Food Engineering Flashcards
Give two foods that are pasteurized using high pressure.
Guacamole; deli meats
What are QUATs & what is their purpose?
Quaternary ammonium compounds; used as sanitizers
What is Biot’s Number and what are it’s units?
Ratio of heat transfer resistance inside of and at the surface of a body; dimensionless
In expressing units for vacuum in the English system, how many inches of mercury is the atmospheric pressure?
0
During the manufacture of ice cream, you discover that 1 liter of mix makes 2.0 liters of frozen ice cream. What’s your overrun percentage?
100%
What pH value is used to determine when a food is acid or low acid?
4.6
What is pH cutoff for high acid and low acid foods?
4.6
A retort temperature of 250 F is achieved with how many pounds of pressure per square inch?
15
What is the cutoff Reynold’s number for laminar flow in pipes?
2100
What are two factors critical for potato chis color and texture?
Free reducing sugars; Specific gravity (for absorption of oil, moisture loss during frying)
The ratio of two extensive properties of a homogeneous system is (a) an extensive property, (b) an intensive property, (c) a dimensionless quantity, or (d) none of the above?
(b) an intensive property
What is the average density of globular proteins?
~1400 kg/m3 or 1.4 g/cm3
What is the Reynolds number in a laminar flow?
What is the freezing point for most natural foods?
0 to -2 C
What is the temperature of triple point for water?
0.01°C.
What are the units for humidity?
1 lb water/ 1 lb air
1 Candela per square meter is equal to what?
1 lux
In brines, salt is measured with a salometer; what is 1° Salometer equal to?
1% of saturated NaCl solution (OR 0.265% salt = 1 degree salometer)
When convection predominates, where is the coldest spot in a can?
1/3 into can? (It can vary)
High-pressure processing of foods is often conducted in what pressure range?
100-800 Mpa
What is the saturation pressure of water at 100 °C
101.325 kPa or 1 atm.
The z-value you have calculated for your process is 18 degrees F. What is the z-value in degrees Celsius.
10C
What is the mean surface area of a Delicious apple?
140.13 cm2
How many BTU’s must be taken from a pound of water to change it from a pound of liquid water at 32°F to a pound of solid ice at 32°F?
144 BTU’s
What is the mean surface area of a Bartlett pear?
145.42 cm2
What is the minimum time and temperature required for batch or vat pasteurized milk?
145F (63 C) and 30 minutes
What are LTLT (low temp/long time) conditions in milk pasteurization?
145F for 30 minutes
What is an Intermediate Moisture Food?
20 - 40% moisture, Shelf stable, No rehydration needed, Combination of Low aw and additives
Given the gauge pressure in a retort is 100 kPa, what is the absolute pressure?
201.3 kPa
A metal container that is 2.6875 inches wide by 4 inches tall is known as what size container in the canning industry?
211 x 400
A 307 X 512 can has what diameter in inches?
3 7/16 inches
A product with a drying ratio of 5 yields 1 kg of dry product for every _______kg of water removed.
4 kg—drying ratio is the amount of fresh material needed to produce 1 kg of dried product
What is the freezing point for “freeze flow” formulated foods?
-5 to -15 C
What does 50 grain vinegar mean?
5% by weight
What is the mean surface area of an egg?
70.5 cm2
Water increases in volume by what amount as it turns to ice?
9% increase in volume
What is a psychrometric chart?
A graphical representation of properties for air-vapor mixtures.
What is a typical rheological property of a shear-thickening fluid?
A higher apparent viscosity at a higher shear rate
What is a subcooled liquid?
A liquid at the saturation pressure and a temperature below the saturation temperature.
What is a Bingham liquid?
A liquid that behaves similar to a Newtonian fluid at a stress greater than yield stress.
What is a typical rheological property of a shear-thinning fluid?
A lower apparent viscosity at a higher shear rate
What is thermal conductivity?
A measure of a material’s ability to transfer thermal energy.
What is syneresis?
A physico chemical process where water is expelled out of a gel or gel-like structure
To transfer cottage cheese from a vat to a tank, what type of pump should be used?
