FDSC 201 Final Flashcards
(152 cards)
1
Q
Food Security
A
Access to sufficient safe, nutritious and affordable food (2100-2200 cal/d).
800 million chronically to 2 billion intermittently food insecure (including an estimated 50 million in the U.S.).
2
Q
Roles of the food scientist in increasing food security…
A
- by reducing post-harvest losses through preservation and processing,
- by extending the shelf-life of food, making it easier to reach urban areas where most people live,
- by adding value to commodities and thereby increasing incomes and creating employment,
- by improving the quality and safety of foods.
3
Q
Bananas (matooke)
A
- Musa acuminata East African highland cultivar (AAA-EA genotype) predominates in Uganda.
- Are an important staple crop in Uganda, providing food for over 7 million people including 2/3 of the urban population, and accounting for 35% of food expenditures.
- Per capita consumption in Uganda ranges between 220 kg – 460 kg/annum, the highest in the world.
- Are grown by 75% of the nations farmers on 40% of the arable land.
- A cash crop in southwestern and central Uganda, contributing 8-22% of rural revenue.
4
Q
Prevent browning on peeled matooke
A
Treatment with 1000 ppm sodium metabisulfite for 30 seconds prevented browning
phenol → catechol → quinone
melanins
5
Q
IFPRI
International Food Policy Research Institute:
A
mission aimed at sustainable solutions to ending widespread hunger and poverty. “To achieve sustainable food security and reduce poverty in developing countries through scientific research and research-related activities in the fields of agriculture, livestock, forestry, fisheries, policy, and natural resources management.”
6
Q
WFP- World Food Programme
A
mission aimed at eradicating hunger and poverty, namely in underdeveloped countries
7
Q
FAO- Food and Agriculture Organization
A
aim to provide access to high-quality food, raising the level of nutrition, improving agricultural productivity, bettering lives of rural populates, all contributing to the growth of the world economy.
8
Q
UNIDO-United Nations Industrial Development Organization
A
aims to reduce poverty through sustainable industrial development internationally, allowing for participation in trade and safeguard their environments.
9
Q
IMF- International Monetary Fund
A
aims to ensure stability in the international system by tracking the global economy, lending to countries, and giving practical help to countries in need.
10
Q
What is a climacteric fruit?
A
A climacteric fruit ripens after being picked due to the fruits high respiration rate during ripening.
Ex: bananas, apples, tomatoes.
11
Q
What role does ethylene play in fruit ripening?
A
Ethylene rapidly produced during the ripening stage.
12
Q
What happens if you store bananas in the refrigerator?
A
If bananas are stored in the refrigerator… before their ripening stage, they will not ripen as well—however if ripened bananas are put in the fridge they will give off ethylene which affects the ripening of other fruits, additionally the skin will turn black and the banana is still perfectly edible.
13
Q
Planck’s equation
A
To determine the change in the freezing point, of a pure solvent when mixed with a solute
14
Q
Convective heat transfer
A
The transfer of thermal energy from one place to another by the movement of fluids or gases. Convection is usually the dominant form of heat transfer in liquids and gases.
Convection oven–air helps move heat within oven
15
Q
Conductive heat transfer
A
is the transfer of heat energy by microscopic diffusion and collisions of particles or quasi-particles within a body due to a temperature gradient.
Conduction takes place in all forms of ponderable matter, such as solids, liquids, gases and plasmas.
16
Q
Radiant heat transfer
A
Is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation.
17
Q
PID– Proportion Integral Derivative
A
Used in the freezing machine–reason why machine knows when to let in more liquid N
18
Q
Absolute zero (K) & C & F conversions
A
No thermal movement C= (F-32)*5/9 F=(C*1.8)+32 K=C+273.15 C= K- 273.15
19
Q
Thermocouple:
A
two conductors of different materials (alloys) to produce a voltage / circuit
-Electrical potential depends on temp. If one wires different than the other–theres a relationship b/w electrical potential and temp.
20
Q
Sensible heat
Latent heat
&
Flux= (driving force gradient/ resistance)
A
- Sensible heat is heat exchanged by a body or thermodynamic system that has as its sole effect a change of temperature
- The terms sensible heat and latent heat are not special forms of energy. Rather, they describe exchanges of heat under conditions specified in terms of their effect on a material or a thermodynamic system.
- Latent heat is the heat released or absorbed by a body or a thermodynamic system during a process that occurs without a change in temperature. A typical example is a change of state of matter, meaning a phase transition such as the melting of ice or the boiling of water.
21
Q
Colligative Properties [molarity]
A
- Properties of solutions that depend upon the ratio of the number of solute particles to the number of solvent molecules in a solution.
