Food Science Exam 2

  1. All liquid dispersed in another liquid with which it is usually immiscible
  2. Examples of oil-in-water emulsion
    mayo, salad dressing, cheese, sauce, gravy
  3. Examples of water-in-oil emulsion
    butter, margarine
  4. Examples of naturally occurring emulsions
    milk, cream, egg yolks
  5. Type of emulsion: salad dressing (oil and water)
  6. Type of emulsion: need the addition of stabilizers (yogurt, french dressing)
  7. Type of emulsion: very stable and viscous (mayo)
  8. Act as a bridge between oil and water (hydrophilic and hydrophobic)

    Examples: mono and diglycerides, starches, soy and milk protein, vegetable gum, gelatin, etc
    emulsifying agents
  9. Ways of "breaking the emulsion"
    extreme temperature, too fast of addition of dispersion into continuous phase, add much in the dispersion phase, agitation, long periods of storage
  10. Two stages of breaking the emulsion
    • Flocculation (reversible) 
    • Coalescence (irreversible)
  11. The temperature at which a compound changes from a solid to liquid state
    melting point
  12. 4 determinants of a melting point
    • degree of saturation--increase SAT increase solidity at room T
    • length of C chain--shorter=lower melting point
    • cis-trans configuration--more trans double bonds, higher melting point
    • crystalline structure--larger fat crystals, higher melting point
  13. Determine the spreadability of liquid oils held together by the solid fat crystals

    the more unsaturated the more____
  14. Fats and oils are _____ in water but will dissolve in organic solvents such as benzene, chloroform, and ether
  15. Sense of fullness that fats introduce
  16. Two methods to help delay the onset of hunger
    • 1. fats take longer to digest
    • 2. delay the emptying of the stomach contents
  17. What part of milk is used to make butter
    the cream that floats to the top of undisturbed, unhomogenized milk
  18. how USDA defines butter:
    • 80% milk fat
    • 16% water
    • 4% solids