A positive displacement pump, the lobe type
What is the triple point?
A state where the three phases (solid, liquid and vapor) may all be present in equilibrium.
What is saturated vapor?
A substance occurs as a vapor at the saturation temperature and pressure.
What is a saturated liquid?
A substance occurs in a liquid state at its saturation temperature and pressure
What is a closed system?
A system that has no mass exchange with the surroundings
How are absolute pressure and gauge pressure related?
Absolute pressure = gauge pressure + atmospheric pressure
What is tempering with respect to flour milling?
Addition of water to raise moisture of wheat directly before milling
In cheese production most of the flavor is released during…
Aging
What thermal processing feature is essential for processing of food in glass containers?
Air overpressure
In SI system, what is the unit of magnetic field strength?
Ampere per meter
In SI system, what is the unit of current density?
Ampere per square meter
What is the permeate in UF?
Any substance not retained by the filter
What is a “food additive”?
Any substance that becomes part of a food product either directly or indirectly during some phase of processing, storage, or packaging.
What is reverse osmosis?
Applying pressure to exceed osmotic pressure of the solution
Explain the relationship between freezing rate, ice crystal size, and quality of frozen food products.
As the freezing rate increases, the crystal size decreases, and the product quality increases
How is water activity related to ERH?
aw = ERH/100
What is “double acting” baking powder?
Baking powder + 2 different acids, one which reacts at room temp, and one reacts at high temp.
What equation is used to describe mechanical energy balance for pumping?
Bernoulli equation.
The polysaccharides in oats that provide viscosity and filtration problems in the brewing industry are called?
Beta-glucans
A mild heat treatment to inactivate enzymes is called?
Blanching
What is the standard instrument worldwide for measuring the gelatinization properties and enzyme activity of flour?
Brabender amylogrpah
How may the seam tightness of a can be judged visually?
By the degree of wrinkling of the cover hook
In cheese making, the “cheddar” process involves: a. adding lactic acid to milk, b. adding rennet, c. turning and piling the curds, d.chopping the curds and adding salt
c. turning and piling the curds
What is the “method champenoise”?
Carbonation of wine by secondary fermentation in the bottle
Of processed cheese, processed cheese food and processed cheese spread, which has the most and which has the least water?
Cheese (most) and spread (least)
What acid in milk is fermented by bacteria to provide a source of diacetyl and volatile flavor compounds in fermented dairy products?
Citric acid
What is CIP?
Clean in place
The repirating burst associated with the fruit ripening process is called:
Climacteric rise
What is CUT?
Come up time in canning
What term describes the processing of a product, intended for room temperature storage, with the goal of preventing the growth of spoilage and pathogenic bacteria (although spores may be present)?
Commercial sterility
Name the isoentropic phase of refrigeration.
Compressor phase (compression)
What is the term for the change from a gas to a liquid?
Condensation
What are the units for thermal conductivity?
Conductivity (k) = J/msK or W/mK
What is the primary mechanism by which heat transfer occurs in a canned liquid?
Convection
What are the units for the convective heat transfer coefficient?
Convection (h) = J/m2K or W/m2K
What is the major reason that copper should not be used in food processing equipment, especially in dairy plants?
Copper acts as a strong oxidizing agent and promotes (catalyzes) oxidative rancidity
In SI system, what is the unit of electric charge density?
Coulomb per cubic meter
In SI system, what is the unit of electric flux density?
Coulomb per square meter
Which of the following are not part of a can’s double seam? coverhook; body hook; overlap; coverslip
coverslip
A maximum or minimum value for which a biological, chemical or physical parameter must be controlled by a CCP is what?
Critical limit
What is the name of the law that states “the total pressure of a mixed gas phase is equal to the sum of the partial pressures of the individual components”?
Dalton’s Law
Of the following, which method of food preservation will probably result in the greatest loss of vitamin A? A. Canning B. Refrigeration C. Freezing, D. Dehydration
D. Dehydration
Name the stage in fat processing where unwanted odors and flavors are removed.
Deodorizing
What type of fluid becomes more viscous when more force is applied to it?
Dilatant (shear thickening)
What is the rheological term for time-independent shear thickening?