- Vapor pressure lowering
- BP increases & Freezing point decreases
- Osmotic pressure
22
Q
Insulation
&
Vacuum
A
- Slows heat, can’t stop heat, just slow it down, low conductivity
- Nothing moves
23
Q
Hazard Analysis Critical Control Point (HACCP) plan–Prerequisite Programs–Company-Wide Commitment to Food Safety
A
Supplier specifications Receiving, storage, and shipping Water safety and quality Personal hygiene Facilities layout and maintenance Traceback and product recall Equipment design and maintenance Waste disposal Cleaning and sanitizing Toxic chemical control Pest control Plant security Employee training Biosecurity
24
Q
GMP –Good manufacturing practice
A
Ranges from appropriate pH
to definitions of words like should, shall, batter, lots, blanching
also sanitation, pest control, microbes,
25
(Sanitation) Standard Operating Procedures (SSOPs)
```
Monitoring goal
What to monitor
How to monitor
Corrective measures
Verification procedures
Records
```
26
SSOPs required in Meat & Poultry HACCP
- Describe daily procedures before and during operations and how often they are to be conducted.
- Identifies person(s) who are responsible for maintaining daily sanitation activities.
- Daily records must demonstrate that sanitation procedures in their SSOP plan including corrective actions taken
- Signed and dated by an official with overall on-site authority
27
FDA Key Sanitation Control Areas
1) Safety of water that comes into contact with food or food-contact surfaces
2) Condition and cleanliness of food contact surfaces
3) Prevention of cross-contamination from unsanitary objects to food, food packaging material and other food contact surfaces
4) Maintenance of hand washing, hand sanitizing, and toilet facilities
5) Control of employee health conditions
6) Protection of food from adulterants
7) Proper labeling, storage, and use of toxic compounds
8) Exclusion of pests from the food plant
28
Adulterated Food
```
If it (food) bears or contains any poisonous or deleterious substance which may render it injurious to health…
If it (food) has been prepared, packed, or held under unsanitary conditions whereby it may have become contaminated with filth, or whereby it may have been rendered injurious to health
```
29
Sanitation 4 x 4
1. Pre-Rinse (e.g. protein vs. fat)
2. Wash/Cleanse (remove soil)
Concentration Temperature Time Mechanical Force
3. Rinse
4. Sanitize (kill microorganisms)
30
What is the “hygiene hypothesis” and how does food plant sanitation relate to it?
The hygiene hypothesis is an idea that those who lacked exposure at a young age to certain things (bacteria, allergens, etc) , become more so sensitive as adults when exposed than do others. This concept can relate to food plant sanitation in a few ways: extra care needs to be taken with products that might have been in contact with common allergenic food types, alternatively sanitation might prevent us from being exposed to needed bacteria
31
Difference between a cleaner and a sanitizer?
- Cleaners remove food particles (soil) with specific concentration of cleaner, using hot water, elapsed time, and mechanical force of scrubbing.
- Sanitizers kill microorganisms; sanitizers often work best in cooler water.
32
Why does “quick freezing” produce better quality products than slow freezing?
Quick freezing prevents large ice crystal formation within a product, where in slow freezing the cell membranes could be come damaged from formation of large ice crystals.
33
What does IQF stand for and what are its advantages?
IQF stands for individually quick frozen which is used to prevent frozen products to be a solid brick—at Hanover we saw IQF of green beans, this allowed the individual green beans to exist loosely within a frozen package. & efficiency high quality.
34
What is blanching and what are its goals?
Blanching cooks the food substance in boiling water and/or—as seen at Hanover—by steam for a short period of time, then the food substance is shocked with cold water, there-by ending the cooking process.
The goal of blanching is to cook the substance but still retain a fresh texture.
- Does so by deactivation of enzymes that would otherwise degrade the product.
35
How does vapor compression refrigeration differ from the liquid nitrogen freezing we saw last week?
is vapor compression refrigeration lowers the internal temperature by expelling the heat from the enclosed area, while liquid nitrogen freezing inserts the lowering temperature medium through direct contact.
- Also LN2 gets used up. VCR refrigerant gets condensed & recycled
- Both cool latent heat of vaporization as the refrigerant is evaporated
36
How does freezing affect the microbiological safety of foods? Does it effectively kill pathogens?
Inactivates microbes--but they might grow once thawed.
- Some die--
- Overall increases the safety of long term food storage.
- Best with less water activity
37
Theobroma (Cacao)
```
T. cacao ssp. cacao L. – criollo
Porcelana (Venezuela)
Naçional (Ecuador)
T. cacao ssp. sphaerocarpum – forastero
Amelonado (most common)
Trinitario (cross)
```
38
Cacao grow zone
20degrees N & S of the equator
39
Cacao pod-->chocolate
```
Harvest & pod storage
Breaking pods
Fermentation
Sun drying 5-10 days
Roasting (also looses moisture)
"nib" break shell-- can only legally have 1% shell. Commercially use screens
```
40
Purpose of Fermentation
- Stops germination preventing cocoa butter degradation
- Aids in removal of the pulp
- Develops flavor precursors (final flavor developed in roasting)
- Establishes color potential for powder
41
Changes occurring during fermentation
- Sugar in pulp fermented to alcohol by yeasts then to lactic and acetic acid by bacteria
- Together with the heat generated (40-50 ºC), this kills the seed
- Fluid permeates the seed, swelling it
- Enzymes (anthocyanin glucosidases, polyphenol oxidases and proteases) gain access to their substrates
- Bitterness is reduced, bean color changes, and flavor precursors are produced
42
Cacao Farmers
```
70% of world crop grown by 5-6 million growers with 1-2 Hectare farms.