    *may contain salt, colorings, etc added but USDA doesn't ask to define those
  19. Butter production
    phosholipids surrounding fat in milk--(agitation)-->breaks membrane--> splits into fat globules and liquid-->fat globules--(churned)-->butter
  20. Butter grading
    • Voluntary and based on processor
    • AA, A and B
  21. What is butter grading based on?
    texture, flavor, color, salt content
  22. Regular margarine contains the same amount of calories as butter but the ___ ____ differ
    fat sources
  23. Plant oils that have been hydrogenated to make them more solid and pliable to make this product and many are super glycerinated to make them more pleasing to the mouth
  24. Derived from plants, primarily the seeds of soybeans, corn, cottonseed, rapeseed, etc
  25. When oil is removed from the plant source by either cold-pressing or chemical solvents
  26. Process by which a neutral, low-ramona, bland-flavored oil is produced
  27. The fat from swine (pigs)
  28. Animal fat from beef, cattle, or sheep
  29. Solid fat from kidneys and loin of beef and sheep
  30. Originates from the seeds of the theobroma cacao tree, melting point just being body temperature, used for soaps or cosmetics
    Cocoa Butter
  31. The temp that the fat will release a blue/gray smoke
    Smoke point
  32. The temp at which tiny wisps of fire streak to the surface of a heated substance
    Flash point
  33. Uses for eggs in food prep
    leavening (foam), thickening, coloring, flavoring, emulsifying, etc
  34. 5 structural components of an egg
    yolk, albumin, shell membrane, air cell, shell
  35. ~30% of egg weight, nourishment for embryo, color dependent on feed of the hen
  36. surrounds the yolk
    vitelline membreane
  37. rope-like structure, anchors yolk
  38. sits on the surface of the yolk
    germ spot
  39. ~58% of egg weight, make up largely of protein and water, constructed of layers differing in viscosity, alternating thick to thin
    albumen (egg white)
  40. Found between the egg white and the wheel are two membranes (inner and outer), protects against bacterial invasion
    shell membranes
  41. Between shell membranes at wide end, increases as eggs age, larger in pasteurized eggs
    air cell
  42. Hard and made of calcium carbonate, ~12% egg weight, contains thousands of small pores, color dependent on green of hen
  43. The waxy coating on an eggshell that seals the pores from bacterial contamination and moisture loss
    cuticle (bloom)
  44. Nutrient Content of a large egg
    75 kcals, 7g protein, 5g fat, 186 mg cholesterol, vitamins A,D,E,K and several B vitamins, minerals: selenium, iodine, zinc and iron
  45. Downside of egg substitutes
    Remove yolk and replace it with vegetable oil and this decreases the cholesterol but they add sodium
  46. Upside of egg substitutes
    ultra-pastuerized, packaged then refrigerated, good for uncooked foods (reduces the risk of contamination)
  47. True or False: all poultry produce eggs
    True: these include quail, duck, goose, turkey, ostrich
  48. True or false: eggs from quail, duck, goose, turkey and ostrich are more likely to contain harmful bacteria
    True and they should be well cooked
  49. Key to cooking eggs
    keep the temperature low and or the cooking time short
  50. Egg white coagulation temp
  51. Egg yolk coagulation temp
  52. Increases the coagulation temp and more heat is required
  53. lowers coagulation temp--added to mixture prior to heating
  54. lowers coagulation temp, too much causes curdling, prolonged heating results in thinning
    acid (vinegar or tomato products)
  55. During egg prep bring ____ to max thickness before adding uncooked egg
  56. High heat during hard cooking eggs causes sulfur in white to combine with iron in yolk and
    forms ferrous sulfide and causes a greenish blue ring around yolk
  57. Hard cooked eggs should be cooked at a
    simmer NOT boil to avoid tough rubbery eggs
  58. Advantages of Hot start method:
    greater temp control, easier to peel, shorter total cooking time (12-15 min)
  59. disadvantages of hot start method:
    greater tendency to crack when lowering into boiling water
  60. advantages of cold start method:
    less attention, eggs easier to add water, less likely to crack
  61. disadvantages of cold start method:
    egg white more rubbery, "greenish tint" more likely
  62. Why do boiled eggs some times crack
    • extreme cold to extreme hot and pressure builds up in egg
    • To prevent: stir eggs out to come to room T or poke pin hole in air cell
  63. Formation and stability of foam depend on:
    beating technique, temperature, type of bowl, separation of yolk and white (even a small amount of fat can affect this), effect of added ingredients (water, oil, cream of tartar)
  64. increases beating time, creates smooth stable foam, less likely to be over beat, add at soft peak stage
  65. decreases stability and volume of egg white foam, rarely added
  66. Old egg whites whip easier, greater volume
    Fresh whites-->more stable foam
    age of egg
  67. Adding ____ causes faster denaturation of white
    acid because it lowers the pH from the norm 7.6-7.9
  68. Bubbles on the surface but not all of white is broken up, foam extremely unstable, air cells variable in size but large, starts to become opalescent
    add acid, cream of tartar, salt, vanilla at this stage
    Foamy stage
  69. air cells medium fine, all of white exists as foam, mass is elastic ,soft peaks fall over near the same of foam when beater is lifted

    add sugar quickly but gradually at this stage
    soft peak stage
  70. fire are cells, very white and opaque, foam white table, shiny, only tip of peak falls over as beater is pulled from foam
    stiff peak stage
  71. mixture extremely white, foam not stable, drainage occurs rapidly on standing, mass brittle and inelastic, peaks remain rigid in points
    dry stage
  72. True or False: freezing a whole egg is possible
    false: not possible, it will crack under expanding liquids 