Dilatency
Dehydration by contact with a heated surface of a revolving drum is called what?
Drum or roller drying
Why does extruded material puff when it leaves the extruder?
Due to pressure drop when exposed to the atmospheric pressure
What is the capacity of a material for taking recoverable deformation known as?
Elasticity
The HLB value is a number from 1 to 18 used to describe the effectiveness of what types of compounds?
Emulsifying agents
What is the 1st law of thermodynamics?
Energy can neither be created or destroyed
What is “oven Spring” that occurs during break baking?
Expansion of gas cells because of heat (oven spring is the rapid rise in bread loaf volume when placed in oven)
Name 2 encapsulation techniques?
Extrusion and spray drying
What is Newton’s second law of motion?
F = ma (force = mass x acceleration)
What are F values calculated at 250° F (121C) with a z value of 18F (10C) called?
F0
With regards to wheat flour processing, what are course particles of endosperm called?
Farina
Which federal authority approves frequencies used in the microwave and radio frequency heating of foods?
Federal Communications Commission (FCC)
What is aseptic processing?
Food and container are sterilized separately and then filled in a sterile environment.
What is the name of dQ/dt = -KA dT/dx?
Fourier’s law
What is another method/process for orange juice other than evaporation?
Freeze concentration
What is the processing difference between fresh pack and salt stock (genuine) pickles?
Fresh pack pickles are only marinated, whereas salt stock pickles are fermented.
What are the SI units of poise?
G/cm or pascals
Name 2 methods of irradiating foods.
Gamma rays, electron beam, also x-rays
What is the primary mechanism by which microwaves heat foods?
Generation of intermolecular friction caused by polar molecules attempting to oscillate at the frequency of the electrical field reversal (915 to 2450 MHz)
The unit for dose rate in ionizing radiation preservation is the ________________?
Gray
In the equation E=hv, what letter designates the “Planck constant”
h
What the term used to describe the level of calcium and magnesium salts in water?
Hardness
What packaging material has the highest moisture barrier?
HDPE
What is the name given to the volume of gas between the surface of the food product and the package?
Headspace
Why is wheat tempered before milling?
Helps to remove bran and reduces energy required in milling
A container that is absolutely impermeable to gases and vapors throughout its entirety is called?
Hermetic
Milk jugs are most commonly made of what polymer?
High Density Polyethylene
What part of the pasteurization controls the time?
Holding tube
What piece of equipment is used to uniformly disperse lipids in bovine mammary secretions?
Homogenizer
The major traditional preservative in beer is?
Hops
What is case hardening?
In drying, outer cells can collapse and form a water impenetrable layer that makes the product difficult to rehydrate.
Why is it necessary to pressure cool large diameter (401 or more) cans after low acid thermal processing?
In order to prevent buckling.
Where do you find the “greasy bag syndrome”?
In potato chips
Cloud stability in products like tomato and orange juice is favored by:
Inactivation of PME
What is the purpose to form agglomerations of powdered foods?
Increase hydration ration
If the temperature increases, what happens to the rate of heat transfer?
Increases
Give an example of a product made using “agglomeration”
Instant coffee, instant milk
What is the difference between intensive and extensive properties?
Intensive properties do not depend on the mass of a system.
Water hardness can be reduced using a water softening system; what is the principle used to reduce water hardness in these systems?
Ion exchange
The radura symbol indicates that a food has been treated by or with what food processing system?
Irradiation
What is the major component of hop, which carries the bitterness of beer?
Isohumulones (converted from humulone in brew process)
What must be done to milk before it can be used as an ingredient for bread?
It has to be scalded
What is the main reason that stitch pumping is the most used curing method in the meat industry?
It is conducive to mechanization (conveyor and automation)
What is the triple point of water?
It is the point on a pressure vs. temperature diagram where solid, liquid, and gas phases co-exist.
What is the winterization process for an oil?
It is the process of cooling the oil and filtering of the solids formed so that long chain saturated fats do not crystallize at low temperatures
What is the role of carrageenan in infant formula?
It stabilizes milk protein, protecting it from heat
What Australian is known as the father of refrigeration?
