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83 Cards in this Set
- Front
- Back
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food engineering
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the application of engineering principles to the manufacture of foods
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tempurature scales
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fahrenheit, celsius, kelvin
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tempurature at which motion ceases
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absolute zero
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measurements of heat
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calorie, joule, BSU
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conduction
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heat transfer from molecule to molecule
ex: frying pan to eggs -deals with solids |
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convection
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transfer of heat between liquid or gas and solid surface
ex: fire to frying pan |
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radiant
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transfer by electromagnetic radiation
ex: sunlight/suntan |
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thermal conductivity
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rate of heat transfer through a unit of thickness
--foods with more water have more conductivity |
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dialectric conductivity
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the ability of foods to store and dissipate electrical energy
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dielectric properties
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1. foods dont heat equally in a microwave...carrots heat faster then pork chop
2. foods with higher absorptivity are more polar-water:polar, fat:non-polar |
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steady state
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material input through the system equals material output through the system
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transient heat transfer
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OPPOSITE of steady state
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thermodynamics
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study of how natural processes are affected by changes in temp.
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heat
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transfer in energy due to difference in temp.
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1st law of thermodynamics
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energy can be transformed, but total stays the same
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2nd law of thermodynamics
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heat flow from hot objects to cold and natural processes move to disorder rather then order
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heat transfer
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manner in which heat energy is transported from the foods surroundings to the surface and interior
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knowledge of heat transfer are used for...
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canning, drying, and frying
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heat capacity
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amount of heat energy necessary to speed up a material's molecules enough to raise the temp. of a unit mass of a material by 1 degree C.
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specific heat
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ratio of the heat capacity of a food to that of water..similar to water activity
-lower values heat more quickly -air=.25, protein=.4, fat-.5, water=1 |
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heat exchanger
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equipment used to either add or remove heat from food
-function is to transfer heat from one fluid to another |
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common designs of heat exchangers
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1. double PIPE for parallel or counterflow...juices, milks, liquids
2.scraped SURFACE heat exchanger for chocolate 3.PLATE heat exchanger for milk and beverages |
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deep fat frying
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conduction occurs within a solid while convection occurs between the food and cooking oil
-migration of oil into food and moisture escapes into the oil |
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boundary layer
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dividing line between dissimilar materials
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physiocochemical states
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movement of water and ingredient molecules in a food
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crystalline
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LOW MOBILITY (ice)
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glassy
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high viscosity, LOW MOBILITY (toast)
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rubbery
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LOW VISCOSITY, high mobility (soggy.processed cheese)
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liquid
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HIGH MOBILITY (water)
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ideal gas law
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relationships between pressure, volume, temp., and amount of gas
equation: PV=nRT |
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latent heat
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heat input that results in a change of state
-freezing/melting and boiling/condensing |
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sensible heat
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change that can be detected by touch
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Rheology
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study of flow and deformation characteristics of foods
-food structure -design processing equipment -food shelf life -sensory development and product development |
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shear stress-strain relationships are used to measure.....
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plasticity, elasticity, and fluidity of foods
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newtonian food
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HOMOgeneous mixture that shows no change in viscosity as shear rate is increased
ex:water, juice, honey, oil |
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non-newtonian food
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HETEROgeneous mixture that change as shear rate is increased
ex:SALAD DRESSING, mayo, applesauce, chocolate syrup |
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extruder
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device that uses rotating screw technology within a tunnel to cook and shape products very efficently
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food biotechnology
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technology to manipulate or modify DNA for improving quality or safety of food
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What repairs DNA
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DNA ligase
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FDA Policies
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1.genetic modifications
2.toxicants-no toxic substances 3.nutrients-level of nutrients must be same in modified and unmodified foods 4.new substances-treated as food additives and must go through ore-market approval 5.allergenicity-tests must be given 6.antibiotic resistance markers- 7.animal feeds-animal feeds have same safety measures as other foods 8.labeling |
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biotechnology derived foods are safe if:
TRUE/FALSE |
1. nutrients do not differ from those of traditional foods
2.any toxicant is within typical and acceptable levels found in traditional foods 3.new products do not present an unacceptable risk *1 in 500,000 is NOT acceptable |
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food processing aids
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-amino acids
-gums -enzymes-chymosin for cheese-microorganisms |
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enzyme responsible for softening tomatoes
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polygalacturonase
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FLAVR SAVR is...