Ghana 13%
Ivory Coast 43%
Indonesia 12%
Brazil 6%
Nigeria 5%
Cameroon 4%
Malaysia 4%
```
43
“emulsifiers”
Surface active agents (surfactants), contain both hydrophilic and lipophilic character, so they are effect in reducing the surface tension of dispersed systems containing both polar and non-polar compounds (e.g. sugar and cocoa butter).
Soy lecithin
Poly(glycerol)-poly(ricinoleate) (PGPR)
Mono- and diglycerides
Sorbitan monstearate, sorbitan tristearate
Glycerol esters of fatty acids and organic acids (lactic)
Diacetyl tartaric acid esters of monoglycerides (DATEM)
Ammonium salts of phosphatidic acid
Polysorbates
Sucrose esters of fatty acids
44
“lecithin”
```
Phosphaptidylcholine 23%
Phosphatidylethanolamine 20%
Phosphatidylinositol 14%
Phosphatidic acid 8%
Mostly a by-product of soy oil refining.
```
45
Viscosity impacts:
Confectioner’s handling of chocolate
- Dipping, enrobing, molding
- Coverage %, Thickness & uniformity, side coating, feet/tails, air bubbles, decoration
- Pumping, sensory perception, tank agitation
46
Viscosity Units of Measure
1 Poise = 1 dyne-sec/cm2
10 Poise = 1 Pascal-sec, PaS
1 Poise = 100 centipoise
47
Newtonian Viscosity of Common Foods
```
Viscosity, cp Temp
water 0.89 25°C
milk 1.45 27°C
coconut oil 26 40°C
20 50°C
cocoa butter 41 40°C
31 50°C
cream, 40% 210 48°C
glycerine 954 25°C
honey 10,000 25°C
```
48
Rotational viscometer
A viscometer (also called viscosimeter) is an instrument used to measure the viscosity of a fluid. For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Viscometers only measure under one flow condition.
49
Casson Equation
Yield stress: plot data, fit straight line/establish line
50
Panning (coating w/ chocolate)
espresso beans~ m&ms
| might need to add coco powder b/c oil. will clump but eventually will be separate, add layers
51
Release chocolate liqueur & refine w/ sugar
- Stone mill grinder, releases oils, 20microns releases oil--coco butter also heated b/c grinding
- mix liqueur with sugar and refine~preroller--> 15 microns for smooth texture
52
Coco butter
Hydrolic press--> screen holds back pardicals/ powder, gets butter/oil out ~ 10-12% fat left
Conche-- turns into paste (dry conching) then wet conching--two days later of heating & mixing = fluid choco.
53
positive health claim of Chocolate/ chemical component
- The cocoa bean has flavonoids which act as antioxidants. The main type of flavonoids in cocoa and chocolate are flavanols.
- In a July 2010 study by UCSF, high concentrations of flavanols were found to improve health of blood vessels, decrease blood pressure and increase the number of circulating angiogentic cells in patients with heart disease.
54
What is PGPR? What is it used for in chocolate manufacture?
- PGPR (polyglycerol polyricinolcate) is used as an emulsifier.
- PGPR is added to chocolate to reduce the viscosity similar to when cocoa butter is added.
- It has the ability to reduce and even stop the yield value of chocolate, thus it is used to in manufacturing to get the wanted yield value for any particular product.
55
Find the Standard or Identity for milk chocolate in 21CFR Part 163
-“Not less than 3.39 percent by weight of milk fat and not less than 12 percent by weight of total milk solids”
56
What is the minimum percentage by weight of a dry milk powder containing 26% by weight of milk fat and 2% moisture that would need to be included in the formula to produce milk chocolate as legally defined by the Standard of Identity (show calculations)?
(.26 milk fat) x=3.39g
| x=13.03g milk fat →13.03%
57
Will this also meet the 12% minimum for total milk solids (show calculations)?
13.03g(.98)=x
| x= 12.76g →12.7% yes this meets the 12% minimum for total milk solids
58
What viscosity (high, medium, low) and yield value (high, medium, low) would be required for; printing chocolate, molding the eggs, spraying (airbrushing) chocolate
- Printing chocolate: medium viscosity; requires high yield
- Molding eggs: low viscosity; low yield
- Spraying chocolate: very low viscosity; low yield
59
Thermally processed in a pressure retort
Vs.
Hot Fill
- Thermal processed foods are commercially sterile and shelf stable products. Used in canning--uses water-steam-air mixture
- Hot fill is usually used for acidified foods, product is filled into containers at temp around 206-214F which decontaminates inside--seal and invert.
60
What is the structure of lycopene?
Lydopene in a fresh tomato appears in a linear all trans conjugated configuration.