James Harrison
Who is considered the father of mechanical refrigeration in the U.S.?
John Gorrie
In SI system, what is the unit of energy density?
Joule per cubic meter
In SI system, what is the unit of heat capacity?
Joule per kelvin
In SI system, what is the unit of entropy?
Joule per Kelvin
In SI system, what is the unit of specific energy?
Joule per kilogram
In SI system, what is the unit of specific heat capacity?In SI system, what is the unit of specific heat capacity?
Joule per kilogram Kelvin
A Brik-Pak is an example of what general class of packaging material?
Laminate
What is the term used to describe the energy needed for changing between the states?
Latent heat
Less starch granule damage occurs during milling of soft wheats because?
Less energy is required for reduction of grain to flour
Name a purification step used to produce high fructose corn syrup after starch
liquefication.
What are two materials used in cryogenic freezing?
Liquid nitrogen and carbon dioxide
Ultrafiltration requires (lower/higher) pressures than reverse osmosis.
Lower
Candela per square meter is the unit of what in the SI system?
Luminance
In SI system, what is the unit of specific volume?
m3/kg
What is distilled vinegar?
Made from distilled alcohol
What problem may arise when potato tubers are taken from cold storage and immediately processed?
Maillard browning
What is produced by grinding corn that has been steeped in calcium hydroxide?
Masa
The part of the beer making process that involves heating malt and water to 60 degrees C to facilitate enzymatic reactions is called_____________?
Mashing
Name the defect in cottage cheese where a few curds are oversized.
Matted
What is the improvement of baking properties in flour called?
Maturation or aging
In the SI system, what is the unit applied to length?
Meter
What commercial product was first produced in 1947, weighed 750 pounds, and was patented by the Raytheon Co.?
Microwave oven
What is a break roll?
Milling equipment used to remove bran and are corrugated
What is sous vide?
Minimal processing of food under vacuum
What is the “F” value?
Minutes required to destroy a given number of microbes at a given temperature
What diagram is used to determine friction factor?
Moody diagram
What is term for the the force that gives to a mass of 1 kilogram an acceleration of 1 meter per square second?
Newton
In the SI system, what is the unit for surface tension?
Newton per meter
What are the SI units of force and pressure?
Newton, pascal
Who first developed canning as a food preservative method?
Nicolas Appert patented preservation of food by canning in France in 1810
All but which one of these factors combine in the preservation of jams: water activity, heat, nitrites, and pH?
Nitrites
What gas used in modified atmosphere packaging is the most abundant gas in the earth’s atmosphere?
Nitrogen
What is the equation “PV=nRT” called?
Noble or Ideal gas law
What are the units of a Reynold’s number?
None, it is dimensionless
The ability to raise 33,000 pounds one-foot high in one minute is the definition of one unit of what?
One unit of horsepower
What measure of foam capacity is defined as: (volume of foam – volume of initial liquid)/(volume of initial liquid) x 100?
Overrun
In SI system, what is the unit of dynamic viscosity?
Pascal second
What does PU stand for in beer manufacturing?
Pasteurization units, 10 PU (1PU=1 min 60 degrees C)
What is patent flour?
Patent flour is bleachable coloration due to xanthophylls in the endosperm
The hot break process is commonly practiced in the manufacture of tomato paste and tomato juice products. This involves quickly heating the products to about 82 C. What enzyme does this process seek to inactivate?
Pectin methyl esterase
What test is used to determine adequacy of blanching before freezing?
Peroxidase test of catalase test
The name of degradation compound of chlorophyll.
Pheophytin
What is the type of heat exchanger most commonly used for milk pasteurization?
Plate heat exchanger
The milling of rice involves a process called:
Polishing
What is designed for pasteurization to give extract or metered flow?
Positive displacement pump
What is the saturation temperature?
Pressure at which vaporization takes place at a given temperature.
What are comminuted products?
Products made from raw meat materials that have been subdivided into small meat pieces; chunks, chips, etc.
What is the functional difference between propylene glycol alginate and alginate gums?