    food processors will crack egg and freeze  separate or mixed components
  73. egg storage
    • time: short
    • temp: low temp, just above freezing, avoid storing at >60*f
    • humidity: high, retards moisture loss
    • shrinkage: increases air cell size--rate dependent on storage conditions, and retention of protective covering on shell
  74. white/yolk stand take, yolk firm, large proportion thick white to thin white
    fresh eggs
  75. white runny, yolk flat, equal amounts (or >) of thin to thick whites
    "old" whites
  76. USDA grade B
    lowest grade and not sold in supermarkets but sold to food service establishments
  77. method used to grade eggs based on observing eggs against a light
  78. freshness detected by cracking egg open onto flat surface and observing at height of its thick albumen, numbering system, lower number= lower quality
    measuring haugh units
  79. Grade AA in haugh units
    • 72 or >
    • whites sit up tall and firm
  80. Grade A in haugh units
    • 60-71
    • yolk round and upstanding, thick white is large in proportion to thin white, stand fairly well around yolk
  81. Grade B in haugh units
    • 31-59
    • spreads out, yolk flattened, much more thin white than thick white
  82. Eggs (under egg products inspection act of 1970) must be:
    • wholesome, unadulterated, truthfully, labeled
    • monitored by USDA
    • applies to eggs shipped inter and intra state
  83. egg thats DO NOT pass inspection due to cracked, dirt stained, rotten, blood stains, etc
    Restricted eggs
  84. True or false: size and grading are related
    False they are UNrelated
  85. Large egg is how many cups? ounces?
    1/4 cup or 2 ounces
  86. If egg cracked keep yolk
    cover, submerged in water and use within 2 days
  87. if egg cracked keep white
    covered in glass container, store no more than 4 days
  88. Keeps eggs in the fridge and use within _____
    4-5 weeks of pack date or by expiration
  89. The chances of an egg being internally contaminated are relatively low less than
    1 in 10,000 commercial eggs
  90. True or false: it is more common for contamination to occur during handling and prep of eggs than interally
  91. Internal infection of salmonella
    infection in ovary, absorbing bacteria through pores
  92. External infection of salmonella
    more common and happens during improper handling of infected person by fecal contamination
  93. Precautions to prevent food borne illness
    do not wash eggs, cook all eggs to 145*F, pasteurized eggs for recipes that have light cooking, use separator rather than passing back and forth between shell
  94. Elderly, infants, youth children, immunocompromised (HIV, AIDS, etc) all have this in common
    high risk individuals for food borne illness
  95. Overall dairy consumption in the us by adults (less than 3 cups consumed)
  96. Overall dairy consumption in the us by adults (more than 3 cups)
  97. Overall percentage of people NOT consuming any dairy
  98. Dairy consumption over time
  99. Fermented yogurt with lactic acid bacteria causes
    increased shelf life, improves digestibility of milk, changes in flavor
  100. Yogurt consumers consume more of these nutrients than non-yogurt consumers
    calcium, potassium, magnesium

    **not necessarily yogurt but yogurt consumers are consuming more dairy as a whole
  101. True or false: yogurt is more concentrated in nutrients than milk
  102. Percentage of adults consuming yogurt is
    • increasing (almost doubled percent 4-9%)
    • statically significant data

    **different than dairy intake because ppl don't eat yogurt everyday but may eat dairy everyday
  103. Non-hispanic whites are consuming ____ yogurt than mexican americans and non-hispanic blacks
  104. true or false:non-hispanic blacks think they are lactose intolerant even if they aren't and so they consume little to no dairy or yogurt
  105. Which income category consumes more yogurt than lower income category?
    highest income category
  106. In US which gender eats more yogurt for breakfast and snack?
    Women and this is increasing over time
  107. In children, which gender is consuming more yogurt?
  108. True of false: the yogurt market markets children and adult yogurt
  109. Has cultures specifically for digestive well being
  110. Strains in activita
    bifido bacteria--helps digestion but works while eating it, if one stops problems will arise again
  111. Contains cultures specifically for immune health
  112. strain in danactive
    L. casei immunitas--very specific, only yogurt in US with this bacterium in it!!!
  113. This yogurt has the most strains of bacteria in it of all yogurts
    Siggi's-- has 6 or 7 strains
  114. Different types of fibers (pre biotics) in yogurts
    inulin, gelatin (can be kosher), oligofructose, pectin, natural, agar agar, chicory root extract
  115. Issues with organic yogurt
    no preservatives and so mold was growing in it
  116. Organic branches of dannon
    stony field and brown cow
  117. Condition to call something oikos
    cannot contain any artificial sweeteners
  118. Greek yogurt has more ____ but less ____
    • protein
    • potassium
  119. DGA for dairy is now ____ because people were not getting enough potassium (AI=___)
    • 3 cups from 2 cups in 2005
    • 4700 mg

    *K is almost impossible to get from food
  120. Can only claim certain things by the percentage you____ it by

    example: reduce sugar and alternative sweeteners by 25%
  121. This artificial sweetener is very expensive
  122. This artificial sweetener is 30 to 300x sweeter so you can use less
  123. if there is no artificial sweetener in yogurt
    the sugar content will be higher
  124. Will never find artificial sweetener in children yogurt but to reduce sugar intake
    they will use stevia or another fruit from china
  125. If you add a small amount of a product it can go under the _____ section in the ingredients list
  126. _____ varies amount sizes of yogurt but_____ is the same per amount of yogurt
    • vitamin D
    • calcium
  127. ____ has been fortifying their products for forever
  128. __% of american's ____ comes from dairy products