61
What are the claimed health benefits of lycopene?
It is in the carotenoid family; there by having antioxidant properties that become more available when the tomato is processed.
62
Bioavailability of lycopene is higher from raw foods or processed foods?
Processing tomatoes through heat changes the lycopene into the bent form of the molecule that is found in the human bloodstream. In the bent form and with the addition of fat (oil) the absorption of lycopene is greatly increased.
63
What is the scientific name for the common tomato?
| What is the geographical origin of the tomato?
- S. lycopersicum is the scientific name for the common tomato.
- The tomato originated in South America.
64
When did the tomato reach Italy?
| Name at least two other edible species from the genus Solanum.
- It was brought back to Europe by the Spanish and was later grown in the Mediterranean region where it was received by Italy for ornamental purposes—but later was became a staple of their cuisine.
- S. tuberosum (potato) and S. melongena (eggplant) are two other edible species from the Solanum genus.
65
Co-packing
is a company that manufactures and packages foods or other products for their clients.
66
Food fermentation
| Happens through glycolysis
- Alcoholic ferm. (CO2, ethanol)
- Cheese, yogurt, soy sauce (Lactic acid)
- Meats & fish
- Fruits & Veggies
- Beans & seeds
- Pickled or acidified foods
67
Fermentation
| What happens
An anaerobic process that occurs in cells where pyruvic acid from glycolysis serves as a final electron acceptor from NADH forming lactic acid or is decarboxylated to acetaldehyde which serves as a final electron acceptor forming alcohol
68
Fermentation
| Food preservation
A food preservation process using microbial action to produce a food product and "is the basis for some of the strongest regional and cultural food preferences"
69
In cheese making--
Secondary action of proteases and lipases
70
Fermentation
| Industrial uses
Industrial process using microbial action to produce a product
- Large scale growth
- Siphon off spent media
- Isolate desired metabolite(s) such as ethanol, enzymes, antibiotics, insulin, HGH
71
Benefits of fermentation
-Flavors altered & intensified-- adds variety
-Easier to digest
-Extended shelf life
-Quicker to cook
-Improve nutritive value of the food
(remove antinutritionals & toxins--adds vitamines)
72
Probiotics
FAO/WHO definition: "live microorganisms which when administered in adequate amounts confer a health benefit on the host"
73
What are the main conclusions from does the article by Dunlap et al
Commercial yogurts contain a high enough concentration of probiotic bacteria to aid acute gastroenteritis in children, however physicians should use caution when recommending commercial brands because the bacterial strain and concentration is not listed on package—alternatively capsuled probiotics list strain and concentration (despite this study also finding the concentration to actually be less than listed).
74
With regard to the microbial fermentation process, what is the purpose of the salt added to the cabbage?
Why should it be non-iodized salt?
By adding salt to the cabbage, water is drawn out of the plant cells by creating a hypertonic environment.
It is important to use non-iodized salt because iodine would inhibit the fermentation process due to its antibacterial properties.
75
Sauerkraut making
Use wooden paddle--wild uncontrolled fermentation, by changing environment-->different microbes = different flavors
-Smash cabbage~submerge in liquid for anaerobic & use bag to seal.
76
Potential problems for sauerkraut
-Softing- pectinolytic enzymes of yeast & molds
-Off odors & flavors- Coliform (fecal) growth
-Discoloration - growth of yeast
Might have insufficient/excess salt; too much air; not enough juice, temperature too high--unwashed or improperly trimmed cabbage
77
Organic products are grown and processed
WITHOUT:
- toxic and synthetic pesticides and fertilizers
- genetic engineering
- antibiotics
- synthetic growth hormones
- artificial flavors, colors, and preservatives
- sewage sludge
- irradiation
78
What is meant by a “tolerance” for pesticide residues in food
- Tolerance is defined as the maximum residue limit. This quantity is determined as the amount of pesticide residue allowed to be in or on each treated food commodity. If the tolerance residue level is surpassed, the commodity will be subject to seizure by the government.
79
What are the four steps for assessing the human health risk posed by pesticide residues?
- EPA must find the pesticide can be used with “reasonable certainty of no harm”—and does so by assessing the toxicity of the pesticide and its break-down products, how much the pesticide is applied and how often, and how much of the pesticide residue—remains in or on food by the time it is marketed and prepared. EPA’s tolerance levels are applicable to all food imported to the U.S. and home grown food
80
What is the status of genetically modified organisms (GMOs) in the US?
Can GMOs be labeled “USDA Organic”?
Do GMOs need to be label as such in the US?
- Currently there are no laws prohibiting GMOs in the US
| - GMO’s can not be labeled USDA Organic—“The use of GMOs is prohibited in organic production and handling”
81
What is “vitalism” or “vital force theory,” and how does it relate to the terms “natural” and “organic” when applied to foods?