Propylene glycol won’t gel with calcium addition, alginate gums will form gels with calcium ion additions
What general class of enzymes are typically used for For the chill-proofing of beer, tenderization of meat and production of animal and plant protein hydrolysates?
Proteases
What is a purifier in milling?
Provides separation of bran from endosperm especially pieces which are similar in size
The viscosity of egg white decreases with shearing force. In rheology this is called.
Pseudoplastic
A shear-thinning fluid is also called what?
Pseudoplastic or power law
What reference tool relates wet bulb temperature and relative humidity?
Psychrometric chart
The change in the reaction rate constant for a change in temperature of 10 C is known as what?
Q10
What is the equation for converting degrees Fahrenheit to Rankine?
R = F + 459.67
The commercial term used to describe the decanting of a fermenting wine from yeast is what?
Racking (or riddling, in the case of Champagne)
In SI system, what is the unit of plane angle?
Radian
What is the major type of heat transfer used to cook meat during broiling?
Radiation
Which processing factor is most responsible for the resulting texture of a frozen dessert such as ice cream?
Rate of Freezing
Purpose of homogenization?
Reduce fat globule size and stabilization of the emulsion by protein coherence
What does the 12-D concept refer to?
Refers to the process lethality requirement used in the canning industry and implies that the minimum heat process should reduce the probability of survival of the most resistant C. botulinum spores to 10-12
The ratio of inertial forces to viscous forces is represented by what dimensionless number?
Reynolds number
What parameters are needed to determine friction factor from the Moody diagram?
Reynolds number and relative roughness.
What branch of physics deals with the shaping and flow of matter and its behavior when a mechanical force is exerted on it?
Rheology
A succession of grinding stages are used to reduce grain to flour. What device is used?
Roller mills
What is the primary target organism during pasteurization of egg products?
Salmonella
Name two types of heat exchangers used to process particulate foods.
Scraped surface and tubular
The modulus of rigidity is a relationship for elastic, homogeneous, and isotropic materials. How is the modulus of rigidity (shear modulus) calculated?
Shear stress/shear strain
To make cultured buttermilk, what is the starting ingredient?
Skim milk
What is reduction roll?
Smooth roll which crushes the grain into flour
What is vacuum packaged food that is minimally thermal processed and refrigerated called?
Sous-vide
What physical property is the reciprocal of density?
Specific volume
What is incipient spoilage in thermally processed foods?
Spoilage that occurs prior to thermal processing
What process converts liquids to powder?
Spray drying
Why does water have a high specific heat?
Stabilizing effect of hydrogen bonding.
In SI system, what is the unit of solid angle?
Steradian
“Sharp” freezing can be described as
Still air freezing
What is the equation of centrifugal separation?
Stoke’s Law (v=2r2(ps-pf)*G/9µ
What term describes the phase transition of water directly from a solid state to the gaseous state during freeze drying?
Sublimation
What is the principal behind lyophilization?
sublimation
What is freezer burn?
Sublimation of water from frozen food
Agents that are used for production and stabilization or dispersions are called:
Surface active agents (surfactants)
Which style of yogurt is likely to have hydrocolloids in it?
Swiss-style since it has to be cooled, broken, stirred and so there is a greater chance for wheying-off
Who developed the equations to predict falling rate drying?
T.K. Sherwood
What is the saturation pressure?
Temperature at which vaporization takes place at a given pressure.
What is the definition of a Calorie?
The amount of heat required to raise the temperature of 1 gram of water 1 C
what’s the basic mechanism behind a positive displacement pump?
the application of direct force to a confined liquid
What is clear flour?
The color is not effected by bleaching
The point at which the air is saturated or the relative humidity is 100% is called what?
The dew point
What is the first law of thermodynamics?
The energy of an isolated system remains constant. Or Energy can be neither created nor destroyed but can be transformed from one form to another.
What is the definition of Newton?
The force that gives to a mass of 1 kg an acceleration of 1 m/s2.
What is absolute zero?
The lowest possible temperature in the universe. The point at which all molecular motion stops. The complete absence of heat.
What is the definition of “cold point?”
