Exam 2
3. Draw the basic structure common to all fatty acids; recognize the structures of the following fatty acids: butyric, lauric, palmitic, palmitoleic, stearic, oleic, linoleic, linolenic.
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5. Explain the various methods of freezing, including the effect of freezing rate.
*Freezing rate: rapid freezing gives best quality and texture chemical reaction slows down ice crystals and causes less damage A. Air freezing (still or blast): still air= cheapest/ slowest & air blast= frigid air -18 to -57 B. Indirect contact freezing- plate freezer at -18 to -46 C. Immersion Freezing: direct immersion of food D. Cryogenic Freezing: liquid sprayed directly on foods; creates "snow" and vapor that removes heat from good E. Individually Quick Frozen (IQF): Rapid freezing of individual food pieces -fluidized bed (sm-medium fruits, veggies, etc.) -continuous contact/ Blast Freezer: also handles large pieces (Poultry, fish fillets)
9. Explain the heat penetration properties of food and containers, including cold-point and the purpose of headspace.
*Heat penetration- the food in the center of the can must receive sufficient heat treatment to achieve 3 keys of commercial sterilization: -achieve bacterial destruction -minimize adverse sever heat effects -be the mildest heat treatment necessary *Cold point- the coldest spot inside of a can or the last spot to be heated to the optimum temperature of sterilization to comply with food safety regulations through condition or convection heating processes *Purpose of head space- allows contents to expand and helps create a partial vacuum after processing and cooling *can seal is formed before the vacuum *glass seal is formed after the vacuum
8. Explain the proper packaging for frozen foods, including size and headspace.
*Warm Point: the warmest spot int he 4 food item which needs to be evenly frozen with food item *keep the packaging small so the warm point is reached fast 1. easy to seal plastic, or tight fitting lids 2. water proof packages 3. moisture proof packages 4. warer vapor proof (or resistant) 5. low permeability to other gases 6. Durability: high wet strength- will not become brittle and crack when cold A. Use small containers because the warm point location accessibility when freezing -> 1/2 gallon or 5 libs is not recommended B. Cry products- continuous may be filled to capacity C. Liquids- leave 10% headspace to allow expansion of liquid during freezing *Headspace is important when freezing item to allow enough space for expansion during freezing process
6. Explain egg white foam structure, formation and stabilization.
- egg white is an aqueous dispersion protein -it incorporates air when beaten (whipped) -as more air is incorporated, the aqueous film separating adjacent air cells becomes thin -protein denatures, with hydrophobic groups orienting toward the air; this lowers the surface tension of the water, facilitating foam formation -Stabilization of egg white foam is obtained because denatured egg white proteins promote stabilization of the surface of "meringue-type foam" with the hydrophilic and hydrophobic regions reducing the surface tensions -The zig-zag lines around the surface of the foam represents the denatured egg white protein stabilizing the surface
3. Explain the changes in food during cool storage.
- microbial growth: slowed, but continue -chemical changes: starch to sugar in potatoes -off-texture: staling of bread -off flavors: when stored with certain foods -chill injury (some foods): bananas avocados, -off odor
2. Draw the structure and explain the formation of a monoglyceride containing butyric acid.
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2. State the treatments used to preserve food, including specific types.
a. Water removal or binding i. Drying ii. Solute addition b. High temperature i. Thermal processing c. Low temperature i. Refrigeration ii. Freezing d. Oxygen control i. Vacuum or inert atmosphere packaging e. Chemical Preservatives i. Anyimicrobials ii. Antioxidants iii. Acidifiers f. Aseptic conditions: i. Pachaging, processing in sterile conditions (free of microorganism) g. Other processes i. Irradiation ii. High pressure iii. Ohmic heating
Heat Transfer Methods
Conduction- slow; heat is transferred by molecular activity (ex. heat from hot stove to saucepan) Convection- fast; heat is transferred by circulation of the heated parts like for example air so food cooks evenly Radiation- faster; heat is transferred directly from one place to another without intermediate source (medium source)
11. In contrast to pathogenic and spoilage roles, state useful purposes served by mold, yeast and bacteria.
a. Mold i. Soy sauce ii. Roquefort (blue) cheese iii. Camembert chees b. Yeast i. Bread ii. Beer iii. Wine iv. Vinegar (and bacteria) c. Bacteria i. Yogurt ii. Buttermilk iii. Swiss cheese iv. Fermented pickles v. Sauerkraut vi. vinegar
7. Explain the importance of proper temperature in dried yeast rehydration.
a. Requires proper temperature i. 43-46 celsius or 109-115 F b. too low: substance leak from the cells, e.g. glutathione, a reducing agent that converts disulfide bonds to sulfhydryls- affect dough quality c. too high: yeast is inactivated; thermal death point is 54.4. C or 130 F
6. Draw the overall reaction of carbon dioxide production via yeast; state the genus and species of yeast utilized in baked products.