- Vitalism: “doctrine that a nonphysical energy permeates all living organisms and that gives them the property of life”
- “The theory or doctrine that life processes arise from or contain a nonmaterial vital principle and cannot be explained entirely as physical and chemical phenomena”
- Vitalism believed organic substances could not be made artificially. In the scientific aspect of what defines organic, the idea of vitalism was disproven, but in the realm of food I’m unsure if the general public would accept genetically engineered or constructed food/food parts as being organic. Food vitalists would probably hold to the idea that organic compounds SHOULD not be made artificially (when in reference to food), but this is certainly not true based on the variety of foods offered in today’s market.
82
What is a “supply chain” and how does it differ from a “value chain”?
The supply chain is a production and sales mentality of pushing produces on consumers at low prices—assuming all consumers care about is cost, this process has very little information flow from consumers to sellers, creating vender centered marketing. Alternatively the value chain is centered on the customer. Individuals work collectively to give consumers what they want, removing cost by removing uncertainty, and add more value—all while ensuring sustainable business practices (through reduced waste). The value chain is interdependent on their customers—developing trust and loyalty.
83
What is the current size of the organic foods market in total dollars and as a percentage of total food expenditures?
- $31.5 billion in 2011 (based on presentation by Robert Anderson)
- $1,317,828,000,000.00 total food expenditures from 2011 (Sources: Calculated by the Economic Research Service from various data sets from the U.S. Census Bureau and the Bureau of Labor Statistics)
- (1,317,828,000,000.00 / 31,000,000,000.00)(100) = 2.35%
84
Moisture content
Xwet basis = mass moisture/total mass
Xdry basis = mass moisture/mass dry matter
Xdry basis = Xwet basis/(1-Xwet basis)
Example: meat 68.3% moisture w.b.
Xdry basis = .683/(1-.683) = 2.15 kg water/kg solids
85
Pyschrometrics
thermodynamic properties of air – water vapor mixtures
-As temp increases, RH decreases
86
Dry bulb:
| Wet bulb:
- Temp of air shielded from moisture & radiation
- Wet-bulb temperature is largely determined by both actual air temperature (dry-bulb temperature) and humidity, the amount of moisture in the air. (temp at which water begins to condense)
- Warmer air holds more water--as air cools dew forms
87
How significant is cassava to consumers in Asia, South America and Africa?
- “Cassava is planted on about 16 million hectares, with 50 percent in Africa, 30 percent in Asia, and 20 percent in Latin America. Total root production is around 152 million tons”
- In Asia and South America cassava is used for it’s starch in products ranging from textiles to food (noodles, crackers, cakes, bread, and live stock feed). In Africa cassava is a staple source for vitamin C, calcium, carotenes, and potassium, due to it’s ability to grow in poor soils—cassava is important during droughts.
88
What is the toxin present in cassava that must be reduced by processing?
- Cassava has two cyanogenic glucosides: linamarin and lotaustralin—the amount of these can vary among cassava variety (sweet verse bitter). Boiling and drying are adequate methods for decreasing toxicity from low-cyanogenic cultivars, while high-cyanogenic varieties require methods like fermenting, sun-drying or grating.
89
What is the process of osmotic dehydration?
| What types of products are osmotically dehydrated?
- Osmotic dehydration harnesses the natural force that drives water out of the cells through a hypertonic environment.
- Fruits, vegetables and even meat are osmotically dehydrated.
90
What are the major differences between atmospherically dehydrated and osmotically dehydrated foods?
The main difference between osmotic dehydration and atmospheric dehydration is the use of an hypertonic environment in osmotic dehydration—there is something being added to the food product to draw the moisture out. Conversely, atmospheric drying depends on the transfer of air to draw water from the product.
-The products also differ--osmotically dehydrated will probably retain more moisture
91
What is the vaporization of water vapor directly from the solid (ice) called? What food process utilizes this phenomenon?
Sublimination is the main idea behind freeze-drying
92
Two main types of Drying
Oven drying
Spray drying
OD: for solids
SD: for liquids ex. food powders
93
Cassava vs. Mango drying
Mango has a higher sugar content--water does not want to let go--remaining water activity will be higher.
- evaporation of water from food product = h2o is migrating out of product
- mass transfered, heat transferred, momentum transfer
94
Relative humidity
"relative" to max amount of vapor it can hold at that air temp
95
Adiabatic process
Is any process occurring without input or output of heat within a system (i.e. during the process the system is thermodynamically isolated- there is no heat transfer with the surroundings). This is the opposite of a diabatic process, where there is heat transfer.
96
What is the difference between Maillard browning and caramelization?
- Maillard browning is a reaction between a reducing sugar and an amino acid; this reaction produces both color and flavor depending on ratio of amines in product.
- Caramelization does not involve amine groups—instead it essentially dehydrates sugar, often used to get caramel color. (drives off water molecules)
97
What is measured by a calorimeter?
-A calorimeter measures heats of reactions. In food science it is used to determine caloric content of any particular food using a bomb calorimeter that combusts the food—releasing the heat/energy that item holds and heats the water surrounding the chamber. The change in temperature within the water is used to determine energy contained in food.