The point in a can or mass of food which is the last to reach the final heating temperature
The depression in the bottom of a bottom of red wine or champagne is called what?
The punt
What does the c stand for in the equation E=mc2?
The speed of light
What is superheated vapor?
The temperature of vapor is greater than the saturation temperature at the existing pressure.
The temperature and pressure at which a substance can exist as a solid, liquid and gas in equilibrium is call what?
The triple point
What early processing method led to the name of soda being used to referred to as soft drinks?
The use of sodium bicarbonate or sodium carbonate to carbonate the beverages
In a Bingham plastic, what is the initial resistance that must be overcome before the flow starts and Newtonian behavior is observed?
The yield value or yield stress
What common purpose do sodium metasilicate, sodium hydroxide and sodium tetraborate serve in the food industry?
They are all alkaline cleaners
What is carboxy-methyl cellulose often used for?
Thickener in foods
A material that has a decreasing apparent viscosity over time at a fixed rate of shear or a time-dependent thinning is called what?
Thixotrophic
What is the type of non-Newtonian fluid that exhibits reversible shear-thinning?
Thixotropic
What is the type of non-Newtonian fluid that exhibits reversible shear-thinning?
Time independent
What is the particle size range for ultrafiltration?
to 10 microns - not really sure there is an exact definition
What is the function of a bleeder in a retort?
To bleed the air out before starting retort—air is a bad conductor for heat, causes rust also.
The purpose of malting barley is to ______________.
To germinate it to acquire the necessary enzymes to break down starch.
What is the Hot Break Process in tomatoes used for?
To inactivate pectin methyl esterase (PME)
Why add AlSO4 to a pickle mix?
To keep the pickles firm (the Al acts as a crosslinker between pectin polymers)
The internal friction that tends to bring to rest portions of the fluid that are moving relative to one another is called
Viscosity
In SI system, what is the unit of electric field strength?
Volt per meter
For what is rapid sand filtration used?
Water purification
What does WVTR stand for?
Water Vapor Transmission Rate
Name types of blanching methods.
Water, air, IQB, steam, MW (microwave)
In SI system, what is the unit of thermal conductivity?
Watt per meter kelvin
In SI system, what is the unit of power density, heat flux density and irradiance?
Watt per square meter
What was the first “food aerosol” product?
Whipped cream in 1937 (nitrous oxide + CO2)
In 2009, the microwave was approved for what process by the FDA?
Sterilization of low acid foods in hermetic containers
The precooling treatment to remove fat crystals from oil is known as what?
Winterizing
What is the definition of Joule?
Work done when force of 1 Newton at the point of application is displaced by a distance of 1 m in the direction of the force.
The mashing step of the brewing of beer produces a liquid known as what?
Wort
What are the steps for converting corn processing waste to ethanol?
Yeast fermentation and Distillation
What is the rheological expression for the force that must be applied before a substance will flow freely?
Yield stress
What are the parameters used to estimate Reynolds numbers in a pipe?
Density of fluid, diameter of a tube or pipe, average velocity of the flow, and viscosity of a fluid
Water has a latent heat of fusion of 144, a specific heat before freezing of 1.00, and a specific heat after freezing of 0.48. How many BTU’s would have to be removed from one pound of water to reduce its temperature from 60 to 0 degrees F?
(60-32)* (1.00) = 28 BTU + Water to ice = 144 BTU + (32-0)*(0.48) = 15.4 BTU = 187.4 BTU
From the highest to lowest, rank the magnitude of 1 atm, 1 bar, 1 lb/ft2, 1 Pa, and 1 mm Hg, and 1 psia
1 atm (101.325 kPa) > 1 bar (100 kPa) > 1 psia (6.895 kPa) > 1 mm Hg (133 Pa) > 1 lb/ft2 (48 pa) > 1 Pa
A 603 X 700 metal container has what dimensions in inches and what is the common name for such a container?
6 and 3/16 inches in diameter by 7 inches tall, No. 10 can
What are the three types of clotting in cheese production?
Acid, heat coagulation of whey proteins, and enzymatic
List the three radioactive particles: alpha, beta, and gamma in the order of their increasing penetration power
Alpha
What are seven base units in the SI system?