a. Saccharomyces cerevisiae b. C6H12O6>2C2H5OH +2CO2 i. Four sugars fermented by yeast: glucose, fructose, sucrose, and maltose 1. Not starch and lactose so recipes require some other sugar for the yeast to eat
4. Explain how sodium aluminum sulfate acts as a slow acting acid.
a. Slow acting because SAS requires heat to convert it to an acid in water b. Without heat it is just a salt c. Then the acid reacts with sodium bicarbonate to form carbonic acid which then breaks down to CO2 d. Recognize the chemical structure
3. Define the terms: birefringence, waxy starch, syneresis, staling.
a. Solution of amylose b. Birefringence: under light it exhibits birefringence due to crystalized structure; presence of cross on granule i. When you heat in the presence of water it swells and then begins to retrograde ***
3. Explain the drying processes discussed in class and their related advantages/disadvantages.
a. Sun-drying b. Solar Dryers in Fiji c. Spray drying d. Freeze drying e. Drum drying f. Tunnel drying g. Deep fat frying i. Hot oil replaces hot air as drying medium h. Osmotic dehydration i. Product tossed in bed of sucrose crystals which pull water from cells i. Baking i. Water is vaporized j. Extrusion drying i. Slurry of cereal is passed through heated tube under pressure; as product exits through a sized opening, sudden pressure release causes water to evaporate
5. State the defects in baked goods containing too much or too little baking soda.
a. Too much: i. Too alkaline ii. Soapy flavor iii. Brown color (sometimes as spots) iv. Yellowing of flavonoids b. Too little: i. Too acidic ii. Not enough leavening (soggy, compact structure) iii. Whitening can occur
7. Explain how foodborne pathogens can be controlled, including proper food handling techniques (clean, separate, cook, and chill).
a. Wash hands and surfaces often b. Don't cross-contaminate c. Cook to proper temp d. Refrigerate promptly
Standards of Lethality
Chicken: 160 Pork: 145 Fish: 145 Beef: 145 Ground meet: 160 turkey/ chicken grounded: 165
8. Define D-value and the meaning and purpose of using a "12 D process."
-D-Value: time at given temperature to reduce the microbial count by 1-log reduction -12-D value: Time at given temperature to reduce the microbial count by 12-logs .78 min-127C 1.45 min-124C (D124C= 1.45 min.) 2.78 min-121C 5.27-118C 10.0-116C 36-110C 150-104C 330-110C *D value for C Botulinum destruction is 1.45 min **1.45 min is the amount of time required to kill 90% (1-log) of the original number of organisms present at that specific time. ** At 124C a 12-D process for C Botulinum is 12*1.45 min -12D process is 12D124C=17.4 min
7. Explain freezer burn and how to prevent it.
-Dehydrated surface on frozen food; the area becomes dry and tough in texture; caused by water molecules sublimation How to avoid? A. Understand how freezer burn works- when you freeze food, the water molecules in it form ice crystals; if one spot int he food is colder than the other the water molecules will sublimate and migrate to the coldest spot leaving everything else dehydrated; the dry spots changes the flavor, smell, and texture B. Keep the freezing temp constant-the temp fluctuation encourages sublimation (water, molecular sublimation and migration to the coldest spot -freezer door needs to be closed when you open it be quick to shut it -keep plastic containers with 3/4 water to stabilize the temperature in the freezer -don't put hot foods directly in the freezer C. Keep the temperature in your freezer below 0F; freezer burn only happens when temperatures fluctuate above 0F use thermometer to be sure D. Package food-tightly: keep food exposure to air to a minimum to avoid water molecule to sublimate and migrate. Use proper package and remove axcess air from package; always leave enough room for expansion of food E. Don't store food in the freezer for too long- follow guidelines for the item freezing storage time and use date label.