98
What is a kinetic process vis-à-vis a thermodynamic one?
A thermodynamic process looks at the initial state and final state of energy development within a system while kinetics looks at the rate in which a reaction takes place in addition to how the given conditions and outcomes relate to transition states and mechanisms.
99
What is the legal definition of the color additive “caramel” and what sugars are allowed in its manufacture?
-“The color additive caramel is the dark-brown liquid or solid material resulting from the carefully controlled heat treatment of the following food-grade carbohydrates: Dextrose, invert sugar, lactose, malt sirup, molasses, starch hydrolysates and fractions thereof, sucrose.”
100
What are colligative properties? Which colligative properties are relevant to our caramel lab and the shelf stability of caramel?
-Properties that result depending on amount of dissolved particles—solute to solvent—example- the amount of sugar or salt in the caramel mixture results in elevated boiling point and changes the water activity in the end product
101
Caramel making
- Need constant stirring for thick viscous caramel
- Need to heat about 212F to caramelize b/c when adding stuff to water--BP increases--need 248F (120.1C)
- Use ingredients w/ least water to most water in order to dissolve sugar
102
Caramel ingredients
- Butter-> 80% milk fat & 20% water
- Sweetened condensed milk--emulsion helps to mix butter
- Corn syrup--18% water, cornstarch, (hydrolyze--chopped up glucose)--dextrox=100, ve=42
- Water ~40degrees C
- Sugar- cook for 1 hour
If you want a darker caramel, higher pressure and temp are needed
If you want a lighter caramel--low pressure
103
Colligative property
f (# of dissolved molecules)
Fat does not dissolve in water--thus the colligative properties are not effected.
Sugar dissolves and dissociates--the same with NaCl.
-BP elevation, freezing point depression, water activity
104
Glass transition
-From a hard and relatively brittle state into a molten or rubber-like state.
-An amorphous solid that exhibits a glass transition is called a glass.
-Supercooling a viscous liquid into the glass state is called vitrification
-Can manipulate glassy state by moisture content--H2O lowers glass transition.
-Brittle--hard candy
-Rubbery-chewy candy
-liquid-caramel sause .702 water activity
Ex: Mango b/c sugar content glass transition is lower (hold more water) and is more rubbery
Cassava has mostly starch--chains of sugars- high glass transition temp@ room temp = brittle
105
Structure Function
-Fondant--> sugar crystal & bob syrup (saturated sugar solution & corn syrup)
-Caramel component w/ "short" texture--> grainy texture when pulling--> white ends: graining sugar crystals
"Shortening"--> fat
-More sugar, less corn syrup, more likely to crystalize
106
Starch molding
- Tray full of starch--makes imprint into starch
- Demolding: dump tray over screen, starch falls out, reuse starch, candy leftover
- Allows better handling and protects from sticking together
- Finally product might be coated in confectioners glaze, wax, shalack.. mineral oil
- Ex: circus peanuts, swedish fish
-Pros: reduces storage of molds, use one mold board apposed to needing storage of molds
107
What is sensory evaluation?
…a scientific method used to evoke, measure, analyze, and interpret those responses to products as perceived through the sense of sight, smell, touch, taste, and hearing.”
108
Tastes
Basic tastes: sweet, sour, salty, bitter, umami
How do we taste?
-G-protein coupled receptors: sweet, umami, bitter
-Over 25 different bitter receptors!
-Ion channels: salt and sour
109
Receptors & channels
- Sweet receptors are T1R2+T1R3
- Bitter are T2Rs
- Umami are T1R1+T1R3
- Ion channels (sodium, potassium, calcium) are important for transduction of sour and salty tastes- not surprising as we know that these will form ions in solution
110
Taste buds
-Are where the taste receptors are, & housed within the fungiform, foliate, and circumvallate papillae.
(filliform papillae are not involved in taste)
-These papillae are like houses for our taste buds. They are distributed all over the tongue, (except the CV in the back) so we taste everything all over.
-Tastants have to diffuse through the taste pore to come into contact with and bind with the taste receptors.
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Taste + Aroma = Flavor
Aroma:
Orthonasal olfaction
Retronasal olfaction
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Why do we use sensory evaluation?
Quality Assurance:
-Ensure product consistency/standards
-Protect final product when changing processing, packaging, ingredients, suppliers
-Shelf life tests
Product Development:
-Test if the product is liked, acceptable, preferred
-Compare to competition
-Compare to goal if matching a product
Sensory testing is often used as an assurance that the product will succeed on the market.
It is a lot cheaper to run sensory tests than to just throw a new product on the market and see how consumers react to it.
Sensory gives you the insight into why or why not a product might be liked, purchased, rejected, etc.
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Why else?
Basic research:
- How do we taste?
- Influence of taste genetics
- Influence of external factors on food choice
- How preferences are formed
- Why we like what we like
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Where
- Individual booths
- Focus group rooms
- Home-use tests occur in homes! (send the product with you) e.g. leg shaving sensory
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Careful preparation
- Equal, appropriate sized portions
- Blinding codes
- Serving temperatures
- Presentation order
- Lots of consideration goes into figuring out how to present your samples without introducing any sort of bias. You want every judgment to be made as unbiased as possible.