Answer: (1) unit of length (meter), (2) unit of mass (kilogram), (3) unit of time (second), (4) unit of electric current (ampere), (5) unit of thermodynamic temperature (Kelvin), (6) unit of amount of substance (mol), (7) unit of luminous intensity (candela).
Name the four colligative properties and the effect of solute addition of each property.
Boiling point (increase); freezing point (decrease); osmotic pressure (increase); and latent heat of vaporization (decrease)
What are two common types of viscometers used to measure viscosity of a liquid?
Capillary tube viscometer and rotational viscometer
What are the common problems associated with dehydration?
Case hardening, browning, shrinkage, water holding capacity, losses of volatile constituents and nutritional losses
What is the difference between counter-current and parallel-current tunnel driers?
CC=air and material flow in opposite directions; PC=air and material flow in same direction
What are the quality implications of the increase in volume of water turning to ice on plant products?
cellular disruption and membrane rupture accompanied by cell wall breakdown and loss of cellular turgor pressure; upon thawing the tissue is markedly inferior in texture with loss of firmness and a complete loss of crispness.
What are the two common types of pumps in food processing?
Centrifugal pumps and positive displacement pumps
Name three of the four components of the Bernoulli Equation.
Change in potential energy, change in kinetic energy, change in pressure, friction effects
What are the typical ranges for chilling, refrigeration, and freezing?
Chilling: 10-15 C, refrigeration: 0-9 C, freezing:
Name (2) chemical agents used to accelerate bleaching of flour.
Chlorine gas (good for cake flour), chlorine dioxide (widely used), benzoyl peroxide, acetone peroxide, lipoxygenase (may cause off-flavor)
Name three gases used in MAP?
CO2, N2, O2, CO
Name two things which happen to whey proteins when they are heated to high temperatures?
Coagulation, denaturation, or sulfide group release (cooked flavor)
Give (3) reasons for adding starch to food?
Coating and glazing agent, thickening agent, colloidal stabilizer, moisture retention, gel forming, binder
From the highest to lowest, rank the densities of cocoa beans, soy beans, shredded coconut, green coffee beans and roasted coffee beans
Cocoa bean (1073 kg/m3), soy beans (800 kg/m3), roasted coffee beans (368 kg/m3), shredded coconut (300-352 kg/m3)
Name the three basic unit operation of a mechanical refrigeration system?
Compressor, condensor, evaporator
Name 3 basic mechanisms of heat transfer and explain each.
Conduction - thermal and transferred from one molecule to an adjacent molecule without large change in relative position; Convection - molecules move at giving mix of warmer and cooler portions; Radiation - electromagnetic mechanisms
What are the two phases of drying?
Constant rate period and falling rate period
Name two of the three mechanisms by which emulsions are destabilized.
Creaming or sedimentation; Flocculation or clustering; Coalescence
Name two direct and two indirect methods of thermal processing.
Direct—steam injection, steam infusion, baking, frying, microwave cooking, retorting Indirect—plate heat exchange, scraped surface heat exchange, tube type heat exchange)
What are the quality implications of the increase in volume of water turning to ice on meats?
disruption of cell orientation and cellular membrane rupture which results in drip loss upon thawing. It also may result in a slight tenderization of the thawed muscle tissue
Name some applications for the addition of fungal proteases.
Dough conditioning, flour bleaching, flour malting, and antistaling
What is the statistical system used to optimize a process that is performed with a minimum of interruption to production called? Who developed it?
Evolutionary Operations (EVOP); George Box in 1950
Name four processes where phase diagrams are important.
Extraction, crystallization, distillation, precipitation, and freeze concentration.
What are (3) sections of extrusion screw?
Feed, compression, and metering
What is the difference between a foam and an aerosol dispersion systems?
Foam—inner phase is gaseous, outer phase is liquid; Aerosol—inner phase is liquid or solid, outer phase is gaseous
What are two types of cockroaches that need to be controlled in a food processing plant?
German, American, Oriental, Brown-banded
For pasteurization using heat, what do HTST, UHT and LTLT stand for what?