4. Explain the structure of cis- and trans- fats, and omega-3 fats.
-cis is the priniciple configuration found in nature -trans fat have similar effect as saturated fats in heart diseases (bad for your heart) ** **Omega 3?
5. Explain foam formation.
-energy is required foam: substance that is formed by trapping (the energy-whipping) pockets of gas (air) into a liquid or solid -the energy of whipping the liquid to incorporate gas (air) into the liquid and break up large bubbles into smaller ones, and spread the liquid phase around the gas bubbles as they form -foaming agent in liquid phase absorbs at liquid surface, forming a film -surface tension of the liquid must be low so liquid will spread rapidly around the gas bubbles during whipping mechanism
11. For any given food, state whether it would typically be hot packed or raw packed, and processed with a pressure canner or boiling water canner.
-green peas: hot packed- pressure canner -stew meat: hot packed- pressure pears: hot packed or raw- boiling water bath apples: hot or raw-boiling water bath rasberries: hot or raw-boiling water bath pineapple: hot or raw-boiling water bath tomatoes: hot or raw-boiling water bath lima beans: hot packed- pressure canner *all of them should be hot packed but fruits can be raw packed; fruits should be boiled except pineapple needs a retort
1. State the functions of fat in food.
-modify flavor -provide satietyy-texxture -flakiness andtenderness in baked products -leaven batters and doughs -emulsify -transfer heat/ frying -prevent sticking
7. Recognize the factors affecting the susceptibility of microorganisms to destruction by heat.
-pH and salt concentration -Clostridium Botulinum does Not grow in ph <4.6 -Clostridium Botulinum does not grow in high salt content food -so when these conditions are resent then low heat is required (boiling water bath) to kill the microorganisms
3. State the various categories of emulsifying agents, both manufactured and naturally occurring, and how they function.
-substances that are soluble in both fat and water and enable fat to be uniformly dispersed in water as an emulsion Natural: protein, phospholipids (lecithin), solid particles (spices) Synthetic: Fatty acid esters (monoglucerides and diglycerides & other non-glycerine polyl esters -agar -albumin -alginates -casein -acetyl alcohol -cholic acid -desoxycholic acid -diacetyl tartatic acid esters - egg yolk 0glycerol -gums -irish moss -lecethin mono and diglycerides -monostearate -ox bile extract -propylene glycol -soaps
7. Explain whipped cream foam structure and formation.
-whipping the cream incorporates air into the liquid -cream contains fat droplets with their emulsifiers -as air is incorporated into liquid a film of water thins and fat globules are oriented in this film stabilizing the surface layer- the more you are whipping and disrupting the fat globule membrane, the more the fat globules stick together imparting stiffness to the foam and promoting its stability -the stability of whipped cream is produced by a rigid yet fragile structure formed by clumping of an infinity of fat globules on surface of air cells
Log Reduction Survivors and Destruction
0-1,000,000-0% (90%)1-100,000-90% 2-10,000-99% 3-1,000-99.9% 4-100-99.99 5-10-99.999 6-1-99.9999 7-0.1-99.99999 8-0.01-99.999999 9-0.001-99.9999999 10-0.0001-99.99999999 11-0.00001-99.999999999 12-0.000001-99.9999999999 *12 log reduction to achieve a commercial sterilization
4. Explain the types and causes of emulsion instability.
1. Coalescence: merging of droplets (oil/vinegar) 2. Creaming: Separation into 2 phases with cream on top and liquid on bottom (unhomogenized milk 3. Inversion: changing of emulsion type o/w> w/o (churning of cream to butter)
State factors to consider when preserving food at home:
1. Is it in season? 2. Equipment involved (too big, too expensive) 3. Energy for processing 4. Storage containers 5. Space available for storing 6. Quality of available foods 7. will you use the food you're producing? 8. Ability to be self-reliant
2. Explain emulsion formation.
1. Mix emulsifier with continuous phase+ 2. Agitation, shake, mix, or blend+ 3. Slowly add dispersed phase By themselves, oil and water do not combine but +emulsifier+ agitation = Emulsion * a monoglyceride is an emulsifier which uses emulsion to apply glycerol **
5. State the conditions which allow for growth of Clostridium botulinum spores.
Clostridium Botulinum is the most heat resistant pathogen and the conditions for its growth are: -anaerobic environment -ph greater than or equal 4.6 -water activity greater than .92 -temperature 3.3 to 97 celsius -type E grows at 3.3 -Protein/ carbohydrate medium favors growth -low salt content: growth is prevented in products with 5-10%salt, e.g. salt-cured meats
10. Explain the following processing techniques: retort (pressure canner), aseptic, hot fill and hold, and boiling water bath; explain the need to vent retorts.