- Safe food handling is essential! We are presenting people with things to taste!
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Types of Tests
- Descriptive analysis
- Discrimination (difference)
- Affective/Hedonic
The type of test used depends on the question we are asking
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Descriptive Analysis
Goal is to describe samples quantitatively
Use panels of judges who have been trained to consistently identify specific attributes
Usually between 8-12 people
Methods: Flavor Profile, Quantitative Descriptive Analysis, Texture Profile, Spectrum
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Descriptive Analysis
| pro/con
Advantages: Gives you specific information about your product that can relate back to consumer opinion and purchasing habits, or also ingredient/processing/packaging variables.
For example- product isn’t doing well after you switch a few suppliers. Descriptive analysis shows that milk flavor is drastically different from your ideal…
Disadvantages: numerous sessions means it takes a long time to gather information (slow), can be very expensive, and it is difficult to schedule sessions with so many people repeatedly.
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Discrimination Tests
- Used to tell if a different exists (further testing is often required to find out where the difference is or if it is important)
- Use ~25-50 untrained consumers
- Methods: triangle, duo-trio, 2-alternate forced choice, etc.
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Discrimination Tests
| pro/con
Advantages: quick and simple to carry out and to analyze, few number of participants can yield significant results
Disadvantages: limited information (yes there is a difference, but where?), lacks sensitivity if not focused
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Hedonic Testing
- Remember: acceptance ≠ preference
- Use large number of untrained consumers
- Methods: hedonic scales, paired preference tests, etc.
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Hedonic Testing
| pro/con
Advantages: can be related to descriptive profile and/or variables for optimization, can tell you if people like something or not!
Disadvantages: consumer vocabulary is not always standardized which can make it difficult to interpret, it is crucial to use a representative sample of consumers.
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What is the basic structure of pectin?
-The main structure of pectin is composed of homoglacturonan—an unbranched molecule made of poly α-1,4 D-galacturonic acid. Recent research indicates pectin is made up of rhamnogalacturonan with neutral sugar and homogalacturonan side chains
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For corn syrups, DE meant dextrose equivalent. What does DE refer to in the context of pectin chemistry?
-Pectin DE refers to degree of esterification. This value indicates the speed at which the pectin will set into gelation. A rapid set pectin has a DE above 69% and slow set pectin is 60-61%. Temperature and time also play a role in gelation.
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What is a gel? Why, despite the physical immobilization of water in a gel, is the water activity so high? (In our pectin candies, the sugar and corn syrup lower water activity, the pectin does not.)
-Gel is any semisolid product like jelly—in reference to edible gel like we made in the practicum water was the dispersion medium. I would think that pectin traps water in matrix but in the presence of sugar and corn syrup—water would be pulled out/away from the pectin. But as a whole—the pectin gel candies contain all of those ingredients—leaving the same amount of water bound within the product.
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Why did we add ¼ underripe fruit
-When fruit ripens/softens, the pectic substances are being solubilized and enzymatically degraded. So by adding unripe fruit—more pectin will be available for extraction.
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What compound is responsible for the unique aroma of quince?
The quince aroma can be attributed to carotenoid metabolites—C10 constituents of irregular isoprenoid structures: marmelo lactones and marmelo oxides
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What country produces the most quince? What is quince paste called in Spanish speaking countries?
- China at 105,000 metric tons followed by Turkey at 96,282 metric tons
- Membrillo
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Quince jelly making:
Sea level 10 mins but @ 1,200 ft BP decreases 98.8--need to increase time to at least 11 mins
- Want to eliminate molds, yeast spores & cysts
- Quince until ripe are astringent--usually baked for 4 hrs.
- High in pectin, want to extract pectin (animal equivalent gelatin:collegen)
- Use the whole quince, aroma is in the peel, core olds most pectin
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Bledding
One freeze thaw cycle, leave quince on tree--helps break down structure of fruit-enzymes
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Refractometer
refraction index
uses light--checks for soilds
-We were looking for 70-75% solids for shelf stable.