High-temperature-short-time; Ultra-high-temperature; Low-temperature-long-time.
List three positive effects of properly used thermal processing on the nutritive value of foods.
Improves digestibility, inactivates degradative enzymes, and inactivates antimetabolites
Name 5 types of air convection driers (heated air driers)
Kiln; cabinet; tunnel; conveyor; fluidized bed; air lift; rotary; spray drier
Cake recipes need to be adjusted for atmospheric pressure changes. Name one change that will prevent problems associated with using an unmodified recipe at high altitudes.
Less baking powder, more flour, stronger flour, less fat, or less sugar
Give (3) advantages of coextrusion films over laminates.
Lower cost; Thinner; Easier to use; Layers do not separate
Name four examples of extensive properties?
Mass, length, volume, energy, enthalpy
Name two substances that may be used for commercial caffeine extraction.
Methylene chloride or supercritical carbon dioxide or Water
List types of filtration in descending pore size
Microfiltration; Ultracentrifugation; Nanofiltration
Give (3) advantages of food dehydration over sun drying.
More controlled condition, shorter drying time, better sanitary conditions, climate losses from weather, some products (like milk) cannot be sun dried
Give an example of each of these fluid types: Newtonian, Shear thinning, Shear thickening, Bingham plastic
Newtonian: water, fruit juice, milk; Shear thinning: apple sauce, banana puree; Shear thickening: concentrated starch slurry Bingham plastic: tomato paste
What are the three most common rodent pests in food plants in the U.S.?
Norway rat, roof rat, and house mouse
During thermal processing of glass jars of low acid foods what step must be taken to assure that jar caps will fit tightly to jars such that no leakage or cap blow-off occurs?
Overriding air pressure in the retort and immersion in water
What are four parameters which effect the efficiency of a lye peeling operation?
Peeling operation, concentration of lye, time used, temperature of the solution, lye and peel removal systems
Name three concentration methods.
Removal of solvent by evaporation, sublimation, freeze concentration, and osmosis
What is converted rice?
Rice is steeped in water, steamed and dried again before milling
Name three drying methods used
Solar; Direct (tunnel, fluidized bed, spray); Indirect (drum, vacuum, freeze dry)
Name two processes for producing dried milk products.
Spray drying, drum drying
Name four methods used for freezing foods
Still air, blast air (tunnel and fluidized bed), indirect contact, direct contact
Name three types of retorts:
Still; agitating; continuous; discontinuous; still with overpressure; hydrostatic
Define sublimation, fusion, and vaporization lines on phase diagrams
Sublimation line: solid/vapor phases equilibrium; Fusion line: solid/liquid phases equilibrium; Vaporization: liquid/vapor phases equilibrium
From the highest to lowest, rank the densities of glucose, sucrose, starch and fat
Sucrose (1590 kg/m3), glucose (1560 kg/m3), starch (1500 kg/m3) Fat (900-950 kg/m3)
How much chocolate liquor must be in sweet chocolate, bittersweet chocolate, and white chocolate?
Sweet: >15% chocolate liquor, Bittersweet: >35% chocolate liquor, White: No chocolate liquor
What are five factors that control the freezing rate of foods?
Temperature difference between food and medium, geometry, composition
Intensive properties do not depend on the mass of a system; what are three examples of intensive properties?
temperature, pressure, viscosity, density
What properties cause foods to freeze faster than they thaw?
Thermal conductivity and thermal diffusivity of ice is great than water
What do TTT and PPP stand for?
Time, Temperature and Tolerance; Product quality, processing, and packaging
What are the wavelength ranges for the following types of light: visible, ultraviolet, infrared?
Visible light: 400-700 nm; UV light: 700 nm
What cryogenic freezing medium Is used in the commercial production of Dippin’ Dots ice cream?
Liquid nitrogen
What is the difference between steady state heat transfer and unsteady state heat transfer?
Time has no influence on temperature distribution within an object in steady state heat transfer whereas temperature changes with time and location in unsteady state heat transfer.
When the temperature of a product increases, what happens to its isotherm and water activity?
Isotherm Decreases (or shifts to the right) AND water activity increases
