 degrees F or 0 Celsius). E.g. the freezing point of ice cream is 27 degrees Fahrenheit e) kinetic

SOLUBILITY a) How many grams of sucrose is a saturated solution? b) How many grams of sucrose makes a supersaturated solution?

a) 66.6 g b) >66.6 g

CORN SYRUP a) What percentage of sugar and water is in corn syrup? b) How is corn syrup made? c) Beta-amylase = more of which disaccharide? d) Glucoamylase = more of which monosaccharide?

a) 75% sugar and 25% water b) CORN STARCH is acted upon by Beta-amylase or Glucoamylase to form GLUCOSE which is acted on by Invertase to make HFCS c) Maltose (made up of glucose + glucose) d) Glucose - Sweeter, less viscous

ENERGY REQUIRED TO TRANSFORM 1 GRAM OF ICE TO STEAM a) Ice (0 C) to Water (0 C) b) Water from 0 C to 100 C c) Steam - 100 C water to steam d) *What is the total energy required to transform 1 gram of ice to steam?* *

a) 80 cal - melting/heat of fusion b) 100 cal c) 540 cal - needed to go against atmospheric pressure d) *720 cal* *

HYGROSCOPICITY a) What is hygroscopicity? b) What monosaccharide is the most hydroscopic? c) *With hygroscopicity, what reaction should attention be given to?*

a) Absorption of water. sugar is caked/lumpy in moist storage b) Fructose - use honey, molasses, fructose crystal/syrup produce moist cakes/cookies & stay moist longer c) *Maillard reaction & protein quality*

VAPOR PRESSURE a) Liquid boils when Vapor Pressure just exceeds: b) *What is the value of Atmospheric Pressure?* * c) At standard atmospheric pressure, what temperature does water temperature freeze and boil in Celsius?

a) Atmospheric Pressure b) 760 mm Hg or 101.325 kilopascal (kPa) c) 0 degrees Celsius; 100 degree Celsius

BROWNING (NON-ENZYMATIC) a) What is non-enzymatic browning? b) Is caramel/browning more sweet or less sweet? c) What is the chemical break down the caramelization of sucrose? d) What is the Maillard reaction (a non-enzymatic browning rxn)?

a) Caramelization - dry heat used to turn sugar into liquid state. E.g. Sucrose - clear liquid - brown liquid (caramel) (sucrose to clear liquid = 320F/160C & clear liquid to brown liquid = 338F/170C) b) Decreased Sweetness c) Sucrose -> Glucose & Fructose -> Acetic acid (sour), Maltol (Caramel taste), & Furan (Nutty) d) - Reducing sugar + amino acids - Heat, alkaline, moisture - Brown baked products, BBQ, discolored powdered milk

Functions of Sugar a) Texture does what? b) Fermentation does what? c) Preservation occurs with what percentage of sugar? d) Leavening is placed in what?

a) Carry mouthfeel b) Acts as food source for microorganisms (yeast) c) 60-65% d) Baked goods such as cakes

POLYSACCHARIDES a) What is glycogen? & Where is it stored? b) What happens to glycogen in meat during slaughtering?

a) Digestible polysaccharides of glucose from animals, human, fungi, and bacteria. Stored in long chains in liver and muscle b) It gets converted into lactic acid, so it is not present after slaughter (why protein doesn't have carbs)

SOLUTIONS a) What is a True Solution b) What is a Solute c) What is a Solvent d) Unsaturated Solution e) Saturated Solution f) Supersaturated solution

a) Dispersion in which ions or molecules no larger than one millimicron are dissolved in a liquid (usually water) b) Substance dissolved in a liquid to form a true solution c) Liquid in which the solute is dissolved to form a true solution d) True solution *capable of dissolving additional solute* at the temperature of the solution e) True solution *holding the maximum amount* of solute that can be dissolved at its current temperature f) True solution containing *more solute than theoretically can be dissolved at that temperature*, a situation created by cooling a heated saturated solution carefully (rock candy & fudge)

STATE OF WATER a) *What is Specific Heat?* * b) *What substance takes the most energy to heat?* * c) *What is the value for water's specific heat?* * d) The presence of hydrogen bonding between water molecules is important because without it: e) Because water has a high heat capacity and absorbs a lot of heat before it begins to get hot, it is used in: f) Why is the temperature change between seasons gradual rather than sudden, especially near the oceans?