1. Retort (pressure canner) and why do we vent retort? Retorts are pressure cookers designed to increase the vacuum pressure inside of the pressure cooker in order to raise the boiling point of the water and destroy the pathogen in short amount of time! The reason for the pressure cooker vent is to release the air from the cooker in order to make sure the cooker has only steam. Steam is much hotter and raises the boiling point of the vessels. 2. Hot fill and hold- process where hot food is filled into container, sealed, inserted and held before cooling to sterilize lid only use with acidified foods where c. boultium is Not a concern (jams and jellies) 3. Boiling water bath: large container use to process up to 7 giant cars in boiling water only used with acidic foods where c botulinum is not a concern. 4.Aseptic: process where food is commercially sterilized and cooled, filled into separately sterilized container -advantage is that there is less heating required therefore better nutrient quality, less energy required, plastic containers can be used
3. State and explain the variables that must be known to preserve food using heat.
1. time and temperature combination inactivate the most heat resistant pathogens and spoilage microorganisms. 2. Heat penetration properties of each specific food in its container (This gives you the cold point) **Product development: clostridium botulinum (spores) the most heat resistant pathogen
Why is 12-D process reduction is needed?
A 12-D process is required for commercial sterilization -a 12-D process is used in commercial sterilization in order to achieve the level of sterilization needed in the food industry to provide food safety -the overkill process of at least 12 logs reduction is used to account for potential higher counts or variations in microorganisms resistance, etc. - the most heat resistant food pathogen is the clostridium b spores- A as D-process sterilization apply to clostridium B
1. Draw two amino acids joined together with a peptide bond; describe amino acid and protein structure, including primary, secondary, tertiary and quaternary structure.
A. ** B. -contain both a carboxylic acid and an amino froup -there are about 2o unique amino acids -they differ in their side groups (R groups) amino acids can be positively charged, negatively, or neutral ** C. Protein structure: amino acids are the building blocks of a protein forming the backbone of a protein; amino acids are joined by peptide bonds; the chain of amino acids is called polypeptide chain; the chain consists of a repeating structure "NCC-NCC-NCC..." atoms along the length of the molecule. this is referred to as the backbone of the proteins -the nature of the R groups determines the protein structure or conformation (the shape the protein assumes in space) Primary- linear sequence of amino acids, covalently linked through peptide bonds** -secondary: spatial arrangement of amino acids residues at certain segments of the chain (alpha helix, beta pleated sheet, random coil, beta turn); stabilizied by hydrogen bonding** -tertiary: spatial arrangement when the linear chain alpha helix, with secondary structure folds into a compact three dimensional structure ** -quaternary: when a protein contains more than one polypeptide chain(combo of primary, secondary, and tertiary) -denaturation: when the bonds are destroyed in the 2nd, 3rd. 4th. but not in the primary (high levels) -Hydrolysis: when you destroy the entire protein
6. State the types of starch modifications, including their applications
A. Acid midified starch: heat the starch with acid to reduce the viscosity of the starch which allows the starch to form a clean gel (gummy bears) B. Cross Linked starches: binds two different starches together to minimize breakdown (canned and frozen foods) C. Pregelatinized starch: pree-cooked and dried (instant pudding) they expand during cooking and then dry afterward
8. Explain fat and oil processing, including vegetable oil, shortening, butter, margarine, and lard. List the steps in making vegetable oil.