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a product produced that supresses the PG in tomatoes which makes them soft
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bacillus thuringiensis....
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produces a natural insecticide
-useful for cabbage, potato, and tomato protection |
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substantial equivalence
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if a food is found to be substantionally equivalent as the conventional food it should be considered safe
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foods not _______ _______ to exsisting foods CANNOT enter the marketplace but may have a future if proven to be safe
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substantially equivalent
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DNA Injection: ballistic bombardment
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technique used to insert DNA into plant cells
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DNA Injection: electroporation
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another technique (like ballistic bombardment) for plant cells
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DNA Injection: microinjection
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technique used for ANIMALS
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genetics
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the field concerned with the elements of nature for passing traits from one generation to another
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restriction enzyme
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in bacteria cut DNA only at specific sequences of base pairs
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RNA....
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-is possible to manipulate mRNA more then DNA in many cases
-much smaller then DNA - |
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plasmids
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short segments of DNA that are easily shuttled from cell to cell
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cross-breeding
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only works for SAME or CLOSELY related species
-results are random and time consuming |
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A plant or animal that is modified by genetic engineering is called _______
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transgenic
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sensory evaluation
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assessment of all food qualities as percieved by the human senses
-SIGHT, SMELL, TASTE, TOUCH, and HEARING |
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The tongue recognizes main tastes:
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sweet
sour bitter salty |
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FLAVOR is a combination of :
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taste
odor mouthfeel trigeminal perception(cooling and warmth) |
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taste...
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IF YOU CANT TASTE IT, it is WATER SOLUBLE
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mechanical sensory characteristics
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-hardness
-cohesiveness -viscosity -chewiness |
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geometrical characteristics
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graininess
fibrousness coarseness |
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_______is needed for the receptors in the eye to communicate information to the brain
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Reflected Light
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affective tests
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quantify the degree of liking or disliking of one product over another
-consumers work well with these ex:pepsi challenge |
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discrimination tests
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answers whether any difference exsists between products
-employee based |
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descriptive tests
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describe characteristics of product
-employee based |
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define: product development
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process in which new food product ideas are generated and the products are created and marketed
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Product development
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-new products can be novel or simply modifications of exsisting ones
-teams combine various skills to complete the development process |
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Role of Sensory specialists
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-determine project objective
-determine test objective -screen samples -design the test -conduct the test -analyze the data -interpret and report results |
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Scientific Method
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-define problem
-create hypothesis -test hypothesis -accept or reject hypothesis |
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reasons for corporate development
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-satisfy corporate mission
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line extension
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new form of an established product
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Product Development Stages
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1. Idea stage
2. Development stage 3. Commercial stage |
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Important roles of marketing
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-tracking market trends
-developing concepts for products -testing responses |
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Identify the consumer...
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Demographics:age, gender, income, location, education, motivation
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Identify the need....
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gap analysis: form, quality, and price
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Product Life Cycle
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the birth of a new product, its duration as a good selling item, and the time required to see the sales decline and eventual removal from the market
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restructuring process
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grind
mix form set |
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Restructuring Technologies
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hot-set method-favored method
cold-set method |
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Meat extrusion equipment
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-antique stuffer
-hydraulic stuffer -vacuum stuffer |
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extrusion technology used for low moisture products
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single screw extrusion
-corn puffs |
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extrusion technology used for high moisture products
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twin screw extrusion
-corny meat |
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extrusion cooking
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mix
feed cook form |