a) Heat required to raise the temp of *1 gram of a substance to 1 degree Celsius* b) *Water* - e.g., same amount of heat to make oil burning hot would only make water lukewarm. This property allows animals & humans to endure hot & cold temperatures c) *1.00* * - 1 calorie will raise 1 gram of water 1 degree Celsius d) water would be a gas at room temp e) industries and in radiator as a coolant f) bc water helps regulate the rate at which air changes temperature

WATER - *Simplest of all nutrients, but most important* * a) What are the 3 main functions of water? b) What 6 thing is water necessary/need for? c) *How much water is in the human body?* * d) What percentage of water loss can result in death? e) How long can a human being go without food or water?

a) Heat transfer Universal Solvent Reagent used in reactions b) 1. Assimilating (2 processes needed to get nutrients into cells) 2. Digesting 3. Absorbing 4. Transporting 5. Metabolizing 6. Excreting nutrients & by-products "ADA MET" c) *60-70%* * d) 10% e) Food - 8 to 21 days Water - 3 to 5 days

COLLOIDAL DISPERSIONS a) Unlike solutions, not all particles dissolve ______________ because of their large sizes. Give examples of Colloids. b) What are the two phases of colloidal dispersions?

a) Homogeneously; E.g., proteins, starches, fats b) 1. Continuous phase: Medium surrounding all parts of dispersed phase 2. Discontinuous (dispersed) phase: Phase distributed in discontinuous fashion throughout the entire colloidal system E.g., Take flour & put in water. Water surrounds flour. Flour = discontinuous (dispersed) phase & Water = continuous phase

*DIFFERENT COLLOIDAL DISPERSIONS* * a) Emulsion b) Gel c) Foam d) Sol e) Suspensoid

a) Liquid in liquid mixture. Food examples include water-in-oil or oil in water emulsions (milk, cream, sauces, salad dressing, mayo, butter) b) Liquid-in-solid dispersion (jam, gelatin, cheese) c) Gas-in-liquid (whipped egg white or whipped cream foams) d) Solid-in-liquid (gravies, jellies) e) Gas-in-solid (whipped jello)

POLYSACCHARIDES a) What are Polysaccharides? b) *What are the 3 most common polysaccharides?* * c) What two major groups are polysaccharides divded into?

a) Many monos linked together b) starch, glycogen, fiber c) 1. Digestible (starch & glycogen) 2. Indigestible (fiber)

VAPOR PRESSURE a) What is Vapor Pressure? b) *With an increase in temperature, what happens to water molecules?* * c) What happens to Vapor Pressure with an increase in Temperature?

a) Pressure exerted as molecules go from liquid state to gaseous state b) *Molecules move more RAPIDLY, therefore increasing tendency of molecules to escape from liquid & become vapor* * c) Increase Temp = Increase Vapor Pressure

STATE OF WATER a) Lowest state of water b) Highest state of water c) What dictates whether a substance is solid, liquid, or gas? d) When does water become less dense?

a) Solid b) Gas c) Molecular movement d) when completely FROZEN

a) What reduced Vapor Pressure? b) Soluble substances like sugar and salt cause *Freezing Point _________* * c) Soluble substances like sugar & salt cause *BOILING Point _______* *

a) Solutes b) *DEPRESSION* * (ice cream) c) *ELEVATION* * (candy making)

MELTING POINT a) What is Melting Point? b) *How many calories & kcals must be returned for ice to reach melting point?* * c) *What is Latent heat?* *

a) Temperature that solid turns to liquid b) *80 calories or 0.08 kcal* * c) *Amount of energy per gram absorbed or emitted as a substance changes states* * (E.g. when changes from solid to liquid or liquid to gas)

CORN SYRUP a) What are Dextrose equivalents? b) *High conversion corn syrup has how many Dextrose equivalents?* * c) *What percentage of fructose and glucose is in High Fructose Corn Syrup?* *

a) The extent to which starch is converted to glucose syrup. It is the percentage of the total solids that have been converted to reducing sugars: the higher the DE, the more sugars. 100 means that there is complete conversion of starch to glucose. (Liquid glucoses are commercially available ranging from 2 DE to 65 DE. A complete acid hydrolysis converts all the starch into glucose but produces bitter degradation products.) b) *>50 DEs* = less viscous, sweeter, fermentable, & contributes to browning c) *42% fructose & 55 % glucose* *