  129. Milk is primarily
    water (87.4%)
  130. Other components of milk are
    • CHO (lactose)
    • protein--casein (80%) and whey (18-20%)
  131. Primary milk protein
  132. Liquid portion of milk protein, mainly lactalbumin and lactoglobulin
  133. Fat (milk fat or butter fat) composition (SAT,MUFA,PUFA)
    • SAT: 66%
    • MUFA: 30%
    • PUFA: 4%
  134. Cholesterol amount in whole milk
    33 mg
  135. Cholesterol amount in 2% milk
    18 mg
  136. Cholesterol amount in nonfat milk
  137. Vitamins in milk
    vitamin A, D riboflavin, and trptophan
  138. MInerals in milk
    major is calcium, others: phosphate, potassium, magnesium, sodium, chloride, sulfur
  139. Why is milk packaged in cardboard or opaque plastic containers
    light affects the riboflavin in milk and so the contained help to block the light to reduce degradation
  140. Milk grades are graded according to
    bacterial count
  141. Grades for liquid milk
    A (highest, mostly found in stores) and B
  142. grades for fat free/dry milk
    US extra and US standard
  143. US standard grading is ______, and the ____ pays for it but is a responsibility of _____
    voluntary, dairy industry, USDA
  144. A good preservation process in which liquids are heated to a specific temperature for a certain period of time to destroy most microorganisms that could cause disease, spoilage, or undesired fermentation
    Milk pasteurization
  145. Enzyme that if it is no longer active, milk safe for consumption
    alkaline phosphatase
  146. True or false: pasteurized milk will spoil
    • True, nonpathogenic bacteria in it still will convert lactose to lactic acid
    • still contains some pathogenic bacteria (cannot get rid of it all)
  147. milk heated to 280*F for 2 seconds to kill bacteria, longer shelf life
    Ultra pasteurized
  148. milk heated to 280-302*F for two seconds, very high temp, aseptically sealed; no refrigeration needed (except after opening)
    Ultra high temp (UHT)
  149. good medium for microorganism growth (yeast, bacterial molds)
    may cause TB, undulant fever, scarlet fever, septic sore throat
    some states allow the selling of it but mostly not
    Raw (non homogenized) milk
  150. Prevents the separation of water and fat in milk
  151. Homogenization is a mechanical process that
    reduces fat globule size but does NOT effect the nutrient content
  152. Homogenization process alters
    color, viscosity, flavor, surface, tension, cooking properties (helps milk coagulate easier)
  153. Fluid Milks include
    whole (3.25% milk fat), reduced fat (2%), low fat (1%), non fat (0.5%)

    *note all contain 8.25% milk solids non-fat (primarily proteins and lactose)
  154. Which milk type(s) require vitamin A fortification (but vitamin D is required)
    Reduced fat and fat free
  155. True or false: vitamin A and D fortification is not required
    true, but normally it is
  156. Has appearance, taste, and function of milk but nutritionally inferior with little to no dairy content
    imitation milk (FDA definition)
  157. In imitation milk what is used to replace lactose
    water or corn syrup
  158. In imitation milk what is used to replace milk fat
    vegetable oils
  159. In imitation milk what is used to replace protein
  160. Cultured milk products commonly consumed in america
    butter milk, yogurt, acidophilus milk, kefir sour cream
  161. little to no butter fat (<0.5%), longer shelf life,  culture: streptococcus lactose (vitamin A and D fortification optional)
    butter milk
  162. cultured with milk with the assistance of lactobacillus acidophilus, bacterial is beneficial (lives in human intestines, produces some B vitamins, recommended during antibiotic treatment and lactose intolerant)