A. Clean, Pressing, Refining, Bleaching, Deodorize B. oil 1. cleaned; cracked; tempered 2. pressing- removes oil 3. refined- by using alkali to remove free fatty acids and non fatty materials 4. bleached- with "fullers earth" to lighten color 5. steam distillation in a vacuum to get rid of volatile substances (can get into air) C. ** D. Shortening: vegetable oil is made into shortening by hydrogenating it before deodorizing: 1. clean 2. processing 3. refining 4. bleaching 5. hydrogenated 6. deoderize 7. emulsifier is added 8. chilled and agitated 9. whipped E. Margarine: there is the fat and water phase and they are blended together to form margarine. There is an emulsifier which keeps them in the solution F. Butter: cream and milk separated by centrifugation 1. pasteurized-killing the pathogens 2.churned-churcning the cream until the water is dispersed in the food 3.Inversion- fat in water becoming water in fat -buttermilk is removed and salt is added to the better 4. Lard: comes from the fat tissues of pork; by cutting the fat small pieces 5. Rendered: heated with or without water to remove the fat G. Prime steam: lard is heated with water H. Kettle rendered: heated without water and has some flavor -antioxidant is added to lard -the lard has the same steps in processing as in vegetable oil (5 steps) cleaning, pressing, refining, bleaching, deodorizing
1. State the types of low temperature preservation and recommended temperatures.
A. Common or clear storage: <15C (slightly cooler than outside temp); short term; root crops, potatoes, cabbage, celery, apples B. Refrigeration: 0-10C; weeks to months; most foods C. Freezing: <-18C or 0F; months to 2 years; most foods
4. State the changes in foods during freezing/frozen storage.
A. Formation of ice-crystals: large crystals disturb the cell walls; loss of texture B. Movement of water from cells: -increased concentration of solutes in the remaining unfrozen liquid- salting out -Oxydation of fats, pigments, loss of flavor, and color quality -Dessication (freezer burn): loss of water causes tissue to dry out then upon thawing, tissue tends not to reabsorb water in that location -Mocrobial load: slow the growth of microbial population but doesn't destroy
2. State the advantages and disadvantages of low temperature preservation.
Advantages; better sensory quality; better nutrient retention Disadvantages: cost (requires continual input of energy);shorter shelf-life (compare to canning and drying); doesn't last very long in the fridge
4. List and explain the 7 basic steps of flour milling. a.
Blend: types of wheat mixed to make specific flours b. Clean: Screening, air aspiration, washing etc. c. Temper: water added held 6-24 hours; toughens bran and softens endosperm d. Break: Corrugated rolls break up wheat pieces into coarse particles e. Purify: air currents and sieves remove brand and classify particles (middlings) by size and weight f. Reduce: smooth rolls reduce middlings into flour g. Sift: broken wheat separated through successive screenings that increase in fineness
2. Define /explain the following terms: cooking, pasteurization, blanching, canning, sterilization, commercial sterilization.
Cooking: heating or reheating food (consumer) Pasteurization: treatment to destroy pathogens, reduce bacterial count, and inactivate enzymes Blanching: steaming or boiling with water; immersion for a short period of time vegetable into boiling water then place in ice bath for 10 min; inactivates the enzyme prior to freezing vegetables Canning:Treatment to destroy all pathogenic and spoilage organisms; thermophiles may be present; (2 types: retort (pressured pan) and boiling water bath) Sterilization: treatment to destroy all microorganism and spores Commercial sterilization: treatment to destroy pathogenic and spoilage organisms only! May contain thermophiles.
6. Contrast heat processing requirements for low acid and acid foods, including pH, and why they require different heat processes (steam under pressure versus boiling water).
Effects of heat on microorganisms low ph/ high acid -high acid <3.7 (berries, sauerkraut) -acid 3.7-4.6 (tomatoes, pear, pineapple) -boiling water bath high ph low acid -med acid 4.6-5.3 (spinach, asparagus, beets, pumpkin) -low acid >5.3 (peas, corn, lima beans, fish, poultry) -pressure cooker PH 4.6 used as dividing line because botulinum does NOT grow at 4.6 -Clostridium Botulinum grows at pH greater or equal to 4.6
Celsius to F
F= C*1.8+32 (F-32)/1.8=T
9. Explain how food safety is enhanced via food label statements, including the meaning of the various dating codes.
Food safety is enhanced through food label warning consumers and store employee about the freshness of the food item through the following date codes: a. Best if used by date- informs consumers of the food's optimal period for retenetion of high quality b. Expiration date- indicates a deadline for recommended use c. Pack date- indicates when the food was packaged d. Pull date- signifies the last day the food may be sold as fresh e. Allergen statement- states if any of the following allergens are present: milk, eggs, fish, crustacean, shellfish, tree nuts, peanuts, wheat, or soybeans