MONOSACCHARIDES - Simplest sugars a) *How are monosaccharides classified?* * b) What does -ose mean? c) What monosaccharide classifications are most common in food? d) *What is the most common hexose found in foods?* * e) What is the name for refined glucose? f) *What is the sweetest of all sugars?** g) What disaccharide is galactose a part of?

a) by number of carbons - *triose, tetrose, pentose, hexose* * b) sugar c) Pentose & hexose d) *Glucose - fruits, honey, corn syrup, some veggies* * e) Dextrose - used in production of a variety of foods; derived from starches f) *Fructose* * aka fruit sugar or levulose g) lactose

OTHER SWEETENERS a) How is molasses obtained? What is it used in? b) How is Maple Syrup extracted? *What are the two different kinds of maple syrup?* *

a) by repeatedly boiling sugar cane or beets. used in baking to enhance flavor b) from the sap of maple tree. *"Real" vs. blended maple syrup* *

CRYSTALLIZATION a) What is crystallization important for? b) What are 3 ways to prevent crystallization?

a) candy making. it involves the development or inhibition of crystallization. In Noncrystalline candy - key is to prevent grainy texture caused by crystallization b) 1. Clear sides of pan of particles 2. Don't agitate during cooling (patience) 3. Use high soluble sugar (fructose)

DISACCHARIDES a) What is lactose intolerance caused by b) What is Maltose primarily found in? c) STRUCTURES

a) lack on enzyme lactase needed to break down lactose b) beer & breakfast cereals c) BE ABLE TO IDENTIFY DRAWINGS!

NON-NUTRITIVE SWEETENERS a) Do they provide energy? b) *How many times sweeter than sucrose?* * c) What are the seven types currently approved by the Food & Drug Administration (FDA)?

a) minimal to no energy b) *30 to several thousand times as sweet as sucrose* * c) Acesulfame (130-200 x) Aspartame (180x) Luo han guo (250-300 x) Neotame (8000 x) Saccharin (200-700x) Sucralose (600 x) Stevia extract (25-300 x)

STATES OF WATER a) liquid to gas b) gas to liquid c) solid to liquid d) liquid to solid (See diagram of Slide 18 and be able to label)

a) vaporization b) condensation c) melting - heat of fusion d) freezing

Monosaccharides STRUCTURES

*KNOW HOW TO DRAW THEM* * (See slide 39 for Glucose, Fructose, and Galactose structures)

HFCS PRODUCTION Describes the steps of HFCS Production: 1) Cornstarch is first treated with what enzyme, producing polysaccharides. 2) What enzyme is then added to break polysaccharides into glucose molecules? 3) What enzyme is added next to convert glucose syrup into 42% fructose syrup (HFCS-42)? 4) HFCS-42 is concentrated (through an ion exchange column) resulting in what percentage fructose syrup? 5) HFCS 90 is blended with what to create HFCS-55? b) From 1970 to 1990, consumption of HFCS increased more than:

1) ά-amylase 2) Glucoamylases 3) Glucose isomerase enzyme 4) 90% fructose syrup (HFCS - 90) 5) blended with HFCS-42 b) 1000% and currently accounts for 40% of all added caloric sweetners

WATER PROPERTIES What are the 5 PROPERTIES of water?

1. High Specific Heat (Heat required to raise the temp of 1 gram of a substance 1 degree C) 2. Neutral pH - Pure water 3. High Heat of Vaporization 4. Cohesive and Adhesive Properties 5. Less dense as solid than as liquid

WHAT ARE THE 8 FUNCTIONS OF SUGAR?

1. Sweetness 2. Solubility 3. Crystallization 4. Browning reactions (sucrose = browning) 5. Hygroscopicity (sucrose = holds water) 6. Texture 7. Fermentation (sugar feeds yeast) 8. Preservation (more sugar = higher shelf-life

In baked goods, sugar contributes to what 5 things:

1. Texture 2. Flavor 3. Browning 4. Fermentation of Yeast 5. Extends Shelf life PLUS, 6. Adds body to soft drinks 7. Offsets acidic, bitter, and salty tastes

BASIC CHEM All Living things contain what six key elements?

CHNOPS - Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, Sulfur which are the building blocks for organic material

*FUNCTIONS OF SUGARS IN FOODS*

SEE TABLE 21-1 and Know this table for Essay Question on Exam