    very sweet--lactose-->glucose and galactose (2x the sugar molecules)
    acidophilus milk
  163. "campagne of milk", very bubbly and fizzy in nature, made by added lactobacillus caucasicus and yeast, originally made from camel's milk but now cow's milk
  164. Light cream or half and half fermented with streptococcus lactose or other acid
    minimum of 18% milk fat is required, but if sweetness added this can be lowered to 14.4%
    Sour cream
  165. Whole or fat free milk that has 60% of water removed  (reconstitute equal volumes of canned milk and water)
    evaporated milk
  166. whole milk evaporated by 50% and 15% sugar is added, cannot be used in place of evaporated milk
    sweetened condensed milk
  167. Milk that has all moisture removed, two types: nonfat and instant, nutritionally similar, long shelf life, inferior taste
    Dry milk
  168. Flavor of milk comes from
    lactose, salts, sulfur compounds, short-chain fatty acids
  169. caused by exposure to heat, acid polyphenolic compounds, salts, enzymes (rennin)
  170. Ways to prevent scorching
    constant stirring, slow temp increase, double boiler
  171. caused by water evaporation which is accompanied by increased concentration of casein fat and mineral salts, scorches easily and can trap steal--milk boils over
    skin formation
  172. Ways to avoid skin formation
    use lid, stir continually, float butter, whipped cream or marshmallows (why they are on hot cocoa!)
  173. Adding acid to milk will cause
    casein to coagulate
  174. Prevention of coagulation by acid
    thicken milk or acid with starch before, add acid milk (not milk to acid), avoid high temperatures when acid and milk mixed
  175. Milk coagulated and form curds when combined with certain____ from animal, plant, and microbial sources
  176. salt can cause milk to

    prevention: add to milk base, avoid high temp after combined
  177. Fat content in light or coffee cream
  178. Fat content in light whipping cream
  179. Fat content in heavy whipping cream
    not less than 36%
  180. Fat content in half and half (not true cream, combination of cream and pasteurized milk)
  181. Factors affecting stability of milk foam
    fat content (>fat=stability), temperature of cream (optimal 45*F 2 hours before whipping), age of cream (older=greater viscosity and ability to foam), sugar (increases stability)
  182. Storage rule for all fluid milk products
    refrigerate all fluid milk except unopened aseptic packs of UHT pasteurized milk
  183. Classifications of cheese defined by
    microbial characteristics, appearance, mode of packaging, place of origin
  184. Common ways of classifying cheese
    processing methods, milk source, moisture content
  185. Classification of cheese according to moisture content: fresh

    examples: cottage cheese, feta, cream cheese
    moisture content is over 80% and they are note aged
  186. Classification of cheese according to moisture content: soft

    examples: brie and hispanic cheeses
    water content ranges from 50-75% and are aged for just a short time
  187. Classification of cheese according to moisture content: semi-hard

    examples: bleu cheese, munster
    water content ranges from 40-50%
  188. Classification of cheese according to moisture content: hard

    examples:cheddar, swiss
    water content ranges from 30-40%
  189. Classification of cheese according to moisture content: very hard

    examples: parmesan and romano (hardest cheese)
    water content is approximately 30% and are aged the longest
  190. Cheese making starts with
    • coagulation of casein protein in milk 
    • method used to determine the many characteristics of the resulting cheese
  191. Two main methods to aid coagulation are:
    the action of enzymes (renin) and acid
  192. True or false: any mammal's milk can be made into cheese
    True! examples listed in notes
  193. 10 lbs of milk to make
    1 lb of cheese
  194. The curd may be treated to remove more whey by
    cutting, heating, salting, knitting and or pressing (last two are future optional treatment)
  195. To expose cheese to controlled temperature and humidity during aging
  196. the chemical and physical changes that occur during the curing period
  197. a cheese made from blending one or more varieties of cheese with or without heat and mixing in with other ingredients
    processed cheese
  198. USDA grading of cheese is
    voluntary and optional
  199. Cheese grades by USDA
  200. Cheese grading is based on
    variety, flavor, texture, finish, color and appearance
  201. Exceptions to cheese grading criteria:
    colby cheese:
    swisse cheese:
    • colby cheese: color not considered
    • swisse cheese:graded additionally for its salt level and eyes (holes)
  202. the two most important principles when preparing foods with cheese
    select the best cheese, keep temperatures low and heating times short
  203. Chemical composition of cheese determines its functional properties which include
    meltability, oiling off, shredbility, blistering (form with increased aging in cheese) browning and stretchability
  204. cheese storage
    most should be refrigerated and some can be frozen, but processed can be stored in cool, dark cupboard (but refrigeration more effective)
Card Set
Food Science Exam 2
Food Science Exam 2 Material