6. Explain the risks if frozen foods are not stored below the recommended temperature.
Food should e stored a t -18C or below if temperature goes above this level and fluctuates then food loses moisture and freezer burn occurs (dehydrated surface on a frozen food)
7. Explain hydrogenation, interesterification and superglycerination of fats and their significance.
Hydro: addition of H2 to double bonds converting unsaturated fats to saturated fats -The oil is treated with nickel catalyst; the system is evacuated and H2 is admits -as unsaturated> saturated it changes the textre and improves stability B Interesterification: process of treating fats with catalyst to hydrolyze the fatty acids and re-esterify them with glycerol in a more random order ** C. Super: the process of incorporating 3-6% emulsifier (glycerol monosterate into shortening to improve its baking qualities D. emulsifier: prevents liquid from being separated (when shortening combines with an emulsifier then prevents it from coming apart
12. State where to find reliable information regarding home canning procedures and explain the precautions to take when processing low acid foods.
In order to safely learn the rules and procedures of home canning, along with tips and precautions to take when home canning your own food, read publications form USDA under the National Center for Home Food Preservation Dept. -Low acid foods: must be prepared with retort canners to destroy clostridium botulinum organisms
Oils
Liquid at room temp
1. State the purposes of thermal processing and how these purposes are accomplished.
Make food sell, extend shelf life, improve palatability (taste) Accomplished by: eliminating all pathogens, eliminating or reducing spoilage organisms Inactivating enzymes and other biological factors that lead to nutritional quality losses
10. List the steps and explain the purposes of blanching vegetables before freezing.
Purpose: improves color, flavor and texture reduces microbial food, provides better packing, preserves nutrients, removes odor/ flavors undesirable, inflates enzymatic reaction Steps: 1. Prepare a put of salted, boiling water and an ice bath pot 2. Place the vegetables in the boiling water; keep the water at constant boiling; test for doneness after 1-2 minutes 3. Quickly remove the vegetables form the boiling water and plunge them into he ice bath pot (this is called shocking) by immersing the veggies infold water will halt the cooking process immediately 4. Keep the veggies in the ice-water bath long enough for them to cool them completely; if removed too soon they will continue to cook from the inside out resulting in a mushy finished product
Why do some microorganisms require different heat processes to be destroyed?
Some microorganisms are heat resistant and thus requiring high heat in order to be destroyed. The high heat resistants are usually present in food with high ph and low acidity. They require tge use if retire canners. Microorganisms ub kit pH and acidity will be destroyed with the boiling water bath system.
9. Explain recommended thawing procedures for meat and why refreezing is not recommended.
Thawing procedures for meat: -use refrigerator -use microwave -use cold water, replace the water every 1/2 hour -never at room temp -never use hot water to defrost meat, as that can cause the outer layer of the food to heat up to a temperature where harmful bacteria begins to multiply Refreezing problems: -increased microbial load -texture changes -off flavors
4. Contrast the thermal resistance of bacterial spores with that of yeast and mold spores.
Yeast/ Mold spores are much less resistant to heat. 5 to 10 minutes at 60 celsius will destroy yeast and mold spores but NOT bacteria spores.
10. Define antioxidant; state the names and acronyms of common antioxidants; explain how they work.
a molecule that donates the hydrogen ion and becomes stabilized by resonance ** BHA- Butylated hydroxyanisole BHT- Butylated hydroxytoluene TBHQ- Tertiary Butylhydroquinone PG-Proply Gallate Vitamin E- Alpha- tocopherol
5. Define and explain the flour treatments: aging/oxidation, bleaching, and enrichment.
a. Aging/ chemical oxidation: i. Form disulfides ii. Aging increases s-s bonds iii. To hasten the process, oxidants are usually use to convert SH groups to s-s bonds iv. End result is dough that is stronger. Ess sticky and easier to handle b. Cleaning: i. Removes yellow xanthophylls c. Enrichment: i. Addition of thiamin riboflavin, niacin, iron, and folate
1. State the two main starch molecules and describe their chemical structure.
a. Amylopectin: branched i. Makes up about ¾ of granule ii. Larger of the two molecules iii. 15-30 glucoses per branch iv. millions of glucose-units per molecule v. glucose polymer with alpha 1>4 and alpha 1>6 linkages vi. branches contain 15-30 glucoses b. Amylose: straight i. Linear ii. Makes up about ¼ of granule iii. Smaller of the two molecules iv. Thousands of glucose-units per chain v. Glucose polymer with alpha 1> 4 linkages