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Main objectives of packaging
- Ensure product safety and quality
- Reduce product loss (waste)
- Enclosing food to protect food from tampering or contamination from
- physical, chemical, or biological sources
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Functions of Food Packaging
```
Basic:
-Containment
-Protection
-Preservation
-Information
Sophisticated:
-Communication
-Convenience
```
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Packaging as a system
Includes food, package, environments
| contributes to overall shelf life of packaged food
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Packaging materials and properties
- Paper (usually coated with wax, plastics, or aluminum foil) – cartons of milk, crackers
- Metal (steel, tin, and aluminum) – canned foods
- Glass – jelly, pickles, beverages
- Plastics (dominant form of food packaging material) – milk jugs, beverages, deli salad,
- Laminated structures (multilayer) – drink cartons
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Important properties of plastics
```
Mechanical properties:
-Impact, tensile, & tear strength
-Puncture resistance
Barrier properties:
-Gas (O2, CO2, etc)
-Water vapor
-Aroma
-Light
Sealing properties
Chemical properties
```
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Lamination
| Aseptic carton
```
Environment
Outer polyethylene
Paperboard
Laminated polyethylene
Aluminum foil
Inner PE (oxidized)
Inner PE (nonoxidized)
```
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Package formation
```
Metal:
-Canning
Glass:
-Blow molding
-Compression molding
Plastics & Composites:
-Blowing molding
-Thermoforming
-Injection molding
-Injection-blow molding
-Compression molding
-Extrusion
-Sealing
```
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Retortable thermally preserved foods
- Raw food and incoming package meet to
- Fill & Seal
- In-container sterilization
- Cooling
- Shelf-stable product
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Aseptic processing and packaging
- Pumpable Raw food--> in-flow sterilization (heat & hold), enters aseptic zone where it is continuous cooling then meets
- incoming package that gets continuos sterilization before aseptic zone.
- Aseptically (form) fill seal
- Shelf stable
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Vacuum packaging
```
Remove all air, including oxygen, from inside the packaging environment
Used with:
-Country ham slices,
-deli meats,
-bacon
-vegetables
-fresh meats
```
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Controlled Atmosphere Packaging
Controls the movement of gases inside the package.
Used with:
-fresh-cut salads
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Modified Atmosphere Packaging
Flush the food container with a gas, CO2 or N2, before the container is sealed
Used with:
-potato chips and other snack foods
-coffee
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Active Packaging
- Remove an unwanted component (e.g. C2H4 produced by respiring fruits or O2 present inside the packaging)
- Add a desirable ingredient (e.g. CO2 to inhibit microbial growth)
- Prevent microbial growth (e.g. an antimicrobial chemical incorporated into a film)
- Change the permeability to gases as the temperature changes by several of orders of magnitude greater than normal polymeric films
- Change the physical conditions inside the packaging (e.g. remove water vapor by absorption or change the temperature of the food)
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List the main quality deterioration modes for fresh pork during storage. What protections are provided by vacuum packaging to ensure storage stability and shelf life of fresh pork?
- Pork that is exposed to oxygen will be faced with oxidative and autolytic changes that cause rancidity. Oxygen also causes the discoloration on the pork surface.
- Vacuum packaging is supposed to remove oxygen from the package and prevent it from getting back into the package—in addition the environment within the package should have at least 25% carbon dioxide. In order to enable oxygen from reentering the package, the material used must be impermeable to oxygen.
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What are the differences between the packaging for pasteurized milk and UHT milk? Why?
-Pasteurized milk as discussed in class—is a short-term product—it’s a spoilable item that should be used within a week or so of bringing the product home. The packaging used for pasteurized milk is usually thin plastic jugs or thicker cardstock/board containers that has a waxy coating. Alternatively, UHT milk is shelf stable, the container product inside the container is sterile until it is opened. The packaging has several layers that protect the milk from light, oxygen, external contaminates—the package’s layers consist of both outer and inner layers of polyethylene which protects the paperboard or cardboard used to print information on the outside, and acts as a barrier for the aluminum foil on the inside—there is also a laminated polyethylene layer in between the paper board and foil.
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What is the difference between modified- and controlled-atmosphere packaging?
-Controlled atmosphere packaging, controls the movement of gases inside the package while modified atmosphere packaging involves inputting gas (carbon dioxide or nitrogen) into the sealed container.
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Red pepper powder is degraded in quality by two modes of color loss, carotenoid destruction and nonenzymatic browning, whose rates are influenced by water activity and/or package atmosphere. Elaborate a packaging strategy to keep quality of red pepper powder for long time period of shelf life.
-Based on information gathered in the above mentioned documents, the red peppers should be stored in a package where the products aw is below 0.3 and is flushed with nitrogen to aid carotenoid retention, at a water activity below 0.3, enzymatic browning is reduced but is not effected by a modified environment. The modified packaged red pepper powder should be coarse with seeds and have reduced free space for optimal color and carotenoid retention.
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What is the legal definition of a “Potentially Hazardous Food.”
-According to the FDA website, the definition of Potentially hazardous food is constantly changing. The term applies to foods that have potential pathogenic microorganism and what methods are used to prevent and control the growth and colonization of these pathogens. Among the factors that may contribute or inhibit growth are—time/temperature a product is cooked, the pH, aw and whether a particular pathogen is a spore former. The research on how pH and aw interact in a particular food product is under constant study and changes accordingly.
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Why is the soy milk heated?
the soybean milk needed to be heated in order for the trypsin inhibitors to be destroyed and that our bodies will not digest it otherwise. We can see the breakdown of trypsin (and other proteins) through the froth that accumulates and eventually subsides.
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Neotonian foods
```
Any pure substance
Veg oil
Any oil
Honey
any purified fluid
water
alcohol
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xantham gum
used to keep spices distributed in salad dressing