8. Explain the HACCP system of food protection.
a. Assess the hazards b. Identify critical control points (ccps): prevent injury and death to the customers c. Set up control procedures and standards for ccps d. Monitor ccps e. Take corrective action f. Develop a record-keeping system g. Verify the system is working i. System depends on prevention rather than inspection
3. Explain why food preservation is beneficial despite any related nutrient losses.
a. Availability: local food products are typically not available year round b. Variety: types of food available locally are usually extremely limited c. Quality: quality deterioration, including nutritional losses, can occur rapidly when food is not preserved in some way d. Convenience: weekly trips to local market are time consuming, as is producing your own food e. Cost: food is often more economical when large quantities are packages where produced and then distributed majority of the nutrients preserved
State the general characteristics of bacteria, yeast and mold.
a. Bacteria: i. One-celled microorganism ii. Distinguished by shape: round, rod, spiral, or filament iii. May form spores b. Yeast i. One-celled microorganism ii. Oval or spherical shaped iii. May form spores c. Mold i. Multicellular microorganism ii. Filaments give fuzzy or cotton-like appearance iii. Strict aerobes (need oxygen) iv. May form spores
State three general categories of food safety concerns and give examples of each.
a. Biological Concerns i. Fodborne illness: bacteria, molds, ciruses, parasites ii. Biotechnology/ genetically modified organisms b. Chemical concerns i. Naturally occurring toxins present in foodstuffs ii. Pesticide residues iii. Food additives iv. Accidental chemical contamination v. Toxic metals c. Physical concerns i. Glass, metal, plastic, wood, stones, bone, fruit pits, insects and other fifth or foreign objects
1. State the basic causes of food deterioration, including specific factors.
a. Biological factors: i. miscroorganisms (bacteria, yeasts, and molds) ii. Infestation (insects, parasites, rodents) b. Chemical factors i. Nonenzymatic reactions, e.g. lipid ixidation, Maillard browning ii. Enzymatic reactions c. Physical/ Environemntal Factors i. Inappropriate storage temperatures ii. Gain or loss of moisture iii. Reactions with oxygen or light iv. Physical stress or abuse v. time
5. State factors to consider when preserving food at home.
a. Cost i. Food ii. Equipment for processing iii. Energy for processing iv. Storage containers b. Space for storing c. Quality of available food d. Will you use it? e. Ability to be self reliant
Explain the temperature danger zone of bacterial growth, including the temperature range involved, and define the following terms: thermophile, mesophile, psychrotroph, psychrophile.
a. Danger Zone: do not hold at 40-140 F best temperature for microbial growth b. Thermophiles (40-70) i. Optimum growth at 45 c. Mesophiles (10-50 i. Optimum growth at 20-45 d. Psychotrophs (0-30) i. Can grow at refrigerated temperatures but optimally grow at higher temperatures (some grow slowly even when frozen) e. Psychrophiles (-10-20) i. Grow well at refrigerated temps ii. Capable of growth below 10
1. Define the following terms: drying, dehydration.
a. Drying: i. Removal of water from a food using ambient conditions ii. Often used as a synonym for dehydration b. Dehydration: removal of water from a food using controlled conditions of heating, forced air circulation, and relative humidity
10. Discuss who has the responsibility for producing, marketing and consuming safe food.
a. Food producers b. Food manufacturing and processing companies c. Food service establishments d. Consumers e. Government agencies
4. Explain gelatinization/pasting and the influence of sugar, acid, salts and fats on gelatinization
a. Gelztinaztion: the loss of the cross and the swelling of the granule ***
4. Explain how to optimize the storage life of dried foods (hint: HALT).
a. H: humidity (moisture) i. Allows mold growth, accelerates chemical reactions b. A: Air (oxygen) allows mold growth, destroys fats and pigments c. L: Light i. Destroys fats, pigments, and some vitamins d. T: Temperature i. Accelerates chemical reactions
2. State the general parameters that are controlled during dehydration.
a. Heating, forced air circulation, relative humidity
5. Define the 3 categories of microorganism-caused food borne illnesses and designate which organisms belong to which category.
a. Intoxication (food Poisoning) i. Illness caused by ingesting a performed toxin (poinson) produced by an organism b. Infection i. Illness caused by ingesting living organism that grows in G.I. tract (salmonella) c. Toxin- mediatted infection i. Illness caused by ingestion of living organism which also produces a toxin in G.I. tract (E. Coli)
4. Discuss (pros and cons) of preserving food, including the feasibility of eating only locally produced fresh foods.
a. Loss in nutrients b. ^^^^ see 3 //a. Availability: local food products are typically not available year round b. Variety: types of food available locally are usually extremely limited c. Quality: quality deterioration, including nutritional losses, can occur rapidly when food is not preserved in some way d. Convenience: weekly trips to local market are time consuming, as is producing your own food e. Cost: food is often more economical when large quantities are packages where produced and then distributed
2. Describe starch granules, including appearance and physical characteristics.
a. Microscopic packages, within plant cells, consisting of starch molecules arranged in an orderly fashion; unique for each type of starch i. Form of native uncooked starch ii. Storage vessels for starch molecules iii. Special plastids (known as amyloplasts) in certain plant cells iv. Surrounded by lipid bilayer membrance v. Site of starch molecule synthesis from glucose vi. Sit of starch molecule hydrolysis (conversion to glucose) when plant needs energy
5. Define retrogradation and explain its consequences.
a. When you heat in the presence of water it swells and then begins to retrograde and collapse back into itself because water is lost b. Retrogradation: partial re-crystaliziaiton of starch milecules after gelatinzation; not enough to exhibit birefringence c. Waxy starches will not gel because they have no amylose d. If it happens slow= retrogredation; rapidly= gelation i. syneresis is the expulsion of free liquid from a gel during aging
Based on the limiting factors for growth and common knowledge about food, determine the type of microorganism that would likely be the initial cause of spoilage in any given food.
b. Whole wheat: mold c. Milk: bacteria d. Ground beef: bacteria e. OJ: yeast f. Unpeeled orange: mold g. Whole tomato: mold h. Cheese: mold i. Jam: mold j. Bologna: bacteria k. Honey: yeast l. Ground chicken: bacteria
Best foaming agents:
egg whites, gelatin, milk proteins
examples of emulsifiers
french dressing italian dressing miracle whipping margarine and butter milk and cream cake and cream puff batters
6. Recognize the names of the common food-borne pathogens.
i. Bacillus cereus- intoxication ii. Campylobacter jejuni- infection iii. Clostridium botulinum- intociation iv. Clostridium perfringens- toxin-mediated infection v. Escherichia coli- tpxin-mediated infection vi. Listeria monocytogenes- infection vii. Salmonella species- infection viii. Shigella- infection ix. Staphylococcus aureus- intoxication x. Vibrio parahaemolyticus- infection xi. Yersinia enterocolitica- infection xii. Norovirus
1. Define emulsion, including types of emulsions with food examples.
mixture of water and lipids (fat/oil) -any food system that involves an aqueous fraction intimately commingled with a liquid fraction -a colloidal dispersion of one liquid in another liquid, where the two liquids are naturally immiscible - types are dependent on whether water or oil is the continuous phase -oil in water (o/w): most food emulsions are oil droplets in water -Water in oil (w/o): butter and margarine water droplets in oil
Fats
solid at room temp
Stabilizing emulsions
solid particles can temporarily stabilize and emulsion (mustard and paprika in french dressing)
6. Define plasticity and state the factors that alter plasticity.
the capacity of a fat to retain its sha[e (olive oil vs butter butter is more plastic than olive oil) **
Unsaturated
the greater the number of double bonds, the lower the melting point 18:0 tristerian 65C 18:1 Triolein -12C 18:2 trilinolein -43 MP
Saturated chains
the longer the saturated chain, the higher the mp 12:10 Trilaurin 35 C MP 16:0 tri palmitin 56C 18:0 tristearin 65C
9. Explain the two types of rancidity and their mechanisms.
the off odor and taste of oil when the fat breaks down (shortening and nuts) Type 1: oxidative- lipid oxidation- requires O2 ** Type 2: Hydrolytic rancidity: the hydrolyzation of short chains fatty acids giving off bad odor- requires H20
5. State the effect of chain length and degree of unsaturation on melting point.
unsaturation and chain length effects melting point -short chains have lower melting point -longer chains have higher melting point -the greater the unsaturation the lower the melting point -cis causes looser fit= lower MP
